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Biology 205 Spring 2006 Final Exam
75 pts. Total
NAME________________________
1. (12 pts.) True/False Answer False if any part of the statement is false.
1 pt if no explanation required. 3 pts if explanation required; explanation is
worth 2 pts.
T F The redox reactions that occur in the electron transport chains are endothermic reactions.
T F Glycolysis is thought to be the most ancient pathway for the catabolism of glucose
because it does not require O2.
Which statement(s) are false about control of protein function by phosphorylation
T F Protein phosphorylation is a regulatory mechanism commonly used by prokaryotes but
rarely used by eukaryotes.
T F Protein phosphorylation is catalyzed by a group of enzymes called kinases and allows a cell
to respond very quickly to extracellular signals.
*********
On the redox potential energy scale, H2 is at a higher level than CO2. The potential energy
difference is about the same as the difference between glucose and pyruvate, but small
compared to the difference between glucose and O2. Are the following statements True or
False.
T F Despite the marginal energy yield, bacteria exist that obtain energy by transferring
electrons from H2 to CO2
T F Despite its chemical stability, CO2 must be more electron hungry than H2.
*********
T F All biologically significant polymers are made of chemicallly variable monomer units.
One-two sentence explanation:
The first statement is true. Is the second statement true or false?
T F Control of protein activity can occur at level of transcription, splicing, translation or at the
posttranslational level. Allosteric control of protein activity is one example posttranslational
control.
One-two sentence explanation:
1
2. (14 pts.) Each MC question is worth 2 pts. NOTE: There may be more than
one correct answer. Circle all correct answers
2.1 In reference to the DNA double helix, the term anitparallel
a. refers to the specific base pairing of A with T and G with C.
b. refers to the order of nitrogenous bases in the DNA.
c. refers to the sugar-phosphate backbones of the DNA which are organized with one free end of
the backbone having the 5’ carbon of the sugar opposite to a free 3’ carbon on the the other
backbone.
d. refers to the sugar-phosphate backbones of the DNA which are organized with one free end of
the backbone having the 5’ carbon of a purine opposite to a free 3’ carbon of pyrimidine.
2.2 A sexually reproducing animal has two genes on different chromosomes, one for head shape
(H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is
possible in a gamete (meiotic product) from this organism?
a. HT
b. Hh
c. HhTt d. T
e. tt
2.3 Suppose you were provided with an actively dividing culture of E. coli bacteria to which
radioactive thymine had been added. What would happen if a cell replicated once in the presence
of this radioactive base?
a. One of the daughter cells, but not the other, would have radioactive DNA.
b. Neither of the two daughter cells would be radioactive.
c. All four bases of the DNA would be radioactive.
d. Radioactive thymine would pair with nonradioactive guanine.
e. DNA in both daughter cells would be radioactive.
2.4 Cells switch from cellular respiration to fermentation:
a. when terminal electron acceptors are not available
b. when the proton-motive force runs down
c. when NADH and FADH2 supplies are low
d. when pyruvate is not available
2.5. You provide a photosynthesizing green alga with radiolabelled CO2: the oxygen atoms are
labelled with the heavy isotope 18O. Subsequent analysis identifies 18O - containing molecules.
These will include:
a. glucose
b. Calvin cycle intermediates
c. both a and b
d. O2
e. all of the above
2.6 Which of the following sequences correctly represents the flow of electrons during
photosynthesis?
[One correct answer.]
a. NADPH  O2  CO2
b. H2O  NADPH  Calvin Cycle
c. NADPH  chlorophyll  Calvin Cycle
d. H2O  photosystem I  photosystem II
e. NADPH  electron transport chain  O2
2
2.7 The hydrophobic effect is a critical factor for which of the processes listed below: (may be
more than one answer)
a. membrane bilayer stability
b. tertiary folding of a polypeptide in the cytoplasm
c. separation of oil and vinegar phases in a vinaigrette (salad dressing)
d. interaction between purine and pyrimidine bases in the two strands of DNA
e. none of the above
Short Answer Questions
3. 1 (3 pts.) When a purified preparation of chlorophyll is exposed to ultraviolet
light, it will emit red light and heat. Briefly explain why this happens under these
conditions but not in the photosystems in the chloroplast thylakoid membrane. 1-2
sentences.
