Final Exam Study Guide
KEY
Textbook Chapters: 2 – 11, 18, 43
Recommendation: Watch Bozeman videos and Knuffke Prezis on topics we covered (especially on viruses, the
immune system, and cell communication b/c there are no practice questions). Study ALL PowerPoints and
notes from class! Study all the “Essential Knowledge” handouts that I give you before exams.
- Bart believes that mice exposed to red light will be more attracted to red colored apples than green colored apples. He
decides to perform this experiment by placing 10 mice under a red light for 5 hours. He compared these 10 mice to
another 10 mice that had not been exposed to the red light. He found that 8 out of 10 of the red light mice ate red apples,
while 2 out of 10 ate green apples. 4 out of 10 of the nonexposed mice ate the red apples, while the other 6 out of 10 ate
the green apples.
a. What is the control group?
Mice not exposed to red light
b. What is the independent (manipulated) variable? Exposure to red light
c. What is the dependent (responding) variable?
# of mice eating red apples (or green apples)
d. How could the experiment be improved? Larger sample size, more trials
e. Calculate the chi-squared value using only the data of the mice exposed to the red light using the
following Null Hypothesis: “Mice have no preference for red apples or green apples.” What is your conclusion?
Chi-squared value = 3.6 Using p value of 0.05 with 1 degree of freedom, I accept my null hypothesis – using only
the data of the mice exposed to the red light, they do not have a preference for red or green apples.
- One study in grand juries in Alameda County, CA, compared the demographic characteristics of jurors with the general
population to see if jury panels were representative. The results for age are shown below. The investigators wanted to
know if the 66 jurors were selected at random from the population of Alameda County. (Only persons over 21 and over
are considered; the county age distribution is known from Public Health Dept data.) The study was published in the UCLA
Law Review. Do we have evidence that grand juries are selected at random for the population of Alameda County?
Age
Countywide %
# of jurors
observed
# of jurors
expected
21-40
42%
5
27.72
41-50
23%
9
15.18
51-60
16%
19
10.56
over 60
19%
33
12.54
Total
100%
66
(O-E)
(O-E)2
(O-E)2/E
2.516
- Here is the structure of the molecule glycine:
a. Is this molecule hydrophilic or hydrophobic? Explain.
b. Draw two glycine molecules and show how they can be linked by a condensation reaction.
- Draw a molecule of glucose. Identify all the functional groups present.
- Construct a bar graph that displays the relative amounts of H, C, O, and N in each of the four types of macromolecules.
Carbohydrates would have a 1:2:1 ratio of C:H:O
Lipids would have a lot of carbons and hydrogens because they have long hydrocarbon chains (about 2:1 ratio of C:H)
Proteins would contain C, H, O, but also N (because of the amino group)
Nucleic Acids would have C, H, O, and N as well
- Describe the structure and function of each the four types of macromolecules.
Review the Chapter Summary for Chapter 5 in the textbook.
- Why are phospholipids amphipathic and how does this result in a lipid bilayer membrane?
Amphipathic = both polar and nonpolar ends. Phospholipids have a polar phosphate head (phosphate group is negative)
and 2 fatty acid tails (which are nonpolar because they are long hydrocarbon chains). The tails form the inside of the lipid
bilayer membrane because they are excluded from water.
- Which of the 4 levels of protein structure is maintained after denaturing? Explain.
Only the primary level is maintained after denaturing.
- What evolutionary advantages does a eukaryotic cell have compared to a prokaryotic cell?
Compartmentalization. Increased surface area because of internal membranes.
- Embedded proteins are often found spanning the membrane of a cell or organelle. These proteins serve
as channels for specific molecules to travel through the membrane, either into or out of the cell.
a. What sections of the embedded protein chain are most likely to contain amino acids with hydrophobic
R-groups? Explain your reasoning.
The inside part (helix shaped area)
b. What sections of the embedded protein chain are most likely to contain amino acids with hydrophilic R-groups?
Explain your reasoning.
The parts exposed to water
- Some membranes have surface proteins on them. These proteins often serve a signaling function
between cells. Propose a mechanism by which these surface proteins are able to attach to the membrane.
The part of the protein attached to the phospholipid heads are probably hydrophilic.
QuickTime™ and a
decompressor
are needed to see this picture.
- Biological systems rely heavily on the properties of water movement. Excretion, digestion, and blood pressure are just a
few examples of situations where water balance is important. Suppose you have a semi-permeable membrane that ONLY
water can pass. On one side of the membrane you have 0.1 M CaCl2. On the other side of the membrane, you have 0.1 M
Glucose. CaCl2 ionizes in water to produce 3 ions. Glucose does not ionize in water.
0.1 M CaCl2
0.1 M Glucose
a. Calculate the water potential for each side of the membrane.
Assuming temperature is 25C
Water potential of left side = -7.42
Water potential of right side = -2.47
b. Describe which way water will move and explain your answer.
Water will move from the right side to the left. (b/c higher water potential on the right than on the left. Water moves form
high water potential to lower water potential)
- DNA polymerase from T. aquaticus (Taq) is used in PCR (polymerase chain reaction). PCR is a technique where
millions of copies of DNA can be made from one original copy. In this method, the target DNA molecule is subjected to
temperatures over 95 °C to make the double-stranded DNA separate. The temperature is then lowered slightly to allow
primers to anneal before the Taq polymerase catalyzes the reactions to incorporate new nucleotides into the
complementary strands. The cycle is then repeated over and over until there are millions of copies of the target DNA.
a. Predict why this bacterial polymerase is used instead of a human polymerase. Because it won’t denature at high
temperatures
b. What would happen if you used a human polymerase in a series of PCR reactions?
- We learned earlier that fats store about 2xs more energy than carbohydrates. Now, after studying cellular respiration
and redox reactions, explain why this is true. Fats have lots of hydrogen-carbon bonds, and each of these store energy.
Ex: fats have more bonds that can be oxidized compared to carbs.
- The figure to the right (figure is from POGIL packet) outlines
the process of cellular respiration. Glucose and oxygen are
both reactants in this process.
a. Describe the journey of a single carbon atom from glucose
in cellular respiration
carbon from glucose will eventually be released in the form of
carbon dioxide (it will first become a part of pyruvate, then it
could be a part of acetyl CoA and enter the krebs cycle)
b. Describe the journey of a single hydrogen atom from
glucose in cellular respiration
the hydrogen may end up on an electron carrier NADH or
FADH2 and then in the ETC, it would be pumped into the
intermembrane space of mitochondria to form a proton
gradient. Then it will travel through ATP synthase. They may also end up in water.
c. Describe the function of the oxygen molecules in cellular respiration
they draw the electrons through the electron transport chain and are the final electron acceptor.
- The figure below outlines the process of photosynthesis. Carbon dioxide and water are both reactants in this process.
a. Describe the journey of a single hydrogen atom from water in photosynthesis.
Hydrogen is split from water and these hydrogens can be combined with NADP+ and go to the calvin cycle. It may
eventually end up in glucose
b. Describe the journey of a single oxygen atom from water in photosynthesis.
Oxygen is split from water and forms O2 which is relased.
c. Describe the journey of a carbon dioxide molecule in photosynthesis.
Carbon enters photosynthesis during the calvin cycle in the form of CO2. It is then fixed into a molecule that will
eventually become glucose.