BI 171 - Third Exam - 2004
Answer Key
Multiple Choice.
Place the letter of the choice that
best answers the question on the line to the left.
Two Points Each. NOTE: "e" answers are never the correct answer.
___A___ 1. After being filtered through the kidneys, sugar must be recovered by the blood - sugar moves from the filtrate, where there is more, into the blood, where there is less, past the equilibrium point and on until all of the sugar has left the filtrate for the blood. This is done by
a. Passive transport, then active transport
b. All passive transport
c. All active transport
d. Active transport, then passive transport
e. It’s never a good thing when the question is this long...
...as long as movement is from higher concentration to
lower, it's
diffusion and passive; when it's from lower to higher, it's active.
___D___ 2. Animal cells lack cell walls because they need
a. More protection
b. Better transfer of nutrients
c. Less protection
d. Freer movement
e. To use the wall money for video games
...of the multicellular groups, plants and fungi can
have all their
cells "locked" together with cell walls, but animals need more
movement / flexibility available.
___B___ 3. The activation energy of a reaction can be lowered by
a. Adding substrate
b. Enzymes
c. Heat
d. Inhibitors
e. Bargaining it down
...all of the others can affect a reaction, but
enzymes, as catalysts,
affect it by lowering activation energy.
___A___ 4. Peroxisomes are associated with
a. Recycling of materials
b. Digestion
c. Movement
d. Reproduction
e. Blonde cell highlights
...connect the structure to one of its functions.
___B___5. Which help things move inside a cell?
a. Cilia & flagella
b. Microtubules & endoplasmic reticulum
c. Chromosomes & mitochondria d.
Nucleolus & vesicles
e. Levers & pulleys
...the microtubules act as "conveyor belts" to
literally pull things around;
things move often through the internal channels of ER.
___D___6. Which process occurs in mitochondria?
a. CO2 + O2 -------- > H2O
+ C6H12O6
b. C6H12O6 + H2O --------
> CO2 + O2
c. CO2 + H2O -------- > C6H12O6
+ O2
d. C6H12O6 + O2 -------- >
CO2 + H2O
e. Little of this, little of that --------> Whole bunch of the other
...2 levels to this question: you need to know
that mitochondria are
the site of aerobic respiration and you need to recognize that process.
___B___7. When chromosomes are double-stranded, each strand is a
a. Chromosome
b. Chromatid
c. Centromere
d. Glycocalyx
e. Bit embarrassed
...it's term & definition.
___A___8. For many reactions, the Q10 is about
a. Two
b. Ten
c. Twelve
d. Zero
e. To make me scream
...raising the reaction temperature 10 degrees
C usually doubles
the rate, and the Q10 is the change of rate under those
conditions.
___C___9. Which structures have a lot of RNA in them?
a. Mitochondrion & chloroplast
b. Lysosome & chromosome
c. Nucleolus & ribosome
d. Flagella & cilia
e. The gooey ones
...the nucleolus stores and processes RNA in
the nucleus; the ribosome
is a complex of proteins and RNA that processes RNA to produce
protein.
___B___10. In order for a mutation to have a significant biological effect, it needs to
a. Be dominant
b. Change tertiary structure
c. Follow Michaelis-Menten rules
d. All of these
e. Fill out the right bureaucratic forms
...it needs to change the effect of the coded
protein, and for that a shape
change is required.
___A___11. DNA replication produces
a. A strand one way and Okazaki fragments the other way
b. Okazaki fragments both ways
c. Strands both ways
d. Histone bits one way and Okazaki fragments the other way
e. Utter confusion and absolute panic
...because strand-building has a particular
polarity / directionality,
a strand can be built continually in one direction but has to be
built in strips on the other side - it has to wait for a stretch to open
and then add an Okazaki fragment up to the "beginning" of the
previous stretch.
___A___12. High chromosome numbers can produce problems during
a. Cell division
b. DNA copying
c. RNA production
d. Expressing genes
e. Assignment of jersey numbers
...that's the time when the number of
DNA pieces - they need to be
moved and copies need to be distributed properly - is an issue.
___C___13. DNA polymerase begins to do its job where this molecule hooks to the DNA.
a. Helicase
b. Telomerase
c. Primase
d. Topoisomerase
e. Imreallydeaderase
...Primase attaches the molecules to the gene
("primes" it) that the
polymerase needs to hook to to start making a copy strand.
