Download Chemistry of Life Review

Structure and Function of Animals Review: Basic Principles of Animal Form and Function
1. What properties are shared by all types of epithelia?
2. Under what temperature conditions would it benefit a jackrabbit to flatten its ears against its body? Explain.
3. Suppose you are standing at the edge of a cliff and you suddenly slip – you barely manage to keep your balance to keep
from falling. As your heart races, you feel a burst of energy, due in part to a surge of blood into dilated (widened) vessels
in your muscles and an upward spike in the level of glucose in your blood. Why might you expect that this “flight or
flight” response requires both the nervous system and the endocrine system
4. Is it accurate to define homeostasis as a constant internal environment? Explain.
5. Describe the difference between negative feedback and positive feedback.
6. If you were deciding where to locate the thermostat in a house, what considerations would govern your decision? How do
these factors relate to the location of many homeostatic control sensors in the human brain?
7. What mode of heat exchange is involved in “wind chill,” when moving air feels colder than still air at the same
temperature?
8. Flowers differ in how much sunlight they absorb. Why might this matter to a hummingbird seeking nectar on a cool
morning?
9. Suppose at the end of a hard run on a hot day you find that there are no drinks left in the cooler. If, out of desperation, you
dunk your head into the cooler, how might the ice cold water affect the rate at which your body temperature returns to
normal?
10. If a mouse and a small lizard of the same mass (both at rest) were placed in experimental chambers under identical
environmental conditions, which animals would consume oxygen at a higher rate? Explain.
11. Which animal must eat a larger proportion of its weight in food each day: a house cat or an African lion caged in a zoo?
Explain.
12. If you monitored energy allocation in the penguin below for just a few months, the “growth” category might now be a
significant part of the pie chart, even though adult penguins don’t change in size from year to year. What limitation in such
energy budget studies does this lead you to consider?
Structure and Function of Animals Review: Animal Nutrition
1. All 20 amino acids are needed to make animal proteins. Why aren’t they all essential to animal diets?
2. Explain why vitamins are required in much smaller amounts than carbohydrates.
3. If a zoo animal shows signs of malnutrition, how might a researcher determine which nutrient is lacking?
4. Distinguish the overall structure of a gastrovascular cavity from that of an alimentary canal.
5. In what sense are nutrients from a recently ingested meal not really “inside” your body prior to the absorption stage of food
processing?
6. Thinking in broad terms, what similarities can you identify between digestion in an animal body and the breakdown of
gasoline in an automobile? (You don’t need to know anything about auto mechanics.)
7. In the zero gravity environment of space, how does food swallowed by an astronaut reach his or her stomach?
8. What step in food processing occurs more readily for fats than for proteins and carbohydrates?
9. Some early experimenters involved obtaining samples of digestive juices and observing digestion outside the body. If you
mixed gastric juice with crushed food, how far would the process of digestion proceed?
10. What are the two advantages of a longer alimentary canal for processing plant material that is difficult to digest?
11. What features of an animal’s digestive system make it an attractive habitat for mutualistic microorganisms?
12. “Lactose-intolerant” people have a shortage of lactase, the enzyme that breaks down lactose in milk. As a result, they
sometimes develop cramps, bloating, or diarrhea after consuming dairy products. Suppose such a person ate yogurt, which
contains bacteria that produce lactase. Why might you expect that eating yogurt would provide at best only temporary
relief of the symptoms?
13. Explain how people can become obese even if their intake of dietary fat is relatively low compared with carbohydrate
intake.
14. After reviewing the figure below, explain how PYY and leptin complement each other in regulating body weight.
15. Suppose you were studying two groups of obese people with genetic abnormalities in the leptin pathway. In one group, the
leptin levels are abnormally high; in the other group, they are abnormally low. How would each group’s leptin levels
change if both groups were placed on a low calorie diet for an extended period? Explain.
Structure and Function of Animals Review: Circulation and Gas Exchange
1. How is the flow of hemolymph through an open circulatory system similar to the flow of water through an outdoor
fountain?
2. Three chambered hearts with incomplete septa were once viewed as being less adapted to circulatory function than
mammalian hearts. What advantage of such hearts did this viewpoint overlook?
3. The heart of a human fetus has a hole between the left and right ventricles. In some cases, this hole does not close
completely before birth. If the hole weren’t surgically corrected, how would it affect the O2 content of the blood entering
the systemic circuit from the heart?
