HW 3-30 through 4-8

1. Which of the following would be a negative feedback system involving temperature? (A) when the temperature of a system increases, a heater is turned on (B) when the temperature of a system decreases, a heater is turned on (C) when the temperature of a system decreases, a cooler is turned on (D) when the temperature of a system decreases, a heater is turned off

B

1. Which of the following is an example of osmoregulation? Group of answer choices A. Gill tissues in a salt-water fish use ATP to pump salts out of their blood and release salts into seawater B. Eggs of a fresh-water fish are covered with a thick jelly layer to block any exchange of water and solutes C. Cells in an animal living where salinity changes often (as in an estuary/bay) passively equilibrate salinity with their environment

A

2. Which of the following would be a positive feedback system involving temperature? (A) when the temperature of a system increases, a heater is turned on (B) when the temperature of a system decreases, a heater is turned on (C) when the temperature of a system increases, a cooler is turned on (D) when the temperature of a system decreases, a heater is turned off

A

3. Of the three main types of nitrogenous wastes, which is most toxic if accumulates at high levels inside cells? A. ammonia B. urea C. uric acid

A

4. Why is it advantageous for birds (they fly around a lot) to excrete mainly uric acid? A. uric acid requires less water for excretion and elimination B. uric acid is a digestive waste also, can mix with feces C. uric acid is a simpler, cheaper molecule to synthesize compared to urea and ammonia.

A

5. Ammonia is likely to be the primary nitrogenous waste in living conditions that include _____. A) lots of fresh water flowing across the gills of a fish (B) lots of seawater, such as a bird living in a marine environment (C) a terrestrial environment, such as that supporting crickets (D) a moist system of burrows, such as those of moles and mole rats

A

5. How do peptide (water-soluble) & steroid (lipid-soluble) hormones differ in receptor location in target cells? (A) Peptide hormone receptors are on the cell surface. (B) Peptide hormone receptors are intracellular. (C) Steroid hormones don't need a receptor. (D) Receptor location is the same for peptide and steroid hormones (no difference)

A

7. Which best describes how a peptide hormone generally affects its target cell? (A) Binds to a plasma membrane receptor and initiates a signal transduction system (B) Binds to a plasma membrane receptor and is taken in by endocytosis (C) Binds to an intracellular receptor and becomes a transcription factor (D) Stimulates target cell to secrete a chemical signal into the blood

A

8. When blood glucose levels rise above the set level, as after a big meal, which results? (A) insulin is secreted (B) insulin secretion stops (C) glucagon is secreted (D) glucagon secretion stops

A

Consider this pathway of stimulation: Hypothalamus --> X releasing factor --> Anterior Pituitary --> X tropin -->gland X --> hormone X 4. In the above pathway an example of positive feedback would be (A) high levels of X tropin lead to hypothalamus secreting more X releasing factor (B) high levels of X tropin lead to gland X secreting more hormone X (C) high levels of X tropin lead to low levels of X releasing factor (D) high levels of X tropin lead to low levels of hormone X

A

10. Toxins from cholera bacteria cause the intestinal epithelial cells to release Cl- ions and to secrete Na+ ions, K+ ions, and bicarbonate ions out of the cells into the gut cavity. Also, the normal movement of Na+ from the gut into the epithelial cells is blocked. So, what happens in the cholera patient to cause massive diarrhea and dehydration? A. because water follows solutes, more water is taken into intestinal epithelial cells B. because water follows solutes, more water is lost in the feces C. because of high bacterial concentrations in the gut cavity, more water is taken into intestinal epithelial cells D. because of high bacterial concentrations in the gut cavity, more water is lost in the feces.

B

10. [application question] In order to test the hypothesis that the hypothalamus is the body's thermostat, scientists insert probes into a mouse brain that can gently warm or cool the hypothalamus. If the hypothesis is correct, then when the hypothalamus is warmed what will happen? (A) the rate of metabolism will decrease (B) sweat glands will become active (C) muscle shivering will increase (D) insulin will be released into the blood

B

2. Of the three main types of nitrogenous wastes, ____ is most soluble in water and ___ is least soluble in water. A. ammonia; urea B. ammonia; uric acid C. urea; ammonia D. urea; uric acid E. uric acid; urea F. uric acid; ammonia

B

2. Which of the following best describes hydrolysis reactions? A. dissolving food or other molecules in water B. breaking bonds between monomers in a chain/polymer C. splitting water into its component atoms, hydrogen and oxygen D. releasing a water molecule during a condensation reaction

B

3. Countercurrent exchange in the fish gill helps to maximize ________. A. blood pressure B. diffusion C. active transport D. osmosis

B

6. How does co-transport (through symport proteins) increase the uptake of specific substances from the gut lumen into the transport epithelium cells? A. Uses ATP to pump substances out of lumen into cells against their concentration gradient B. Uses an ion gradient to pump substances out of lumen into cells against their concentration gradient C. Co-transport symport protein uses ATP to set up ion gradients D. Two of these are how co-transport works in the gut