___B___14. In prokaryotes, duplicate chromosomes separate by attaching to
a. Spindle fibers
b. The membrane
c. Centrioles
d. Nothing
e. Cells with money
...there are two membrane-mounted
chromosome-binding structures;
each is on opposite ends of the cell, so that when each is engaged
and the cell divides, each new cell has a chromosome.
___D___15. Which is the most logical feature of a cell whose main function is absorption?
a. Cell wall
b. Lysosomes
c. Cilia
d. Microvilli
e. It’s very self-absorbed
...absorption occurs across the membrane
surface, and microvilli increase
membrane surface.
___B___16. Metals and minerals often show up in biological systems as part of
a. Vitamins and salts
b. Cofactors and prosthetic groups
c. Vitamins and cofactors
d. Carbohydrates and nucleic acids
e. The Sludge of Life
...cofactors are small mineral-containing
molecules (or just mineral ions);
prosthetic groups are complexed on proteins and often contain minerals.
___C___17. In a ______ reaction, the ______ reaction feeds energy into the _______ reaction.
a. Linked...exergonic...endergonic
b. Linked...endergonic...exergonic
c. Coupled...exergonic...endergonic
d. Coupled...endergonic...exergonic
e. Relationship...dumb male...outraged female
...you need to know the term, and which one
releases energy while the
other absorbs energy.
___A___18. Cell membrane phospholipids are made up of
a. Glycerol, 2 fatty acids, and a phosphate group
b. 3 lipid molecules plus an ATP
c. Cholesterol and a nucleotide
d. 1 lipid molecule plus 3 ATPs
e. Well, there’s the phospho, and a lip, and the id...
...it's a lipid with a phosphate where one of the 3 fatty acids should be.
Short Answer.
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. Briefly describe how two different types of indirect enzyme inhibition work. | |
| Molecule binds to enzyme away from active site but blocks substrate access. | Molecule binds to enzyme and changes its shape, including the shape of the active site. |
| 2. What are two different ways that the flux of a particular type of molecule into a cell can be increased? This has to include things that cells can reasonably do. That means that raising the temperature (not something cells do) or changing the particle size (you're working with a particular type of molecule) wouldn't be an answer. | |
| Increase the gradient. This can be done by changing or sequestering the incoming molecules, dropping their internal concentration. | Increase the surface across which the flux is moving. |
| 3. What are two different features that cilia and flagella have in common? | |
|
Surrounded by membrane. Long thin projections (similar shapes even if they are different sizes). |
Microtubule core (same 9 + 2 arrangement). |
| 4. What are two ways that a chemical reaction can be kept from reaching dynamic equilibrium? | |
| Remove products. | Add reactants. |
| 5. What are two different ways that prokaryote chromosomes differ from eukaryote chromosomes? | |
|
They are loops (instead of 2-ended). They work directly with ribosomes (instead of at a distance from inside the nucleus). |
They are single (not homologous pairs). They don't have centromeres (copies separate). They may produce plasmids. |
| 6. Briefly explain the
adaptive significance of introns and exons. ...they allow the production of varied proteins (like antibodies) from just a few genetic stretches, as bits are left or subtracted to change the protein structure. |
|
| 7. What are two cell organelles that should be more numerous in cells that produce secretions? | |
|
Golgi bodies, since they package secretions. |
Ribosomes, which make the secretion components in the first place. Possibly endoplasmic reticulum, moving the components to the packagers. |
| 8. In the fluid mosaic model of the cell membrane, explain what’s meant by - | |
| The
The phospholipids, which flow around fluid each other, held in place by their part? hydrophobic nature. |
The
The embedded molecules, mostly mosaic various types of proteins. part? |
| 9. What does MTOC stand
for? ...Microtubule Organizing Center. |
|
| 10. Give one thing each that happens during interphase - | |
| Division-
DNA is copied and related: division-related structures are made. |
Non- Division- Cell does its "regular" functions related: (its job, whatever that is). |
| 11. For homeothermic, or so-called "warm-blooded" organisms, give a metabolic - | |
| ADVANTAGE
Enzymes are always TO at optimum temperature. HOMEOTHERMY |
DISADVANTAGE
Requires a lot of energy TO = fuel and oxygen. HOMEOTHERMY |
| 12. What, exactly, is an
allele? ...it is a variant of a particular type of gene code. The DNA sequences vary in different alleles. |
|
| 13. What are dynein and
kinesin? ...molecules involved in the movement function of microtubules.
|
|
| 14. What are two different parts that all cells, no matter the type, have in common. | |
|
Membranes. Chromosomes. |
Ribosomes. |
| 15. What are two different types of vacuoles? | |
|
Food. |
Contractile. |
Long Answer.
