LS7C Practice Exam Questions
Referring to the figure, select whether each statement below is true or false. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/graphdebaxon.jpg A - true B - false format ex: 1A, 2A, 3B 1. Resting potential is generated mainly by the outward movement of K+ ions from inside the cell. 2. The voltage changes shown in the figure are measured just across the plasma membrane 3. The changes in voltage seen at #2 and #4 in the figure are caused by similar movements, in the same direction, of the same types of ions across the membranes. 4. The trace in the figure is following the voltage change as it moves down the axon. 5. The voltage change shown in the figure is an all-or-nothing response. 6. Different ion channels are responsible for generating the voltage change seen at #2 and #4 in the figure. 7. All voltage changes along the plasma membrane of an axon have the characteristic shape shown above. 8. The changes in voltage shown in the figure are due to ligand-gated ion channels opening and closing along the axon. 9. An EPSP of sufficient strength to reach threshold occurred at #1 on the figure. 10. A membrane that has no K+ channels will have a resting membrane potential that is higher than the one shown on the figure.
1A, 2A, 3B, 4B, 5A, 6A, 7A, 8B, 9A, 10A
Dilated pupils, inhibited digestive activity, increased respiratory rate, and release of glucose from the liver are all signs of activity of: a) the parasympathetic division of the autonomic system. b) the sympathetic division of the autonomic system. c) the somatic nervous system. d) both divisions of the autonomic nervous system.
b
Stimulation by the parasympathetic nervous system increases the permeability of the SA node to potassium ions, whereas stimulation by the sympathetic nervous system decreases the permeability of the SA node to this same ion. a) True b) False
b
/brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Sequencing%20raw%20data.png How many different sequences are represented in this dataset? a) 3 b) 4 c) 5 or more d) 1 e) 2
a
/brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/gene%20model.jpg There are 7 introns in this gene model. a) False b) True
a
A cell in a chick embryo is tested to determine whether it is a stem cell of some kind. These tests find: 1. The SR receptor is present 2. DIV genes are on 3. The DIFF (skin) genes are blocked 4. TF of the neural pathway is in the cytoplasm 5. Transducer 2 of the skin pathway is not phosphorylated Based on these results, the transcription factor of the Skin pathway is in the cytoplasm. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Cell%20differentiation.jpg a) True b) False
a
Aging can sometimes lead to an increase in the stiffness at the base of the basilar membrane. What effect would this have on a person's hearing? a) The person would lose the ability to hear high-pitched sounds. b) The person would not be able to distinguish the amplitude of a sound. c) The person would only be able to hear loud sounds. d) The person would lose the ability to hear low-pitched sounds.
a
An interneuron may receive multiple stimuli from the same sensory neuron over a very short period of time. The firing rate of the receiving neuron is proportional to the number of signals received from the sensory neuron over time. Of which of the following is this an example? a) temporal summation b) spatial summation c) action potential d) hyperpolarization
a
During heavy exercise, the pO2 in muscle may drop to 20 mm Hg. Considering the oxygen-hemoglobin dissociation curve below, what is the approximate percent O2 saturation of hemoglobin in venous blood returning from skeletal muscles during heavy exercise? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_39/39_65.jpg a) approximately 100% b) approximately 20% c) nearly 0% d) approximately 50% e) approximately 75%
b
Figure 9.15 shows how normal signaling works with a Ras protein acting downstream of a receptor kinase. You examine a cell line in which Ras is always activated even in the absence of a signaling molecule. This causes constant activation of the kinases in the MAP kinase pathway. Which of the following conditions would be MOST likely to turn off this abnormally active signaling pathway? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_9/9_156.jpg a) the addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus b) the addition of a drug that prevents the dimerization of the receptor kinase c) the addition of a drug that prevents the phosphorylation of the receptor kinase d) the addition of a drug that increases the binding affinity of Ras for MAP kinase enzymes in the cytoplasm
a
Freshwater fish are in a hypotonic environment. How do their gill chloride cells function in this environment? a) Freshwater fish have chloride cells that actively move chloride ions into the gills, with sodium ions following. b) Freshwater fish have chloride cells that actively move chloride ions out of the gills into the surrounding water, with sodium ions following. c) Freshwater fish have chloride cells that actively move chloride ions out of the gills into the surrounding water, with sodium ions moving in the opposite direction. d) Freshwater fish have chloride cells that actively move chloride ions into the gills, with sodium ions moving in the opposite direction.
