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2004 Clemson Biology Merit Exam
Clemson University Biology Merit
Exam
26 March 2004
Please choose the best answer for each of the
following questions. Questions marked with a "*" 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
answers. 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 sea turtles, large turtles of warm
seas that make epic migrations, but return to the beach of
their birth to lay their eggs.
Loggerhead sea turtle, Caretta caretta.
The loggerhead is named for its exceptionally large
head.
1. Sea turtles and humans ... to the same
kingdom.
a) belong b) don't belong
2. The animal below that is most distantly related to
sea turtles is a(n)
a) robin. b) kangaroo. c) octopus. d) lizard.
3. All turtles belong to the Order Chelonia. The taxon that
is the next up in size from an order is a ...; the taxon
that is the next lower in size from an order is a
a) species ... phylum. b) class ... family.
c) kingdom ... phylum. d) class ... species.
4.* Sea turtles are
well adapted for life in the ocean. Their front legs are
modified into flippers that can propel some species through
the water as fast as 35 mph! The flippers are very similar
to penguin wings and the fins of whales and sharks. Because
birds, turtles, whales, and sharks are only distantly
related, we would say that their flippers/fins/wings are so
similar due to
a) divergent evolution. b) diversifying selection.
c) convergent evolution. d) stable polymorphism.
Leatherback sea turtle, Dermochelys coriacea.
Leatherbacks lack a hard shell, are the largest sea turtles,
and eat only jellyfish.
5.* Sea turtles tend
to be large. A leatherback, pictured above, may reach 2,000
pounds and be 10 feet long! That is, it may weigh ... kg and
be ... meters long.
a) 60 ... 5.4 b) 900 ... 3.0 c) 775 ... 4.8 d) 1,250 ...
7.1
6. A leatherback can eat twice its weight in jellyfish each
day. Could you imagine a human who ate 200-300 pounds (twice
his weight) of meat each day? The leatherback probably needs
to eat such great quantities of jellyfish because
jellyfish
a) are mainly water.
b) have toxic nematocysts.
c) have high amounts of vitamins.
d) harm many useful animals.
7.# Like penguins, whales, and
humans, sea turtles breathe air. This leads to sea turtle
deaths when the turtles become entangled in fishing nets and
cannot get to the surface. If a human inhaled air, the air
would go through or past the ... last.
a) bronchiole. b) trachea. c) pharynx. d) glottis.
8. A sea turtle can store large amounts of oxygen in its
muscles and blood. In humans, the protein that serves this
oxygen-storing function is
a) collagen. b) albumin. c) hemoglobin. d) perforin.
9.# Both turtles and humans use
the oxygen in air as a(n)
a) energy source. b) reducing agent.
c) energy storage compound. d) final electron acceptor.
10.# The step(s) of cellular
respiration that directly use(s) the oxygen is (are)
a) glycolysis. b) the Krebs cycle.
c) electron transport. d) All of these.
11.# Oxygen that has been used
in the process(es) in question 10 turns to
a) water. b) glucose. c) carbon dioxide. d) pyruvate.
12.* When a sea
turtle swims, it must take a breath of air every few
minutes. However, when it is sleeping on the bottom, it can
go without breathing for as long as two hours. If we monitor
the oxygen consumption and CO2 production of a
sea turtle swimming at various speeds, we should see a
pattern like
13.* In addition to
being an air-breathing animal in the ocean, sea turtles have
an osmotic problem. Sea turtles evolved on land drinking
fresh water, and went back into the ocean about 150 million
years ago. Thus they are similar to humans in that their
cells are ... to seawater, meaning that if their cells were
placed in seawater, they would
a) hypertonic ... expand. b) hypertonic ... shrink.
c) hypotonic ... expand. d) hypotonic ... shrink.
14.# Sea turtles solve this
problem with a "salt gland" behind each eye. This allows
them to drink seawater and yet maintain osmotically correct
body fluids. The salt gland ... the surrounding water.
a) absorbs salt from b) sheds salt into
Hawksbill sea turtle, Eretmochelys imbricata
Hawksbills are hunted for the colorful "tortoise shell"
scutes on their shells.
15.# Sea turtles eat a variety
of foods, but some diets are very restricted. For example,
the huge leatherback eats only jellyfish, and the hawksbill
prefers sponges. Sponges and jellyfish belong to the phyla
..., respectively.
a) Ctenophora and Adenophora b) Porifera and Cnidaria
c) Chelonia and Annelida d) Nematoda and Trematoda
16.# Sometimes sea turtles eat
various kinds of marine trash, such as plastics or globules
of spilled oil. These objects can block its gut. For
example, many leatherbacks die each year when they eat
floating plastic bags that they think are jellyfish. If a
human ate an indigestible item and it lodged in his stomach,
it would probably be closest to his
a) epiglottis. b) appendix. c) pyloric sphincter. d)
scapula.
