Review Projects – 2013
Big Idea 2
Mr. Bennett
LO 2.1: The student is able to explain how biological systems use free energy based on empirical data that all organisms
require constant energy input to maintain organization, to grow and to reproduce.
SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices.
Explanation: Life requires a highly ordered system to maintain homeostasis and allow organisms to continue biological
function. As organisms use free energy, that energy is degraded in accordance with the 2nd Law of Thermodynamics.
However, certain biological processes coupled with these entropy-increasing processes decrease entropy. For example, the
conversion of ATP to ADP and the reverse reaction can be used to manage free energy within organisms. All organisms
require a constant flow of free energy to maintain biological function, as this energy is used to regulate various processes in
the body. For example, organisms must use energy in homeostasis to maintain a constant body temperature.
M.C. Question: Which of the following adaptations does NOT illustrate energy conservation within an organism?
A) Large ears on the Fennec Fox
B) A thickened cuticle on plant leaves
C) American Black Bears hibernating through the winter
D) Male emperor penguins huddling in large rotating
masses during Antarctic winters
E) Changes in the E. Coli bacteria metabolism
dependent upon the outside environment
http://www.accessexcellence.org/RC/VL/GG/ecb/ATP_ADP.php
Learning Log/FRQ-style Question: Over time, evolution has favored various methods of free energy capture in organisms. In
plants, chloroplasts collect free energy from the sun and convert it to carbohydrates via the equation: 2 H2O + CO2 + light
→ carbohydrate (CH2O) + O2 + H2O. Suppose you are a scientist who wishes to conduct an experiment that will show how
various environmental conditions can influence a plant’s ablility to capture free energy. If you wish to alter only the plant’s
environment, what other variables need to be accounted for to ensure an accurate experiment?
LO 2.2: The student is able to justify a scientific claim that free energy is required for living
systems to maintain organization, to grow or to reproduce, but that multiple strategies exist in
different living systems.
SP 6.1: The student can justify claims with evidence.
EXPLANATION: All living organisms capture and store free energy to complete metabolism and other processes.
Photosynthetic autotrophs convert solar energy into usable energy, whereas chemosynthetic autotrophs capture energy
from small inorganic molecules and convert it into usable energy. All life depends on these processes, as heterotrophs are
only able to obtain free energy from other organisms’ carbon compounds, transforming them into ATP through cellular
respiration, whether it be anaerobic or aerobic. From a cellular perspective, different electron acceptors are used in various
energy capturing processes—NADP+ in photosynthesis and oxygen in cellular respiration—thus exemplifying the multiple
strategies exhibited in different living systems. The science practice can be applied through incorporating specific
information from each process, such as including the fact that glycolysis occurs in the cytoplasm and produces ATP and
pyruvate without using oxygen.
MULTIPLE CHOICE: Which of the following events occur during the light-independent reactions of photosynthesis?
I. Carbon gets reduced.
II. ATP is produced.
III. Oxidation of NADPH+ occurs.
A)
B)
C)
D)
E)
I. only
II. only
I. and III.
II. and III.
I., II. and III.
LEARNING LOG: Describe in detail the difference between substrate level phosphorylation and oxidative phosphorylation in
producing ATP. Then classify glycolysis as one or the other and explain why. Finally, discuss how glycolysis directly relates to
the citric acid cycle.
LO 2.3 The student is able to predict how changes in free energy availability affect
organisms, populations and ecosystems.
SP 6.4 The student can make claims and predictions about natural phenomena based on
different scientific theories and models.
Explanation: Life must be highly ordered. Order is maintained by the flow of free energy
throughout a system. When energy or order is disrupted, organisms can die. Luckily, biological processes
offset the increasing entropy and continually keep things in order. Although the 2nd law of
thermodynamics states that entropy increases over time, biological systems do not defy this law because
systems involve cellular processes that have negative changes in free energy, thus increasing entropy,
and processes that have positive changes in free energy, which decreases entropy.
Energy input must be higher than energy lost to entropy in order to be maintain cellular processes.
Energy pathways are sequential and may be entered at various places. (see Krebs Cycle,
Fermentation, Calvin Cycle and Glycolysis). The energy produced can then be used in different metabolic
functions in order to maintain normality. If there is energy leftover, that energy can either promote
storage or growth in the organism. However, if there is a lack of energy then what is needed to maintain
processes, the organism could undergo a loss in mass an eventually die.
Within an organism energy runs the metabolism and is essential in maintaining
functioning processes. The metabolisms is made up of catabolic and anabolic reactions. Catabolic breaks
down molecules and anabolic builds molecules. In endotherms, thermal energy from the metabolism is
used in order to normalize an internal temperature. Ectoderms use outside heat to regulate body
temperature. There is a relationship between metabolic rates and the size or an organisms. If an
organisms is smaller it has a higher metabolic rate. In response to energy availability, an organisms has
different methods of reproducing and rearing their offspring. Most plants and animals undertake in
seasonal reproduction. If they were to reproduce at all times, they would not have enough energy to
carry out all their
biological processes. When differences in available energy occur in an ecosystem, it doesn’t just
affect the photoautotrophs but impacts every trophic level, which ultimately disrupts the ecosystem.
M/C Question: If food is in short supply, which
organism will feel the impact first?
A) A cat
B) A mouse
C) An elephant
D) A wolf
Learning Log/FRQ-style Question: A
certain ecosystem experiences a
volcanic eruption that prevents any
light from penetrating its dust
clouds for a period of two weeks.
What would be experienced by the
autotrophs, primary consumers,
secondary consumers.
LO 2.4: The student is able to use representations to pose scientific questions about what mechanisms and
structural features allow organisms to capture, store, and use free energy.
SP 3.1: The student is able to pose scientific questions.
Explanation: Free energy refers to the portion of a system’s energy that can perform work when temperature and
pressure are uniform throughout the system, such as in a living cell. Only a system that is not at equilibrium can
spontaneously change, allowing it to perform work. The flow of free energy can be represented by an open
hydroelectric system in which flowing water continues to drive a generator due to the fact that the intake and
outflow of water inhibit the system from reaching equilibrium. Such examples include gravitational motion,
diffusion, and chemical reactions (endergonic or exergonic). Free energy is involved in metabolism, as the energy
released from a metabolic reaction can be harnessed to do work (cellular respiration and photosynthesis).
Mechanisms such as Photosystems I and II, ATP synthase, the electron transport chain, and structures such as the
mitochondria and chloroplasts are key in the capture, storage, and usage of free energy.
M.C. Question: Which of the following reactions does not result in the release of free energy?
A) glycolysis
B) ATP hydrolysis
C) lactic acid fermentation
D) Oxidative phosphorylation
Learning Log/FRQ Question:
The light reactions of photosynthesis can be
represented by a “molecular mill,” to which it is
sometimes referred. Describe the flow of free
energy throughout the light reactions and be sure
to include details regarding the production of ATP
through ATP synthase.
LO 2.5: The student is able to construct explanations of the mechanisms and structural features of cells
that allow organisms to capture, store or use free energy.
SP 6.2: The student can construct explanations of phenomena based on evidence produced
through scientific practices.