a
If a skeletal muscle is no longer able to make enough ATP, then: a) actin and myosin in the sarcomeres will remain bound. b) actin and myosin in the sarcomeres are in the unbound state. c) the muscle will be unable to shorten. d) there will be low levels of acetylcholine at the motor endplate.
a
Imagine that you are talking with one of your friends about your biology course. He states that the somatic nervous system is subdivided into sympathetic and parasympathetic components, and is responsible for involuntary responses. Is this statement correct? a) No, the somatic nervous system is responsible for voluntary responses, and is not subdivided into sympathetic and parasympathetic components. b) No, although the somatic nervous system does have both sympathetic and parasympathetic subdivisions, it is responsible for voluntary responses. c) No, although the somatic nervous system controls involuntary responses, it is the autonomic nervous system that is subdivided into parasympathetic and sympathetic components. d) Yes, this statement is correct. The somatic nervous system has both sympathetic and parasympathetic components and controls involuntary responses.
a
Phylogenetic analysis of 16S rRNA-encoding gene sequences from fecal microbiota of control or patients with C. difficile associated diarrhea (both initial and recurrent episodes) are shown below. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Microbiome%20Chang%20et%20al%202008%20data.png Bacteroides are reduced in patients with recurrent CDI. a) True b) False
a
Sensory transduction requires: a) All of these choices are correct. b) a change in membrane potential. c) alteration of the conformation of a channel protein. d) reaction of a receptor protein with a stimulus.
a
Sometimes while traveling, people are infected with a protist parasite, Giardia. One of the side effects of Giardia infection is diarrhea. When someone has diarrhea, they lose excessive water and salt from the body. The result is loss of Na+, dehydration that leads to decreased extracellular volume and plasma volume, and decreased arterial blood pressure. Given this would the vasopressin secretion of a person infected with Giardia: a) increase b) stay the same c) decrease
a
The DNA sequence shown below comes from part of the TP53 gene. It encodes the last amino acids of the p53 protein, which is normally 393 amino acids long. The underlined codon indicates the correct reading frame of this gene. The lower strand of the gene is used as the template during the transcription of mRNA from this gene. ...TTCAAGACAGAAGGGCCTGACTCAGACTGACATTCTCC-3' ...AAGTTCTGTCTTCCCGGACTGAGTCTGACTGTAAGAGG-5' /brainhoney/Resource/9529883,8,0,44,30,2/Assets/codon%20chart.jpg A mutation that changes the nucleotide at position 20 from A to G is a silent mutation. a) False b) True
a
Use the following diagram of the insulin signaling pathway to help you answer the question. A mutation in P4 causes it to be active all of the time (even when it's unphosphorylated). What would be the most likely consequence of this mutation? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Screen%20Shot%202018-10-18%20at%205.01.46%20PM.png a) Glycogen will be made in the absence of insulin b) Glycogen enzyme will be phosphorylated in the presence of insulin c) Glycogen will not be made in the presence of insulin d) P3 will be phosphorylated in the absence of insulin
a
Vascular endothelial growth factor (abbreviated VEGF and pronounced "Veg-F") is a peptide signaling molecule related to platelet-derived growth factor. VEGF is important in the formation of the circulatory system because its signaling pathway causes the formation of blood vessels in developing embryos during normal development. Tumors also produce and secrete VEGF, causing the formation of new blood vessels that supply these tumors. Given what you know about the different kinds of cell signaling and VEGF, which one of the following statements is TRUE? a) VEGF is a paracrine signaling molecule because it binds to receptors on cells at the site where new blood vessels are needed. b) VEGF is an endocrine-signaling molecule because it circulates through the bloodstream inside of platelets. c) VEGF is an endocrine-signaling molecule because it is released from platelets into the bloodstream and is carried throughout the body, causing widespread activation of platelet-derived growth factor receptors on cells in a variety of tissues.
a
What effect does the nervous system have on the heart rate? a) Stimulation by parasympathetic nerves causes the heart rate to slow down. b) Stimulation by sympathetic nerves causes the pacemaker cells of the AV node to depolarize more rapidly than the pacemaker cells of the SA node. c) Stimulation by sympathetic nerves sets the resting heart rate of the pacemaker cells in the SA node. d) Stimulation by either the sympathetic or parasympathetic nerves causes pacemaker cells in the SA node to depolarize more slowly. e) The nervous system does not directly affect the heart rate.