17.# If a turtle's digestion is
similar to a human's, the first attack on proteins in an
ingested meal would be in the ..., and would result in
a) stomach ... small peptides and amino acids.
b) ileum ... monosaccharides and disacharides.
c) large intestine ... amino acids and monoglycerides.
d) mouth ... steroids and polypeptides.
18.# Sailors in the 16th
century used to use sea turtles to provision their ships
because the sea turtles could stay alive for months without
eating. This most directly implies that, in comparison to
humans, sea turtles have
a) smaller fat reserves. b) more efficient digestive
enzymes.
c) more red blood cells. d) a lower metabolic rate.
Green sea turtle, Chelonia mydas.
This turtle is named after the green color of its
fat.
19.* Fat
a) is water-souble in the cis configuration but
water-insoluble in the trans configution
b) contains carbon, oxygen, hydrogen, and nitrogen in a
6:12:6:1 ratio.
c) is made from glycerol and fatty acids linked by ester
bonds.
d) All of these.
20. The green sea turtle gets its green fat from its diet of
sea grasses and algae, probably due to ... in these plant
foods.
a) rhodopsin. b) chlorophyll. c) carotenoid. d)
cholesterol.
21.* The most common
sea grass in Florida is called turtle grass, Thalassia
testudinum. Turtle grass is a flowering plant, a member
of the Phylum
a) Anthocerotophyta. b) Plantae.
c) Bryophyta. d) Anthophyta.
22.# Turtle grass has
ribbon-like leaves that are about 1 cm wide and 35 cm long.
They grow submerged in sea water, but assume that turtle
grass leaves are like the leaves of terrestrial plants. A
green sea turtle biting into a turtle grass leaf from its
upper surface would bite through the tissues ... in order,
from the top to the bottom of the leaf.
a) epidermis, palisade mesophyll, spongy mesophyll, and
epidermis
b) cortex, epidermis, apical meristem, and palisade
mesophyll
c) sclerenchyma, vascular cambium, xylem, and epidermis
d) epidermis, pith, cortex, and endodermis
23.# Submerged turtle grass
leaves might need to deal with the grazing of hungry green
sea turtles, but they don't have to ..., which is a
major problem of terrestrial leaves.
a) absorb light b) take up carbon dioxide
c) transpire d) synthesize sugar
24.# Sea grasses tend to live
in shallow water because deep water absorbs much of the
available sunlight. Red light is absorbed at shallow depths,
then green light disappears, and blue light penetrates the
most deeply (which is why any light in the deep sea is dim
and blue). This light disappearance pattern is called the
"description" in the answers below. Now consider the
following data on the penetration of light of different
colors in seawater:
Are the left graph and the right graph telling the same
story, and does this story agree with the description above
of what happens to light of different colors in water?
a) Both graphs agree, but they depict a light absorption
pattern the opposite to that in the description.
b) The left graph agrees with the description, but the right
one has an opposite pattern of color disappearance.
c) The right graph agrees with the description, but the left
one has an opposite pattern of color disappearance.
d) Both graphs agree with the light absorption pattern in
the description.
25.# Sea grasses are renowned
for their ability to flourish in water with low nutrient
concentrations, and can take up nutrients through both their
leaves and their roots. If sea grasses are like terrestrial
plants, probably the nutrients taken up in greatest amounts
are
a) iron and silicon. b) nitrogen and phosporus.
c) potassium and vanadium. d) chlorine and molybdenum.
26.* You read that a
Florida sea grass bed has a high primary productivity. This
means, most directly, that it
a) has a high concentration of plant biomass.
b) harbors many animals.
c) plays an important role in the local ecosystem.
d) has a high rate of photosynthesis.
27.* Turtle grass,
like all plants, absorbs sunlight and uses its energy to ...
. Until it can be used in the ... cycle, this energy is
stored in
a) reduce CO2 ... Calvin-Benson ... NADPH and
ATP.
b) oxidize pyruvate ... Krebs ... ATP and the electron
transport system.
c) reduce lactate ... Cori ... alcohol and
CO2.
d) oxidze pyruvate ... Fisher ... ATP and NADH.
28.# Sea turtle mating occurs
at sea, either submerged or on the surface. The male grasps
the female's shell with his front flippers and inserts his
long tail into her body. If sea turtle spermatogenesis is
like human spermatogenesis, the sperm that the male deposits
in the female
a) have chromosomes with two chromatids attached at a
centromere.
b) lack homologous pairs of chromosomes.
c) are diploid.
d) All of these.
29. Once the female mates with a male, he swims away. She
will then mate with several other males, and may store these
sperm for months before fertilizing her eggs with a mixture
of them. This multiple mating probably benefits the
population by
a) increasing the diversity of the offspring.
b) removing deleterious mutations from the gene pool.
c) removing sperm that are damaged.
d) allowing only the best eggs to begin development.
30.* Next, the female
sea turtle must produce mature eggs. In humans, which of the
following happens before ovulation occurs?
a) FSH causes follicle growth.
b) Luteinizing hormone spikes in a sudden peak.
c) Estrogen rises slowly and then falls suddenly.
d) All of these.
