BISC 221 Exam 3

1. If ammonia gas (NH3) takes one second to diffuse thru 50 microns of tissue, how long would it take for the ammonia to diffuse thru the wall of a blood vessel that is 1 micron thick? a. 0.4 milliseconds b. 2 milliseconds c. 20 milliseconds d. 44.7 milliseconds e. Cannot diffuse through because vessel walls are impermeable to ammonia

A

12. Which of the following statements is false? a. Thrombin provides negative feedback to regulate the enzymatic blood clotting cascade b. Vitamin K is vital for synthesis of blood clotting factors c. Platelets provide structural support for blood clots d. Fibrin is polymerized fibrinogen

A

14. Small swollen areas in the neck, groin, and axillary region are associated with _____. a. increased activity of the immune system b. blood sugar that is abnormally high c. dehydration d. sodium depletion

A

2. Why do the cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms? A) These proteolytic enzymes, in active form, would digest the very tissues that synthesize them. B) By secreting inactive enzymes, the catalytic activity of the enzymes is maintained for a longer time. C) The stomach is too acidic to maintain these enzymes in their active form. D) Inactive pepsin and trypsin are more easily transported across the cell membrane

A

23. What is true of a secondary immune response? 1. It is brought about by memory cells. 2. It is less effective than a primary immune response. 3. It includes a humoral response but not a cell-mediated response. 4. After it occurs, the immune system can only respond to reinfection with the same antigen by mounting another primary immune response. a. 1 only b. 1 and 2 c. 1 and 3 d. 2, 3, and 4 e. 1, 2, and 3

A

30. Vaccination increases the number of _____. a. lymphocytes with receptors that can bind to the pathogen b. epitopes that the immune system can recognize c. macrophages specific for a pathogen d. major histocompatability (MHC) molecules that can present an antigen

A

33. Following differentiation, single cell DNA sequencing shows that a particular B cell has 35 V segments and a single J segment in the region of the genome encoding the Ig light chain. How many possible variations of the light chain variable region is this cell capable of producing? a. 1 b. 35 c. about 20,000 d. about 400,000

A

39. The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that _____. a. loss of water by osmosis from cells in vital organs resulted in cell death and organ failure b. high amounts of salt had diffused into the fish's cells, causing them to swell and lyse c. the kidneys were not able to keep up with the water removal necessary in this hyperosmotic environment, creating an irrevocable loss of homeostasis d. the gills became encrusted with salt, resulting in inadequate gas exchange and a resulting asphyxiation

A

5. Which phrase makes the statement true? In a single circulation system... a. Blood pressure is higher in the gill capillaries than in the body capillaries b. Blood pressure in the body capillaries is generally higher than in a double circulation system c. Blood leaving the heart passes thru a single capillary bed before returning d. Blood leaving the heart is highly oxygenated

A

An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it _____. a. blocks the openings into the tracheal system b. interferes with gas exchange across the capillaries c. clogs their bronchi d. prevents gases from leaving the atmosphere

A

Antidiuretic hormone (ADH) and the renin-angiotensin-aldosterone system (the RAAS) work together in maintaining osmoregulatory homeostasis through which of the following ways? a. ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and the RAAS maintains the osmolarity of the blood by stimulating Na+ and water reabsorption. b. ADH and the RAAS work antagonistically; ADH stimulates water reabsorption during dehydration and the RAAS causes increased excretion of water when it is in excess in body fluids. c. Both stimulate the adrenal gland to secrete aldosterone, which increases both blood volume and pressure via its receptors in the urinary bladder. d. ADH and the RAAS combine at the receptor sites of proximal tubule cells, where reabsorption of essential nutrients takes place.