a
Some people have low levels of calcium circulating in the blood, a condition known as hypocalcemia. While for many this disorder has little to no effect, for some it can be life-threatening. How could low levels of calcium harm an individual? a) Low levels of calcium would cause sustained depolarization of the presynaptic cell. b) Low levels of calcium would result in fewer signals sent between the pre- and postsynaptic cell. c) Low levels of calcium would not have any effect on synaptic transmission.
b
Which one of the following is a feature of DNA that could allow you to distinguish between a DNA sequence that is protein coding and a DNA sequence that is not? a) Protein-coding regions frequently contain long open reading frames; others rarely do. b) Protein-coding sequences are sets of amino acids; others are sets of nucleotides. c) Protein-coding sequences are single stranded; others sequences are double stranded. d) All of these choices are correct. e) Protein-coding DNA sequences contain U (Uracil), and nontranscribed sequences contain T (Thymine).
a
A stem cell is fate determined once it has received the Self Renewal signal. As result, which genes are newly expressed? (Check all that apply) /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Cell%20differentiation.jpg a) ID genes b) DET genes c) DIFF (skin) genes d) DIFF (neural) genes e) DIV genes f) SR genes
a b e
Consider the figure below showing an EKG trace below the typical action potential for the sinoatrial node. Note: You haven't seen the action potential for the pacemaker cells in the text. (pic) Indicate whether the following statements are true or false. Ventricular diastole occurs at the interval labeled 3 on the graph. a) True b) False Atria are emptying at the interval labeled 4 on the graph. c) True d) False
a c
Sensory cells and sensory neurons allow multicellular animals to sense physical and chemical cues from their environment. What key properties of these cells enable them to perform this function? (Select all that apply.) a) Sensory cells and sensory neurons have electrically excitable membranes that change in charge potential in response to binding an environmental signaling molecule. b) Sensory neurons have myelinated dendrites that serve as nerve endings. c) Sensory cells and sensory neurons have protein receptors linked to intracellular or membrane-based signaling pathways that alter ion channel permeability. d) All sensory cells and sensory neurons fire action potentials when they bind a signaling molecule.
a c
Your computer records the raw sequencing data shown below. [~]/JT/LS 7C/Sequencing raw data.png Which of the following sequences is (are) represented in this dataset? (Mark all that apply) a) 5' -CCGGAT- 3' b) 5' -TAGGCC- 3' c) 5' -CCGGAA- 3' d) 5' -TAAGCC- 3'
a c
[~]/JT/LS 7C/Sequencing.png The three DNA fragments above are about to be sequenced. Which primers could be used to sequence the following DNA fragments? Select all that apply. a) 5'-CCGGG-3' b) 5'-CCATT-3' c) 5'-AATGG-3' d) 5'-GGCCC-3'
a c
Shown here are four ligands (M, H, K, and L) and their corresponding receptors along with three genes (U, V, and W) whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene repression. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_20/20_189.jpg If either U or V is required to activate W, which ligand (or ligands) result in W being active? (Select all that apply.) a) ligand H b) ligand L c) ligand K d) ligand M e) None of the answer options is correct.
a c d
What are desirable characteristics for a gas exchange surface, such as the endothelial cells lining the inside of lung? (Select all that apply.) a) a large surface area b) a thickness of 100 micrometers c) a small surface area d) a thickness under 10 micrometers
a d
Assume that blood pressure drops in a person because of an injury. Indicate which of the following occur by selecting "true" for does occur or "false" for does not occur. Circulating levels of aldosterone will increase. a) true b) false Circulating levels of renin will decrease. c) true d) false The sympathetic nervous system stimulates the adrenal glands. e) true f) false Water absorption by the distal convoluted tubule will decrease. g) true h) false Circulating levels of angiotensin II will increase. i) true j) false
a d e h i
Which of these would be involved in a primary response to viral infection? a) MHC I b) MHC II c) Helper T cell d) Macrophages e) Dendritic cell f) Cytotoxic T cell
a f
For your summer internship you decide to help farmers characterize the microbiotas of their pigs. Below is a graphical representation of the diversity observed after sampling and sequencing the microbiotas present in the small intestine (jejunum and ileum) and large intestine (cecum) of their fattest pigs. Reference the data presented below to address the following statement. Points that cluster together have greater 16s rRNA gene sequence similarity than points that are farther apart. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/microbesls7c.jpg a) False b) True
b
/brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/gene%20model.jpg The open reading frame starts at exon 2. a) True b) False
b
A decrease in cell adhesion, by the introduction of an experimental substance to a tissue, compromises the structural integrity of the tissue. Which cell junction would MOST likely be affected by this treatment causing a decrease in the strength of the tissue? a) gap junctions b) adherens junctions c) hemidesmosomes d) tight junctions
b
A key difference between hormonal regulation of the reproductive systems of males and females is that: a) LH and FSH are released only in females. b) LH and FSH are released cyclically in females but nearly continuously in males. c) LH and FSH are released only in males. d) LH is released in males and FSH is released in females. e) LH is released continuously in males and FSH is released cyclically in females.
