BI 173 - First Exam - 1998
ANSWER KEY
NOTE: “e” answers are never the correct answer.
___C___ 1. A number of unused or poorly-used niches in an area often sets up an opportunity for
a. Mutations
b. Recombination
c. Adaptive radiation
d. Genetic drift
e. Vigorous scratching (got a niche?)
...as new species adapt into the available niches...
...in males, X traits cannot be covered by the other X alleles - there aren't any
___D___ 3. The main reason that proteins can serve so many different purposes is the vast number of different
a. Elements in the protein molecules
b. Amino acids in each molecule
c. DNA sequences used to produce them
d. 3-Dimensional shapes they can have
e. Credit cards they carry
...the functions go along with the shapes
___A___ 4. A cell that is full of Golgi bodies is most likely doing what kind of job?
a. Secretion
b. Respiration
c. Absorption
d. Swimming
e. Something very poorly paying
...out of the notes...
___B___5. When it is said that one allele is dominant over another, recessive one, what is really happening?
a. Only that one allele is being
expressed
b. That allele's protein has an effect that overwhelms the other allele's
protein
c. Both alleles are really identical
d. They are not being expressed at the same time
e. It beats it up and takes its lunch money
...dominance is all about what the protein can do...
___C___6. The idea that there are natural controls on populations is attributed to
a. Lyell
b. Lamarck
c. Malthus
d. Wallace
e. There are?
...he's the population guy you're supposed to know...
___A___7. Which type of molecule is most likely to be used as a quick energy source?
a. Carbohydrate
b. Protein
c. Lipid
d. Nucleic acid
e. The hyper ones
...out of the notes / book
___B___8. Which part of Darwin's ideas on evolution can be traced back to Charles
Lyell?
a. Selection can change traits
b. Slow processes can produce big
changes
c. Traits get passed on
d. Populations are naturally controlled
e. The really stupid ones
...he's the uniformitarianism (everything changes slowly & steady) guy
___D___9. The advantage of electron microscopes over light microscopes is related to the
a. Imaging screen
b. Nature of the stains used
c. Vacuum in the viewing chamber
d. Size of the basic imaging beam
e. Well, it's new, it's cool, it's up to date - what's not to like?
...a tiny electron beam gives better resolution than a bigger light beam
...the "value" of everything evolutionary is dictated by circumstances
___B___11. In an experiment, a control will provide
a. A chance to repeat the results
b. A comparison for the results
b. An explanation for observations
d. Something to actually test
e. A little dial-thingy to turn
...from notes / book
___C___12. Which cell structures are involved in making protein using RNA code?
a. Lysosomes
b. Vacuoles
c. Ribosomes
d. Mitochondria
e. The protein-making-whatsis
...from notes / book
___D___13. New traits that seem to "appear" in a group most likely originated from
a. Diploid speciation
b. Crossing over
c. Founder effect
d. Mutation
e. A mail-order catalog
...it could be a unique recombination, but "new" stuff often
goes with
new / changed / mutated alleles
___B___14. If a material is moved by active transport, it would move
a. From a high concentration area to a low concentration area
b. From a low concentration area to a high concentration area
c. In both directions equally
d. By dissolving through the lipid membrane
e. Whenever the materials it's staying with booted it out
...passive moves according to the diffusion rules (a); active the opposite
___A___15. The number of chromosomes an organism characteristically has involves evolution
that balances between
a. Recombination possibilities and ease of cell division
b. The chance of mutation and the exact duplication of offspring
c. The needs of metabolism and the size of the nucleus
d. The numbers of individuals and the type of reproduction used
e. The nature of these questions and my descent into madness
...from the advantages / disadvantages of high or low numbers
___B__16. In the fluid mosaic model of the cell membrane, the mosaic part is played by
a. DNA
b. Embedded proteins
c. Phospholipids
d. Ribosomes
e. The Artist Formerly Known as Prince
...the fluid part is b; none of the others is in the membrane
___D___17. Most fossilized organisms died in an area with
a. Volcanoes
b. Tar pits
c. Mud flats
d. Bodies of water
e. Low property values
...fossils most commonly form from sediments...
___C___18. Water moves from fresh, almost-pure pond water into the cytoplasm of an ameba
because of
a. Active transport
b. Exocytosis
c. Osmosis
d. Speciation
e. It's much less boring there
...it's following diffusion rules, but it's water, and gets the special name
Short Answer.
Partial credit is possible.
1. Very briefly describe what occurs during:
Meiosis I: Homologous pairs are set up and separated; 2N cell becomes 2 1N cells
2. What are two types of temporal isolation?
...use of a different time of
day, or year; altered reproductive schedules
3. What are two major uses for lipids in living things?
...longterm energy storage,
waterproofing, insulation, hormones, cell membranes
4. How does the imaging system of a scanning microscope work?
...the beam bounces off the
surface of the specimen (reads as a 3D image)
5. What is the significance of "XX - X0?"
...gender determined with 2
sex chromosomes in one sex but only one in the other
6. What was meant by the expression "ontogeny recapitulates
phylogeny?"
