BIO 213 Final ?s
1017 Calculate how many different antigen-specific BCRs could exist in (1) a human and (2) a single human B cell
(1) 51*27*6*200=1,652,400 (2) 1
979.9 Suppose that during a detailed anatomical study of a marine invertebrate, you found a small, previously undescribed structure. How would you test the hypothesis that the structure is a gland that releases one or more hormones?
1. remove the structure from some individuals and compare their behavior and condition to sham-operated individuals 2. make a liquid extract from the structure , inject it, and compare behaviors and conditions of subjects injected with saline solution
1028.15 What two conclusions are supported by the results shown below?
1: infection with H polygyrus inhibits the onset of type 1 diabetes in mice that are prone to developing the disease 2: This inhibition does not require lifelong infection, because a two-week infection early in life stills results in protection
(979.2) What is a hormone-response element?
A segment of DNA where a hormone-recpetor complex binds
1007.14 Explain how the pill affects each of the following: (a) maturation of a follicle, (b) thickening if the uterine lining during the follicular phase, (c) probability of ovulation, and (d) volume of menstrual fluid.
A: follicle would not develop bc FSH level is low B: uterine lining will not thicken because the estradiol level during the follicular phase would be low C: Estradiol levels would never be high enough to stimulate LH needed for ovulation, preventing ovulation D: uterine lining will not thicken as mmuch so the amount of menstrual fluid is less
1007.12 Predict the effect of a daily synthetic progesterone pill on (a) pituitary secretion of LH and FSH, and (b) ovarian secretion of estradiol and progesterone.
A:secretion would decline dure to negative feedback by progesterone B: due to decrease in secretion, follicles dont develop, and estradiol and progesterone is not secreted
(978.1) Explain how feedback inhibition affects the release of ACTH.
ACTH Triggers the release of cortisol but cortisol inhibits ACTH release by blocking the release of CRH from the hypothalamus and by suppressing ACTH production by the anterior pituitary
959.6 Rigor mortis is the stiffening of a body after death that occurs when myosin binds to actin but cannot unbind. What prevents myosin from unbinding?
ATP is needed for myosin and actin to unbind. No ATP is generated after death.
959.2 In muscle cells, myosin molecules continue moving along actin molecules as long as
ATP is present and intracellular CA2+ is high
(976.1) Compare and contrast the roles of the hormones involved in metamorphosis of amphibians and insects.
Amphibians: increase in the concentration of thyroid hormone stimulates metamorphosis without a resting stage Insects: decrease in JH and increase in ecdysone stimulates metamorphosis with a resting stage
1027.3 What is the difference between an epitope and an antigen?
An epitope is the part of an antigen that is recognized by a B cell or T cell receptor or an antibody produced by a B cell
1022.1 Explain how the innate immune response is required for activating the adaptive immune response
Antigen-presenting dendritic cells activate CD4+ and CD8+ T cells
1027.6 What steps are required for most B-cells to become fully activated and differentiate into plasma cells?
B cells must first be activated via interaction b/w the BCR and antigens, most B cells are then fully activated and continue to divide
(976.2) Explain how the various changes induced by elevated cortisol levels result in a response to long-term stress.
By suppressing the immune system function promoting the release of fatty acids from Storage cells and release of amino acids for muscle cells for energy production and preventing the uptake of glucose by adipocytes and resting muscle cells in response to signals from insulin glucose by the brain
1027.4 What is one of the differences between CD4+ and CD8+ T cells?
CD4+ cells interact with MHC II proteins, and CD8+ cells interact with MHC I proteins
(971) If you understand the basic principles of hormone action, you should be able to suggest a hypothesis explaining why different frog cells can respond to T3 in such different ways.
Cells with friend receptors that went down to T3 would induce changes in the expression of different genes
1002.1 Describe the function of FSH, and explain why the FSH level increases at the end of the menstrual cycle.
FSH triggers maturation of an ovarian follicle. Its levels rise bc it is no longer being inhibited by progesterone, which stops being produced at high levels when the corpus luteum degenerates
959.4 True or false: A large animal will experience twice the gravitational force of a small animal half its length if their geometries are the same
False
1006.5 Summarize the experimental evidence that Daphnia require three cues to trigger sexual reproduction. Discuss what these cues indicate about the environment.