b
Bisphosphoglyceric acid (BPG) is a byproduct of glycolysis released into the bloodstream when an animal's supply of oxygen is low. Like protons, it decreases hemoglobin's affinity for O2. The effect ofhigh BPG levels would be that: a) hemoglobin loses its cooperative binding of oxygen. b) hemoblobin releases more of its bound O2 than it would without BPG. c) hemoglobin now binds more oxygen at low partial pressures than at high partial pressures. d) hemoglobin picks up more O2 in the lungs than it would without BPG. e) hemoglobin holds on to more of its O2 than it would without BPG.
b
Chemoreceptors in the circulatory system detect changes in circulating CO2. If CO2 concentrations get too high, the rate of ventilation increases. Why does this make sense? a) It makes sense because CO2 is formed from O2, and therefore CO2 is a sign that oxygen is being consumed. b) It makes sense because tissues that are more actively working produce more CO2. c) Actually it doesn't make sense. There is no relationship between CO2 and ventilation rate. d) It makes sense because hemoglobin carries CO2 and therefore blocks oxygen binding to the heme site, creating an oxygen deficiency.
b
Circle plots show changes in cancer genomes vs. the reference genome. Use the circle plot below to answer the following question. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/Circos%20diagram.png Regions of the genome with higher tumor/normal cell read copy ratios are more likely to be associated with intrachromosomal rearrangements. a) True b) False
b
For your summer internship you decide to help farmers characterize the microbiotas of their pigs. Below is a graphical representation of the diversity observed after sampling and sequencing the microbiotas present in the small intestine (jejunum and ileum) and large intestine (cecum) of their fattest pigs. Reference the data presented below to address the following statement. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/Figure%20Microbioms%20w8%20PEQ.png Each point on the graph above represents one microbial species present in the either the small intestine or the large intestine. a) True b) False
b
From the information provided, mutations in this breast cancer-associated gene tend to be primarily synonymous substitutions. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/7s7synanomous.jpg a) True b) False
b
If a mutation occurred in the cadherin gene so that the cytoplasmic domain no longer attached to the cytoskeleton, which of the following would occur? a) Cadherins in desmosomes would no longer be anchored to microfilaments. b) Cadherins in desmosomes would no longer be anchored to intermediate filaments. c) Cadherins in hemidesmosomes would no longer be anchored to intermediate filaments. d) Cadherins in adherens junctions would no longer be anchored to microtubules.
b
Imagine you created a toxin such that when a neuron fired an action potential, the toxin would bind immediately to the sodium-potassium pump at the top of the action potential, but the sodium and potassium channels would still function. What process(es) would be affected? a) the hyperpolarization phase of an action potential b) maintaining resting potential and returning to resting potential after the hyperpolarization phase of an action potential c) returning to resting potential after the hyperpolarization phase of an action potential d) the depolarization phase of an action potential e) maintaining resting potential
b
In many cells, the adhesion to the extracellular matrix through integrins causes the activation of kinases in the cytoplasm. This suggests that: a) integrins are kinases. b) integrins promote the activation of signal-transduction pathways. c) extracellular matrix proteins are receptors and integrins are ligands.
b
In systemic tissue fluids, the enzyme carbonic anhydrase catalyzes the reaction CO2 + H2O → H2CO3 (which then can dissociate into H+ and HCO3-). In fact, CO2 released from cells is converted to HCO3- ions and travels in that form in the bloodstream. HCO3- is reconverted to CO2 + H2O in the pulmonary capillaries by the same enzyme, and there the CO2 is exhaled. How is it possible for the same enzyme to catalyze reverse reactions? a) The lungs contain an allosteric inhibitor that prevents the formation of carbonic acid. b) The direction of a reversible reaction is influenced by the concentrations of reactants and products. In pulmonary circulation, the low CO2 concentration favors the formation of CO2 and H2O. c) There must be two forms of carbonic anhydrase. One form catalyzes the forward reaction CO2 + H2O → H2CO3 and the other catalyzes the reverse reaction H2CO3 → CO2 + H2O.