B

7. Which of the following describes the process of filtration in excretory tubules? A. selective transport of water and solutes from blood into the tubule B. non-selective transport of water and solutes from blood into the tubule C. selective transport of water and solutes from the tubule into the blood D. non-selective transport of water and solutes from the tubule into the blood

B

7. Which of the following would we expect to see in transport epithelial tissues with extensive uptake of water? A. membrane proteins that use ATP to pump water against its gradient B. membranes with abundant aquaporins C. membranes with a thinner phospholipid bilayer D. two of these would increase uptake of water

B

7. Which set of traits is matched with the correct adrenal gland? (A) adrenal cortex is stimulated directly by nerves from the brain (B) adrenal medulla is stimulated directly by nerves from the brain (C) adrenal cortex is stimulated directly by a tropic hormone from the hypothalamus (D) adrenal medulla is stimulated directly by a tropic hormone from the pituitary

B

8. Blood hemoglobin that has just been in lung capillaries (where PO2=100) is next in a capillary in the liver (PO2=40). When it arrives at the liver capillaries, that hemoglobin will A. take up (bind more) O2, B. give up (unbind) O2, C. have little change in O2 binding

B

8. The pH within the stomach is about 2, and most digestive enzymes in the small intestine have a pH optimum of 7-8. When the stomach's acidic food mass starts to pass into the small intestine a hormone signal is released into the blood. To be effective, that hormone should trigger the release of which of these? (A) acid into the stomach (B) bicarbonate into the small intestine (C) hydrolytic enzymes into the small intestine (D) uptake of glucose into cells (E) aggregation of fats into globules.

B

9. Many mammals whose diet includes a great deal of leafy plant matter have extra compartments or extensions of their digestive tract that are not present in similar mammals that do not eat leaves. The function of the extra compartments is to A. increase surface area for absorption of nutrients into the blood B. provide a region for their symbiotic bacteria to live C. provide an area to store the leafy matter before digestion D. provide an area to store water required for digestion.

B

9. What would be the effect on the volume of urine excreted (eliminated from the body) if there is increased water reabsorption in the excretory tubule? A. urine volume would increase B. urine volume would decrease C. no change in urine volume

B

1. Respiratory systems are likely to have many adaptations that maximize diffusion because: A. gas exchange readily occurs through the skin and body wall B. membranes have O2 pumps for transporting oxygen. C. gas exchange involves passive transport across membranes D. membranes exchange gases whenever osmosis is occurring

C

1. Which of these is a distinctive feature of all tropic hormones ("tropins")? (A) all hormones from the hypothalamus are tropins (B) all steroid hormones are tropins (C) the target cells of all tropins are other glands

C

10. Among mammals that have their kidney tubules extended and forming a loop of Henle, which of these would be expected to have more tubules with long loops of Henle? (P.S. Do you know which this relationship exists? P.S. human kidneys have a mixture of long and short loops) A. beaver, otter, or other mammal living in freshwater streams B. animals that ingest a great deal of plant material in their diet C. kangaroo rat or other desert-adapted mammal

C

10. In regulation of blood glucose, if blood glucose level falls below the set point, which one of these responses represents what happens in the effector part of the control system? (A) Beta cells secrete insulin into the blood; (B) Glucagon hormone triggers cells to increase glycolysis (C) Liver cells break down glycogen starch and release glucose into the blood (D) Brain cells without sufficient glucose to function start using fats for energy

C

10. Some mammals are adapted to high elevations. For instance, the llama, a member of the camel family native to the high Andes, lives where pO2 in lung alveoli could be < 80 mmHg. Llamas have a slightly different hemoglobin with a different binding curve from that of humans and other low-elevation mammals. Predict the shift of the binding curve of llama hemoglobin relative to the adult hemoglobin curve and choose why that is an adaptive advantage: A. it is shifted to left of the normal hemoglobin curve, so during exercise hemoglobin holds O2 and gives up much less to cells B. it is shifted to right of the normal hemoglobin curve, so during exercise hemoglobin holds O2 and gives much less to cells C. it is shifted to the left of the normal hemoglobin curve, so that hemoglobin could bind more O2 from inhaled air in lungs D. it is shifted to the right of the normal hemoglobin curve, so that hemoglobin could bind more O2 from inhaled air in lungs

C

2. The process of bringing oxygenated water or air into contact with a gas-exchange surface is A. respiration B. gas exchange C. ventilation D. diffusion

C

4. In order to be a target cell for a particular animal hormone signal, the cell must: (A) Be able to produce that hormone (B) Be very close to the cells that produce that hormone (C) Have a specific receptor for that hormone (D) Two of these are true.

