Answer Key….THINK THE ANSWERS THROUGH…
Dynamic Equilibrium
In some land plants, guard cells are found only on the lower surfaces of the leaves. In some water
plants, guard cells are found only on the upper surfaces of the leaves. Explain how guard cells in
both land and water plants help maintain homeostasis. In your answer be sure to:
• identify one function regulated by the guard cells in leaves [1]
• explain how guard cells carry out this function [1]
• give one possible evolutionary advantage of the position of the guard cells on the leaves of land
plants [1]
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Which statement describes a feedback mechanism involving the human pancreas?
(1) The production of estrogen stimulates the formation of gametes for sexual reproduction.
(2) The level of oxygen in the blood is related to heart rate.
(3) The level of sugar in the blood is affected by the amount of insulin in the blood.
(4) The production of urine allows for excretion of cell waste.
We learned about this feedback loop specifically with diabetes.
24
The normal sodium level in human blood is 135 mEq/L. If a blood test taken immediately
after a meal reveals a sodium level of 150 mEq/L, what will most likely result?
(1) Antibody production will increase. Is there an infections?
(2) The person will move to an ecosystem with a lower sodium level. Hellloooo!
(3) The nutritional relationships between humans and other organisms will change. Would
this happen “immediately?”
(4) An adjustment within the human body will be made to restore homeostasis. The body
is constantly working to maintain….HOMEOSTASIS.
4
A glucose-tolerance test was conducted to observe the effect of time on glucose
concentration in the blood. An animal was fed 10 milliliters of glucose solution. At five
different times after the ingestion of the solution, the blood glucose concentration was
determined, and the results were recorded in the data table below.
The change in glucose concentration in the blood between 0 and 30 minutes was probably
due to
(1) the liver releasing glucose into the small intestine liver does not release glucose
(2) glucose being absorbed from the digestive system absorbed from digestive system into
the blood stream causes the rise in glucose in the blood.
(3) the synthesis of glucose from starch not possibles
(4) glucose being used for cellular respiration this would cause a decrease not increase
4
Insulin is a hormone that has an important role in the maintenance of homeostasis in
humans.
Identify the structure in the human body that is the usual source of insulin. [1]
Identify a substance in the blood, other than insulin, that could change in concentration and
indicate a person is not secreting insulin in normal amounts. [1]
*pancreas
* glucose
Two primary agents of cellular communication are
(1) chemicals made by blood cells and simple sugars
(2) hormones and carbohydrates
(3) enzymes and starches
(4) hormones and chemicals made by nerve cells both are used in cellular communication
When humans perspire, water, urea, and salts containing sodium are removed from the blood.
Drinking water during extended periods of physical exercise replenishes the water but not the
sodium. This increase in water dilutes the blood and may result in the concentration of sodium
dropping low enough to cause a condition known as hyponatremia. Symptoms of hyponatremia
include headache, nausea, and lack of coordination. Left untreated, it can lead to coma. and even
death. The body has a variety of feedback mechanisms that assist in regulating water and sodium
concentrations in the blood. The kidneys play a major role in these mechanisms, as they filter the
blood and produce urine.
The best way to reduce the symptoms of hyponatremia would be to
(1) drink more water that does nothing to reduce the symptoms of hyponatremia…you need
sodium
(2) eat chocolate yummy, but would only increase blood sugar
(3) eat salty foods replenish the sodium
(4) drink cranberry juice increase blood sugar level
Many runners pour water on their bodies during a race. Explain how this action helps to maintain
homeostasis. [1]
Talk about temperature regulation
Which situation indicates that a disruption of homeostasis has taken place?
(1) the presence of hormones that keep the blood sugar level steady
(2) the maintenance of a constant body temperature
(3) cell division that is involved in normal growth
(4) a rapid rise in the number of red blood cells rapid rise indicates a disruption from the normal
production of red blood cells.
Yellow highlighted words all indicate homeostasis: constant, normal, steady.
Energetics
A student placed a solution of glucose and yeast in a vacuum bottle and sealed it with a
two-hole stopper as shown in the diagram below. The temperature of the yeast-glucose
solution increased gradually with time, and the color of the indicator was observed and
recorded throughout a 2-day period.
The purpose of the investigation was most likely to
(1) study the relationship between temperature and pressure pressure measure?
(2) demonstrate the release of energy by a chemical process increase in temp shows energy
release
(3) show that proteins are produced by yeast we don’t know what the indicator tests for
(4) study autotrophic nutrition in yeast how would this be measured from this experiment
0
The diagram below represents a biological process.
Which set of molecules is best represented by letters A and B?
(1) A: oxygen and water
B: glucose
(2) A: glucose
B: carbon dioxide and water
(3) A: carbon dioxide and water
glucose
B: glucose
(4) A: glucose
B: oxygen and water
A student studied how the amount of oxygen affects ATP production in muscle cells. The data
for amount X are shown in the graph below.
If the student supplies the muscle cells with less oxygen in a second trial of the investigation, a
bar placed on the graph to represent the results of this trial would most likely be
(1) shorter than bar X and placed to the left of bar X
(2) shorter than bar X and placed to the right of bar X
(3) taller than bar X and placed to the left of bar X
(4) taller than bar X and placed to the right of bar X
1
The energy found in ATP molecules synthesized in animal cells comes directly from
(1) sunlight
(2) organic molecules
(3) minerals
(4) inorganic molecules
The arrows in the diagram below indicate the movement of materials into and out of a single-
celled organism.
The movements indicated by all the arrows are directly involved in
(1) the maintenance of homeostasis
(2) respiration, only
(3) excretion, only
(4) the digestion of proteins amino acids as a product?
The graph below shows photosynthetic activity in an ecosystem over a 24-hour period.
Data for a study on respiration in this ecosystem should be collected during
(1) interval A, from only the producers in the ecosystem
(2) intervals A and B, from only the consumers in the ecosystem
(3) intervals A and B, from both the producers and consumers in the ecosystem
(4) interval A only, from abiotic but not biotic components of the ecosystem
A student studied the location of single celled photosynthetic organisms in a lake for a period of
several weeks. The depth at which these organisms were found at different times of the day
varied greatly. Some of the data collected are shown in the table below.
A valid inference based on these data is that
(1) most photosynthetic organisms live below a depth of 150 centimeters during full light
(2) oxygen production increases as photosynthetic organisms move deeper in the lake no
proof/indicator
(3) photosynthetic organisms respond to changing light levels notice the change from full
light/average depth to no light/average depth.
(4) Photosynthetic organisms move up and down to increase their rate of carbon dioxide
production lake no proof/indicator
Energy from organic molecules can be stored in ATP molecules as a direct result of the process
of
(1) cellular respiration
(2) cellular reproduction
(3) diffusion
(4) digestion
The diagram below represents events associated with a biochemical process that occurs in some
organisms.
Which statement concerning this process is correct?
(1) The process represented is respiration and the primary source of energy for the process is the
Sun.
(2) The process represented is photosynthesis and the primary source of energy for the process is
the Sun.
(3) This process converts energy in organic compounds into solar energy which is released into
the atmosphere.
(4) This process uses solar energy to convert oxygen into carbon dioxide.
In the transfer of energy from the Sun to ecosystems, which molecule is one of the first to store
this energy?
(1) protein
(2) fat
(3) DNA
(4) glucose