3.2 (2 pts.) Where is ATPsynthase located in a plant cell? BE very explicit (zip
code is not enough -- need house address as well). Hint: two locations
Location 1:
Location 2:
3.3 (4 pts.) Cytochrome oxidase is the terminal member of the respiratory electron
transport chain. Both cytochrome oxidase and hemoglobin (found only in red
blood cells) carry an Fe++ atom in a porphorin ring structure. Given the very
different biological roles of these proteins, why would they share this common
structural component? 2 sentences Be sure to clearly state the biological roles
of these two proteins indicating what they share in common.
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4. 6pts Examine this figure carefully.
a. What is one clear measure of organismal complexity? No explanation needed.
b. Name one type of non-coding DNA that is transcribed.
Use proper term____________________ No explanation necessary.
c. Briefly explain the last sentence in the legend to this figure by explaining how
non-coding sequences could increase an organism’s complexity. 2-3 sentences
using proper terminology
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5. (12 pts.) Recall the SRY gene that was mentioned in lecture a few times. It is located on the
Y chromosome in mammals and directs the formation of a testes in the developing embryo by
controlling the activity of a number of different proteins. Embryos without this gene develop
into females. This figure shows the SRY protein “in action” binding to a promoter region.
a. Using the above information, speculate as to the specific molecular function of the SRY
protein. In general, how is it regulating the level of activity of other genes? One sentence
only.
b. In lecture we looked at the nucleic acid sequence of the SRY gene and amino acid sequence of
the SRY protein. But, the existence of the SRY gene and its importance in mammalian sex
determination was first indicated by the traditional (ie Mendelian) way of knowing that a gene
exists. Briefly explain this last statement. 1-2 sentences.
c. On the figure, circle the SRY protein and label SRY. What type of protein secondary
structure is prominent here? No explanation needed _____________________________
d.
What type of nucleic acid is shown in this figure? Acronym is suffcient:___________
e. On the figure, draw arrows pointing to regions where hydrogen bonding is known to stabilize
the structures shown. NOTE your arrows must be precisely directed or you will get no credit.
Label each arrow with an H.
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The phosphate bond
between the α and β
phosphorus atoms is
broken in this
reaction. Also the
phosphate bond
between the β and
γ phosphorus atoms
is hydrolyzed.
phosphates left to right: γ β α
6. (6 pts.)
a. Does this drawing show replication, transcription or translation?Briefly
defend your choice by indicating what features of the drawing were important for
answering this question.
b. Briefly explain how this diagram shows the coupling of endergonic and
exergonic reactions. Be sure to explain what these terms mean and to indicate
which part of the diagram illustrates each type of reaction.
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7. (10 pts.)
Champagne production is based
on fermentation in yeast.
a. Briefly explain how “the bubbly” component is produced during fermentation.
Describe in words (or draw out structures if you prefer).
b. Trace the flow of electrons (originating in glucose or some grape sugar) during
champagne formation. Your answer MUST be in the following format -- no
explanation is necessary
Example: a  b  c
Select from these terms: glucose, CO2, pyruvate, lactic acid, NADH, electron transport
chain, O2, Krebs cycle intermediates, ATP synthase, pyruvate dehydrogenase
ethanol, methanol, acetyl CoA
Consider the following scenerio. You have a sealed champagne barrel full of
happily fermenting yeast. The barrel develops a crack and oxygen seeps inside.
Sacre bleu! (Holy cow). What is(are) the problem(s) with oxygen seeping into the
barrel?
c. Will the “bubbly”component of the champagne continue to be produced in the
presence of oxygen? Why or why not?
Circle YES or NO. Briefly explain your answer in 2-3 sentences.
Be very explicit about the biochemistry (and cellular compartments) and use
proper terminology.
d. Will the important waste product of fermentation continue to be
produced? Circle YES or NO. Briefly explain your answer in 2-3 sentences.
Be very explicit about the biochemistry (and cellular compartments) and use
proper terminology.
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8. (6 pts.) Your mom has been exploring the Biol 205 web site to see if your
tuition dollars are being well-spent […..apologies to those of you who are paying
your own way] and she is curious about the pictures on the 205 home page.
Choose ONE figure and, in 4-5 sentences, explain the content of the figure. Your mom
has an eye for detail, so be sure to explain specifics as well as big picture/conceptual
issues. Your mom always appreciates a well-organized, coherent explanation of science
stuff. Use proper terminology and indicate whether your mom has previously taken a
course in biology (Circle YES or NO -- your choice). The latter will determine whether
you need to explain basic terminology to her.
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Question( pts.) Score
Q 1 (12)
Q 2 (14)
Q 3 ( 9)
Q 4 (6)
Q 5 (12 )
Q 6 (6)
Q 7 (10)
Q 8 (6 )
Total (75 pts)
9