4. Explain why blood in the pulmonary veins has a higher O2 concentration than blood in the venae cavae, which are also
veins.
5. Why is it important that the AV node delay the electrical impulse moving from the SA node and the atria to the ventricles?
6. After exercising regularly for several months, you find that your resting heart rate has decreased. Given that your body
now requires fewer cardiac cycles in a given time, what other change in the function of your heart at rest would you expect
to find? Explain.
7. What is the primary cause of the low velocity of blood flow through the capillaries?
8. What short term changes in cardiovascular function might best enable skeletal muscles to help an animal escape from a
dangerous situation?
9. If you had additional hearts distributed throughout your body, what would be one likely advantage and one likely
disadvantage?
10. Explain why a physician might order a white cell count for a patient with symptoms of an infection.
11. Clots in arteries can cause heart attacks and stokes. Why, then, does it make sense to treat hemophiliacs by introducing
clotting factors into their blood?
12. Nitroglycerin (the key ingredient in dynamite) is sometimes prescribed for heart disease patients. Within the body, the
nitroglycerin is converted to nitric oxide. Why would you expect nitroglycerine to relieve chest pain in these patients?
13. What is the position of lung tissues within the body an advantage for terrestrial animals?
14. After a heavy rain, earthworms come to the surface. How would you explain this behavior in terms of an earthworm’s
requirements for gas exchange?
15. The walls of alveoli contain elastic fibers that allow the alveoli to expand and contract with each breath. If alveoli lost
their elasticity, how might gas exchange be affected? Explain.
16. How does an increase in the CO2 concentration in the blood affect the pH of cerebrospinal fluid?
17. A slight decrease in blood pH causes the heart’s pacemaker to speed up. What is the function of this control mechanism?
18. Suppose that you broke a rib in a fall. If the broken end of the rib tore a small hole in the membranes surrounding your
lungs, what effect on lung function would you expect?
19. What determines whether O2 and CO2 diffuse into or out of the capillaries in the tissues and near the alveoli? Explain.
20. How does the Bohr shift help deliver O2 to very active tissues?
21. A doctor might use bicarbonate (HCO3-) to treat a patient who is breathing very rapidly. What assumption is the doctor
making about the blood chemistry of the patient?
Structure and Function of Animals Review: The Immune System
1. What are the main advantages and disadvantages of relying on a physical barrier against infection?
2. Although pus is often seen simply as a sign of infection, it is also an indicator of immune defenses in action. Explain.
3. If a microbe grew optimally at low pH how might this affect its ability to act as a human pathogen? Explain.
4. Sketch a B cell receptor. Label the V and C regions of the light and heavy chains. Now mark the positions of the antigen
binding sites, disulfide bridges, and transmembrane regions. How do the positions of these features relate to the location of
the variable and constant regions?
5. Explain two advantages of having memory cells when a pathogen is encountered for a second time.
6. If both copies of a light chain gene and a heavy chain gene recombined in each B cell, how would this affect B cell
development/?
7. If a child were born without a thymus, what cells and functions would be deficient?
8. Treatment of antibodies with a particular protease clips the heavy chains in half, releasing the two arms of the Y-shaped
molecule. How might the antibodies continue to function?
9. Suppose that a snake handler bitten by a particular venomous snake species was treated with antivenin. Why might the
treatment for a second such bite be different?
Structure and Function of Animals Review: Osmoregulation and Excretion
1. The movement of salt from the surrounding water to the blood of a freshwater fish requires the expenditure of energy in the
form of ATP. Why?
2. Why aren’t freshwater animals osmoconformers?
3. Researchers found that a camel standing in the sun required much more water when its fur was shaved off, although its
body temperature remained the same. What can you conclude about the relationship between osmoregulation and the
insulation provided by fur?
4. What advantage does uric acid offer as a nitrogenous waste in arid environments?
5. Suppose a bird and a human are both suffering from gout. Why might reducing the amount of purine in the diet help the
human much more than the bird?
6. Compare and contrast the different ways that metabolic waste products enter the excretory systems of flatworms,
earthworms, and insects.
7. What is the function of the filtration step in excretory systems?
8. Kidney failure is often treated by hemodialysis, in which blood diverted out of the body is filtered and then allowed to flow
on one side of a semipermeable membrane. Fluid called dialysate flows in the opposite direction on the other side of the
membrane. In replacing the reabsorption and secretion of solutes in a functional kidney, the makeup of the starting
dialysate is critical. What initial solute composition would work well?
