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2002 Clemson Biology Merit Exam #
Clemson University Biology Merit Exam
12 April 2002
Please choose the best answer for each of the
following questions. Questions marked with an "*" are worth
4 points each; questions marked with a "#" are worth 2
points each; the unmarked questions are worth 1 point
each.
CAUTION: Incomplete erasures and smudges can be read as
marks. To avoid having a choice read incorrectly, make your
marks lightly at first. After you have made all your
changes, blacken in your marks just before you turn in your
answer sheet.
The theme of this exam is that annoying and sometimes
dangerous vine, poison ivy:
1. Poison ivy belongs to the Kingdom
a) Plantae. b) Angiospermae. c) Eucarya. d) Chlorophyta.
2. The Latin name of poison ivy is Toxicodendron
radicans. These two names, respectively, are the
a) species and genus. b) genus and specific epithet.
c) genus and species. d) species and race.
3. The custom of naming species with two names as shown
above was originated by
a) Francis Bacon. b) Chares Darwin.
c) Carolus Linnaeus. d) Louis Pasteur.
# 4. Poison ivy belongs to the
sumac family, the Anacardiaceae, which has about 600
species. Poison ivy in the US has seven varieties; two are
Toxicodendron radicans radicans (plant 1) and
Toxicodendron radicans verrucosum (plant 2). The
sumac family also contains poison sumac (Toxicodendron
vernix, plant 3) and a Florida plant called poison-wood
(Metopium toxiferum, plant 4). Of these four plants,
you would expect the fewest DNA similarities between
plants
a) 1 and 2. b) 2 and 3. c) 3 and 4. d) 1 and 3.
*5. A book on poisonous plants
lists 68 unrelated families in which poisonous plants are
found. However, most of the plants in these 68 families are
not poisonous. This seems to be evidence that being
poisonous
a) evolved independently in many different plant
lineages.
b) gives a plant species a decisive selective advantage.
c) arose before most current plant families evolved.
d) is not controlled by the genetics of a plant.
#6. Poison ivy cells would
have ..., but human cells would not.
a) an endoplasmic reticulum b) a cell wall
c) mitochondria d) a membrane-bound nucleus.
#7. The picture below shows an
important poison ivy cellular process--making ... . The
organelle shown in the picture is a
a) proteins ... ribosome. b) enzymes ... Golgi
apparatus.
c) starch ... centriole. d) ATP ... mitochondrion.
# 8. In the picture above, the
"beaded" molecule that is emerging from the organelle is ...
and the long, ribbon-like molecule is
a) a protein ... DNA. b) cytochrome ... starch.
c) a polypeptide ... mRNA. d) a carbohydrate ...
amylase.
*9. Poison ivy contains large
amounts of both of the molecules 1 and 2 below. The first
molecule has a long hydrocarbon tail attached at its bottom
left, and the second one is part of a very long series of
units like the three shown.
Molecule 1
Molecule 2
These two molecules are ... and ..., respectively.
a) ATP and starch. b) DNA and RNA.
c) glucose and fructose. d) chlorophyll and cellulose.
#10. We would expect to find
most of the first molecule above in a poison ivy cell's ...,
and the second molecule would be found in its
a) nucleus ... ribosomes. b) mitochondria ... food
vacuoles.
c) chloroplasts ... cell walls. d) nucleus ...
lysosomes.
*11. The "protoplast" of a
plant cell includes the cell membrane and everything inside
it. Human red blood cells are isotonic to a 0.85% NaCl
solution. A botanist places some poison ivy tissue (with
intact cell walls) in this solution, and the cell
protoplasts inside the cell walls neither swell nor shrink.
From these data alone, she can conclude that poison ivy
cells are ... to human red blood cells.
a) isotonic b) either isotonic or hypertonic
c) either isotonic or hypotonic d) either
hypotonic or hypertonic
*12. The botanist collects
further data on the equilibrium volume of the poison ivy
cells in several different solutions:
With these new data, we can conclude that poison ivy
cells are ... to human red blood cells.
a) hypertonic b) isotonic c) hypotonic
d) None of these. The new data do not show a pattern
consistent with osmosis.
#13. Like most plants, poison
ivy produces its own complex organic molecules by
photosynthesis. This means that it is a(n)
a) autotroph. b) heterotroph. c) mixotroph. d)
homotroph.
#14. Photosynthesis is an ...
reaction, meaning that the products contain ... bond energy
than the reactants did.
a) exergonic ... more b) exergonic ... less
c) endergonic ... more d) endergonic ... less
*15. The graphs below show
three curve shapes that depict either how absorption of
light or photosynthesis might vary with light color in a
green poison ivy leaf. "VBGYOR" gives the colors of light as
violet, blue, green, yellow, orange and red.