b
Kisspeptin is a protein in humans that has an important role in initiating secretion of the releasing factor gonadotropin-releasing hormone (GnRH). Endocrinologists are finding that the protein kisspeptin and its receptor are central to sexual maturation at puberty. Neurons that release kisspeptin carry estrogen receptors. If this is a negative feedback system, high levels of estrogen would be expected to: a) neither increase nor decrease kisspeptin synthesis because steroid hormones do not affect protein synthesis. b) decrease kisspeptin synthesis. c) increase kisspeptin synthesis.
b
Many birth-control pills release a constant amount of synthetic estradiols and progesterone for 21 days, followed by 7 days when no hormones are ingested. Which of the following statements MOST accurately describes the effects of birth-control pills? a) Birth-control pills maintain constant levels of estrogens and/or progesterones and mask the release of the oocyte from the follicle. b_ Birth-control pills maintain constant levels of estrogens and/or progesterone so there is no surge in FSH and ovulation does not occur. c) The 7 days with no hormones does not allow a thick enough uterine lining to form so a fertilized oocyte cannot implant. d) Birth-control pills inhibit the development of the uterine lining so implantation of a fertilized oocyte cannot occur.
b
One of the roles of the kidneys is to help buffer body fluids so that they are not too acidic or too basic. The cells of the renal tubule secrete H+ into the tubule lumen, and absorb bicarbonate (HCO3-), passing it into the tissue fluid. Consider the reaction catalyzed by the enzyme carbonic anhydrase, shown in the accompanying figure and below. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_41/41_116.jpg During heavy exercise, the reaction shifts to the right in the nephron (lumen of the tubule). a) False b) True
b
Phylogenetic analysis of 16S rRNA-encoding gene sequences from fecal microbiota of control or patients with C. difficile associated diarrhea (both initial and recurrent episodes) are shown below. [~]/JT/LS 7C/Microbiome Chang et al 2008 data.png People with recurrent CDI have more resilient microbiomes a) True b) False
b
Refer to the figure if needed to complete the following: The transduction of sound waves to changes in membrane potential takes place: /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_36/36_82.jpg a) in the oval window, which vibrates at the same frequency as the original sound. b) when stereocilia bend against the tectorial membrane, causing hair cell depolarization. c) within the tectorial membrane as it is stimulated by the hair cells. d) in the basilar membrane as it vibrates at different locations. e) as the vibrations received by the outer ear cause the eardrum to vibrate.
b
Referring to Figure 10.14, identify which type of cell-cell interaction is most likely to force the products of digestion to be absorbed across microvilli of intestinal cells rather than allowing them to leak between cells. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_40/40_136.jpg a) desmosomes b) tight junctions c) hemidesmosomes d) gap junctions e) plasmodesmata
b
Sequences that are conserved (i.e., similar in many different organisms) are unlikely to be functionally important. a) True b) False
b
Sequencing results can determine SNPs in cancer cells or provide evidence for large-scale mutations. You sequenced a tumor genome and a healthy tissue genome, then aligned your sequences with a reference genome. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Tumor%20vs%20healthy%20cell%20ratio.png The blank region indicated by the arrow means that there are more reads in cancer cells compared to healthy cells. a) True b) False
b
The DNA sequence shown below comes from part of the TP53 gene. It encodes the last amino acids of the p53 protein, which is normally 393 amino acids long. The underlined codon indicates the correct reading frame of this gene. The lower strand of the gene is used as the template during the transcription of mRNA from this gene. ...TTCAAGACAGAAGGGCCTGACTCAGACTGACATTCTCC-3' ...AAGTTCTGTCTTCCCGGACTGAGTCTGACTGTAAGAGG-5' /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/codon%20chart.jpg A mutation that changes the nucleotide at position 23 from C to G is a nonsense mutation. a) False b) True
b
The arrow in the figure below, pointing at an "empty space", represents sequences that are missing from the reference genome. /brainhoney/Resource/9529883,8,0,44,30,2/Assets/Log2%20Plot%20arrow.png a) True b) False
b
The loop of Henle is a countercurrent exchanger because it creates a concentration gradient rather than simply maintaining it. a) True b) False
b