9. What do the number and length of nephrons indicate about the habitat of fishes? How do these features correlate with rates
of urine production?
10. Many medications make the epithelium of the collecting duct less permeable to water. How would taking such a drug
affect kidney output?
11. If blood pressure in the afferent arteriole leading to a glomerulus decreased, how would the rate of blood filtration within
Bowman’s capsule be affected? Explain.
12. How does alcohol affect regulation of water balance in the body?
13. Why could it be dangerous to drink a very large amount of water in a short period of time?
14. Conn’s syndrome is a condition caused by tumors of the adrenal cortex that secrete high amounts of aldosterone in an
unregulated manner. What would you expect to be the major symptom of this disorder?
Structure and Function of Animals Review: Hormones and the Endocrine System
1. How do the mechanisms that induce responses in target cells differ for water soluble hormones and lipid soluble
hormones?
2. In what way does one activity for prostaglandins resemble that of a pheromone?
3. Which explanation of the distinct effects of epinephrine in different tissues might best account for the distinct effects of
hormones in different species? Explain your answer.
4. In a glucose tolerance test, periodic measurements of blood glucose level are taken after a person drinks a glucose rich
solution. In a healthy individual, blood glucose rises moderately at first but falls to near normal within 2-3 hours. Predict
the results of this test in a person with diabetes mellitus. Explain your answer.
5. What property of a stimulus might make negative feedback less important for a hormone pathway?
6. Consider a diabetes patient who has a family history of type 2 diabetes but is active and not obese. To identify genes that
might be defective in the patient, which genes would you examine first?
7. How do the two fused glands of the pituitary gland differ in function?
8. Suggest a reason why hypothalamic control of oxytocin involves only an inhibiting factor.
9. Propose an explanation for why people with defects in specific endocrine pathways typically have defects in the final gland
in the pathway rather than in the hypothalamus or pituitary.
10. How does the fact that two adrenal hormones act as neurotransmitters relate to the developmental origin of the adrenal
gland?
11. How would a decrease in the number of corticosteroid receptors in the hypothalamus affect levels of corticosteroids in the
blood?
12. Suppose you receive an injection of cortisone, a glucocorticoid, in an inflamed joint. What aspects of glucocorticoid
activity would you be exploiting? If a glucocorticoid pill were also effective at treating the inflammation, why would it
still be preferable to introduce the drug locally?
Structure and Function of Animals Review: Animal Reproduction
1. Compare and contrast the outcomes of asexual and sexual reproduction.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Parthenogenesis is the most common form of asexual reproduction in animals that at other times reproduce sexually. What
characteristic of parthenogenesis might explain this observation?
If a hermaphrodite self fertilizes, will the offspring be identical to the parent? Explain.
How does internal fertilization facilitate life on land?
What mechanisms have evolved in animals with external fertilization and internal fertilization that help ensure that
offspring survive to adulthood?
Suppose you were analyzing chemicals found in the ejaculate of male fruit flies and discovered a peptide that kills
microbes. What hypotheses might you formulate as to the function of this peptide?
In the human sexual response, which organs undergo vasocongestion?
In theory, using a hot tub frequently might make it harder for a couple to conceive a child. Why?
Suppose each vas deferens in a male was surgically sealed off. What changes would you expect in sexual response and
ejaculate composition?
How does the difference in size and cellular contents between sperm and eggs relate to their specific functions in
reproduction?
Oogenesis is often described as the production of a haploid ovum, or egg, by meiosis; but in some animals, including
humans, this is not an entirely accurate description. Explain.
Suppose you are analyzing the DNA from the polar bodies formed during human oogenesis. If the mother has a mutation
in a known human disease gene, would analyzing the polar body DNA allow you to infer whether the mutation is present in
the mature oocyte? Explain.
FSH and LH get their names from events of the female reproductive cycle, but they also function in males. How are their
functions in females and males similar?
How does an estrous cycle differ from a menstrual cycle, and in what animals are the two types of cycles found?
If a human female begins taking estradiol and progesterone immediately after the start of a new menstrual cycle, what
effect on ovulation should she expect? Explain.
Why does testing for hCG (human chorionic gonadotropin) work as a pregnancy test early in pregnancy but not late in
pregnancy? What is the function of hCG in pregnancy?
In what ways are tubal ligation and vasectomy similar?