Explanation: Autotrophs and heterotrophs capture free energy in differing ways. Autotrophs capture it through their
physical sources in the environment while heterotrophs capture it through carbon compounds produced by other
organisms. NADP+ in photosynthesis and oxygen in cellular respiration foster the way organisms capture, store, and use free
energy. Light reactions are the steps of photosynthesis that convert solar energy to chemical energy. During photosynthesis,
chlorophylls absorb free energy from light, boosting electrons to a higher energy level in Photosystems I and II. Cellular
respiration occurs when oxygen is consumed as a reactant along with the organic fuel. Cellular respiration also involves in a
series of coordinated enzymecatalyzed reactions that harvest free energy from simple carbohydrates. Glycolysis, pyruvate,
and the Krebs cycle essentially leads ATP which is synthesized from ADP. Free energy becomes available for metabolism by
the conversion of ATP→ADP, which is coupled to many steps in metabolic pathways.
M.C. Question: All of the following statements about glycolysis
are true EXCEPT
A) glycolysis has steps involving oxidation-reduction reactions.
B) the enzymes of glycolysis are located in the cytosol of the
cell.
C) glycolysis can operate in the complete absence of O2.
D) the end products of glycolysis are CO2 and H20.
E) glycolysis makes ATP exclusively through substrate-level
phosphorylations.
Learning Log/FRQ-style Question: The two stages of photosynthesis
are known as the light reactions and the Calvin cycle. Identify and
explain the steps within each of the stages and how light reactions and
the Calvin cycle work together. Then describe the connection between
photosynthesis and cellular respiration within plants.
LO 2.6: The student is able to use calculated surface area-to-volume ratios to predict which
cell(s) might eliminate wastes or procure nutrients faster by diffusion.
SP 2.2: The student can apply mathematical routines to quantities that describe natural
phenomena.
Explanation: In order for a cell to eliminate wastes and procure nutrients faster, it needs a larger
surface area because it is the cell membrane that allows for these objects to pass through. The cell
also needs a volume as small as possible so that energy is not used to fuel itself which would
increase the use of the nutrients and increase the amount of waste produced and excreted. This is
why a higher surface area-to-volume ratio is more ideal in organisms.
M.C. Question: Which would be more beneficial to a cell?
A. Having a small surface area and a large volume.
B. Having a small surface area and a small volume.
C. Having a large surface area and a small volume.
D. Having a large surface area and a large volume.
Learning Log/FRQ-style Question: How and why would
evolution favor organisms that develop structures like the root
hairs shown in the picture or like the cells of the villi that line
humans intestines? What would be the consequences to the
organisms if they did not develop these structures?
Image provided by Bing
LO 2.7 Students will be able to explain how cell size and shape effect the overall rate of nutrient intake and the rate of
waste elimination
SP 6.2 The student can construct explanation of phenomena based on evidence produced through scientific processes.
Explanation: Oxygen, nutrients, and waste pass through the plasma membranes of all types of cells. When it comes to
the cell size and shape affecting the overall rate of nutrient intake and waste elimination, there is a direct correlation
between the area (in square micrometers) of the membrane and the amount of the particular substance that can pass
through or be excreted. The makeup and polarity of the substance moving through the membrane is significant and the
phospholipid bilayer structure of the plasma membrane can interfere with the transport of the substance. A
significantly high ratio of volume to surface area is essential for cells to exchange materials with their external
surroundings; ex: intestinal cells. Size relates to function, the rate of cellular metabolism sets a limit on size; cells need
to have the proper equipment and the necessary amount of space to carry out functions such as waste excretion and
nutrient intake.
(Slide 1 of 2)
LO 2.7
Multiple Choice Question:
The cells of an ant and an elephant are, on average, the same size; an elephant just has
more cells. What is the main advantage of small cell size?
A. Small cell has larger plasma membrane surface area than does a larger plasma
membrane surface are than does a large cell, facilitating the exchange of sufficient
materials with its environment.
B. A small cell has a larger plasma membrane surface area than does a large cell, facilitating
the exchange of sufficient materials with its environment.
C. A small cell has a smaller cytoplasmic volume relative to its surface area, which helps to
ensure the exchange of sufficient materials across its plasma membrane.
D. Small cells require less oxygen than do large cells.
Free Response/Learning Log Question: Explain in detail why there
would be both upper and lower limits to the size of a cell.
(slide 2 of 2)
LO 2.8: The student is able to justify the selection of data regarding the types of molecules that an animal, plant or bacterium will take up as
necessary building blocks and excrete as waste products.
SP 4.1: The student can justify the selection of the kind of data needed to answer a particular scientific question.
Explanation:
Animals, plants, and bacteria take up a variety of molecules including Nitrogen, Carbon, Water, Carbon Dioxide, Glucose, Oxygen, Phosphorous, Salt, Potassium, and Calcium
(to name a few of the most important). The basis for determining the importance of these molecules , their placement, and their role in an organism can stem from a variety of scientific
procedures such as experimental investigation, or historic reconstruction. However, in regards to the composition of an organism (the importance of these molecules as building blocks, rather
than in chemical or mechanical processes) the most important type of data comes from the culmination of past and present scientific observation , and the ability to take these separate
observations and combine them into fully-realized conclusions.
The justification of the selection of data regarding the types of molecules taken up by various organisms can be more easily explained by depicting a common, yet elaborate,
example: the uptake of water in plants. The conclusion that scientists have come to is that the transpiration of water from the leaves pulls water upward from the roots, through the xylem in
the plant, and this allows the water to be dispersed throughout the plant and used for a variety of growth (or other) processes which require water either directly, or as a means of transport for
solutes. But how did scientists come to this conclusion, and what data was important to this?
After various observations, scientists were able to extract important data, which at the time might have been conducted independently of the plant transport example, but
would then be selected for use in developing the understanding of water transport in plants. The basis of this was observation regarding the properties of water. After observing and recording
various characteristics that were possible because of molecular composition of water, they were able to give water unique properties such as cohesion due to hydrogen bonding (helps hold
together the column of water within the xylem) and adhesion (helps water adhere to the cell walls and resist gravity). Further experimental and observational testing in regards to osmosis,
water potential, diffusion, gradients, evaporation, ATP, etc. would have to be conducted, but these individual snippets of data could then be selected to support the big idea of water transport,
which is crucial to the build up of all complex molecules in living organisms. This “cumulative observation” method is a crucial part of analyzing the role of variety of molecules as building blocks
or waste products in plants, bacteria, and animals.
MC Question:
Johnny is a young boy, but he loves to conduct experiments, because he wants to be a scientist when he grows up. For his latest experiment, he wants to test the impact of
a light breeze on the growth of a species of water plant. He purchases three bowls to place the seeds inside, and two small fans to create the breeze; one plant will be his control and the other 2
will be his experimental plants. He places both plants in the same room under almost identical conditions, places the fans the same distance from each of the experimental plants, and fills the
three bowls with the same amount of water. However, halfway through filling the bowl for his control plant, he runs out of distilled water and finishes filling it with tap water. After this, he
turns the fans on low, and lets the plants grow for one week, before taking his first measurement and recording it. Is Johnny’s first measurement a justifiable selection of data?
a) Yes, all of the conditions are almost identical, and tap water in the control will not affect the outcome because the plant will take up the water regardless.
b) No, the tap water contains more solutes than distilled water, so the water potential of the water outside the plant in the control bowl will be higher than it should be, and the plant will
take up water more quickly.
c) No, the tap water contains more solutes than distilled water, so the water potential of the water outside the plant in the control bowl will be lower than it should be, and the plant will take
up more slowly.
d) Yes, even though there are more solutes in the tap water, they will not make it past the selectively permeable Casparian strips.
e) No, the tap water will definitely be toxic to the plants.