A

Urea is produced in the _____. a. liver from NH3 and carbon dioxide b. liver from glycogen c. kidneys from glycerol and fatty acids d. bladder from uric acid and water

A

What is a major reason why erythrocytes are biconcave? a. To make gas diffusion between inside and outside the cell easier b. To fit the most hemoglobin molecules in an object with the smallest possible surface area c. To improve plasma and blood separation under high centrifugal forces d. To enable cooperativity between hemoglobin subunits

A

Which of the following is required to activate a cell-mediated or humoral immune response to a foreign molecule? a. cytokines secreted by helper T cells b. perforins secreted by cytotoxic T cells c. granzymes secreted by cytotoxic T cells d. antibodies secreted by plasma cells e. complement proteins secreted by the liver

A

28. Dr. Wang is lazy and clever. She has DNA for a red fluorescent protein and a green fluorescent protein and wants to evolve new colors with minimal effort. She cleverly inserts both the red and green DNA sequences into the genome of a cell line and grows the cells in culture. When she examines the culture after 2 months, she is thrilled to see many new colors of cells. What is the most likely cell type she used to grow her colored cells? a. Polychromatic erythrocyte b. B lymphocyte c. Embryonic kidney d. Macrophage e. Helper T lymphocyte

B

36. The force driving simple diffusion is _____, while the energy source for active transport is _____. a. the concentration gradient; ADP b. the concentration gradient; ATP c. transmembrane pumps; electron transport d. phosphorylated protein carriers; ATP

B

37. Blood flukes are parasitic flatworms that live in the bloodstream of the host. The worm's interstitial fluids are isoosmotic to the host's blood, so which of these is/are true? 1. The worms lack flame bulbs, or have nonfunctional flame bulbs. 2. The worms have flame bulbs that are mostly active in performing osmoregulation. 3. The worms have flame bulbs that eliminate nitrogenous wastes. 4. The worms have flame bulbs whose role is to eliminate excess water that enters the worm by osmosis. a. 1 only b. 3 only c. 2 and 3 d. 2 and 4 e. 3 and 4

B

4. Which one of the following best explains why a person whose job requires him to stand all the time is likely to come home at the end of the workday with swollen feet? a. The relative lack of activity keeps cardiac output low, which reduces blood flow to the feet. b. The lack of skeletal muscle pumping reduces venous return to the heart, and the increased blood pressure in foot capillaries causes increased fluid leakage. c. Increased activity in sympathetic nerves causes smooth muscle in capillary walls to contract, which squeezes more fluid out of capillaries. d. Increased pressure in blood vessels in the foot causes an increase in drainage of lymphatic fluid from the foot.

B

43. A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that _____. a. they have membranes of varying permeability to water b. they operate an extensive set of active-transport ion pumps c. they are the body's only means of shedding excess nutrients d. they have an abundance of myogenic smooth muscle

B

44. Under which circumstance should reabsorption of water from kidney filtrate back into the bloodstream be most effective? a. if neither ADH nor aldosterone is present in circulation b. if both ADH and aldosterone are present in circulation c. if ADH, but not aldosterone, is present in circulation d. if aldosterone, but not ADH, is present in circulation e. if renin, angiotensin II, and aldosterone are present in circulation, but not ADH

B

45. The loop of Henle dips into the renal medulla. This is an important feature of osmoregulation in terrestrial vertebrates because _____. a. absorptive processes taking place in the loop of Henle are hormonally regulated b. differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient c. the loop of Henle plays an important role in detoxification d. additional filtration takes place along the loop of Henle

B

6. A blood pressure cuff is inflated to 115mmHg in a patient with 130/70 blood pressure. During which periods of the cardiac cycle does blood flow thru the artery immediately downstream of the cuff? a. Flows during both systole and diastole b. Flows during systole, does not flow during diastole c. Flows during diastole, does not flow during systole d. Does not flow during both systole and diastole

B

7. A molecule of CO2 that is generated in the cardiac muscle of the left ventricle would not pass through which of the following structures before leaving the body? a. right atrium b. left atrium c. right ventricle d. left ventricle

B

All clonal descendants of a single activated B cell produce immunoglobulins with a. Identical heavy chain constant regions b. identical variable region of the heavy chain and identical variable region of the light chain. c. identical variable region of the heavy chain and different variable region of the light chain. d. different variable region of the heavy chain and identical variable region of the light chain. e. different variable region of the heavy chain and differend variable region of the light chain.