The magnitude of the action potential is correlated with the strength of the stimulating input. a) True b) False
b
Use the Genome Browser information on the TP53 gene below: /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/TP53%20genome%20browser.jpg Histone acetylation near the promoter of the gene is conserved in Zebrafish. a) True b) False
b
Using current DNA-sequencing technology, it is possible to sequence an entire chromosome (e.g., human chromosome 1, which contains approximately 250 million nucleotides) as one long molecule. a) True b) False
b
When a doctor suspects that a patient may have diabetes, she will often have the patient take a glucose challenge test. After the patient drinks a large amount of sugary solution, his blood is drawn and the circulating levels of glucose in the blood are determined. Which of the following curves do you expect from a patient with diabetes? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_38/38_2.jpg a) curve A b) curve B c) curve C
b
When a person has a few drinks containing alcohol, they often feels the need to urinate. This response suggests interplay between alcohol and antidiuretic hormone (ADH). Which of the following could explain how alcohol and ADH interact? a) Alcohol facilitates the binding of ADH to receptors in the brain, so individuals "feel" the need to urinate. b) Alcohol decreases the release of ADH. c) Alcohol inhibits the binding of ADH to receptors in the brain, so individuals "feel" the need to urinate. d) Alcohol increases the release of ADH.
b
Which of the following statements explains why there is an elastic layer found in arteries, but not veins? a) The total length of arteries in the body is more than the total length of veins, and the elastic layer helps push the blood over the longer length. b) Blood pressure is higher in arteries than veins, and the elastic layer helps maintain the structure of the artery. c) Valves present in veins provide a mechanism for withstanding high blood pressure flow going through veins. d) Arteries are thicker than veins, and the elastic layer is necessary to support the additional weight of arteries.
b
Which of these would be involved in a primary defense to viral infection? a) Humoral immune response b) Cell-mediated response c) Complement pathway d) B cells
b
You discover a new type of marine organism that has the kidneys of a fish but no gills. What effect would the absence of gills have on excretion of nitrogenous waste? a) No effect. Nitrogenous wastes diffuse across the skin. b) Nitrogenous excretion increases at the kidneys because it cannot be lost at the gills. c) Nitrogenous excretion decreases because no nitrogen uptake is occurring at the gills. d) No effect. Fish kidneys excrete all nitrogenous waste.
b
You measure levels of Ca2+ in various locations within a motor neuron and a skeletal muscle fiber when the motor neuron is NOT depolarized, and the muscle fiber is at rest. Where do you expect to find high levels of Ca2+? a) binding to the receptors at the motor endplate of the muscle cell b) within the sarcoplasmic reticulum of the muscle fiber c) bound to troponin d) diffusing into the motor neuron through specialized channels in the plasma membrane e) within the T-tubules
b
During certain stressful moments, some individuals will begin to hyperventilate—that is, their breathing will be very shallow and quick. A by-product of hyperventilation is much lowered levels of CO2 in the blood. Which of the following would you also expect to find? (Select all that apply.) a) decreased blood pH, less than 7.2. b) increased blood pH, greater than 7.2 c) decreased stimulation of chemoreceptors in the brainstem d) increased stimulation of chemoreceptors in the brainstem
b c
The random thermal motion of molecules from a region of higher concentration to a region of lower concentration is called diffusion. The rate of diffusion across a barrier is defined by Fick's law of diffusion: Rate of diffusion = k • A • (C2-C1)/2 k = diffusion coefficient, which depends on solubility and temperature A = surface area for exchange C2 - C1 = difference in partial pressure of gas on either side of the barrier L = thickness of the barrier to diffusion In the design of respiratory systems, respiratory membranes 1 and 2 represent membrane barriers between the outside medium and the inside of the organism. (pic) Which would have the higher rate of diffusion, respiratory membrane 1 or respiratory membrane 2? a) respiratory membrane 1 b) respiratory membrane 2 Which term in the equation above is different between respiratory membranes 1 and 2? a) C2 - C1 b) k c) A d) L
b c
In humans, the stomach secretes: (Select all that apply.) a) cellulase. b) pepsin, an enzyme that digests proteins. c) hydrochloric acid. d) amylase. e) enzymes that digest lipids.