If a spermatid nucleus were used for ICSI (intracytoplasmic sperm injection), what normal steps of gametogenesis and
conception would be bypassed?
Structure and Function of Animals Review: Animal Development
1. How does the fertilization envelope form in sea urchins? What is its function?
2. Frog zygote and frog blastulas are nearly the same size. Explain this observation.
3. Contrast the effects of cleavage and gastrulation on development of the embryo.
4. Explain how the neural tube forms and how neural crest cells arise.
5. Predict what would happen if you injected Ca2+ into an unfertilized sea urchin egg.
6. How many chorions and amnions are present in the case of conjoined (“Siamese”) twins? (These twins are always
monozygotic.)
7. During formation of the neural tube, cube shaped cells change to wedge shaped cells. Describe the roles of microtubules
and microfilaments in this process.
8. In the frog embryo, convergent extension is thought to elongate the notochord along the anterior-posterior axis. Explain
how the words convergent and extension apply to this process.
9. Predict what would happen if, just before neural tube formation, you treated embryos with a drug that blocks the function
of microfilaments.
10. Although there are three body axes, only two must be determined during development. Why?
11. If the ventral cells of an early frog gastrula are experimentally induced to express large amounts of a protein that inhibits
BMP-4 (bone morphogenic proteins, a family of related proteins with a variety of developmental roles), could a second
embryo develop? Explain.
12. If you removed the ZPA (zone of polarizing activity) from a limb bud and then placed a bead soaked in Sonic hedgehog
(growth factor) in the middle of the limb bud, what would be the most likely result?
Structure and Function of Animals Review: Neurons, Synapses, and Signaling
1. Describe the basic pathway of information flow through neurons that cause you to turn your head when someone calls your
name.
2. One cone snail species is nicknamed the cigarette snail because the victim is said to have just enough time to smoke one
cigarette before dying. What properties of the nervous system account for the rapid action of cone snail venom?
3. How would severing an exon affect the flow of information in a neuron? Explain.
4. Under what circumstances could ions flow through ion channels from regions of low ion concentration to regions of high
ion concentration?
5. Suppose a cell’s membrane potential shift from -70mV to -50mV. What changes in the cell’s permeability to K+ or Na+
could cause such a shift?
6. Suppose you treated a neuron with ouabain, an arrow poison and drug that specifically disable the sodium-potassium pump.
What change in the resting potential would you expect to see? Explain.
7. How does an action potential differ from a graded potential?
8. In the disease multiple sclerosis, myelin sheaths gradually harden and deteriorate. How would this affect nervous system
function?
9. Suppose that a mutation caused gated sodium channels to remain inactivated for a longer time following an action potential.
How would such a mutation affect the maximum frequency at which action potentials could be generated? Explain.
10. How is it possible for a particular neurotransmitter to produce opposite effects in different tissues?
11. Organophosphate pesticides work by inhibiting acetylcholinesterase, the enzyme that breaks down the neurotransmitter
acetylcholine. Explain how these toxins would affect EPSPs (excitatory postsynaptic potentials) produced by acetylcholine.
12. If a drug mimicked the activity of GABA (gamma-aminobutyric acid) in the CNS, what general effect on behavior might
you expect? Explain.
Structure and Function of Animals Review: Nervous Systems
1. Which division of your autonomic nervous system would likely be activated if you learned that an exam you had forgotten
about would start in 5 minutes? Explain your answer.
2. The parasympathetic and sympathetic divisions of the PNS use the same neurotransmitters at the axon terminals of
preganglionic neurons (see below), but different transmitters at the axon terminals of postganglionic neurons. How does
this difference correlate with the function of the axons bringing signals into and out of the ganglia in the two divisions?
3.
4.
Suppose you had an accident that severed a small nerve required to move some of the fingers of your right hand. Would
you also expect an effect on sensation from those fingers?
When you wave your right hand, what part of your brain initiates the action?
5.
6.
7.
8.
9.
When a police officer stops a driver for driving erratically and suspects that the person is intoxicated, the officer may ask
the driver to close his or her eyes and touch his or her nose. When can you deduce from this test about alcohol’s effect on
a particular part of the brain?
Suppose you examine individuals with damage to the CNS that has resulted in either coma (a prolonged state of
unconsciousness) or general paralysis (a loss of muscle function through the body). Relative to the position of the reticular
formation, where would you predict the site of injury to lie in each group of patients? Explain.