FRQ Question: Explain how the light reactions and the Calvin cycle of photosynthesis
work together to nourish a plant with the necessary sugar, and describe the role of each of
the following molecules in a plant as either a building block, or waste product.
a)H20
b)O2
c)CO2
d)Sugar
LO 2.10: The student is able to use representations and models to pose scientific questions about the properties of cell membranes and selective permeability based on
molecular structure.
SP 1.4: The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively.
SP 3.1: The student can pose scientific questions.
Explanation: Membranes are composed of a phospholipid bilayer that is amphipathic. Membranes are selectively permeable due to the amphipathic phospholipids that form
a cell membrane. Non-polar particles, such as steroids, can pass through the membrane easily and are selected for. Large, polar, charged molecules are selected against (like
glucose, amino acids, and ions). Membranes are held together mostly by hydrophobic interactions, which are weaker than covalent bonds, which contributes to the fluidity of
the membrane. If the membrane is composed of phospholipids with unsaturated carbon tails, then it will remain fluid to a lower temperature due to the kinks in the tails,
which keep the phospholipids from packing as close together. Cholesterol also controls fluidity by moderating it. In colder temperatures, cholesterol keeps phospholipids
spaced out, keeping them more fluid, but in hotter temperatures, it gets in the way and restrains movement, keeping them less fluid. Lipids in the membrane move laterally
about 107 times per second. Also, various proteins are embedded in or attached to the membrane; the alpha helix holds integral proteins in the membrane. Transport proteins
help hydrophilic substances enter the cell. An example of this is the aquaporins that help transport water into the cell.
M.C. Question: A plant cell starts off in an isotonic solution with 20 water molecules, 15 sodium molecules, 15 glucose molecules, and additional molecules necessary for
photosynthesis. After completing photosynthesis, the plant cell still has the 20 water molecules and 15 sodium molecules, but now it has 30 glucose molecules. Do not
account for the change in concentrations of the molecules needed for photosynthesis. What happens to the movement of water and other materials into and out of the cell?
A) 15 glucose molecules leave the cell to create an isotonic environment again.
B) 15 sodium molecules leave the cell to create an isotonic environment again.
C) With help from aquaporins, 15 water molecules enter the cell to balance out the increased glucose concentration with the cell.
D) The cell is a plant cell and has no plasma membrane for water and other materials to move in and out of.
Learning Log/FRQ-style Question: Suppose you place a cell in a colder environment. a). What does this environment do to the membrane’s fluidity? Why? b). Draw what
the phospholipids in the membrane would look like. c). Explain the ways that membranes remain fluid in spite of temperature changes. d). Explain the importance of
membrane fluidity with regards to selective permeability. e). Hypothesize ways that cells might evolve in warmer and colder environments if their membranes no longer had
cholesterol.
LO 2.11: The student is able to construct models that connect the movement of molecules across membranes with
membrane structure and function.
SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the
domain.
SP 7.1: The student can connect phenomena and models across spatial and temporal scales.
SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across
enduring understandings and/or big ideas.
Explanation: Cell membranes exist to separate the internal environment of a cell from the external environment. Plasma
membranes accomplish this through their unique selective permeability. The physical structure of the membrane allows
some molecules to enter and exit, while preventing the passage of others. The phospholipid bilayer prevents polar
molecules from diffusing across the membrane, while nonpolar molecules,such as steroids, can penetrate the bilayer. To
allow for the passage of larger molecules and polar molecules, integral proteins stud the surface of the membrane. Their
structure dictates which substances can be transported across the membrane, with the concentration gradient in passive
transport or against it in active transport.
Multiple Choice Question:
In a U-tube such as the one in the diagram to the right, the concentration
of solutes in the left side X is 2M Sucrose and 1M Glucose while the
concentration on the right side Y is 1M Sucrose and 2M Glucose.
Note: The membrane pores are only permeable to Glucose.
After the system reaches equilibrium, what changes are observed?a. The
water level is higher in side X than in side Y.b. The water level is higher in
side Y than in side X.c. The water level is unchanged.
d. The molarity of sucrose and glucose are equal on both sides.e. The
molarity of glucose is higher in side X than in side Y.
FRQ:
Cell membranes separate the internal environment of a cell from the outside
environment.
a) Explain why small plants or animals often die after a winter freeze. Be sure to
include the effects of water crystallization on plasma membranes.
b) Create a diagram and explain how the Casparian strip blocks the passive flow
of dissolved materials into the interior of a plant. The Casparian strip is composed
of hydrophobic suberin.
Lo 2.12 The student is able to use representations and models to analyze situations or solve
problems qualitatively and quantitativley to investigate whether dynamic homeostasis is
maintained by the active movement of molecules across membranes.
SP 1 .4 Evidence of student learning is a demonstrated understanding of each of the following:
1. Passive transport plays a primary role in the import of resources and the export of wastes.
Explanation
Passive transport does not require the input of metabolic energy; the net movement of molecules
is from high concentration to low concentration.
Active transport requires free energy to move molecules from regions of low concentration to
regions of high concentration.
The processes of endocytosis and exocytosis move large molecules from the external environment
to the internal environment and vice versa, respectively.
Multiple choice
The compounds in biological membranes that form a barrier to the movement of hydrophilic
materials across the membrane are ?
A. Lipids
B. Carbohydrates
c. Nucleic Acids
D. Integral membrane proteins
Learning Log Question/ FRQ style question
Using a diagram describe the fluid-mosaic model of the cell membrane. Indicate the following;
phospholipid molecules, hydrophobic and hydrophilic ends, types of membrane proteins and
glycoproteins. List substances to which the membrane is relatively permeable and those
substances to which it is relatively impermeable.
Slide 1 of 2
LO 2.12 Key Concepts:
• 1. Small, uncharged polar molecules and small non-polar molecules, such as N2, freely pass
across the membrane. Hydrophilic substances such as large polar molecules and ions move
across the membrane through embedded channel and transport proteins. Water moves
across membranes and through channel proteins called aquaporins.
•
2. Passive transport does not require the input of metabolic energy; the net movement of
molecules is from high concentration to low concentration.
•
Passive transport plays a primary role in the import of resources and the export of wastes.
•
3. Membrane proteins play a role in facilitated diffusion of charged and polar molecules
through a membrane from low concentration to high concentration.
•
4. Membrane proteins carry out active transport, which requires free energy (often in the
form of ATP) to move molecules from regions of low concentration to regions of high
concentration.
5. External environments can be hypotonic, hypertonic compared to internal environments
of cells. As a result, a concentration gradient is present that will influence movement of
water and solutes. As well, equilibrium exists when the external environment is isotonic to
the internal environment of a cell.
•
•
6. The processes of endocytosis and exocytosis move large molecules from the external
environment to the internal environment and vice versa, respectively.
•
Slide 2 0f 2
•
•
LO 2.13: The student is able to explain how internal membranes and organelles contribute to
cell functions.
SP 6.2: The student can construct explanations of phenomena based on evidence produced
through scientific practices.
