SC 135 - Third Exam 1999
Answer Key
MULTIPLE CHOICE.
On the line to the left, place the letter of the choice that best answers the question.1. Setting up an effect to control a reaction is known as
____C_____ a.
Activation
b.
Optimization
c. Feedback
d. Cofactoring
e. Taking the easy way out
...the reaction, directly or indirectly, produces the effect -
as the effect drops, the reaction is made to increase,
and vice versa.
2. Spindle fibers are a type of
____A_____ a.
Microtubules
b.
Chromosomes
c. Membrane
d.
RNA
e. New candy
...one of several microtubule usages.
3. A karyotype is
____B_____ a. Way of doing
photosynthesis b. Overall
chromosome analysis
c. Feature of light
energy
d. Anaphase structure
e. What airline people call the bags you stuff under your seat
...match the term to a description.
4. Occam’s razor
_____D____ a. Appears during
anaphase
b. Explains how light frequency and wavelength relate
c. Is part of the Krebs Cycle
d. Advises that the simplest explanation is usually right
e. Could be found in Occam’s medicine cabinet
...match the term to the definition.
5. The various roles or "jobs" performed by living things in the environment:
____B_____ a. Ecoroles
b.
Niches
c.
Homologies
d. Fixations
e. Don’t know, but the want ads must be weird!
...or the definition to the term.
6. Which would have been energy sources for the development of the first "living" molecules?
____B_____ a. Oxygen & Primordial
Soup
b. Sun & volcanic vents
c. Water & organic
molecules
d. ATP or glucose
e. What, Niagara Mohawk wasn’t around -?
...only b and d involve energy at all, and d requires advanced life.
7. Oxygen debt involves
____A_____ a. A buildup of lactic acid in muscle
cells
b. Removal of light during photosynthesis
c. Early aspects of the Heterotroph Hypothesis
d. Optimal respiratory enzyme levels
e. Another of those weird investment companies
...which needs to be processed with oxygen later.
8. A dark surface absorbing light and giving off heat is an example of
____D_____ a.
Conversion
b. Potential energy
c. Electron
transport
d. Reradiation
e. The existence of slackers in nature
...on type of radiation in, a different type out = reradiate.
9. Meiosis produces
____C_____ a. 4 diploid
cells
b. 2 diploid
cells
c. 4 haploid cells
d. 2 haploid
cells
e. Your what does what -?
...2 divisions, 4 cells, each with just one set of chromosomes.
10. The animals that survived the Cretaceous Extinction
that killed most of the dinosaurs
were most likely
____A_____ a. Small
scavengers
b. Small plant-eaters
c. Sea
animals
d. Single-celled
e. Out of town at the time
...least affected by having the plants knocked out for a significant
period of time.
11. Bioaccumulation occurs with
____C_____ a. Chlorophyll and
sunlight
b. The light independent reaction
c. Nutrients and
pollutants
d. Anaerobic respiration
e. Some of the stranger mutual funds
...they are what can build up in individuals over time and up a
food chain.
SHORT ANSWER.
Answer any ten of the following questions for 7 Points
Each.
Note: if you answer more than ten, only the first ten will be
corrected.
1. Define mutation.
...a change in DNA at any level (from molecule components to whole chromosomes)
2. Briefly explain what a coupled reaction is.
...an exergonic reaction supplies energy to an exergonic reaction.
3. When, where, and why are polar bodies made?
|
WHEN - |
WHERE - On the very edge of the egg cell |
WHY - |
4. In double-stranded chromosomes, the strands are called chromatids , and are
connected by a structure called a centromere .
5. Of autotrophs and heterotrophs, which...
... have the greatest number of species? heterotrophs (more niches to occupy)
... makes up most of the Earth’s biomass? autotrophs (base of entire food chain)
6. Chromosome are only visible as actual features during cell division. Why are they in a visible form at that time? What purpose is served?
...they are tightly packed to be easily moved around the cell - can't tangle up with each other.
7. What are the four levels of a simple food chain?
|
PRODUCERS |
> |
PRIMARY |
> |
SECONDARY, |
> |
DECOMPOSERS |
8. What are two things that happen to the high frequency radiation from the Sun when it reaches the Earth?
...it gets reflected, absorbed by the atmosphere, absorbed by water, absorbed by the land surface, absorbed by living things.
9. What is activation energy?
...the energy needed to get a chemical reaction started.
10. What are histones?
...proteins around which DNA is wrapped and packaged in a cell.
11. What are two different ways that anaerobic organisms have an impact on humans?
...they are used commercially in alcoholic beverages, baking, yogurt, cheeses, etc.
...they live in our colons and help do some jobs for us.
...some can produce illness, such as botulism or tetanus.
12. What are the two types of dietary nutrients that act as cofactors in enzyme reactions?
...minerals and vitamins.
