Exam 1 - Zoology 250
version D
Instructor: John Godwin, Fall 2006
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This exam has 6 pages, Please check that your copy is complete.
Terminology/Short answer - These questions require terms or brief answers. (16
questions + 2 bonus questions, 1 pt. each except where noted, 28 total pts plus two bonus)
1. An elephant weighs approximately 200,000 as much as a mouse. Would you expect that the
elephant’s total energy consumption would be 200,000 times that of a mouse (answer ‘yes’
or ‘no’ for 1 pt)? Explain briefly why this would or would not be the case (1 pt, 2 pts total
for this question).
No, it would less than 200,000 times that of a mouse. This is because the elephant’s
‘specific metabolic rate’ is much lower than that of a mouse (~1/10th).
2. Is the epithelium of the stomach of the ‘simple’ or ‘stratified’ type? (1 pt) Why would you
expect the type of epithelium that is found there (i.e., why the type you indicated [‘simple’ or
‘stratified’] rather than the other choice?) (1 pt, 2 pts total for this question)
Stratified. This epithelium must be many cell layers thick (i.e., stratified) to avoid
destruction in the harsh environment of the stomach.
3. Give an example of a ‘zymogen’ and briefly note their importance (i.e., why a zymogen?).
Several are possible (Pepsinogen, Trypsinogen, Chymotrypsinogen,
Procarboxypeptidase are all ones we talked about). The release of these enzymes in
inactive form is important for avoiding digestion of the digestive system itself. Note:
Prothrombin is also a good example here.
4. What are the four main processes/stages in animal nutrition? (i.e., the four main things or
actions that happen when animals obtain and process nutrients). Single word answers for
each process/stage are acceptable. (1/2 pt each, 2 pts total for this question).
Ingestion, Digestion, Absorption, Elimination
5. What four features of the small intestine increase its internal surface area? (1/2 pt each, 2 pts
total)
- it is long, has folds in the walls, has villi, and has microvilli (elaborations of the surface
area of each epithelial cell).
6. What is the health significance of the bacterial species Helicobacter pylori?
This bacterium is very important in the development of ulcers.
7. Tadpoles are herbivorous while frogs are carnivorous. What basic intestinal change is seen
at metamorphosis and why does this ‘make sense’ functionally?
The intestine shortens as the animal transforms from being a herbivore to being a
carnivore (plants are harder to digest than animal material).
8. The spaces occupied by osteocytes in bone are termed lacunae while the connections
between them are termed Canaliculi. (1 pt each, 2 pts total)
9. List two reasons why it is important to have living cells in bone (i.e., two functions this
serves). (2 pts total)
- Several are possible here: Growth, Repair, Mobilizing minerals, a point can also be
given for blood formation
10. Imagine you are a sports physiologist and an ambitious young runner comes to you seeking
advice about whether she should focus on sprint or distance events. You decide to do a
biopsy of her leg muscles in order to provide better informed advice. What is the main thing
you would be looking for (1 pt) and why (1 pt)? Is it possible to substantially affect this
characteristic by training or is it determined by something else? (1 pt). (3 pts total)
The proportion or amount of fast and slow twitch fibers (also okay if myosin type is
indicated as these are related to fiber type). The reason for this is that the proportion of
fiber types is relatively fixed and sets limits on performance from that muscle, even with
training. For example, muscles that are mainly fast twitch are good for rapid, powerful
contractions. This would be good for a sprinter, but not for a distance runner.
11. The term for the type of skeleton found in earthworms: Hydrostatic.
12. The structures that prevent backflow from the ventricles to the atria during the cardiac cycle
are termed the: atrioventricular or ‘AV’ valves
13. List the three ways in which the exchange of gases and other substances is maximized across
the walls of capillaries. (hint: think ‘DAnG’). (3 pts total)
Distance: capillary walls are very thin, Area: we have an enormous number of
capillaries, providing a huge surface area for exchange, Gradients: Constant
movement of blood prevents equilibrium from being reached between the blood and
cells outside the bloodstream.