•
Explanation: The internal membranes of cells allow for greater surface area for reactions to take place and also offset
competing interactions, thus facilitating cell processes. In eukaryotic cells, membrane bound organelles
provide specific locations for metabolic processes and enzyme reactions to take place. The Golgi apparatus acts as the
packaging and shipping center for the cell by packaging macromolecules for transport elsewhere in the cell. The rough
Endoplasmic reticulum makes membrane and secretory proteins, while the smooth ER is involved in lipid and
carbohydrate synthesis. Chloroplasts, found only in plants, are the site of photosynthesis. Mitochondria are the power
houses of cells because they generate most of the cell’s supply of ATP. The nuclear envelope is the double layer
membrane that surrounds the nucleus of eukaryotic cells. Ribosomes can either be free floating or attached to the
rough ER and are responsible for protein translation. The scientific study of cells and discovery of microscopes makes
understanding the cell and its components possible.
•
MC Question: Which of the following statements is/are true?
A) Smooth ER is abundant in cells that synthesize large amounts of lipids
B) Chloroplasts have their own DNA, while mitochondria do not
C) Molecules travel from the rough ER to the Golgi apparatus
via vesicles that break off the ER and fuse to the Golgi
D) Both A and C are true
E) A, B, and C are true
FRQ Question: Your cousin was recently diagnosed with a
mitochondrial disease that is causing his mitochondria to
deteriorate quickly. The doctors have told him that his
mitochondria may be completely nonfunctional within a few
years. What is likely the result of this disease? Will his cells
still be able to carry out passive transport without enough ATP?
•
Learning Objective 2.14
The student is able to use representations and models to describe differences in prokaryotic and eukaryotic cells.
Connect Science Practices
1.4 The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively.
The objective intends to make sure that the student is able to identify and explain the function of various parts of the two
major kinds of cells. This shows an understanding of the differences between the two types of the cells and what their
function is.
Multiple Choice Question
Using figures 1.1 and 1.2, identify the function of
the cell part labeled in each figure.
a. I is used for transcription and II is used to
store genes.
b. I is used for cellular respiration and II is used
for gene storage
c. I is used to facilitate diffusion and II is used for
protein synthesis
d. I is used for endocytosis and II is used for fluid
storage
e. I is performs dehydration reactions and II is
used to filter the cytoplasm.
Figure 1.1
I
Figure 1.2
II
Learning Log Style Question:
Figure 1.1 is a liver cell and figure 1.2 is a Escherichia coli cell. Describe 3 distinct differences between these two
different kinds of cells.
LO 2.15 The student can justify a claim made about the effect(s) on a biological
system at the molecular, physiological or organismal level when given a scenario
in which one or more components within a negative regulatory system is altered
SP 6.1The student can justify claims with evidence.
Explanation: Mechanisms of homeostasis moderate changes in the internal environment of an organism. Homeostasis in
organisms is maintained through a negative feedback loop. In a negative feedback a receptor detects a change in some
variable in the internal environment. The signal received by the receptor is then interpreted by the “control center” and
directs an appropriate response known as the effector. An example of negative feedback at work is thermoregulation.
For example, in thermoregulation, when heat detecting cells detect an increase in body temperature a signal is sent to
the hypothalamus. The hypothalamus activate the body’s thermostat, which is part of the nervous system, which in turn
opens sweat glands and expands blood flow to the skin to increase heat radiation. The cooling of the internal
environment in turn shuts off the thermostat in the hypothalamus to maintain homeostasis
Thermoregulation
Multiple Choice:
What physiological change might occur in an individual if there is an inhibition of ADH?
A. The individual would experience an increase in urination because of lack of reabsorption in the
B.
C.
D.
E.
kidney tubules.
The individual would not feel the need to rehydrate because inhibition of ADH results in water
reabsorption.
Inhibiting ADH would cause an individual to feel dehydrated as there would be an increase in water
loss through urination resulting in “hangover” like symptoms
A and C
A, B, and C
Frq style question:
Using specific evidence justify the
following claim. Why is that individual
who consume alcohol experience water
loss in urine instead of reabsorbing
water back into the blood stream?
LO 2.16: The student is able to connect how organisms use negative feedback to maintain their internal
environments.
SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/ or
across enduring understandings and/ or big ideas.
Explanation: Mechanisms of homeostasis moderate changes in the internal environment. Any homeostatic
control system has three functional components: a receptor, a control center, and an effector. The receptor detects
a change in some variable of the organism’s internal environment, such as a change in body temperature. The
control center processes information it receives from the receptor and directs an appropriate response by the
effector. For example, when the room temperature falls below a “set point”, the thermostat switches on the
heater (the effector). When the thermostat detects a temperature above the set point, the thermostat switches
the heater off. This control circuit is called negative feedback because a change in the variable being monitored (in
this case temperature) triggers the control mechanism to counteract further changes in the same direction.
Negative feedback mechanisms prevent small changes from becoming too large.
M.C. Question: All of the following internal variables are moderated by negative feedback circuits EXCEPT
A) Blood pressure
B) Respiration rate
C) Uterine contractions
D) Blood glucose level
Learning Log/ FRQ- style Question:
Antidiuretic hormone (ADH) enhances fluid
retention by making the kidneys reclaim more
water. Discuss how negative feedback circuits
regulate water balance in kidneys. Be sure to
reference specific endocrine glands in your
response.
LO 2.17: The student is able to evaluate data that show the effect(s) of changes in concentrations of key molecules on
negative feedback mechanisms.
SP 5.3: The student can evaluate the evidence provided by data sets in relation to a particular scientific question.
Explanation: A negative feedback mechanism is one in which a change in a monitored physiological variable triggers a response that counteracts
the initial fluctuation, returning the physiological variable to its homeostatic state. Most organisms use homeostasis through negative feedback to
regulate necessary concentrations of key molecules in their internal environments. In negative feedback, the response, or end product, is
connected to and directly controls the initial stimulus. For example, in cellular respiration, ATP is constantly being produced via glycolysis, the
citric acid cycle, and oxidative phosphorylation. However, when there is plenty of ATP for a cell to access, a negative feedback mechanism uses
ATP to allosterically bind to phosphofructokinase to inhibit glycolysis. Conversely, when the ATP concentration is too low, a negative feedback
mechanism will use AMP to allosterically activate phosphofructokinase and glycolysis.
M.C. Question: A pharmaceutical company is testing the impact of different chemicals on
Graves’ disease, or hyperthyroidism. Graves disease results from the inhibition of the
negative feedback mechanism of the thyroid gland, which produces T₃ and T₄ hormones.
Which of the following chemicals best stimulates the negative feedback mechanism,
effectively combating Graves’ disease. Assume all chemicals are tested on a patient with
the same homeostatic T₄ concentration of 6.7 micrograms per deciliter (mcg/dL).
Chemical
Initial T₄
Concentrati
on (mcg/dL)
0 hrs
T₄
Concentrati
on (mcg/dL)
1hour
T₄
Concentrati
on (mcg/dL)
2 hours
T₄
Concentrati
on (mcg/dL)
3 hours
T₄
Concentrati
on (mcg/dL)
4 hours
A
13.8
11.5
8.4
5.2
2.8
B
13.8
14.5
14.9
15.6
16.0
C
13.8
13.6
13.4
13.2
13.0
D
13.8
11.1
9.5
7.2
6.8
E
13.8
13.8
13.9
14.0
14.1
A) A
B) B
C) C
D) D
E)E
FRQ-style Question: Use the given figure as a reference.
a) Suppose you have just eaten a carbohydrate-rich meal.
I Identify the stimulus on blood glucose.
II Describe the body’s response to the stimulus.
b) Suppose you have just skipped a meal.