Females switched to sexual only when exposed to short day lengths, crowded populations, and low food concentration
1006.6 Many frogs and mice are similar in size, yet a frog egg is vastly larger than a mouse egg. Propose a plausible explanation for this difference in the egg size.
Frog eggs contain all the nutrients that an embryos needs making it large. Mice are nourished inside the womb so the egg is smaller
1026 If you understand how abnormal immune response can be generated to self molecules, you should be able to predict the consequences of producing self-reactive IgE antibodies
If self-reactive IgE antibodies were produced, a strong response would occur anywhere the self molecules are present, leading to chronic inflammation or anaphylactic shock
1028.12 Which type of adaptive immune response is activated by infection with parasitic worms? How is the innate immune system involved in this response?
IgE antibodies. mast cells sensitized by IgE respond to worm antigens by releasing chemicals
1025.2 Compare and contrast inactivated and attenuated viruses, and predict which would result in a more effective cell-mediated immune response
Inactivated: damaged by chemicals and cannot infect, remain as extracellular particles Attenuated: consists of weak particles that cant infect well enough to cause disease; since they infect, they promote a stronger cell mediated response than inactive viruses
(966) Discuss why it is often difficult to differentiate between the functions of the nervous and endocrine system?
It is difficult to differentiate between the nervous and endocrine systems because some neurons secrete hormones and some endocrine glands respond to neural signals
1011 Which of these events would cause the three classical signs of an infection:redness, swelling, and heat?
Mast cells release histamine, which triggers the dilation of blood vessels causing all three symptoms
1007.8 Give examples of negative feedback and positive feedback in hormonal control of the human menstrual cycle. Why can high estradiol levels be considered a "readiness" signal from a follicle?
Negative: LH triggers secretion of estradiol, but at low levels of estradiol inhibits further release of LH Positive: High levels of estradiol trigger release of more LH. the follicle can produce high levels of estradiol only if it has matured. High levels of estradiol can be considered a signal tht oocyte is ready for ovulation
954.2 Predict what would happen if neurons simultaneously stimulated the biceps brachii and triceps brachii muscles to contrast
No movement would occur because one must be relxed for the other to contract
990 Do these data show that sperm from the second male physically displace sperm from the first male?
No- the data are consistent with the displacement but do not provide direct evidence for it
(978.2) Discuss the relationship between processing centers in the brain, neurosecretory cells in the hypothalamus and hormone-secreting cells in the anterior pituitary.
Processing centers of the brain responsible for integrating a wider a sensory input. to start a response to the sensory input they stimulate neurosecretory cells in the hypothalamus. Neurohormones from the cells travel to the anterior pituitary where they trigger the production and release of other hormones
1018.1 Cite two that must occur during lymphocyte maturation to ensure a safe and effective adaptive immune response
Production of TCR and BCR through recombination must occur along with elimination or activation of self-reactive lymphocytes
1028.14 Parasitic worms modulate their host's immune response by inducing the proliferation of regulatory T cells. What role do these cells play in the adaptive immune system? How could this effect on regulatory T cells be linked to the hygiene hypothesis?
Regulatory T cells suppress parts of the immune system, limiting the magnitude of the adaptive immune response. They also may help inhibit self-reactive lymphocytes, which are involved in autoimmunity. In hygiene areas, parasitic worm infections are rare, so regulatory T cell numbers would be lower, self-reactive lymphocytes would not be inhibited, and the incidence of autoimmunity would be higher
958 About how much more costly is it to run than to swim for animals with a body mass of 100g?
Running is about as 10 times as costly as swimming
(974) Why did researchers bother to inject volunteers on the control group with saline? Why they inject them with anything?
Saline injection control for any stress induced by the injection procedure and for introducing additional fluid into the body
(967) If you understand how steroid hormones affect target cells, you should be able to predict what would happen to the estradiol response if an individual had mutations that changed the DNA sequence of its hormone-response elements.
Steroid hormone receptor complex would probably fail to buy the hormone response element. Then gene expression would not change in response to the hormone the arrival of the hormone would have little or no effect on the target cell
(979.1) How do steroid hormones differ from polypeptide hormones and most amino-acid-derived hormones?
