BI 171 - Third Exam -
Answer Key - 2010
Each question's number
is linked to the relevant part of the online book, if possible (some questions
relate to multiple sections).
Place the letter of the choice that best answers the question on the line to the
Two Points Each. NOTE: "e" answers are never the correct answer.
1. Which will have a lot of RNA in it?
b. Nuclear envelope
d. Intermediate filament
e. The RNA supermarket
...its main function is to store and process RNA.
2. The rate "drop off" from optimum temperature and
pH may both involve
a. Changes in flux
b. Changes in particle speed
c. Changes in substrates
d. Breaking of hydrogen bonds
e. How close to the weekend it is
...both rising temperatures and extra ions can disrupt H bonds and make it
hard for the enzyme molecules to
stay in a working shape.
3. Recycling of materials generally happens in
a. Golgi bodies
e. Itty-bitty special bins
...match the organelle with the function.
4. Microfilaments provide motion to
a. Muscle cells
c. Flagella d.
e. Avatar effects
...match the structural element with a function.
5. An enzyme always works by affecting
a. Substrate shape
b. Electron distribution
c. Speed of breakdown
d. Activation energy
e. How angry the tiny bits are
...that's how it gets reactions to go more easily.
6. Which division stages are the
most different compared to mitosis?
a. Prophase and anaphase of Meiosis II
b. Prophase and anaphase of Meiosis I
c. Anaphase and telophase of Meiosis I
d. Anaphase and telophase of Meiosis I
e. Differ-phase and not-so-much-the-same-phase of Meiosis Whatever
...during prophase, homologous pairs are put together in the middle, and in
anaphase, chromatids do not
separate, and double-stranded chromosomes move toward the poles.
7. Minerals are commonly working in
a. Enzymes and coenzymes
b. Osmosis and enzymes
c. Cofactors and prosthetic groups
d. Cofactors and coenzymes
e. Small third-world countries, where they are being exploited
...cofactors work separately, prosthetic groups are actually parts of the
molecules, but both are usually minerals.
8. In response to insulin, sugar moves from the blood
into liver cells; soon, the concentration in the liver cells exceeds that of
and it keeps moving in. This involves
a. Active transport
b. Facilitated diffusion
c. Osmotic pressure
d. Passive transport
e. The liver...and the blood...
...figure the relative concentrations - movement from high to low (downhill)
is diffusion, happens by itself, passively;
if movement is low to high (uphill), it's got to be pushed, active.
9. A high chromosome number is associated with
what type of mutation?
a. Deletion point mutation
b. Extra set of chromosomes
c. Extra or missing chromosome
d. Crossing over mutation
e. Chromosomes mutate by getting high???
...more pieces, more chance for a piece to not go where it's supposed to be
during cell division. Extra in one daughter cell,
missing in the other.
10. The inside layer of a cell membrane stays in
place because it is
a. Covalently bonded
b. Hydrogen bonded
e. Under contract
...it's sandwiched between the hydrophilic layers facing in and out, stable
because there's water there.
11. Chromatin (but not chromosomes) is visible
to a light microscope during
a. Prophase and interphase
b. Metaphase and anaphase
c. Prophase and telophase
d. Anaphase and telophase
e. Is it nice to spy on chromatin?
...that's when it's either condensing on its way to visible chromosomes, or
unwinding back to invisible but usable chromatin.
12. Radiation damage often kills
a. Just before they divide
b. After they divide
c. Just after exposure
d. Weeks after exposure
e. After they become dog-sized and eat people
...it breaks chromosomes, and if they aren't repaired properly, leaves
pieces that can't be distributed correctly during
divisions - that's why radiation illnesses are tied to fast-dividing tissues
and it's used to kill fast-dividing cancers.
13. Okazaki fragments are a feature of
e. Sushi slices
...copying happens on just a small opened area of DNA - because of polarity,
it can happen continuously on one side,
but must be done bit-by-bit (fragments) on the other.
14. A regulatory site would be a
d. Prosthetic group
e. Little government office
...a functional region on an protein molecule (here, used to turn it on and
15. Two research areas very interested in
a. Aging and cancer
b. Alzheimer's and diabetes
c. Birth defects and heart disease
d. Mutations and evolution
e. Erectile dysfunction and megaburping
...non-repair of telomeres may be a big factor in aging, and continuous
repair may allow cancers to grow indefinitely.
16. The purpose of a typical polar body is
a. Increase sperm count
b. Store nutrients
c. Produce spindle
d. Remove unneeded chromosomes
e. Look like it's wearing a tuxedo
...during egg cell production, where only one food-filled egg cell will be
produced, but meiosis divisions have to be done.
17. In dynamic equilibrium,
a. Reactant amounts equal product amounts
b. Reaction rates are equal forward and backward
c. Flux rates are equal across and back
d. Particle amounts are equal on both sides of a barrier
e. It sounds like it was named by an ad executive
...both equilibria are about rates, but dynamic is about reactions.
18. In group translocation, which two
functions occur together?
a. Transport through membrane and chemical change
b. Osmosis and diffusion
c. Synthesis and breakdown
d. Messenger RNA production and DNA replication
e. You stick them on a bus and drive them somewhere
...carriers are also enzymes.