Select and answer completely any four
of the following questions.
Note: if you answer more than four, only the first four will be
corrected.
Seven Points Each. Partial credit is possible.
| 1. Give three sets of differences between - | ||||
|
CILIA |
FLAGELLA |
|||
| Smaller | Larger | |||
| On cells in large numbers | Rarely more than 12 on a cell | |||
| No added structures | May have added structures | |||
| Tend to stroke | Tend to spin | |||
| Usually act in coordinated fashion | Often not coordinated | |||
| 2. Give three different ways of adapting to hypotonic conditions, and for each give an example of an organism that uses that adaptation. Shown are groups from which examples can be drawn. | ||||
| Rigid barriers that restrict cell expansion | Freshwater plants | |||
| Pumps to remove incoming water (contractile vacuoles, kidneys, etc) | Freshwater protists, freshwater fish | |||
| Waterproofing | Freshwater fish | |||
| 3. Answer for the endosymbiont theory - | ||||
|
What two organelles does the theory apply to? |
Mitochondria
|
Chloroplasts | ||
|
What are two features of the organelles / pieces of evidence that support the theory? |
Homologous features with prokaryotes
|
|||
|
Homologous chemistry with prokaryotes |
Have prokaryotic DNA
|
|||
| 4. Give four different functions performed by proteins embedded in cell membranes. | ||||
| Pores or channels, constantly open, to allow materials in | Gates that open and close to allow materials in | |||
| Receptors for environmental signals | Markers for cell-cell recognition | |||
| Carriers to help move restricted materials | Pumps to actively move materials against flux | |||
| 5. For each X mark on this graph of Michaelis-Menten Kinetics, explain what is happening on the molecular level to produce the slope of the curve in that particular spot. | ||
|
All enzymes are active all the time,
|
||
| 6. For the graph of pH effects on an enzyme-catalyzed reaction, explain what’s happening on the molecular level at each spot marked with an X. | ||
| The marks are on each slope and the central peak. On the lower slope, a deficiency of H+ affects hydrogen bonds and denature the enzyme molecules (more to each side); on the upper slope, an excess of H+ does the same thing. At the peak, all of the enzyme molecules are the right shape and so are all working best.
|
||
| 7. For each stage of actual mitosis(INTERPHASE is NOT), name the stages in order and for each describe one thing that happens only during that stage. | ||
| PROPHASE | Chromosomes condense. Nuclear envelope disappears. Spindle forms. Chromosomes move toward middle of cell. | |
| METAPHASE | Chromosomes settle in middle plane of cell. Strands separate at centromere. | |
| ANAPHASE | Chromosome strands migrate away from each other. Cell plate forms in plant cells. | |
| TELOPHASE | Chromosomes unwind. Nuclear envelope reappears. Spindle disappears. Cell may divide. | |
| 8. Two different things that happen during transcription in a cell. | DNA strands open at gene. Promoter helps set beginning of transcription. Messenger RNA gets made, leaves nucleus. | |
| Two different things that happen during translation in a cell. | Messenger RNA moves to ribosome. Transfer RNA brings in amino acids. Chaperonin helps new protein fold properly. | |
No Key for BONUS QUESTIONS.
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.
In genetics, what is the location effect on expression? Three Points.
For Two Points each, what letters are used to represent reaction rates?
How does compartmentalizing a cell contribute to efficiency in its chemistry? Three Points.
What two high-funding research areas are interested in telomeres? Two Points each. For Three Points each, what is each area trying to accomplish with the telomeres?
What are anticodons? Three Points.
What sorts of chemicals often show an ability to irreversibly inhibit enzymes? Three Points.
Intermediate filaments are classified two different ways, according to what two parameters? Two Points each.
What evolutionary implication can be taken from the fact that actin molecules are remarkably similar in a wide variety of organisms? Three Points.
It turns out that mitochondria do have their own particular ribosomes. Why was it logical to expect that? Four Points.