Steroid hormones are lipid soluble and cross plasma membranes readily
(970) Explain why an animal's response to a polypeptide hormone is rapid and short lived compared to its response to a steroid hormone.
Stimulate production of new proteins which take time to occur results and long-lasting effects. In contrast polypeptides rapidly stimulate activation of already existing proteins which is transitory because of proteins can become inactivated just as quickly
979.8 Design a study to test the hypothesis that the symptoms of jet lag are caused by disruption of normal daily cortisol rhythms.
Subject volunteers to travel and jet lag, measure their ACTH and cortisol levels, and correlate these results with the subjects' perceived level of jet lag symptoms
1007.13 Do the data shown below support the hypothesis that the pill affects hormone signaling?
The hypothesis is supported because all the data shown is significant
979.3 Which of the following developmental processes is not controlled by hormones?
The initial development of male and female gonads in mammals soon after fertilization
979.7 Compare and contrast the structure and function of the anterior and posterior pituitary glands.
The posterior pituitary is an extension of the hypothalamus and a storage area for hypothalamic hormones. The anterior pituitary develops from nonneural tissue; it synthesizes and releasing an array of hormones in response to releasing hormones from the hypothalamus
944.2 Explain which elements in this analogy represent the Z discs, which represent the thin filaments, and which represent the thick filaments
The trucks represent the Z discs, the ropes represent the thin filaments, and the burly weightlifters represent the thick filament
1006.3 What happens during cleavage?
The zygote rapidly divides without growth, forming a mass of cells
(965) Now that testosterone is commercially available for use in research, how could Berthold's experiment be modified to yield my specific results?
This would show that any subsequent changes over do specifically to testosterone rather than another chemical released into the blood by the testes
1012.1 Explain the rolls of Toll-like receptors in innate immunity
Toll-like receptors recognize molecules associated with pathogens, bind to them, and the receptors cause signals to be transduced that activate cellular responses
1006.4 True or False: The corpus luteum is retained upon implantation due to the presence of the hormone human chorionic gonadotropin (hCG)
True
979.4 True or False: In hormone systems, feedback inhibition occurs when the pressure of a hormone inhibits release of the hormone.
True
1028.11 What is the hygiene hypothesis? What correlation does it attempt to explain?
allergies and autoimmunity arise due to implementation of hygiene practices. it attempts to explain the correlation b/w the rise of disorders and level of cleanliness
960.15 How does this finding affect your interpretation of the relationship between athletic performance and muscle fiber types?
although elite runners had a higher proportion of slow fibers, the proportion does not necessarily predict the athletic performance of any given athlete, as evidenced by the low percentage in some individuals who performed at the elite level
983.2 Predict the conditions under which asexual reproduction would be found as the favored method of productive offspring.
asexual reproduction would be expected when conditions change little over time
1007.15 Compare and contrast the mechanisms of actions of emergency contraception and mifepristone to that of the pill. Which methods act as contraception and which act to terminate a pregnancy? Explain.
both contain progesterone or progesterone plus estradiol, and both prevent ovulation. mifepristone is a progesterone receptor blocker that terminates a pregnancy
1012.2 Describe how cleaning a wound to remove dirt and applying bandages to halt blood flow mimic events in the innate immune response
cleaning mimics phagocytic activity by eliminating pathogens. Applying bandages mimics the effects of chemokines which help facilitate blood clotting
1018.3 Be able to explain what "clonal" and "selection" refer to
clonal- production of specific copies of cells selection- cells that bind to the receptors of a specific antigen
1027.2 The overall role of the inflammatory response is to
contain and eliminate foreign cells and materials at the site of infection
980.15 In response to a visit by tourists, which penguins-habituated or non-habituated-would show a greater change in expression of genes for liver enzymes involved in converting amino acids to glucose? Explain.
corticosterone is a glucocorticoid similar to cortisol, which induces the synthesis of liver enzymes that make glucose from amino acids. If corticosterone has the same effect as cortisol, and if non-habituated have higher corticosterone levels than habituated penguins, then non-habituated penguins should show a greater increase in expression of genes for those enzymes
980.13 If penguins in a colony are habituated to the presence of tourists, how would their corticosterone response to being visited by tourists compare to that of penguins in a colony not previously exposed to tourists?