b c e
Sensory cells and sensory neurons allow multicellular animals to sense physical and chemical cues from their environment. What key properties of these cells enable them to perform this function? (Select all that apply.) a) All sensory cells and sensory neurons fire action potentials when they bind a signaling molecule. b) Sensory cells and sensory neurons have electrically excitable membranes that change in charge potential in response to binding an environmental signaling molecule. c) Sensory neurons have myelinated dendrites that serve as nerve endings. d) Sensory cells and sensory neurons have protein receptors linked to intracellular or membrane-based signaling pathways that alter ion channel permeability.
b d
/brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Sequencing.png The three DNA fragments above are about to be sequenced. What is the nucleotide sequence that will be recorded from this synthesis reaction for the bottom (3rd) DNA fragment? a) 5'-CCGGGATCAGGACGCCATT-3' b) 5'-CCGGGCAATAGTCACCATT-3' c) 5'-AATGGCGTCCTGATCCCGG-3' d) 5'-AATGGTGACTATTGCCCGG-3'
c
A retrotranspon known as LINE1 is about 1000 base pairs in length and is present in the human genome in about 516,000 copies. Approximately what percentage of the human genome is accounted for by this transposon? a) 0.17% b) 1.7% c) 17% d) 0.017% e) 0.0017%
c
Imagine you genetically engineered a neuron to produce voltage-gated Na+ and K+ channels that opened at the same time in response to a change in voltage. How would that change the recording shown in the figure? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_35/35_76.jpg a) Threshold values would increase. b) The peak voltage would be higher. c) No action potential would be generated. d) The peak would occur over a longer period of time. e) The period of hyperpolarization would be longer.
c
In complex multicellular organisms, bulk flow is an important physiologic character. Why is bulk flow a necessary condition of complex multicellularity? a) Complex multicellularity is related to the increase in oxygen in the environment. Because bulk flow systems are only related to the delivery of oxygen to tissues, higher environmental oxygen selected for individuals with bulk flow systems. b) Complex multicellularity reflects cell adhesion between cells, and this cannot happen without bulk flow of signaling molecules from the environment. c) Organisms exhibiting complex multicellularity are large and have cells/tissues that are not in contact with their environment. Systems that can overcome the limits of diffusion must occur for basic physiologic processes to occur. d) Bulk flow is necessary to move large amounts of liquid through the organism depending on physiologic needs. The tissues can all receive necessary nutrients from the environment, but bulk flow speeds the rate of diffusion.
c
In the figure below, panel a shows a photoreceptor and its postsynaptic cell in the dark, and panel b shows both cells in the light. What causes the change observed in this figure? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_36/36_116.jpg a) Hyperpolarization of the rod cell in the dark causes release of a neurotransmitter. b) This figure is incorrect; dark and light are reversed. c) Hyperpolarization of the rod cell in the light inhibits release of a neurotransmitter. d) Depolarization of the rod cell in the light inhibits release of neurotransmitter.
c
Most nutrient absorption takes place in the: (Select all that apply.) a) large intestine. b) liver. c) small intestine. d) pancreas. e) stomach.
c
One of the effects of the hormone secretin is to stimulate the release of bicarbonate ions into the duodenum, which neutralizes the acid that enters the duodenum with food from the stomach. One consequence of neutralizing the pH in the intestine is that: a) enzymes that catalyze the hydrolysis of carbohydrates are denatured. b) the enzymatically catalyzed hydrolysis of carbohydrate that began in the stomach is halted in the duodenum. c) enzymes that catalyze the hydrolysis of carbohydrates are active. d) carbohydrates are not as easily broken down in this neutral environment.
c
One of the hormones not mentioned in the text is GIP (glucose-dependent insulin trophic peptide), which stimulates the secretion of insulin. It is secreted by cells of the duodenum in response to the presence of glucose. Its secretion and action on insulin production is an example of a: a) homeostatic positive feedback mechanism amplifying the response to glucose ingestion. b) homeostatic negative feedback mechanism changing the set point. c) homeostatic negative feedback mechanism keeping a system near a set point.