B

Dr. Lenti wants to redesign the HIV virus to deliver a new therapeutic gene to neurons to test a cure for autism. Which component of the HIV genome will she need to swap out with a new design to allow the virus to infect neurons instead of helper T-cells? a. p17 - a matrix protein b. gp120 - a surface glycoprotein c. tat - a reverse transcription regulator protein d. pr - a protease e. rt - a reverse transcriptase

B

Glomerular filtration occurs in which one of the following structures? a. Collecting duct b. Bowman's capsule c. Proximal tubule d. Loop of Henle e. Malpighian tubule

B

If ATP production in a human kidney was suddenly halted, urine production would _____. a. decrease, and the urine would be hypoosmotic compared to plasma b. increase, and the urine would be isoosmotic compared to plasma c. increase, and the urine would be hyperosmotic compared to plasma d. decrease, and the urine would be isoosmotic compared to plasma

B

Lymphocytes that become T cells are born in the... a. thymus b. bone marrow c. pancreas d. liver e. thyroid

B

Tissues of sharks are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. What can you infer about the movement of sodium and chloride in these animals? a. To maintain homeostasis of sodium and chloride levels, the shark must take up additional sodium and chloride from seawater. b. Sodium and chloride will diffuse into shark gills from seawater down their concentration gradient. c. Sharks conserve sodium and chloride, limiting excretion. d. Sodium and chloride must be eliminated through the gills.

B

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates? a. The kidneys require constant and abnormally high oxygen supply to function. b. The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys. c. The kidneys require higher than normal levels of hormones. d. The renal artery and vein are the main pathways regulating how much is produced by the kidneys.

B

11. Which cell type is not a descendent of myeloid stem cells a. Macrophages b. Erythrocytes c. Cytotoxic T cells d. Neurophils e. Eosinophils

C

13. Which of the following statements is true a. All veins in the body have a bluish color, indicating they carry partially deoxygenated blood b. All types of blood vessels, except capillaries, contain smooth muscles in their walls c. Immediately following atrial systole, the AV node delays ventricular systole long enough to empty the contents of the atria into the ventricle d. During ventricular diastole, blood pressure in the aorta is lower than blood pressure in the pulmonary artery.

C

21. Mr. Krakauer and Mr. Boukreev both climb to the summit of Mt. Everest at 8848m high and 253mmHg barometric pressure. Shortly after they begin descending to camp IV a terrible storm hits. Mr. Krakauer partially supplements his breathing with canisters of pure oxygen, while Mr. Boukreev does not. What are the most plausible values for their alveolar PO2 as the storm envelops them? a. Krakauer 100mmHg, Boukreev 100mmHg b. Krakauer 35mmHg, Boukreev 35mmHg c. Krakauer 60mmHg, Boukreev 35mmHg d. Krakauer 253mmHg, Boukreev 35mmHg e. Krakauer 253mmHg, Boukreev 100mmHg

C

25. Which one of the following conditions is most consistent with clinical findings of elevated levels of IgE antibodies in the plasma and elevated numbers of eosinophils in the blood? a. bacterial infection b. cancer c. parasitic worm infection d. viral infection e. acquired immune deficiency syndrome (AIDS)

C

29. Which of the following statements are false? a. Immunoglobulin classes are determined by the constant region of the heavy chain. b. IgA molecules have lower molecular weight than IgM molecules. c. Recombination of genes to produce functional B-cell receptors occurs immediately after exposure to antigen. d. An effective immune response to bacterial infection would include production of both memory B-cells and memory T-cells.