corticosterone levels should show a smaller increase in penguins habituated to tourists than in penguins not previously exposed to tourists
980.12 In what part(s) of a target cell would you expect to find corticosterone receptors?
corticosterone receptors would be found in the cytoplasm or nucleus
1007.9 Propose an experiment to test the hypothesis that cells from only one region of a frog blastula form the ectoderm. What results from this experiment would support this hypothesis?
dye a specific region of the blastula and see where the dye ends up. If only the cells from a certain location cover up the cell than the hypothesis is supported
996 Describe how the ectoderm comes to completely cover the embryo.
ectoderm cells begin at one pole of the cell but as the others layers move inward, the ectoderm grows in all directions around the meso/endo
960.14 To discover the relationship between muscle-fiber types and performance, researchers obtained tiny biopsies of the gastrocnemius of 14 elite distance runners, 18 trained but non-elite distance runners, and 19 untrained subjects. What conclusions can you draw from these data?
elite runners on average had a higher proportion of slow fibers than the non- elite and untrained runners
1025.1 Explain how viruses are eliminated by both humoral and cell mediated immune responses
extracellular viruses are opsonized, agglutinated, and neutralized by the humoral response. intracellular virus hosts are destroyed by cytotoxic T cells in the cell-mediated response
1007.10 The table below shows the BMI z-score of pre-pubertal and post-pubertal girls at three ages. The BMI z-score is a relative measure of body mass index that takes into account age. Higher values represent heavier individuals for a given height. Which of the following conclusions can you draw from the table?
girls with high BMI z scores are more likely to have begun puberty than those with low scores
988 Generate a hypothesis to explain why male and female gonads are paired in mammals. How would you test your hypothesis?
having gonads is self protective if one gets damaged. Remove one gonad from males and females. put them in a population with control rats and compare the success of each population
954.1 Compare and contrast the structure and function of hydrostatic skeletons, endoskeletons, and exoskeletons.
hydrostatics are made of soft tissues that vary with the animal; endoskeletons are made of calcium phosphate, calcium carbonate, and proteins; exoskeletons are made of chitin, proteins, calcium carbonate, and others; changes in hydrostatics come from changes in body segment while changes in endo and exo come from changes in angle of joints. All types are attached to skeletal muscle and serve to transmit muscle forces
1004 If you understand how hormones influence pregnancy, you should be able to explain why women who produce low levels of progesterone from the corpus luteum are prone to miscarriage.
if progesterone levels are not high enough, the uterine lining will not be maintained and a miscarriage is likely
946.1 Describe the sliding-filament model
in a sarcomere, thick myosin filaments are sandwiched between thin actin filaments. when the heads on myosin contact actin and change conformation, they pull the actin filaments toward the center of the sarcomere , shortening the whole sarcomere
999 How does control of testosterone and estradiol secretion compare with control of cortisol release by the adrenal gland?
in both, the hypothalamus produces a releasing hormone (GnRH or CRH) that stimulates the anterior pituitary gland. the hormones released from the pituitary gland induces release of hormones from gonads or adrenal glands
959.9 Predict the effect of ingestion of atropine on heart rate. Explain your logic
in cardiac muscle the binding of acetylcholine to its receptors causes the heart rate to slow. ingestion would increase heart rate because it blocks acetylcholine receptors
1027.5 Explain how gene recombination leads to the production of vast numbers of different B-cell receptors.
in each light chain different v and j segments are recombined, heavy chains are formed by recombining v, d, and j segments giving the B cell a unique sequence in both chains of the BCR
998.2 Design an experiment using chick or frog embryos to test the hypothesis that the notochord is needed for formation of the neural tube.
in either embryo, remove a portion of the notochord. the prediction is that a neural tube will not form in the portion. A notochord can be transplanted and predicted that a neural tube will form above the notochord
980.16 Suggest at least two distinct physiological mechanisms that could be responsible for the difference in corticosterone response to a stressor in habituated and non-habituated penguins.
in habituated penguins, the brain could become less sensitive to the stimulus of a tourist's presence, resulting in release of less CRH ny the hypothalamus. The anterior pituitary gland could become less sensitive to CRH, secreting less ACTH
994.2 Explain why fertilization is blocked when a sea urchin egg is treated with a drug that allows Ca2+ to enter the egg.