How is the study of individuals with damage to a particular part of the brain used to provide insight into the normal
function of that region?
Two brain areas important in the generation or perception of speech are Broca’s area and Wernicke’s area. How is the
function of each area related to the activity of the surrounding portion of the cerebral cortex?
If a woman with severed corpus callosum viewed a photograph of a familiar face, first in the left field of vision and ten in
the right field, why would it be difficult for her to put a name to the face in either field?
Structure and Function of Animals Review: Sensory and Motor Mechanisms
1. Which one of the five categories of sensory receptors is primarily dedicated to external stimuli?
2. Why does eating food containing “hot” peppers sometimes cause you to sweat?
3. If you stimulated a sensory neuron electrically, how would that stimulation be perceived?
4. How are statocysts adaptive for animals that burrow underground or live deep in the ocean?
5. Suppose a series of pressure waves in your cochlea causes a vibration of the basilar membrane that moves gradually from
the apex toward the base. How would your brain interpret this stimulus?
6. If the stapes became fused to the other middle ear bones or to the oval window, how would this condition affect hearing?
Explain.
7. Explain why some taste receptor cells and all olfactory receptor cells use G protein couples receptors, yet only olfactory
receptor cells produce action potentials.
8. Pathways involving G proteins provide an opportunity for an increase in signal strength in the course of signal transduction,
a change referred to as amplification. How might this be beneficial in olfaction?
9. If you discovered a mutation in mice that disrupted the ability to taste sweet, bitter, and umami, but not sour or salty, what
might you predict about where this mutation acts in the signaling pathways used by these receptors?
10. Contrast the light detecting organs of planarians and flies. How is each organ adaptive for the lifestyle of the animal?
11. In a condition called presbyopia, the eyes’ lenses lost much of their elasticity and maintain a flat shape. Explain how this
condition affects a person’s vision.
12. If you perceive an object floating across your field of view, how might you determine whether the image represents a real
object or a disturbance in your eye or a neural circuit of your brain?
13. How can the nervous system cause a skeletal muscle to produce the most forceful contraction it is capable of?
14. Contrast the role of Ca2+ in the contraction of a skeletal muscle fiber and a smooth muscle cell.
15. Why are muscles of animals that have recently died likely to be stiff?
16. In what way are septa an important feature of the earthworm skeleton?
17. Contrast swimming and flying in terms of the main problems they pose and the adaptations that allow animals to overcome
those problems.
18. Suppose you wanted to extend your arm from the elbow by controlling your biceps muscle rather than your triceps. How
could you manage this feat?
Structure and Function of Animals Review: Animal Behavior
1. If an egg rolls out of the nest, a mother graylag goose will retrieve it by nudging it with her beak and head. If researchers
remove the egg or substitute a ball during this process, the goose continues to bob her beak and head while she moves back
the nest. What type of behavior is this? Suggest a proximate and an ultimate explanation.
2. How is migration based on circannual rhythms poorly suited for adaptation to global climate change?
3. Suppose you exposed various fish species to the alarm substance from minnows. Suggest why some species might respond
like minnows, some might increase activity, and some might show no change.
4. How might associative learning explain why unrelated distasteful or stinging insects have similar colors?
5. Clark’s nutcrackers hide tens of thousands of seeds each fall, some of which they never retrieve. Why might there be an
evolutionary advantage for the species if individuals forget the location of some caches?
6. Suppose you designed a laboratory environment using just a few objects as landmarks. How might you position and
manipulate the objects to determine whether an animal could use a cognitive map to remember the location of a food
source?
7. Explain why geographic variation in garter snake prey choice might indicate that the behavior evolved by natural selection.
8. Why is it easier to identify mutations affecting courtship than those affecting other essential behaviors?
9. Suppose that a pair of identical twins reared apart behave identically 80% of the time when performing a particular activity.
What additional information would you need to draw a conclusion about the genetic basis of the behavior?
10. Why does the mode of fertilization correlate to a large degree with the presence or absence of male parental care?
11. n/a
12. Suppose a virus that infected a side blotched lizard population killed many more males than females. How would the
infection immediately affect the competition among the males for reproductive success?
13. What is a possible explanation for cooperative behavior among nonrelated animals?
14. If an animal were unable to distinguish close from distant relatives, would the concept of inclusive fitness still be
applicable? Explain.
15. Suppose you applied William Hamilton’s logic to a situation in which one individual was past reproductive age. Could
there still be a selection for an altruistic act?