14. What is the term for the specialized epithelium that lines our circulatory system?
Endothelium
15. The minimum number of capillary beds a blood cell leaving the heart of a mammal will cross
before returning to the heart is One. For a fish, this number is Two. (1/2 pt each, 1 pt total)
16. What are the three main steps in the clotting reaction? (3 pts)
1) Clotting factors are released (okay to mention platelets, but not necessary), 2)
prothrombin is converted to the thrombin (the active form of this protein), 3) fibrinogen
is converted to fibrin (soluble fibrinogen here to insoluble fibrin)
Bonus 2: On the axes to the right here, show two
things. Using a dashed line, show the
relationship between muscle and water temperature
in a fish that does not have a countercurrent heat
system. Using a solid line, show this relationship
for a fish, like a big tuna, that does have such a
system. Both lines should be straight.
Muscle temperature
Bonus 1: Why might the aversion that pregnant women often have to spicy foods be adaptive?
The compounds that make foods spicy are plant toxins and this aversion appears to
prevent pregnant women from exposing the developing fetus to these toxins.
Water temperature
Multiple Choice Section (28 questions, 1 pt each)
1. I am doing version __ of this exam: a) A,
b) B,
c) C,
d) D
2. In order to maximize diffusion across an epithelium where exchange by diffusion takes place,
you would expect that the thickness of the epithelium would be ______ and the total area of
this epithelium would be ______
a) maximized, minimized
b) maximized, maximized
c) minimized, minimized
d) minimized, maximized
3. When a substance (e.g., oxygen) reaches equilibrium concentrations across a membrane
where diffusion takes place, there is no net diffusion of that substance across the membrane.
a) This statement is true,
b) This statement is false
4. Compared to a small organism of similar shape, the surface area to volume ratio of a large
organism will be _____:
a) Larger, b) Smaller, c) No difference
A
Oxygen consumption
5. Which of the lines on the figure to the
right here accurately shows the general
relationship referred to as the ‘Q10’ rule?
(choose the letter next to the line for your
answer)
a) A
b) B
c) C
d) None of the three lines
B
C
Temperature
6. Which structure prevents the entry of food into your trachea (windpipe) during feeding?
a) Glottis, b) Epiglottis, c) Hypoglottis, d) Bronchi, e) Larynx
7. When eating an apple, you typically bite off a chunk with your incisors and then chew it with
your molars and premolars. This specialization is an example of the _______ dentition we
mammals show.
a) Homodont, b) Heterodont, c) Isodont, d) Thecodont,
e) Homotypic
8. Digestion of which major nutrient type begins in the stomach?
a) Carbohydrates,
b) Lipids,
c) Nucleic acids,
d) Proteins,
e) Vitamins
9. Which of the following is the primary site of nutrient absorption in the mammalian digestive
system?
a) Pharynx, b) Stomach, c) Small intestine, d) Large intestine, e) Pancreas
10. Maintenance of diffusion gradients in the small intestine depends most directly on which of
the following structural features of this organ?
a) Villi, b) Lacteals, c) Visceral peritoneum, d) Circular and longitudinal muscles in
walls
e) Pyloric sphincter
11. Digestion of which major nutrient type depends heavily on the process of emulsification?
a) Carbohydrates,
b) Lipids,
c) Nucleic acids,
d) Proteins,
e) Bile salts
12) The diarrhea that is a symptom of diseases like cholera is due to problems in the function of
which digestive organ?
