Biology: Extend and Refine
Study Guide
Cells
1. Match the organelle with the way it maintains homeostasis in a cell.
a. Converts sunlight into chemical energy
b. Synthesizes proteins
i
1. Golgi Apparatus
c. Provides external support
g
2. Vacuole
d. Digests and recycles materials
j
3. Nucleus
e. Produces ATP
b
4. Ribosome
f. Regulates what comes into and out a
5. Chloroplast
g. Stores material
e
6. Mitochondrion
(Particularly large in plants)
c
7. Cell Wall
h. Houses ribosomes
f
8. Cell Membrane
i. Packages materials prior to being
d
9. Lysosomes
exported out of the cell
h
10. Endoplasmic Reticulum
j. Houses DNA
2. In the diagram below, list the differences and similarities between prokaryotes and
eukaryotes:
Prokaryotes
No nucleus
Small
Simple
Ex. Bacteria
Eukaryotes
Cell membrane
DNA/RNA
Ribosomes
Cell wall
Larger
Complex
organelles
Ex. Plants, animals, fungi,
protists
3. Give a comprehensive reason explaining why water moves into and out of cells.
(Consider hypertonic, hypotonic, and isotonic solutions.)
Water moves into and out of cells in order to help organisms maintain homeostasis, a
condition in which the internal environment maintains equilibrium or stability with the
external changes by controlling what substances may enter or leave the cell.
In isotonic solutions the concentration of water is equal on both sides of the cell membrane
(the amount of liquid leaving the cell is equal to that going in to the cell). In hypertonic
solutions the strength of the solution is above strength or concentrated, meaning that there
is less water outside of the cell so that the water will leave the cell to maintain balance,
causing the cell to shrink, shrivel, or die. In hypotonic solutions, the amount of water is
higher outside the cell than it is inside the cell causing the water to move into the cell in
order to maintain balance. The cell will swell and may burst or lyse.
4. Explain how the cell membrane regulates the movement of salt, water, and other
materials into and out of the cell.
Passive Transport
No Energy Required
(Movement of molecules from an area of
high to an area of low concentration)
Diffusion
Molecules move
Osmosis
Water moves
Active Transport
Energy Required
(Movement of molecules from an area of
low to an area of high concentration)
Endocytosis
Entering the cell
Exocytosis
Exiting the cell
Facilitated Diffusion
Protein channels aid in
Movement
Ion Pump
Energy is required to move
particles from an area of low
concentration to an area of
high concentration.
5. Explain why plants, bacteria, and animals often die when exposed to excessive
amounts of saltwater.
Plants, animals, and bacteria often die when exposed to excessive amounts of salt-water
because the saltwater solution is hypertonic to the cell. The water from the cell would
leave the cell and enter the solution in order to maintain homeostasis with this external
environment, causing the cell to shrivel and perhaps die. (The great amount of energy
required for this process (active transport) causes animals/plants to die)
6. Describe experiments that could be used to demonstrate osmosis.
One experiment that could be done would be to take an egg without the shell and submerge
it into three different solutions (saltwater, freshwater, and sugar water) to watch the
movement of liquid and the affect each solution had on the cell.
Another experiment would be to water a plant with saltwater solution and watch the effect
it would have on the plant. (hypertonic solution)
A third would be gargling with saltwater. (Hypertonic solution)
A red blood cell in different solutions (hypertonic, isotonic, and hypotonic)
Biochemistry
7. Macromolecules: Fill in the chart below.
Macromolecule Function
Carbohydrate
Store (Quick)
Energy
Monomers
Saccharide
Found In
Starch
Sugar
Glucose
Characterisitics
Complexity
changes
according to
the number of
monomers
attached
Lipid
Store (Long term)
Energy
Fatty Acid
Oils
Fats
Steroids
Cell
membrane
Wax
Hydrophobic
(does not
dissolve in
water)
Protein
Enzymes,
Antibodies,
Hormone receptors,
Neurotransmitters,
Hair, Nails and
Muscle structure,
Metabolism
Store Genetic
Information
Amino
Acids
Meats
Nuts
Milk
Provides
structure to
organisms
(Muscles, etc..)
Nucleic Acid
Nucleotides Nucleus
DNA
RNA
Strands with
Ribosugar
backbone
Direct Protein
Synthesis
8. Enzymes:
a. Enzymes are defined as biological catalysts, because they accelerate
chemical reactions in living organisms.
b. How could you test the effectiveness of an enzyme as a function of:
i. Temperature: If the temperature gets too hot, the enzyme changes
shape or denatures.
ii. pH: Changes in pH may not only affect the shape of an enzyme but
it may also change the shape or charge properties of the substrate so
that the substrate cannot bind to the active site.
9. Glucose’s major function in a cell is to store chemical energy until the cell goes
through respiration. Respiration goes on in the mitochondria as it converts
glucose’s energy into the cellular energy molecule, ATP.
Energy of Life
10. Plants use light energy to make glucose molecules that will be used later in their
cells for cellular respiration
11. What is the energy molecule for cells? ATP
12. What do plants take in and produce during photosynthesis?
Take in:
Carbon dioxide CO2
Water H2O
Produce:
Glucose C6H12O6
Oxygen O2
Note: Cellular respiration is the opposite!
13. What happens to ATP when it releases energy in cellular processes?
The third phosphate breaks off
RNA, DNA, Viruses
14. Compare sexual reproduction to asexual reproduction:
Sexual
Meiosis
Genetic Variability
Gametes
Asexual
Reproduction
Produce
offspring
Mitosis
Exact Copies
Somatic Cells (body)
15. Compare and contrast the benefits of sexual and asexual reproduction.
Sexual
Asexual
Genetic variability
Keep good characteristics
Tend to survive as a species
When you have something
better with variety
good, keep it!
16. Compare the characteristics of bacteria and viruses:
Bacteria
Reproduce independently
Both
Respiration (metabolism)
Cell membrane
Viruses
Evolve
Diseases
DNA/RNA
Reproduce in a host
Not Both
No respiration (metabolism)
Capsid
Much smaller
17. Compare the general characteristics of DNA and RNA.
DNA
2 strands
Double helix
Template for protein
synthesis (makes an
mRNA)
Thymine
Nucleic acid
Codes for
information
Guanine
Adenine
Cytosine
RNA
1 strand
Carries the code for
protein synthesis
Uracil
18. Protein Synthesis:
a. What molecule is used as the template for the code on what protein to
produce? DNA
b. How does the genetic code get to the point where protein synthesis occurs?
mRNA carries the code to the ribosome
c. What do the following terms have to do with protein synthesis? Circle the
one that happens first.
i. Transcription
1st Makes the mRNA from the DNA
In nucleus
ii. Translation
Makes the protein (amino acid sequence) from the mRNA code
At ribosome
19. Describe the steps of replication and explain why this should occur prior to mitosis.
Basic Genetics
20. What causes certain characteristics to be inherited by offspring? For example, two
heterozygous parents have children who all have the dominant characteristic. What
would explain this? A dominant allele will guarantee its characteristics
(phenotype) will show up. A recessive phenotype requires two recessive alleles.
(Genotypes) In this example, all of the offspring received a dominant allele.
21. A fly with stripes is crossed with a fly having no stripes. (Stripes is Dominant) All
of the offspring have stripes. What is the expected stripe pattern (with or without)
of the offspring of these heterozygous striped flies?
S
S
s
Ss
Ss
s
Ss
Ss
100% would have stripes
22. Two pea plants with the genotype TtRR are crossed. What are the probabilities of
producing offspring with the genotypes:
a. Ttrr
0%
b. TTRR
25%
c. ttRr
0%