The absorption of light by a poison ivy leaf varies with
light color as in curve ... above; the photosynthesis of the
leaf varies with light color as in curve
a) 1 ... 2. b) 1 ... 3. c) 3 ... 1. d) 3 ... 3.
*16. The botanist who did the
osmotic experiment on the poison ivy cells then performs a
photosynthetic experiment. She puts a poison ivy plant in a
sealed container for five days in its natural location on
the edge of a forest. The record of
O2 concentration in the
container is as follows:
Here, the numbers on the x axis are hours since the start
of the experiment, and the light and dark bars underneath
represent periods of daylight and darkness, respectively.
Oxygen rises in the container in periods when ...; it falls
in periods when
a) respiration exceeds photosynthesis ... photosynthesis
exceeds respiration.
b) photosynthesis exceeds respiration ... respiration
exceeds photosynthesis.
c) respiration is occurring ... photosynthesis is
occurring.
d) photosynthesis (but not respiration) is occurring ...
respiration (but not photosynthesis) is occurring.
#17. The strange results around
72 hours could be explained by a
a) very cloudy day.
b) cool day when respiration was low but photosynthesis was
high.
c) sunny day when the plant's stomata were wide open.
d) a hot, sunny day when respiration and photosynthesis both
went up by the same amount.
*18. Notice that the oxygen
plateaus on some days (that is, it never gets higher than a
certain concentration). This could be caused by the fact
that
a) CO2 in the chamber is
all taken up before the day is over.
b) a high oxygen concentration stimulates plant
respiration.
c) plants that have high sugar concentrations respire
more.
d) All of these could limit oxygen increase per
day.
*19. If we were to graph many
observations of the concentration of
O2 in the chamber against
simultaneous observations of the concentration of
CO2 in the chamber over
the five days above, we would see a pattern like
#20. Photosynthesis generates
oxygen mostly directly because
a) CO2 is reduced by the
light-independent reactions.
b) ribulose bisphosphate has five carbons but glucose has
six.
c) the light-dependent reactions split water.
d) oxygen is the final electron acceptor in
photosynthesis.
#21. Poison ivy often climbs up
tree trunks. When a plant stem grows up, this is called ...
geotropism and is caused mainly by different amounts of ...
on the top and bottom of the stem.
a) positive ... gibberellins b) negative ... auxins
c) positive ... cytokinins d) negative ...
oligosaccharins
*22. A poison ivy vine can get
as thick as a person's wrist. If such a thick, woody vine
were cut, the bulk of the vine cross-section would consist
of ... . On the other hand, if a thin, growing tip of a
poison ivy vine were cut, most of the cross-section there
would consist of
a) secondary xylem ... parenchyma. b) parenchyma ... primary
phloem.
c) parenchyma ... sclerenchyma. d) ovary wall ...
endosperm.
#23. In trying to decide
whether poison ivy is a monocot or a dicot, it is relevant
to consider the fact(s) that poison ivy has
a) net-veined leaves. b) secondary growth.
c) a corolla with 5 petals. d) All of these.
*24. Poison ivy is poisonous
because of a heavy, yellow oil called urushiol. This oil is
a mixture of catechol molecules with slightly different side
chains; an example is
The side chain is a long hydrocarbon chain. Urushiol is
probably water-... because it
a) soluble ... has a hydrogen:carbon ratio greater than
2:1.
b) soluble ... has a benzene ring.
c) insoluble ... mostly consists of a highly nonpolar
hydrocarbon chain.
d) insoluble ... is such a large molecule.
#25. Some people are so
sensitive to urushiol that their skin will erupt in blisters
if they are exposed to as little as 2 micrograms. This is
about 1/30 of the weight of a single grain of table salt. If
urushiol has a density of 1 g/mL, like water, then 1 mL of
urushiol contains ... effective doses of 2 micrograms
each.
a) 5 million b) 500,000 c) 500 d) 0.5
26. Contrary to popular belief, the urushiol does not appear
on the surface of undamaged leaves. It is carried in resin
canals near the phloem of the leaf, stem, and fruit, and
only would be on the leaf surface if the leaf is injured
somehow. The normal function of phloem in a plant is to
a) transport organic material. b) synthesize poisonous
oils.
c) absorb water from the soil. d) make gametes.
*27. When urushiol gets on
human skin, it penetrates the top layer of skin cells and
binds to cells deep in the epidermis within about 30
minutes. After this, the urushiol is almost impossible to
wash off. Urushiol itself is harmless, but now the trouble
begins as a cell-mediated immune response is mounted against
all cells that have urushiol on their membranes. This causes
tissue destruction and blistering. This cell-mediated
response will consist mostly of
a) abundant production of antibodies by plasma cells.
b) lysing of affected cells with perforins from cytotoxic
T-cells.
c) a release of histamine from B-cells.
d) enormous production of immunoglobulins by
erythrocytes.