a) Stomach,
b) Small intestine, c) Large intestine, d) Appendix, e) Gall bladder
13) The thick filament is composed of _____ molecules
a) Actin, b) Myosin, c) Troponin, d) Tropomyosin,
e) Thrombin
14) Crossbridges form between _____ and _____ during muscular contraction
a) Actin, myosin,
b) Actin, tropomyosin,
c) Myosin, troponin,
d) Myosin, tropomyosin,
e) Troponin, calmodulin
15) In muscle function at the sarcomere level, the binding of ___ ions to ____ regulates the
formation of crossbridges
a) calcium, troponin,
b) calcium, tropomyosin,
c) calcium, myosin,
d) sodium, troponin,
e) sodium, tropomyosin
16) Release of crossbridges depends most directly on _____
a) Calcium ions, b) Potassium ions, c) Adenosine diphosphate
d) Adenosine triphosphate, e) Creatine phosphate
17) Endurance training (e.g., jogging/running) produces which of the following changes in the
muscles involved?
a) Increases in mitochondria
b) Increases in vascularization/capillary density
c) Increases in myoglobin
d) All of the above
e) None of the above
18) When undergoing strength training, the number of _____ in each _____ undergoes a/an
_____.
a) Myofibrils, muscle fiber, decrease
b) Myofibrils, muscle fiber, increase
c) Sarcomeres, myofibril, decrease
d) Muscle fibers, muscle, increase
e) Motor units, muscle, increase
19) You find a new species of mouse that sprints extraordinarily rapidly compared to the house
mice you are familiar with. On examining its leg muscles, you expect to find increases in
which of the following muscle constituents compared to ordinary house mice?
a) Slow twitch fibers
b) Fast twitch fibers
c) Sarcoplasmic reticulum
d) All of the above
e) B and C, but not A
20) The fluids that are lost across capillary walls are returned to the circulatory system by:
a) The hepatic portal vein
b) The hypothalamo-pituitary portal vein
c) The kidneys
d) The lymphatic system
e) None of the above
21) Imagine your patient experiences a loss of blood, reducing blood pressure. Given what you
know about fluid movement across capillary walls, which of the following is most likely?
a) The amount of fluid lost across the capillary walls will increase
b) The amount of fluid lost across the capillary walls will decrease
c) The amount of fluid lost across the capillary walls will not change.
22) Now, imagine instead that your patient has been given a large infusion of water rather than
saline, decreasing the osmotic concentration of the blood. Again, given what you know
about fluid movement across capillary walls, which of the following is most likely?
a) The amount of fluid lost across the capillary walls will increase
b) The amount of fluid lost across the capillary walls will decrease
c) The amount of fluid lost across the capillary walls will not change.
23) Compared to closed circulatory systems, open circulatory systems are typically ____ and
_____.
a) Low pressure and large volume
b) Low pressure and small volume
c) High pressure and large volume
d) High pressure and small volume
e) No difference between the two types in these characteristics.
24) The main structural difference between an open and a closed circulatory system is in the
presence or absence of ______:
a) capillaries,
b) arteries,
c) veins,
d) a heart
25) Imagine a red blood cell leaving the Right ventricle of your heart. Which chamber of the
heart will that cell return to first?
a) Right atrium,
b) Right Ventricle,
c) Left Atrium,
d) Left Ventricle,
e) Impossible to say from information given
26) Now imagine instead a red blood cell leaving the Right ventricle of the heart of a human
embryo at approximately 7 months of development (i.e., still in utero). Would this cell
definitely first return to the same chamber of the heart you indicated for your answer above?
a) Yes,
b) No
27) Arteries tend to have _____ walls than veins, partly reflecting their function as a _____
resevoir.
a) Thicker, pressure
b) Thicker, blood
c) Thinner, pressure
d) Thinner, blood
e) Leakier, blood
28) The key function of the atrioventricular node is to:
a) Speed up the conduction of the electrical impulse to contract as is passes from the atria to
the ventricles
b) Slow down the conduction of the electrical impulse to contract as is passes from the
atria to the ventricles
c) Act as a barrier that prevents the conduction of the electrical impulse to contract as is
passes from the atria to the ventricles
d) Not alter the speed at which the electrical impulse to contract passes from the atria to the
ventricles
e) Block backflow of blood from the aorta into the right ventricle