Pick NINE questions to answer in the spaces provided.
NOTE: if you answer MORE than nine, only the first nine will be corrected.
Four Points each. Partial credit is possible.
1. What are
the two functional ends of transfer RNA?
Attaches to codon of mRNA
Carries in amino acid to attach to
2. What are two totally different ways to
move materials around in the cytoplasm?
In endoplasmic reticulum
3. What is a turnover number?
...how many substrate molecules an enzyme molecule can process per
4. What are two different functions of
Attach to and move chromosomes
Attach to membrane for anchoring
5. What are
two different organelles found inside both
prokaryote and eukaryote cells?
6. For apoptosis -
Cell dies on purpose /
programmed cell death /
Lysosomes (release digestive enzymes)
7. What are two different ways that
fresh-water organisms prevent damage from osmosis?
Pump water back out (contractile
Cell containers that won't break from
exactly would a cell be in trouble if its chaperonins weren't
...since chaperonins make sure new proteins take on their proper
functional shapes, new proteins wouldn't work and do what the cell needs
to be done.
|9. What is likely
to be a major function in a cell with lots of -
(Process materials for release)
Absorption or secretion
(Increase surface area for movement in or out)
10. Name two different enzymes that are
active in DNA replication.
Topoisomerase (unravels DNA from
Helicase (gets strands apart)
Primase (gets RNA primers attached)
DNA polymerase (makes new strand on old strand)
11. What can be typically expected from a
chemical reaction if you run it at a temperature that is 10o
...that's the Q10,
and usually the rate doubles.
genes are short sequences that get involved in transcription.
What are two?
Boundary Elements / Insulators
13. In the dialysis tubing lab experiment,
maybe the sugar flux was too slow to show up in the time allotted. What
are two different reasons why the iodine flux might have been faster?
Think of things that affect flux rates.
The particles of iodine might have
been much smaller
The concentration of iodine (and
therefore the relative concentration across the membrane) might have
been much higher.
are the two main molecular components of chromatin?
two point mutations involve a frame shift?
This is a change that changes all of the
"downstream" codons because they start in a different spot.
(shifts the codon starts back a space)
(pushes the codon starts down a space)
this DNA code and the
attached to the back of the exam, give the coded amino acid
Strand T A C G C T
A G T G C T T A T G T G C A T T G C A T C
AUG CGA UCA CGA
AUA CAC GUA ACG UAG
Select and answer completely any four of the following
Note: if you answer more than four, only the first four will be corrected.
Seven Points Each. Partial credit is possible.
1. For dynamic equilibrium -
Reaction rates forward
|One way to
Keep adding substrates.
delay it -
2. For the two cell organelles that are
thought to have started as endosymbionts:
indicates that it once was a prokaryote
(Give 2 different features)
Very similar structure to existing
chemistry to existing prokaryotes.
Have small prokaryote chromosomes in
3. Fill in the arrow-headed labels on this drawing of
eukaryote cell structures.
This was a
drawing with different organelles and such pointed at.
Use links in the book to get familiar with how
|3. Describe the
of three different types of membrane proteins.
small enough and properly charged in and out
(Pores / channels)
Open on command to allow particles
Grab and move particles through
React to external stimuli
Move materials against concentration
Produce chemical changes
4. Give three sets of differences between
Always many on a cell
Rarely more than 12 on a cell
Often not well-coordinated
Tend to stroke
Tend to spin
Do not have add-on structures
May have add-on structures
three sets of differences between the chromosomes of -
Only one per cell
Usually in matched pairs
Often produce plasmids
Do not produce plasmids
Genes for pathway enzymes are usually
together, in pathway sequence
Pathway enzyme genes often randomly
6. Briefly describe three different ways that
enzymes can be inhibited.
Inhibitor molecule attaches in active site
attaches, not in active site but blocking access to it
Inhibitor molecule attaches to enzyme,
changes shape, including active site shape
7. In the graph below of Michaelis-Menten
Kinetics, explain why the curve is doing what it's
doing at each marked point, in terms of the enzyme molecules at work.
Along the top flat part Enzymes are all
busy all the time
so adding substrate can't speed the reaction.
Where the rising curve begins to flatten out
Enzymes are getting too busy, hard to get
them to work faster with more substrate.
As the curve rises steeply Many
enzymes available - more substrate gets quickly processed, increasing
Substrate Concentration (as Enzymes remain constant) ---->
Answer as many or as few as you wish. You can't lose points on
the rest of the exam by getting these wrong. Partial credit is possible.
Explain the evolutionary significance of position effect. Three Points.
What was recently discovered about related genes in eukaryote nuclei? Three
Why are chromosomes in drawings almost always shown in double-stranded form?
What cell structure apparently has no name? Three Points.
Some people feel that the appearance of exons and introns in organisms in the
distance past led to complex life. Why would they be important? Three Points.
What evidence supports the idea that a fusion event happened during human
evolution? Three Points.
What organisms seem to be "okay" with polyploidy mutations? Three Points.
What seems to be the limiting factor in many ocean algae populations? Three
What other processes follow a Michaelis- Menten pattern? Two Points Each, up to
What happens during crossing over that helps solve a huge question about
evolution? Three Points.