I Identify the stimulus on blood glucose.
II Describe the body’s response to the stimulus.
LO 2.18 The student can make predictions about how organisms use negative feedback mechanisms to maintain their internal environments.
SP 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models.
Explanation Negative feedback mechanisms maintain dynamic homeostasis for a particular condition (variable) by regulating physiological processes
with specific hormones, returning the changing condition back to its target set point- such as with glucose or calcium regulation in the blood. A change
in the variable being monitored triggers the control mechanism to counteract further change in the same direction.
M.C. Question Which of the following is not an example of negative feedback?
A)
Maintaining the calcium in the blood through calcitonin and parathyroid hormones
B)
Regulating glucose levels with insulin and glucagon hormones
C)
Thermoregulation, in order to stay within a tolerable range
D)
Uterine contractions during childbirth through oxytocin
E)
Control pathways with the thyroid glands or adrenal glands
FRQ Question
a.
Pancreatic hormones, as mentioned above, help regulate the calcium levels in the blood. Identify and describe two pancreatic hormones and
their roles in the blood calcium homeostasis.
b.
Your Uncle Calcio has a vitamin D deficiency, describe the changes in the process of calcium regulation?
http://www.studyb
lue.com/notes/not
e/n/hormones/dec
k/5163934
LO 2.19: The student is able to make predictions about how positive feedback mechanisms amplify
activities and processes in organisms based on scientific theories and models.
SP 6.4: The student can make claims and predictions about natural phenomena based on scientific
theories and models.
Explanation: Positive feedback is a mechanism used to trigger an organism’s response to internal and
external changes in their environment. The response could be behavioral or physiological. It involves a
change in some variables that trigger mechanisms that amplify rather than reverse the change. Positive
feedback mechanisms are one directional, meaning that one (or a few) of something stimulates the
creation of more of the same thing. For example: The hormone oxytocin stimulates and enhances labor
contractions. As the baby moves towards the birth canal it creates pressure (contraction) on pressure
receptors in the uterus that evoke the release of oxytocin from the brain. Once these hormones reach
the uterus they stimulate the pressure receptor, amplify the release of oxytocin and consequently
induce labor. So, the release of oxytocin triggers the release of more oxytocin, therefore amplifying its
concentration.
M.C. Question: Which of the following processes has a
positive feedback mechanism?
a. Heating and cooling a house.
b. Placing a banana in a brown paper bag.
c. A Pancreas releasing insulin.
d. Shivering.
Learning Log/FRQ-style Question: Timmy was racing his friend
down the road when he fell and a rock created a gash in
his knee. What inflammatory response would follow this
incident which exemplifies a positive feedback
mechanism? What would happen if this response did not
occur?
LO 2.20 The student is able to justify that positive feedback mechanisms amplify
responses in organisms.
SP 6.1 The student can justify claims with evidence.
Explanation: Positive feedback is a physiological control mechanism in which a change
in some variable causes a response that amplifies the response rather than reverse it.
Childbirth is an example of positive feedback. The pressure of the baby’s head pushes
against the receptors near the opening of the uterus. This pressure stimulates uterine
contractions that releases oxytocin which then stimulates more contractions creating
greater pressure on the uterus which leads to childbirth.
M.C. Question: Which of the following responses is an example
of positive feedback?
a.After eating your body begins to produce pepsin which
stimulates other proteins in the body to produce more pepsin.
b.After eating a glucose rich meal your pancreas secretes insulin
to lower the blood glucose concentration.
c.After running your begin to sweat in order to cool your body
down.
d.Producing more red blood cells, which transport oxygen from
the lungs to the organs, because of a low concentration of
oxygen.
Free Response Question: After your friend Sara accidentally cuts her finger you inform her not to worry because
her blood will start to clot and she then informs you she is a hemophiliac. Explain the normal positive feedback
response that would occur in a non hemophiliac individual. Identify the receptor, control center and effector in
this response and explain their role in feedback mechanisms.
LO 2.22 The student is able to refine scientific models and questions about the effect
of complex biotic and abiotic interactions on all biological systems, from cells and
organisms to populations, communities and ecosystems.
SP 1.3 The student can refine representations and models of natural or man made
phenomena and systems in the domain.
SP 3.2 The student can refine scientific questions.
Explanation: Abiotic factors, such as climate, temperature, and precipitation
effect the specific organisms that live in each biome. The energy flow in a
community depends on primary productivity as energy is then transferred to
each trophic level above. Energy flows from autotrophs to primary consumers,
then to heterotrophs. While autotrophs depend on sunlight, water, and
nutirents for survival, heterotrophs gain their energy through predator-prey
relationships. Available land and resources, or the lack thereof, cause
competition among the population in the struggle for survival.
MC:
FRQ Question:
Identify all forms of symbiotic relationships
and give and example for each.
Which of the following organisms
gains 10% of the energy originally
retained from the autotroph?
A. Grasshopper
B. Mouse
C. Lizard
D. A and B
LO 2.23 The student is able to design a plan for collecting data to show that all biological systems (cells, organisms,
populations, communities and ecosystems) are affected by complex biotic and abiotic interactions.
SP 4.2 The student can design a plan for collecting data to answer a particular scientific question
SP7.2 The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring
understandings and/or big ideas.
•
Explanation- Growth, reproduction and maintaining organization require free energy and matter, and organisms use biotic factors
to reproduce, and maintain energy to keep up a species. Autotrophs capture free energy from sources in the environment and
photosynthetic organisms capture free energy present in sunlight, an abiotic factor. Organisms exchange matter with the
environment to grow reproduce and maintain themselves. Molecules and atoms are exchanged with the area around the given
group, and new molecules are created. Communities are composed of populations of organisms that interact in complex ways by
the diversity and factors that limit or support growth in an ecosystem. As limits to growth due to density-dependent and densityindependent factors are imposed, a logistic growth model can be made to track the population. Interactions among cells of a
population of a unicellular organism can be similar to those of multicellular organisms, and these interactions lead to more use of
energy and matter.
•
MC Question- Which of the following reproductive action would you expect from a fish in shallow water that is hypersensitive to
light and predators, when there is a scarcity of food and weather is turbulent?
A) The fish would move out to deeper water, in order to find food, and reproductive success would increase
B) The fish would remain in its habitat and abstain from reproduction because of the food scarcity
C) The fish’s reproductive success would plummet and the population size would decrease constantly
D) No change in behavior or population size would occur
E) Both A and C
•
•
•
•
•
•
Learning log Question- Explain the difference between 3 different types of marine biomes and their interactions with species that
inhabit those regions.
Rain shadow effect
LO 2.24 The student is able to analyze data to identify possible patterns and
relationships between biotic or abiotic factor and a biological system (cells, organisms,
populations, communities, or ecosystems).
SP 5.1 The student can analyze data to identify patterns or relationships.
Explanation: Both biotic and abiotic factors greatly impact all levels of biological
organization. For example, in the level of an ecosystem, you have a community in
which biotic organism populations help one another. Fish of all different species
interact to keep a waterfront alive. Not only can biotic components help a community,
but many abiotic factors such as a natural disaster or climate change can impact a
population. As humans advance in technology and continue to only think of their
needs when addressing ecosystems, devastating results may occur to the balance
between both biotic and abiotic components which can ultimately impact the entire
biosphere.
M.C Question: Which of the following is an example of an abiotic factor at work?