...the course of embryo
development replays the species' evolutionary history
7. Why is genetic redundancy such an important aspect of NeoDarwinian theory? What
aspect of evolution does it explain?
...it tells how new traits
can develop from old ones while the old ones still exist (copies
of the traits' genes are used for the new traits, while the originals
keep doing their jobs)
8. What existing idea was seriously challenged when fossils of extinct animals were first
found?
...it was accepted that the animals of Eden were perfect creations of God and could not go extinct
9. What was Alfred Russel Wallace's contribution to the theory of evolution by natural selection?
...he sent his version to be published, which got Darwin to publish his as well, and then write the book that got the theory widely accepted| CILIA | FLAGELLA |
| Smaller; Always many on a cell |
Larger; Rarely more than a few on a cell |
| Always simple in
structure |
May have complex added structures |
...a controlled experiment or
the collection of controlled "real world" observations
12. The branches or breaks in a cladistics diagram represent what event?
...the "appearance"
of new traits that are characteristic of the "new" group
13. Of the three types of bonds that hold molecules together, which two are the most
important in biological systems?
...covalent, which
hold the molecules together, and hydrogen, which give them their
functional shape (since ionic bonds mostly break in water, they don't do
much)
14. What are two components of the cytoskeleton?
...could be microtubules, microfilaments, or intermediate filaments
...from the space dust that
the Earth formed from
16. How is the nuclear envelope structurally different from the cell membrane (other than
where it is)?
...it is
actually two membranes
17. Fill in: A __codon____ is a 3-base sequence in the molecule
____DNA____ that
represents a single _amino acid_ in a _protein_.
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.
Six Points Each. Partial credit is possible.
1. For each type of reproduction, give the requested information.
| ASEXUAL | SEXUAL |
| Definition: Offspring
are genetic copies of the original.
|
Definition: Offspring are a genetic mix from 2 sources (remember, 2 parents are not needed!) |
| Advantage over sexual: It can
make exact copies of successful forms.
|
Advantage over asexual: It produces great variation among offspring (good for evolution) |
| Disadvantage vs sexual: Small
variety makes offspring
much more vulnerable to changes |
Disadvantage vs asexual: Even very successful forms cannot be exactly reproduced. |
| Competition.
Those better able to compete are more likely to survive and reproduce. |
Advantages. Relates to ability to better deal with the current environment. |
| Selection. The "weeding
out" of those who are not as well-suited to the current
conditions. |
Inheritance. The ability to pass advantages on to offspring, who then are more likely to survive and pass them on. |
| Spread of traits. Each
generation of offspring will, as a group, reflect these new
advantages more and more. |
Speciation. The new "typical" individual in the group will become different enough from the "typical" ancestor that a new species can be recognized. |
Law of Segregation - Alleles paired in parents separate, and only one will be passed on to any offspring, who get one of each pair from each parent.
Law of Independent Assortment - Unlinked alleles will be passed on
randomly to offspring - none are more likely to go on than any other.
| 4.Type of structure | Definition | Type of evolution |
| HOMOLOGOUS |
Built from the same basic structure |
Often divergent. |
| ANALOGOUS |
Having a similar function |
Convergent. |
|
Population must be quite large, have no mutations, have random mating,
have no migration in or out, have no natural selection acting on it.
|
| Includes: Unique chemistry; a complex, heirarchical organization; |
| Ability to reproduce & pass on traits; ability to metabolize (utilize energy); |
| presence of life cycle; ability to interact with environment; |
| ability to evolve. |
| 1. Heterotrophs, even before cells | 2 Prokaryotes, the first actual cells | 3 Autotrophs, when the soup started to run out |
| 4. Aerobic respiration, when the autotrophs built oxygen levels | 5 Eukaryotes, advanced cells | 6 Cambrian Explosion, multicelled animals |
...they can survive with no
or little change.
...they can survive with
major changes.
...they can go extinct
NO KEY FOR BONUS QUESTIONS...
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.
What very common group is the center of an "are they really alive or not?" debate because several of the "basic characteristics" of life don't quite fit them? Three Points.
When chemists set up the pH scale, where did they get the numbers of the scale from (not what
do the numbers mean, acid - base - neutral, but why did acids wind up less than 7, neutral at 7,
and bases above 7)? Three Points.
Describe the type of active transport that is at the center of a terminology dispute. Three
Points.
The primordial soup theory solved a huge problem that the "origins of life" theorists couldn't
previously solve. What was it? Four Points.
Gregor Mendel worked out his Laws of Inheritance with pea plants. Why was he working with
pea plants? Three Points.
Why was it considered necessary to hire "Captain's companions," such as Charles Darwin? Four
Points.
Under what general conditions might an organism's evolution produced a non-evolving species?
Four Points.