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Biology 1002B Study Guide - Midterm Guide: Photochemistry, Chlamydomonas, ChannelrhodopsinExam

Course Code
BIOL 1002B
Denis Maxwell
Study Guide

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Biology 1002B February Term Test MakeUp 2016 Page of 11
Code 111 Code 111 Code 111
Circle the best single letter choice for each of the following questions before
transferring your answers to your computer sheet.
Note: Questions may have 3, 4 or 5 choices.
1. Its particular evolutionary relationship with other organisms is one reason that
Chlamydomonas is such a useful experimental organism.
Which of the following descriptions of Chlamydomonas evolutionary relationships
is correct?
A. Chlamydomonas is only distantly related to any multicellular organism.
B. Chlamydomonas is more closely related to plants than to animals.
C. Chlamydomonas is single-celled; therefore it is closely related to Bacteria.
D. Chlamydomonas diverged from the lineage leading to fungi about 6 billion years ago.
2. In the field of optogenetics the Chlamydomonas opsin gene has been expressed in humans
producing functional channelrhodopsin.
Is it possible to do the reverse? Can human opsin be expressed in Chlamydmonas and take
the place of channelrhodopsin?
A. No, because humans are eukaryotes and Chlamydomonas is a prokaryote.
B. No, it wouldn't work because human opsin is not an ion channel.
C. Yes, because Chlamydomonas synthesizes the retinal to make the protein functional.
D. Yes, in a Chlamydomonas opsin mutant that is not phototactic, this experiment will make
the cells phototactic once again.
3. Plants can grow under a wide range of light conditions. It shouldn't surprise you that they
grow faster under certain wavelengths of light than others.
Which of the following accurately reflects the effect of certain wavelengths on growth?
A. Plants will grow about 25% slower under green light than red light.
B. Plants will grow equally fast under red and blue light.
C. Plants will grow fastest under blue light.
D. Plants will grow fastest under ultraviolet light.
4. Photochemistry occurs in photosystems, triggering electron transport. However,
photochemistry also occurs in photoreceptors.
Which of the following consequences results from photochemistry in photoreceptors?
A. Oxidation of opsin.
B. Creation of excited state retinal.
C. Conversion of the cis isomer into the trans isomer of retinal.
D. Change in shape of a protein.

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Biology 1002B February Term Test MakeUp 2016 Page of 11
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5. You can isolate free chlorophyll from a culture of Chlamydomonas by using a non-polar
solvent such as acetone or methanol.
Compared to a culture of intact Chlamydomonas cells, exposure to low light will result in
the solution of chlorophyll producing about 1000 times more fluorescence.
Why is that?
A. The solution of chlorophyll cannot absorb light, it can only fluoresce light.
B. Chlorophyll in solution cannot undergo photochemistry, which is where most of the
absorbed energy goes in the Chlamydomonas culture.
C. Photons cannot pass through the thylakoid membranes of intact Chlamydomonas cells and
thus both light absorption and fluorescence are less.
D. Unlike Chlamydomonas culture, in the solution of chlorophyll the energy cannot be lost as
heat thus fluorescence is higher.
6. The image at right shows the change in mRNA
abundance of the Flacco1 gene in E. coli (top),
and Flacco and actin proteins (bottom), as a
function of time in response to shifting a culture of
E. coli from 22°C to 40°C.
Which of the following explanations is most
consistent with the data shown?
A. The culture has been treated with bencapin a drug that blocks ribosome function.
B. The Flacco1 gene contains a mutation that prevents translation but not transcription.
C. The Flacco1 transcript is very unstable and never accumulates in the cytosol.
D. The Flacco protein interacts with actin which triggers its degradation.
7. The change in free energy (ΔG) of a system is dependent upon the change in enthalpy and
the change in entropy according to:
Based on this formula which of the following statements is correct?
A. If a reaction is endothermic it must be endergonic.
B. An increase in temperature decreases the entropy of a system
C. An increase in entropy can make a endothermic reaction spontaneous.
D. Spontaneous reactions are those that occur on a millisecond timescale.

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Biology 1002B February Term Test MakeUp 2016 Page of 11
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8. Proteins are the dominant structural and functional molecules within a cell.
Which of the following statements about protein structure is correct?
1. The peptide bond is generated by the carboxyl group of one amino acid reacting with the
amino group of another amino acid.
2. While alpha helices are based on hydrogen bonding the beta sheet is based on ionic bonding.
3. Hydrophobic interactions play a role in the tertiary structure of many protein.
4. Most proteins require quaternary structure to be functional.
A. 1, 2 & 3
B. 1 & 3
C. 2 & 4
D. 4 only
E. All of 1, 2, 3 & 4 are correct.
9. The image at right illustrates the "energy funnelling"
model of protein folding.
Based on this model, which of the following
statements is correct?
1. Most proteins are functional in state B.
2. A protein in state D has less Free Energy than a
protein in state C.
3. Heat can move a protein from state A to B.
4. Adding the denaturant urea could shift a protein from
state C to state A.
A. 1, 2 & 3
B. 1 & 3
C. 2 & 4
D. 4 only
E. All of 1, 2, 3 & 4 are correct.
10. The exergonic breakdown of ATP can be written as this:
ATP + H2O --> ADP + Pi
Which of the following statements accurately coveys aspects of this hydrolysis reaction?
1. The water molecule reacts with the adenosine component of ATP.
2. The energy released during bond formation is greater than the energy needed for bond
3. ATP possesses high energy phosphate bonds that release energy when they are broken.
4. The reaction is exergonic, in part due to an increase in entropy.
A. 1, 2 & 3
B. 1 & 3
C. 2 & 4
D. 4 only
E. All of 1, 2, 3 & 4 are correct.
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