A) A deadly virus that mutates every 30 seconds and destroys vital body organs.
B) A storm generating an enormous tidal surge at 6 meters in height, inundating
thousands of acres of coastal marshland.
C) A decomposing body being broken down by bacteria.
D) A swarm of locus in the gregarious phase devastate crops and cause major
agricultural damage.
Learning Log/FRQ-style Question: Using the graph provided, list TWO abiotic
factors and ONE biotic factor that could have contributed to the population fluctuation
of the New Orleans population. Be thorough with each example.
In 2005, the alligator population in New Orleans decreased
significantly.
A virus such as HPV can reduce the survival rate of an
organism such as a human.
LO 2.25 The student can construct explanations based on scientific evidence that homeostatic mechanisms
reflect continuity due to common ancestry and/or divergence due to adaptations in different environments.
SP 6.2 The student can construct explanations of phenomena based on evidence produced
through scientific practices.
Explanation: Millions of years ago, the environment changed and created a drier environment which coaxed
some aquatic plants to adapt and develop a different way to exchange gases. Instead of having aerenchyma
like the aquatic plants, the new terrestrial plants developed stomata to obtain CO2 and lose water. The
continuity of homeostatic mechanisms is demonstrated by common ancestry, but can be susceptible to change
based on the response to different environmental conditions. With fish being one of the first organisms on the
earth, once areas began to become deficient of water they were forced to grow lungs in addition to having gills
so they could breathe air. Eventually the amphibians evolved into mammals which allowed them to live on
land full time. The adaptations to the circulatory systems of amphibians and mammals because of the changes
to their environments proves their common ancestry with fishes.
MC: The lungs that amphibians and mammals developed in order to breathe
on land are an example of what in relation to a fish’s gills?
A.) a vestigial organ
B.) a homologous structure
C.) an analogous structure
D.) convergent evolution
FRQ/Learning Log/Short Answer: How does osmoregulation occur in
most marine animals? Freshwater? Land?
Learning objective 2.27 The student is able to connect differences in the environment with the
evolution of homeostatic mechanisms.
Science practice 7.1 The student can connect phenomena and models across spatial and temporal
scales.
Explanation: Changes in an organism’s environment cause individuals with favorable mutations to be selected over individuals without
the favorable mutations by enabling the favorably mutated individuals to reproduce more frequently and with greater success. This
phenomenon is called natural selection. Natural selection occurs in homeostatic mechanisms quickly when a change in a population’s
environment occurs. For example, if an arid area is experiencing a severe drought, individuals in the population with a mutation that
allows them to conserve water will be more likely to survive and reproduce than individuals without the mutation. Then, members of
the next generation with a more developed ability to conserve water will be more likely to reproduce, enacting directional selection on
the population towards individuals that can conserve water and changing or developing the specie’s homeostatic mechanism for water
use. Also, in accordance with SP 7.1, there should be a clear connection between this concept and a graph of a species’ ability to
conserve water over time.
MC: The habitat of a species of rabbit has a particularly cold winter
six years in a row. Which is most likely to happen to the rabbits?
A. Stabilizing selection because the rabbits of small and large size
will be more commonly preyed upon.
B. Divergent selection because rabbits with medium color fur will
not blend into their environment well.
C. Directional selection because rabbits with thicker fur will have
higher survivorship and reproductive success.
D. The rabbits will likely die because of a lack of food.
FRQ: Explain in detail the effect of a steady increase in temperature of a desert environment on a species of lizard. Why
would this occur? What effects would it have on the species in the future?
LO 2.29 The student can create representations and models to describe immune
responses.
1.1 The student can create representations and models of natural or man-made phenomena and systems in the
domain.
1.2 The student can describe representations and models of natural or man-made phenomena and systems in the
domain.
Plants, invertebrates and vertebrates have multiple, nonspecific immune responses.
Examples:
Invertebrate immune systems have nonspecific response mechanisms, but they lack pathogen-specific defense responses.
Plant defenses against pathogens include molecular recognition systems with systemic responses; infection triggers chemical responses that destroy
infected and adjacent cells, thus localizing the effects.
Vertebrate immune systems have nonspecific and nonheritable defense mechanisms against pathogens.
Mammals use specific immune responses triggered by natural or artificial agents that disrupt dynamic homeostasis. The mammalian immune system
includes two types of specific responses: cell mediated and humoral. In the cell-mediated response, cytotoxic T cells, a type of lymphocytic white blood
cell, “target” intracellular pathogens when antigens are displayed on the outside of the cells. In the humoral response, B cells, a type of lymphocytic white
blood cell, produce antibodies against specific antigens. Antigens are recognized by antibodies to the antigen. Antibodies are proteins produced by B cells,
and each antibody is specific to a
particular antigen. A second exposure to an antigen results in a more rapid and enhanced
immune response.
M.C. Question: Why can normal immune
responses be described as polyclonal?
A) Blood contains many different antibodies
to many different antigens.
B) Construction of a hybridoma requires
multiple types of cells.
C) Multiple immunoglobulins are produced
from descendants of a single B cell.
D) Diverse antibodies are produced for
different epitopes of a specific antigen.
E) Macrophages, T cells, and B cells all are
involved in normal immune response.
Describe the main role of each of the
following cell types, once it is activated by
antigens and cytokines: helper T cells,
cytotoxic T cells, and B cells.
LO: 2.30: The student can create representation or models to describe nonspecific immune defenses in plants and
animals.
SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain.
SP 1.2: The student can describe representations and models of natural or man made phenomena and systems in the domain.
Explanation: The nonspecific immune response is an innate defense that quickly recognizes and responds to a broad range of
microbes regardless of their identity. This immunity consists of external barriers (skin, mucous membranes) as well as
internal cellular and chemical defenses which fight infectious agents that breach the external barriers. The main players in
the internal defenses are macrophages and other phagocytic cells, which ingest and destroy pathogens.
M.C. Question: Which of the following
serve as examples of internal
nonspecific immune responses?
A) Phagocytosis
B) Mucous membranes
C) Natural killer cells
D) A & B
E) A & C
Learning Log Question: You were
slicing an apple, and accidentally
cut your finger. Discuss the
inflammatory response that would
occur in response to the cut on
your finger (use the following:
macrophage, blood clotting,
pathogens, chemokines, etc.). The
cut in infected with a bacterial
infection. Discuss how it may
induce a systemic response that can
lead to septic shock.
LO 2.31: The student can connect concepts in and across domains to show that timing and coordination of specific events
are necessary for normal development in an organism and that these events are regulated by multiple mechanisms.
SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring
understandings and/or big ideas.
Explanation: Although treating biological microprocesses as isolated actions is an ideal way to study cellular operations, treating processes as
disconnected is often unrealistic given the plethora of mechanisms that act simultaneously in complex organisms. One example of such a
relationship is apoptosis (below, right), or cellular suicide. Apoptosis, protecting an organism from infections and cancerous growths, is critical to
development, occurring tens of millions of times per day in humans. A variety of physical and chemical components—including radiation and
stress or hormone, cytokine, and T cell interactions—can either inhibit or induce apoptosis. On a larger scale, specialized but related cell
groups—such as myocytes, red blood cells, and neurons—must work cohesively via both physical and biological means to carry out operations
(for example, neurons communicating with muscle cells in the legs allow an organism to run while red blood cells ensure fluid circulation of
oxygen throughout the circulatory system).