increase in Ca2+ concentration within the egg triggers formation of the fertilization envelope, which blocks fertilization
946.2 Predict the effect on muscle function of drugs that have the following actions: increase acetylcholine release at the neuromuscular junction, prevent conformational changes in troponin, and block uptake of calcium ions into the sarcoplastic reticulum
increased acetylcholine release would result in an increased rate of action potentials in muscle cells and more forceful muscle contraction. Preventing conformational changes on troponin would prevent muscle contraction. Blocking uptake would lead to sustained muscle contraction
983.1 How would you determine which molecule or molecules in "crowded" water serve as a signal that triggers sexual reproduction?
isolate and identify the molecules. test the molecules versus a control
960.13 Predict the effect of training for a marathon on the number of muscle cells in the gastrocnemius. Explain
likely be no difference in the number of muscle cells, even though training could cause the entire muscle to enlarge. Muscle cells can become larger with training; new cells are not added
979.5 Compare and contrast the modes of action of lipid-soluble and water-soluble hormones.
lipid soluble hormones like steroids usually bind to receptors inside the cell, forming a complex that binds to DNA and alters transcription. Water-soluble hormones like polypeptides bind to receptors on the cell surface and trigger production of a second messenger, and, in some cases, a phosphorylation cascade, ending in activation of proteins already present in the cell
959.3 Which of the following is critical to the function of most exoskeleton, endoskeletons, and hydrostatic skeletons?
muscles interact with the skeleton in antagonistic groups
994.1 Predict some advantages and disadvantages of oviparity and viviparity.
oviparity: requires less energy after eggs are laid, more eggs can be laid, but eggs may not be protected after being laid viviparity: usually increases likelihood that offspring will survive until birth, less offspring can be produced, large energy cost
959.7 Predict how a runner's oxygen consumption would change if a runner wore shoes that prevented the arches from changing shape. Explain your reasoning
oxygen consumption of the runner would increase because the arches would no longer store as much elastic energy, which normally reduces the energetic cost of running
1006.1 What term describes the mode of asexual reproduction in which offspring develop from unfertilized eggs?
parthenogenesis
959.1 Which of the following classes of muscle is/are voluntary?
skeletal muscle
960.11 Compare and contrast the structure and function of the three types of skeletal muscle fibers
slow oxidative fibers are red because they hold lots of myoglobin which holds oxygen amount necessary for high rate of aerobic respiration, and they contract slowly and don't fatigue readily; fast glycolytic fibers are white due to their low myoglobin, and they contract and fatigue rapidly; fast oxidative/glycolytic (intermediate) fibers are intermediate in color (pink) and physiological properties
950 Predict the most abundant muscle fiber type in the postural muscles of the human neck
slow oxidative fibers which are sepcialized for endurance
1006.7 How do spermatogenesis and oogenesis in humans differ with respect to numberss of cells produced, gamete size, and timing of the second meiotic division?
spermatogenesis: four haploid cells, smalle gametes, meiosis II is right after meiosis I oogenesis: one haploid cell and polar bodies, large gamete, meiosis II is delayed after meiosis I
980.11 Corticosterone is a(n):
steroid hormone
1027.1 What is the primary difference between innate and adaptive immune responses?
the adaptive response generates immunological memory and is more specific than the innate response
959.5 How did data on sarcomere structure inspire the sliding-filament model of muscle contraction? Explain why the observation that muscle cells contain many mitochondria and extensive smooth ER turned out to be logical once the molecular mechanism of muscular contraction was understood
the banding pattern changed during contraction. the many mitochondria supply the large amounts of ATP needed to power movement of myosin along actin filaments; ER stores the calcium used to initiate the reaction
1018.2 Explain the benefit of having discrete gene segments encoding the variable region rather than having multiple genes that each encode whole variable regions
the cell can make a larger number of differing variable region genes per unit of DNA when the variable region is segmented
944.1 According to the model shown here, why is the dark band in a sarcomere dark and the light band light?
the dark band includes thin filaments as well as thick filaments, which have bulbous extensions; the light band consists only of thin filaments
1002.2 Predict the consequences of a drug that inhibits the release of FSH.
the follicle would not mature and would not produce estrogens. The uterine lining would not thicken
998.1 State when you would first be able to point out the future posterior and dorsal regions of a frog embryo, and explain what clues you would use to identify these regions.