13. Define alternation of generations.
...each lifetime has a sexual reproduction stage and an asexual reproduction stage.
14. What are two different ways that organisms can determine gender in species that have genders? (A way would explain how both sexes appear.)
...with unmatched chromosome pairs; with a singlet-double chromosome process; with a chemical / genetic reaction to environmental factors.
15. What are the three jobs performed by codons?
...mark the beginning of a gene, code for amino acids in a protein, mark the end of a gene.
16. The lesser photosynthetic pigments, carotenoids , reflect mostly reds, oranges, and yellows
and absorb mostly greens and blues
.
17. When only 2% of the energy in the light that hits chlorophyll winds up in chemical bonds, what, according to the laws of thermodynamics, happened? Both laws are at work here.
...the other 98% is not taken in and used or is lost as heat in the processing.
18. In chemical evolution, what are two ways that a molecule can compete with another molecule?
...compete for raw materials, by picking them up, holding them, or processing them faster or more efficiently, can compete through faster reproduction, can compete by trying to consume each other or resist consumption.
LONG ANSWER.
Answer any four of the following questions for 16
Points Each.
Note: if you answer more than four, only the first four
will be corrected.
1. For the steps in aerobic respiration:
|
Step Name: |
Where in cell: |
Brief description of what happens: |
|
GLYCOLYSIS |
Cytoplasm |
Glucose is broken into 2 3-carbon molecules; 2 ATP netted |
|
KREBS CYCLE |
Mitochondria |
3-carbon molecules broken down to carbon dioxide; a couple of ATPs and lots of electrons freed |
|
ELECTRON TRANSPORT CHAIN |
Mitochondria |
Electrons used to produce many ATPs; oxygen picks up electron-carrying hydrogen, producing water |
2. For the main photosynthesis reactions:
|
Name: |
Parts of Overall Reaction Used or Produced: |
Substep Names: |
| LIGHT-DEPENDENT REACTION |
Light, Water Used |
Electron Transport Chain Calvin Cycle |
LIGHT-INDEPENDENT REACTION |
Carbon Dioxide Used; Glucose Produced |
Carbon Fixation |
3. What two important but very different jobs are done by cells in interphase?
The cell's regular functions, PLUS preparation for division if one is coming.
4. Step-by-step, describe how meiosis differs from mitosis. You only have to deal with the steps that meiosis does differently.
Done through 2 divisions. First prophase pairs homologous chromosomes, which never happens in mitosis. Metaphase I puts the pairs in the cell equator, where crossing over can occur, and anaphase separates pairs but not chromosome strands. From telophase on, cells are haploid.
5. Fill in the blanks about the process of protein production.
Messenger RNA (what?) is made from one side of DNA in the nucleus (where?);
it moves out to cytoplasm / ribosomes (where?), at which point transfer RNA molecules bring
in the amino acid molecules which will bind together to form a protein.
6. What are four different ways that, under normal conditions in nature, an enzyme can be "turned off."
|
Molecule blocks substrate access to active site by attaching there directly |
Molecule attaches to enzyme and changes its shape, including shape of active site |
|
Molecule blocks substrate access to active site |
Molecules attach to substrate so it can't fit in active site |
7. For the four phases of mitosis (remember, one of the phases is not part of division!), name the phases in order and for each one, describe one thing that occurs only during that phase.
|
PROPHASE
|
Many choices - chromatin and chromosomes become visible to a light microscope; spindles form; nuclear envelope disappears; spindles attach to and move chromosomes... |
|
METAPHASE
|
Chromosomes occupy the cell equator; the chromatids separate into individual chromosomes and start to separate. |
|
ANAPHASE
|
Chromosomes are pulled to the poles; cell plates start to form in plant cells. |
|
TELOPHASE
|
Many choices - nuclear envelope reforms; spindles detach from chromosomes and break down; chromosomes unwind to chromatin and disappear to light-microscope view... |
NO KEY for BONUS QUESTIONS.
Answer as many as you are able. Wrong answers will not result in points being lost from the main exam.
What two areas of human health may be greatly affected by research on telomeres? Four Points each.
Explain why radiation affects cancer cells much more than most regular body cells - what exactly is happening to kill the cancer but leave the other cells relatively unaffected? Ten Points.
What is the main advantage (Six Points) and the main disadvantage (Six Points) to being warm-blooded?
The first theories on the origin of Life on Earth had to come up with a way for autotrophs to "spontaneously" arise. Why was that thought necessary? Four Points.
What two-step process (combining of two separate processes) might have led to the evolution of photosynthesis? Six Points.
What process (give the steps) leads to the turning of the leaves in the fall? Six Points.
It is thought that Adirondack lakes are "dying off" due to acid rain. What other explanation could be likely? Six Points.