M.C. Question: Exposure to certain types of ultraviolet
radiation can degrade the spindle fibers in meiotic cells. If an
animal cell in prophase I was irradiated with this type of radiation
but went on to fertilize a gamete, which of the following would most
likely afflict the resultant offspring?
A) Red-green color blindness
B) Huntington’s disease
C) Klinefelter syndrome
D) Multiple sclerosis
E) Human immunodeficiency virus
Learning Log/FRQ-style Question: Biologists studying thigmomorphogenesis, a
type of physical change in plants induced by mechanical stress, notice that the
plants raised inside a greenhouse grow taller and skinnier than plants of the
same species outside, even when both groups receive identical sunlight, water,
weather exposure, and nutrients. What environmental conditions might have
induced thigmomorphogenesis outside of the greenhouse? Why might natural
selection continue to favor thigmomorphogenetic plants?
LO 2.33:The student is able to justify scientific claims with scientific evidence to show that timing and coordination of several events are
necessary for normal development in an organism and that these events are regulated by multiple mechanisms. [See SP 6.1] SP 6.1:The
student can justify claims with evidence.
Explanation: The timing and coordination of molecular, physiological and behavioral events are essential for the normal development of an
organism. Induction, for example, causes changes in an organism’s gene expression resulting in observable cellular changes. Due to this,
interactions between embryonic cells eventually induce differentiation of the many specialized cell types. The end product is a new organism.
Evidence is shown by mutations such as insertion, deletion, substitution- all of which result in abnormal development. Other evidence of this is
manifested through the genetic regulation by microRNAs; they play a key role in the development of organisms and the control of cellular
functions. RNA transcripts from miRNA-encoding genes are processed into miRNAs, which prevent expression of complementary mRNAs.
Multiple Choice:
Which of the following is true of apoptosis during the development of mammals?
A) Apoptosis eliminates the cells in the interdigital regions, thus forming the digits.
B) Cancers result from a failure of cell suicide.
C) A built-in cell suicide mechanism is essential for normal growth and development.
D) The action of nucleases and proteases causes changes seen in apoptotic cells and
eventual cell death.
E) All of the above.
Learning Log Question:
Discuss the role of cytoplasmic determinants and the process of induction in respect to gene expression for normal development.
1
The microRNA (miRNA)
precursor folds
back on itself,
held together
by hydrogen
bonds.
2
An enzyme
called Dicer moves
along the doublestranded RNA,
cutting it into
shorter segments.
3
One strand of
each short doublestranded RNA is
degraded; the other
strand (miRNA) then
associates with a
complex of proteins.
4
The bound
miRNA can base-pair
with any target
mRNA that contains
the complementary
sequence.
The miRNA-protein
complex prevents gene
expression either by
5 degrading the target
mRNA or by blocking
its translation.
Chromatin changes
Transcription
RNA processing
mRNA
degradation
Protein
complex
Dicer
Translation
Protein processing
and degradation
Degradation of mRNA
OR
miRNA
Target mRNA
LO 2.34: The student is able to describe the role of programmed cell death in development and
differentiation, the reuse of molecules, and the maintenance of dynamic homeostasis.
SP 7.1: The student can connect phenomena and models across spatial and temporal scales.
Explanation:
Programmed cell death, or Apoptosis is of Greek origin, having the meaning "falling off or dropping off", in analogy to leaves falling off
trees. This analogy emphasizes that the death of living matter is an integral and necessary part of the life cycle of organisms. Various
biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell
shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation without damage to neighboring cells.
The apoptotic mode of cell death is an active process which plays an important role in the development of multi-cellular organisms and in
the regulation , maintenance of the cell populations in tissues . Apoptotic processes are of widespread biological significance, being
involved in development, differentiation, proliferation/homoeostasis, regulation and function of the immune system and in the removal
of defective and harmful cells. Thus, dysfunction of the apoptotic program is implicated in a variety of pathological conditions. Dynamic
homeostasis implies that a system is in a constant state of motion, but in opposite directions. For example, a body's water amount is
controlled through intake versus the opposite function of sweat and urination. Therefore, homeostasis is achieved while also remaining in
motion, or dynamic. Ultimately, the system's equilibrium doesn't change in spite of dynamic motion.
M.C. Question:
Which of the following statement about the apoptotic process it the development of paws in the mouse is
TRUE?
a. Bcl7 regulates the activation of procaspases which only activate cell death.
b. Protein Bax activates procaspases directly, by inducing the release of cytochrome c from
mitochondria into the cytosol signaling the beginning of cell death.
c. Cytochrome C is released from lysosome into cytosol to kill the cell and thus eliminates
interdigital webs.
d. During apoptosis, the cell shrinks and breaks up into membrane-enclosed
fragments called apoptotic bodies with subsequent elimination by a process
similar to phagocystosis
e. All of the above
Learning Log/FRQ-style Question
Discuss how the immune system responds to an initial pathogenic
exposure, and how this initial exposure can lead to a quicker
response following a second exposure to the same pathogen. Draw
and label the processes that occur.
L.O. 2.35: The student is able to design a plan for collecting data to support the scientific claim that the timing and
coordination of physiological events involve regulation.
S.P. 4.2: The student can design a plan for collecting data to answer a particular scientific question.
Explanation: The timing and coordination of many physiological events across all species of organisms involve regulation. In
plants, phototropism is an essential process that involves the differential regulation of cell growth within the stem of a plant
responding to light, as the cells on the shaded side of the plant elongate more-so than the cells on the lighted side, which
allows the plant stem to bend toward light. An experiment completed by Fritz Went supported the hypothesis that
differential distribution of the plant hormone auxin is the driver of this physiological response. In animals, 24-hour circadian
rhythms , hibernation, estivation, and migration are examples of regulated and specifically-timed physiological events. In
bacteria, quorum sensing alters expression of genes when bacteria experience a high population density. As a bacterial
population increases, a signaling molecule called an inducer is produced and received by adjacent bacterial cells, which in
turn stimulates production of more inducer via positive feedback. After significant amounts of inducer are produced,
transcription of certain genes is turned on, producing a response. An example of a response that is stimulated in this way
includes bioluminescence of bacteria within certain species of deep-sea squid.
M.C. Question: Quorum sensing would most likely occur when:
A) A bacterium senses the production of cAMP
B) Tobacco plants are exposed to sunlight
C) Bacteria reach a certain critical concentration
D) Predator insects eat herbivorous insects
E) Insulin binds to target cells
FRQ: Describe the difference between long-day and short-day
plants. How can a long-day plant be induced to bloom in the
middle of winter?
LO 2.36: The student is able to justify scientific claims with evidence to show how timing and
coordination of physiological events involve regulation.
SP 6.1: The student can justify claims with evidence.
Explanation: In plants, physiological events deals with interactions between stimuli in the environment as
well as molecular signals that are internal. One example of this is phototropism which is the plant’s
response to light. Another example is through photoperidodism which is the response to change in the
length of night. Internal and external signals in both animals and fungi, protists and bacteria synchronize
with environmental cycles and cues. These are seen through hibernation, estivation and migration which
are examples of seasonal responses dealing with regulation. In fungi, there is a formation of a fruiting
body.
M. C. Question: Which of the following is not an example of physiological events involved in regulation in
animals?