31.* In humans,
combination birth control pills work by
a) occupying progesterone receptors with a progesterone
antagonist.
b) lysing the follicle with a high concentration of
calcium.
c) suppressing FSH secretion.
d) causing chromosome breakage in the early zygote.
32.* One of the most
studied aspects of sea turtle behavior is nesting. Perhaps
decades after being born on a certain beach, and months
after mating offshore, female sea turtles return to that
same "natal" beach to lay their eggs. Slowly, usually at
night, the female crawls out of the surf and onto dry sand.
This is an enormous effort, especially for the huge
leatherback sea turtle. If muscle contraction in sea turtles
works like that in humans, the actual shortening of
sarcomeres occurs when
a) myosin heads bend.
b) actin coils into its low-energy conformation.
c) ATP is used a create a phosphodiester bond between actin
and myosin.
d) calcium ions polymerize to link actin and myosin.
 
A female sea turtle crawls up on a moonlit beach and digs a
nest.
33.# Sea turtles on land
cannot back up, and if they encounter something that blocks
them on the beach, they may be trapped and die the following
day from overheating in the sun. Turtle enzymes would cease
functioning in hot conditions because
a) they would saturate with substrate.
b) their tertiary structure would change.
c) acidic amino acids in the enzyme would convert to either
neutral or basic amino acids.
d) the enzyme's affinity for its substrate would increase so
much that the substrate would be taken up and then not
released.
34.* Eventually, the
female finds a suitable spot, digs a nest in the sand, and
deposits 80-120 eggs. Then she buries the eggs in the nest,
and throws sand in all directions to hide the nest from
predators. Finally, she returns to the ocean, and makes no
effort to care for her young. Only about 1 in 1,000 baby
turtles will survive to adulthood. An adult female might
nest like this every year for several decades, and might
live to be 100 years old. We would say that sea turtle life
history pattern is ... because of the huge number of young
and their high mortality, but is more ... because of the
adult's long life and many clutches of eggs.
a) big bang ... semelparous. b) iteroparous ...
semelparous.
c) r-selected ... K-selected. d) K-selected ...
r-selected.
35.* An article says,
"Molecular analysis shows that sea turtle populations are
genetically distinct, supporting the idea that females
return to their natal beach." Given the information above
about sea turtle mating, what do these molecular results
probably show?
a) There are certain RFLPs that appear in the females that
return to a certain beach, but these RFLPs are not found in
females on other beaches.
b) All the females that return to one beach are genetically
identical.
c) Sea turtles from different natal beaches cannot
interbreed with one another.
d) Sea turtle males, who don't return to a natal beach, are
more genetically similar than sea turtle females, who do
return to natal beaches.
36. A short section of sea turtle DNA has the sequence
CTAGTC. The complementary DNA has the sequence ... and could
potentially code for ... amino acids.
a) GATCAG ... 2 b) CUACUG ... 3
c) CTGATC ... 3 d) GATCAG ... 1.
37. The turtle eggs develop on the beach for about 60 days.
The sex determination of the turtles is
temperature-dependent. If the sand is hot, the nest will
produce more females, and if it is cool, it will produce
more males. Remember the phrase, "Hot chicks--cool dudes."
This is different from sex determination in humans, in which
sex is determined by the
a) number of autosomes.
b) presence or absence of Barr bodies.
c) presence or absence of an X chromosome.
d) presence or absence of a Y chromosome.
38.* When the sea
turtles hatch, they dig together towards the surface. Then,
once cooling sand shows that it is dark (or that a rainstorm
is going on), they break out of the nest all at once. Moving
through a gauntlet of predators (especially birds, crabs,
raccoons, and dogs), they frantically scurry down the beach
to the surf. They seem to locate the surf by crawling
towards the brightest horizon, which is one reason that
beachfront lighting in places like Florida confuses them and
causes great mortality. A baby turtle can determine that one
horizon is brighter than another one because the brighter
horizon causes ... action potentials to arrive at the optic
lobes of its brain.
a) larger b) more frequent
c) more positive d) more negative
39. * Once in the
water, the turtles swim against the incoming waves. During
the first 48 hours, they continue to suffer high mortality
from large fish and seabirds. Once they are several miles
offshore, they hide in clumps of seaweed and become safer
from predators. After this, the larger they get, the more
immune from predation they are. That is, the survivorship
curve of young sea turtles looks like curve ... below,
and a graph of their mortality rate looks like curve
... below.
a) A ... A b) B ... A c) A ... B d) B ... B
40. Sea turtles born on beaches in Florida may range over
the whole Atlantic Ocean, all the way to Africa. One of the
great mysteries of sea turtle biology is how they manage to
get back to their natal beaches. One theory is that they can
follow the magnetic field of the earth; another is that they
home on the distinct smell of "their" beach. These competing
theories, which we might attempt to test by experiment, are
called
a) nulls. b) treatments. c) hypotheses. d) controls.
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