the future posterior and dorsal regions can be indentified as soon as the blastopore forms, the blastopore will form the posterior region and the side the that cells begin to clump together is dorsal
960.16 Which organism would have the highest cost of locomotion during the race?
the human would have the highest cost of locomotion because running is more energetically costly than flying or swimming
980.14 Scientists tested the hypothesis that penguins habituated to tourists have a blunted stress response overall. They examined the corticosterone response of habituated and non-habituated penguins to another stressor-that being captured and restrained for 30 minutes. They found that both habituated and non-habituated penguins secreted corticosterone in response to being captured and restrained, but that the levels of corticosterone after 30 minutes differed between the groups. Was the hypothesis supported? Explain.
the hypothesis was supported because the corticosterone response to capture and restraint was significantly higher in non-habituated penguins than habituated penguins
1022.2 Generate a hypothesis to explain the observation that individuals who are heterozygous for the genes encoding MHC proteins tend to be healthier than individuals who are homozygous for these genes
the increased genetic variability allows a greater variety of polypeptides to be made
1007.16 Imagine that four different contraceptive are under development. One blocks ovulation, one blocks fertilization, one blocks cleavage, and one blocks implantation. In the United States, which contraceptive is likely to be the least controversial to bring to market? why?
the least controversial is one that blocks either fertilization or ovulation-because life starts at the moment of fertilization. Blocking cleavage or implantation is most controversial because they occur after fertilization
1006.2 In sperm competition, what is "second-male advantage"?
the observation that when females mate with multiple males, the last male to mate fertilizes the most offspring
1007.11 Which of the following is the most effective form of contraception?
the pill
992 Explain why adding a molecule that binds to a bindin-like protein on the human sperm head would be an effective contraceptive?
the protein will not be able to bind to the egg. fertilization cannot occur
1028.9 Which of the following outcomes would be expected if somatic hypermutation did not occur?
the secondary immune response to a repeat infection would produce the same antibodies as those made in the primary immune response
960.12 Predict who would likely have a greater proportion of fast glycolytic fibers in their gastrocnemius muscle-an elite distance runner or an elite sprinter. Explain
the sprinter would likely have a greater proportion of fast glycolytic fibers because thesse cells are specialized for bursts of activity
1028.7 Why is clonal selection necessary for the adaptive immune response but not the innate immune recpetors?
there is more receptor diversity in the adaptive response than in the innate response
1028.13 Pattern recognition have been identified that recognize worm products. Explain how these receptors are used to activate the adaptive response most appropriate for worm infection
they inform antigen-presenting cells to direct CD4+ T cells to become TH2 helper cells which activate humoral immune response
979.6 Why is the observation that one hormone may bind to more than one type of receptor important?
this is one way that the same hormone can trigger different effects in different tissues. For example, epinephrine binds to four different types of receptors in different tissues and elicits a different response from each
1028.8 What do vaccines need to contain in order to be effective? Why don't we have vaccines for HIV?
vaccines must have an antigen that can stimulate a primary immune response. HIV antigens constantly change through mutations, rendering it unrecognizable
959.8 Explain why the energetic cost of swimming decreases as a fish grows
viscosity of water has a greater effect on small fish than large fish making it easier for large fish to swim
1028.10 Propose a hypothesis to explain how self-reactive B cells are identified and eliminated during maturation
when BCRs in self-reactive B cells bind to self molecules during maturation, the cells become inactivated or undergo apoptosis
979.10 Scientists set out to test the hypothesis that the herbicide atrazine is an endocrine disruptor that feminizes male amphibians. They treated male amphibians with atrazine and then compared their circulation testosterone concentrations with those of males and females that were not treated with atrazine (controls). Was the hypothesis supported? Why or why not?
yes-the finding supports the hypothesis that atrazine is an endocrine disruptor that feminizes male amphibians
1028.16 There is a strong association between the prevelance of diabetes mellitus in parents and their children. If you were a physician, would you ask parents who have type 1 diabetes to intentionally infect their children with intestinal worms? What additional information would you need to make this decision?
you need to know if adverse effects are associated with worm infections in children, the level of risk for children to develop type 1 diabetes, and if the worms' modulation of the immune response would affect responses to other pathogens or vaccines