A)
B)
C)
D)
E)
Release and reaction to pheromones
Visual displays in the reproductive cycle
Sensory cues in the nervous system
Circadian rhythms in eukaryotes
Jet lag in humans
Learning Log/FRQ-style Question:
What are examples of physiological events involved with
regulation in plants, animals and fungi? Be sure to include
one example for each category with elaboration on the
process.
http://en.wikipedia.org/wiki/Circadian_rhythm
LO 2.37: The student is able to connect concepts that describe mechanisms that regulate the timing and
coordination of physiological events.
SP 7.2: The student can connect concepts in cross domains to generalize or extrapolate in and or across
enduring understandings or big ideas.
Explanation: Photosynthesis is the main mechanism autotrophic organisms like plants ,use to convert light
energy into chemical energy. This photosynthetic process happens in the chloroplasts, absorbing carbon dioxide
(CO2) from the environment and converting it into oxygen due to the millions of stomata covering the plants surface
area. Phototropism is a physiological event that happens when a plant grows toward a positive stimulus like
sunlight. During the day the plants photoperiodicity response allowing the organism to respond to the duration of
night and day. With this response the plant can raise its leaves during the morning to insure maximum photosynthesis
and lower them during the evening. Due to the nitrogen fixing bacteria the nitrogenous materials and minerals are
converted from N2 to ammonia. This bacteria provides species with a built-in source of fixed nitrogen for
assimilation into organic compounds. These are all mechanism and physical characteristics that a plant need to
survive. Heterotrophic animals like bears for instance express these same adaptive qualities when the temperature
drops and food becomes scares, this process is called hibernation. Hibernation is the low physiological state when
activity is low and metabolism decreases. In sum according to the time of day or season, organisms coordinate
various physical adaptations and changes.
Multiple Choice Question: On the shaded side of a boulder there is a large vine, and on the other there is
sunlight. Which is NOT a result of increase ethylene?
a)
Increase in stem curvature
b)
A thicker plant stem
c)
Increased auxin growth
d)
Increase environmental stress
Free Response Question: A gardener adds a fertilizer that suppose to increase the size of his
sunflowers. Unfortunately the gardener planted the flower in a shaded area inches away from the
sunlight. Describe affects of the plant hormones and will the plant grow toward the light? Explain why
or why not.
LO 2.38: The student is able to analyze data to support the claim that responses to information and
communication of information affect natural selection.
SP 5.1:The student can analyze data to identify patterns or relationships
Explanation: In plants, physiological events involve interactions between environmental stimuli
and internal molecular signals. Phototropism, the response to the presence of light, and
photoperidism, the response to change in length of light results in flowering in long-day and
short-day plants, are both physiological events found in plants. Animals also respond to
environmental stimuli. Some examples would be: circadian rhythms, seasonal responses
(hibernation and migration), release and reaction to pheromones.
M.C. Question: The prayer plant folds up its leaves each night in accordance with a
circadian rhythm. If the plant is shipped halfway around the world to
a location where it is daytime there when it is night here, the plant will
A) slowly adjust to synchronize w/the new day-night cycle.
B) immediately switch to a new cycle & begin to open
leaves in day and close them at night.
C) detect the change but remain on its original cycle,
therefore still fold leaves in day and open them at night.
D) not detect the change, therefore remain on its original cycle.
Learning Log/FRQ-style Question: Behaviors of organisms
may be influenced by environmental factors. For each
of the following behaviors explain: i. how the
environment affects the behavior, and ii) why this
behavior increases the survivorship of individuals of a
species.
A) Taxis/Kinesis
B) Migration
L.O. 2.39 - The student is able to justify scientific claims, using evidence, to describe
how timing and coordination of behavioral events in organisms are regulated by
several mechanisms.
S.P. 6.1 - The student can justify claims with evidence.
Explanation: The varied behaviors of organisms are often regulated by external environmental factors, inner homeostasis functions, and occasionally
circadian rhythms that are not as dependent on these factors but on a biological clock in each organism. In animals, behaviors are sometimes innate and
sometimes “learned” through interaction with the environment. For example, Tinbergen’s study of the male Stickleback fish found that it displayed
agonistic behavior when it encountered the color red – this occurred because the male stickleback was acting on a fixed action pattern – an instinctive
behavior that cannot be interrupted. These innate behaviors are regulated by the innate relasing mechanism - a specific neural network. Natural
selection favored the evolution of this behavior in Stickleback males because of the competition between them for mates and living space. Therefore,
whenever an encounter between two red males occurs, the fixed-action pattern sets in, governing the agonistic behavior displayed by the Stickleback.
Sometimes, a lack of resources or other environmental influence will govern an organism’s behavior. For example, siblicide is a prevalent behavior in
Nazca Booby populations on a desert island of the Galapagos. Two eggs are often laid for insurance purposes, but if both hatch, the elder bird will push
the younger one out of its nest to its certain death. Scientists postulate that this behavior evolved as a direct response to the lack of food resources in this
area.
M.C. Question: What would be an example of a behavioral inhibition to the mating
process of a bowerbird?
A) The sperm fails to fertilize the egg.
B) Two birds live on opposite sides of a mountain range.
C) A male bird builds an insufficient nest and is rejected.
D) Two birds have different mating seasons.
Learning Log/FRQ-Style Question: (a) Deep sea angler fish are known and named for their lure, a
mobile, protruding rod of flesh atop their head which lures prey. Bioluminescent bacteria dwell in
the tip of the lure, benefitting from nutrients while the angler fish benefits from the
bioluminescence of the bacteria. Explain why this relationship is either commensalistic, mutualistic,
or parasitic, and contrast it with examples of the other two symbiotic relationships.
(b) Also, angler fish demonstrate an extreme sexual dimorphism – the females dwarf the males,
which latch onto the females in multitudes during reproduction, releasing sperm directly into the
bloodstream. Explain why this is polygyny, polyandry, or monogamy and contrast it with two other
examples of the other reproductive behaviors.
LO 2.40 The student is able to connect concepts in and across domain(s) to
predict how environmental factors affect responses to in formation and
change behavior
Explanation: This learning objective encompasses how an organism interacts
with its environment and being able to understand that timing and behavior
contribute to natural selection. Also being able to determine what responses
do organisms have to their environment that hurt and also help their survival
chances.
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SP 7.2 : The student can connect concepts across domains to generalize or
extrapolate in and/or across understanding and or big ideas
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Connection : The student should be able to give a general list of interactions
and behaviors between the environment ,but also be able to cite specific
examples that apply to more than just animals.
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Slide 1 of 3
LO 2.40 Multiple choice
C.) A wild goose's flight response to humans
decreases after it turns up from a remote winter
feeding ground to spend the summer on a lake in a
popular park. Compared to its behavior when it
first flew in, it soon tolerates people approaching it
and eventually almost ignores them. It habituates
to the stimuli.
Slide 2 of 3
Observational learning and
insight provide a mechanism to
learn new behaviors in response
to unexpected events without
reinforcement this reduces the
time required for behaviors to be
acquired. Which is an example of
this?
A.) European robins learning to
open milk bottles, robbing cream
from the top of milk bottles and
adapting to the use of aluminum
foil seals on the bottles, learning
to tear them to access the cream
B.) Costal garter snakes feeding
on banana slugs for survival in
California.
LO 2.40 Free response
• Explain phototropism and the relationship
between the environment and organism.
Identify and cite examples of Hibernation,
Estivation, and Migration. Also explain the
interaction between the organism and the
environment.
• Slide 3 of 3