c
Which of the following is an example of the effector's role in maintaining homeostasis? a) decrease in body temperature on a cold day b) vasodilation on a cold winter day c) increased sweating on a hot summer day d) increased body temperature during a workout
c
Below is a diagram of O2 uptake at the fish gill. The values shown indicate percent fluid saturation of O2. Which choice below identifies the fluid and the direction of flow CORRECTLY? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/fishimages2.jpg /brainhoney/Resource/9529883,8,0,44,30,2/Assets/choices2.jpg a) A b) B c) C d) D e) E
e
A newly discovered signaling molecule that binds to a G protein-coupled receptor is being studied by using cells maintained in cell culture. Preliminary results show that the binding of this new ligand causes the activation of adenylyl cyclase. In the next part of this study, a non-hydrolyzable version of GTP (a form of GTP that cannot be converted to GDP) is added to the cell culture dishes and is taken up by the cells. Which of the following would you expect to observe? a) decreased cAMP, decreased protein kinase A activity b) decreased cAMP, increased protein kinase A activity c) increased cAMP, decreased protein kinase A activity d) increased cAMP, increased protein kinase A activity
d
A retrotransposon known as Alu1 is about 300 base pairs in length and is present in the human genome in about 1 million copies. Approximately what percentage of the human genome is accounted for by this transposon? a) 1% b) 0.1% c) 30% d) 10% e) 0.03%
d
Aldosterone, in the figure below, is a hormone secreted by the adrenal cortex, and insulin is a peptide secreted by the pancreas. When aldosterone contacts a target cell, it binds to an intracellular receptor and migrates to the nucleus; insulin binds to extracellular receptors on the plasma membrane. What is the MOST likely reason for this difference? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/resources/chapter_38/38_43.jpg a) Aldosterone is too small to bind extracellular receptors on the plasma membrane. b) Insulin is too large to interact chemically with DNA. c) Aldosterone is hydrophilic and, therefore, must enter the aqueous environment of the cytoplasm to have an effect. d) Aldosterone is lipid-soluble and, therefore, easily crosses the phospholipid bilayer of the plasma membrane.
d
All of the following would lead to an increase in the force generated by a muscle contraction EXCEPT: a) increasing the frequency of muscle stimulation by the motor nerve. b) increasing the number of muscle fibers activated. c) increasing the number of motor units activated. d) increasing the rate at which calcium is pumped back into the sarcoplasmic reticulum. e) maximizing the number of cross-bridges formed during a contraction.
d
Based on the diagram showing the insulin signaling pathway, which protein is a phosphatase? /brainhoney/Resource/9529883,8,0,44,30,2/Assets/JT/LS%207C/Screen%20Shot%202018-10-18%20at%205.01.46%20PM.png a) P2 b) None of the above c) P3 d) P4 e) P1
d
Glucose enters the epithelial cells of the small intestine against its concentration gradient. Select the BEST explanation from the following. a) Glucose is co-transported in the Na+/K+ pump. b) Glucose is transported through a glucose pump in the apical membrane that hydrolyzes ATP to ADP and Pi. c) Glucose follows the water that is pumped into the cell. d) Glucose is co-transported with Na+, which moves down its concentration gradient into the cell. e) Glucose enters by diffusion
d
Which of the following would result in tetanus? a) allowing a muscle fiber to relax for several seconds between twitches b) All of these choices are correct. c) stimulating a muscle fiber to contract immediately after it has relaxed d) stimulating a muscle fiber to contract when it has partially relaxed e) stimulating the muscle fiber so frequently that it cannot relax at all
e
Many birth-control pills release a constant amount of synthetic estradiols and progesterone for 21 days, followed by 7 days when no hormones are ingested. Which of the following statements MOST accurately describes the effects of birth-control pills? a) Birth-control pills maintain constant levels of estrogens and/or progesterones and mask the release of the oocyte from the follicle. b) Birth-control pills inhibit the development of the uterine lining so implantation of a fertilized oocyte cannot occur. c) The 7 days with no hormones does not allow a thick enough uterine lining to form so a fertilized oocyte cannot implant. d) Birth-control pills maintain constant levels of estrogens and/or progesterone so there is no surge in LH and ovulation does not occur.
d
The duct that connects the pancreas to the duodenum can sometimes become blocked. What is the result? a) The digestive enzymes are not affected because they are stored in the gallbladder until they are needed in the duodenum. b) Nothing happens because the pancreas does not produce digestive enzymes. c) The digestive enzymes produced by the pancreas enter the large intestine instead and digestion proceeds as normal. d) The digestive enzymes back up into the pancreas and may start to digest the pancreas. e) The digestive enzymes produced by the pancreas still enter the duodenum because they travel by the blood to reach the duodenum, not by a duct.
d