C

6. Which best describes how a steroid hormone affects its target cell? (A) Binds to a plasma membrane receptor and initiates a signal transduction system (B) Binds to a plasma membrane receptor and is taken in by endocytosis (C) Binds to an intracellular receptor and becomes a transcription factor (D) Stimulates target cell to secrete a chemical signal into the blood

C

6. Which process in the excretory tubule is the least selective? A. active transport B. co-transport C. filtration D. reabsorption E. secretion

C

6. Which set of traits is matched with the correct adrenal gland? (A) adrenal cortex secretes peptide hormones that trigger signal transduction (B) adrenal medulla secretes steroid hormones that trigger signal transduction s (C) adrenal cortex secretes steroid hormones that act as transcription factors (D) adrenal medulla secretes peptide hormones that act as transcription factors

C

7. Molecules of hemoglobin that are saturated with O2 in sites with pO2 100 mm Hg will give up about 25% of their O2 when they reach areas with pO2 values closest to which of these? A. 0 B. 20 C. 40 D. 60 E. 80

C

8. Cells in kidney tubules have many mitochondria and use a great deal of ATP. Which of the following tubule functions requires a large expenditure of cell energy? A. filtration from blood into the beginning of the excretory tubule B. facilitated diffusion of Na+ ions in reabsorption from tubule to blood C. establishing gradients that will power co-transport in reabsorption into blood D. facilitated diffusion of K+ ions from the tubule back into the blood

C

9. In a healthy person, after a carbohydrate-rich meal, the production of _____ will increase, causing the uptake of _____ from the blood into liver cells. (A) insulin; glucagon (B) insulin; insulin (C) insulin; glucose (D) glucagon; protein (E) glucagon; glucose

C

Consider this pathway of stimulation: Hypothalamus --> X releasing factor --> Anterior Pituitary --> X tropin -->gland X --> hormone X 3. In the above pathway an example of negative feedback control would be (A) high levels of X tropin lead to hypothalamus secreting more X releasing factor (B) high levels of X tropin lead to gland X secreting more hormone X (C) high levels of X tropin lead to low levels of X releasing factor (D) high levels of X tropin lead to low levels of hormone X

C

1. Which of these are organs that EXCHANGE molecules between an animal and its environment? (A) Brain (B) Heart (C) Pancreas (D) Intestine

D

2. If a particular tissue is stimulated by thyroid hormones, cells of that tissue must therefore: (A) Secrete thyroxine; (B) Secrete thyrotropic hormone (TSH) (C) Secrete an inhibitor of thyroxine (D) Have specific receptors for thyroxine (E) Have specific receptors for thyrotropic hormone (TSH)

D

3. Which of the following is a good example of regulation in homeostasis? (A) When core body temperature falls, sweating is triggered. (B) When an animal spots a predator, the animal moves to hide or escape. (C) When circulating blood glucose level falls, cells take in more glucose and make starch. (D) When an animal becomes dehydrated, the kidney retains more water.

D

4. The function of tight junctions in epithelial tissue is (A) to increase the surface area; (B) increase the strength and integrity of the tissue layer (C) increase the solute uptake in the tissue (D) increase the selectivity of transport across the tissue layer (E) increase the flow of water across the tissue layer

D

5. In the human digestive tract, the greatest amount of hydrolysis occurs in ____, and the great amount of nutrient absorption, for transport into blood circulation, occurs in ____. (A) stomach, stomach (B) stomach, small intestine (C) small intestine, large intestine (D) small intestine, small intestine (E) large intestine, large intestine.

D

5. To answer questions 5-10, please refer to the hemoglobin binding curve. When hemoglobin in red blood cells is in an area where the PO2 is 40 mm Hg, about what percent of that hemoglobin is bound with O2? A. 0% B. 25% C. 50% D 75% E 100%

D

9. A decrease of blood pH from 7.4 to 7.2 causes the hemoglobin binding curve to shift to the right a little. Therefore, under those conditions hemoglobin will A. release all bound carbon dioxide molecules B. bind more oxygen molecules C. decrease its binding of H+ D. give up more of its oxygen molecules

D

9. Animal cells specialized for secreting steroid hormones are likely to have an abundance of which combination ? (A) rough ER and lysosomes (B) gap junctions and Golgi (C) rough ER and mitochondria (D) smooth ER and Golgi

D

4. The human lung alveolus demonstrates which adaptations to maximize diffusion A. Short diffusion distance B. Counter current exchange C. Large surface area D. Two of these E. All three of these

D (A and C)

3. Which of the following directly increases diffusion rates of sugars and amino acids from the gut cavity into the transport epithelium cells? A. increased food intake B. increased surface area (microvilli) C. increased specific transport proteins in epithelial membrane D. two of these E. all three of these

D (B and C)

5. Considering the hormones involved in regulating thyroid activity, which of the following are circulated in the blood? (A) thyroid releasing hormone from hypothalamus (B) thyroid stimulating hormone from pituitary (C) thyroxine from thyroid (D) two of the above (E) all three of the above

E

6. In lung alveoli (pO2 about 100 mm Hg) hemoglobin will bind O2 until it's about what % saturated? A. 0% B. 25% C. 50% D. 75% E. 100%

E

8. How can the exact same hormone trigger different responses in different tissues? (A) different tissues produce different hormones (B) different tissues contain the same receptor proteins (C) different tissues contain different receptors for the same hormones (D) different tissues contain the same receptor proteins but linked with different intracellular proteins (E) two of these can explain the different responses

E (C and D)