*28. Of course, the poison ivy
symptom that most people notice is itching. The reason for
the itching is not understood, but it must somehow involve
stimulation of sensory neurons in the skin. The inflammation
... the permeability of sensory neuron membranes to ... and
causes the initiation of an action potential.
a) increases ... potassium b) decreases ... sodium
c) decreases ... potassium d) increases ... sodium
*29. When the person scratches
the itchy area, a sequence of events leads to muscle
contraction. Consider this list of events:
1. Calcium ions spill from sarcoplasmic reticulum.
2. Troponin moves aside to reveal actin active sites.
3. Myosin attaches to actin.
4. ATP is split and ADP and inorganic phosphate are
released.
5. Myosin heads bend.
The correct order of these events is
a) 1 2 3 4 5 b) 3 1 2 5 4 c) 3 1 5 2 4 d) 1 3 2 5 4
#30. The body attempts to limit
the damage of poison ivy by secreting anti-inflammatory
hormones called corticosteriods. These also suppress the
immune response that causes the rash. These hormones come
from the ... gland.
a) pituitary b) adrenal c) thyroid d) pineal
31. Ironically, we don't know why poison ivy produces
urushiol. It is not to protect the plant, because many kinds
of mammals and birds eat poison ivy berries without ill
effect. If a raccoon eats a poison ivy berry, and assuming
that raccoon digestion is similar to human digestion,
protein in the berry will be attacked by enzymes for the
first time in the raccoon's
a) mouth. b) stomach. c) small intestine. d) large
intestine.
32. The raccoon needs to eat protein because protein
supplies it with
a) vitamins. b) carbohydrates. c) amino acids. d)
purines.
*33. Some people seem to be
immune to poison ivy. Which of the following is the most
convincing explanation of immunity? "Resistant people don't
have
a) cytotoxic T cells that secrete perforin."
b) a sufficiently high albumin concentration in the
blood."
c) helper T cells that recognize urushiol."
d) erythrocytes that secrete immunoglobulins."
#34. Assume that resistance to
poison ivy is controlled at one X-linked locus, and the
resistance allele is completely dominant. If a resistant man
marries a heterozygous resistant woman,
a) all their offspring will be resistant.
b) all their sons will be resistant, but all their daughters
will be sensitive.
c) half their sons and all their daughters will be
resistant, but half their sons will be sensitive.
d) all their daughters will be resistant, and all their sons
will be sensitive.
*35. Another way of being
resistant to poison ivy is to be able to break down the
urushiol before the immune system recognizes it. Say that
urusiol is broken down by an enzyme controlled at a single,
autosomal locus. Furthermore, there are three phenotypic
classes in the general population: rapid degraders (who show
few poison ivy symptoms), slow degraders (who show
intermediate symptoms), and nondegraders (who show full
symptoms). If we perform electrophoresis on the enzyme in
each of these phenotypic classes, we see the following:
The empty rectangles represent the loading wells. These
data are consistent with the idea(s) that
a) both nondegraders and rapid degraders have the same
enzyme but different genotypes.
b) each enzyme contains four subunits, and its effectiveness
depends on the number of efficient subunits that it has.
c) the enzyme locus can hold four possible alleles, and each
allele produces an enzyme with a different
effectiveness.
d) slow degraders are heterozygotes that make both an
effective and an ineffective enzyme.
36. The gene for one form of this enzyme begins with the
sequence ACTTAG. This segment of DNA codes for ... amino
acids and would be transcribed into the RNA
sequence
a) 2 ... UGAAUC b) 3 ... ACUUAG
c) 3 ... UGAAUC d) 2 ... GATTCA
#37. Some people can get poison
ivy in their respiratory tracts from inhaling smoke that
contains urushiol on tiny particles of soot. This is a
serious problem for firefighters who control forest fires.
If a smoke particle is being inhaled and it has just
passed the larynx, it will next encounter the
a) trachea. b) pharynx. c) alveoli. d) sinus cavities.
38. If the poison ivy rash is scratched excessively, it can
lead to bacterial infection. Bacteria are ... cells, which
means that they don't have
a) prognathic ... DNA. b) eukronic ... ribosomes.
c) prokaryotic ... nuclei. d) intronic ... messenger
RNA.
39. If a doctor wants to identify the bacteria that have
infected a wound, he might determine whether the bacteria
are Gram-positive or Gram-negative. This is decided by
determining whether or not the bacteria
a) have flagella. b) are colored by a certain dye.
c) are resistant to a certain antibiotic. d) can form
spores.
40. Poison ivy functions in an ecosystem as one of the
a) primary producers. b) primary consumers.
c) secondary consumers. d) decomposers.
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