C

34. In what way does the function of reverse transcriptase violate the simplified form of the central dogma of molecular biology, namely that "DNA makes RNA, RNA makes protein" a. Protein is transcribed into RNA by reverse transcriptase b. Protein is transcribed into DNA by reverse transcriptase c. RNA is transcribed into DNA by reverse transcriptase d. DNA is transcribed into RNA by reverse transcriptase e. RNA is transcribed into protein by reverse transcriptase

C

42. Animals that can produce exceptionally concentrated urine should be expected to have nephrons with longer 1. descending limbs of the loops of Henle. 2. ascending limbs of the loops of Henle. 3. distal tubules. 4. proximal tubules. a. 1 only b. 3 only c. 1 and 2 d. 1 and 4 e. all four of these

C

If you hold your breath for a long time, body CO2 levels are likely to ____________, and the pH of body fluids is likely to _____________. a. increase; increase b. decrease; increase c. increase; decrease d. decrease; decrease

C

The number of major histocompatability (MHC) protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because _____. a. the MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways b. MHC proteins from one individual can only be of class I or class II c. each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene d. once a B cell has matured in the bone marrow, it is limited to two MHC response categories

C

17. After surgical removal of the gallbladder, a person might need to limit his or her dietary intake of A) starch. B) protein. C) sugar. D) fat. E) alcohol.

D

22. Which of the following in vertebrates has the same function as hemocytes in insects? a. Toll-like receptor b. interferon c. complement system d. neutrophils e. mast cells

D

3. Most absorbed food travels directly from the _______ to the ________ via the hepatic portal vein, except ________ which are taken up into the ________. a. Large intestine; liver; sugars; pancreas b. Small intestine; kidney; lipids; spleen c. Stomach; liver; proteins; lymphatic system d. Small intestine; liver; lipids; lymphatic system e. Large intestine; kidney; lipids; pancreas

D

8. Which of the following does not directly affect blood flow thru a capillary bed a. Norepinephrine b. Adenosine c. Precapillary sphincters d. HDL/LDL cholesterol levels

D

The fluid most likely to contain high levels of immunoglobulin A is a. plasma b. intracellular fluid c. lymphatic fluid d. breast milk e. whole blood

D

10. Lance Legstrong (blood type O+) wants to win an 8th Tour de France bicycle race by any means necessary. He is worried that a new blood test for erythropoietin (a banned substance) will make it more difficult for him to cheat. How might Lance achieve a similar effect to taking EPO leading up to the race to boost his performance? a. Donate blood to the Red Cross two weeks before the race b. Donate plasma to the Red Cross two weeks before the race c. Transfuse blood into himself from his friend (blood type AB+) d. Transfuse plasma into himself from his friend (blood type AB+) e. Transfuse blood into himself from some bags he donated two months ago and kept in back of the refrigerator

E

16. A genetic mutation reorganizes the gills of a fish so that vessels carrying blood into and out of each lamella are in the opposite position than normal. When the fish is swimming forward, what are the most plausible PO2 levels for blood and water after they pass through the lamella? a. blood 140mmHg, water 30mmHg b. blood 20mmHg, water 150mmHg c. blood 30mmHg, water 30mmHg d. blood 140mmHg, water 150mmHg e. blood 85mmHg, water 85mmHg

E

19. In which one of the following situations would you expect hemoglobin to have the lowest binding affinity for O2? a. in resting skeletal muscle b. in the pancreas when you are breathing normally c. in the pancreas when you are holding your breath d. in the alveolar capillaries e. in the quadriceps when running

E

31. Which defensive chemical is improperly matched with a function? a. perforins—lysis b. antibodies—pathogen neutralization c. histamines—dilate capillaries d. cytokines—immune cell stimulation e. lysozymes—cause fevers

E

9. Blood pressure in a capillary is 32 mmHg at the arteriolar end and 15mmHg at the venular end. The osmotic pressure exerted by plasma proteins is 21 mmHg. The osmotic pressure exerted by proteins in the extracellular space is 2 mmHg. What is the net force producing fluid movement across the capillary wall at its venular end? a. 15mmHg out of the capillary b. 15mmHg into the capillary c. 17mmHg out of the capillary d. 6mmHg into the capillary e. 4mm Hg into the capillary

E

In kidneys, which hormone is most effective at causing increased numbers of aquaporins to be present in collecting duct epithelia, and what is the source of this hormone? a. renin; kidneys b. aldosterone; adrenal medulla c. aldosterone; adrenal cortex d. ADH; kidneys e. ADH; posterior pituitary gland

E