Bio 109 exam 4 (poll questions)

Individuals whose diet consists primarily of corn would most likely become: • A. Malnourished • B. Obese • C. Overnourished • D. Anemic • E. Undernourished

A. Malnourished

Homeostatic mechanisms: • A. keep variables exactly at the set point. • B. help to keep a relatively constant internal environment in the body. • C. act to keep values out of the normal range. • D. usually operate by positive feedback. • E. produce most disease conditions.

B. Help to keep a relatively constant internal environment in the body

How is positive feedback different from negative feedback? • 1. Positive feedback benefits the organism, but negative feedback is harmful. • B. Positive feedback's effector responses are in the same direction as the initiating stimulus, whereas negative feedback's effector responses are in the opposite direction. • C. In positive fcedback, the effector's response increases some parameter (such as body temperature), whereas in negative feedback the parameter decreases. • D. Positive feedback systems have only effectors, wherens negative feedback systems have only receptors. • E. Positive feedback mechanisms are more frequently encountered in the control of homeostasis than negative feedback mechanisms.

B. Positive feedback's effector responses are in the same direction as the initiating stimulus, whereas negative feedback's effector responses are in the opposite direction.

Your body has millions of different antibodies for detecting millions of different antigens because: • A. You have millions of different antibody genes. • B. Antibody genes undergo rearrangement. • C. Antibody genes undergo antigen shifting. • D. All of the above. • E. None of the above.

B. antibody genes undergo rearrangement

Circulatory systems compensate for: •A. temperature differences between the lungs and the active tissue. • B. the slow rate at which diffusion occurs over large distances. • C. the need to cushion animals from trauma. • D. all of the above.

B. the slow rate at which diffusion occurs over large distances.

Which type of surface marker is normally present on every nucleated cell in your body? • A. B receptor • B. T receptor • C. Class I MHC • D. Class II MHC • E. all of the above

C. Class I MHC

Which of the following statements concerning an open circulatory system is true? • A. A heart is not required to pump the circulatory fluid. • B. An open circulatory system has higher blood pressure and is less energy efficient than a closed system. • C. The circulatory flud is also the interstitial fluid. • D. The circulatory fluid does not require respiratory pigments for 02 transport. • E. The lower pressures provide for more effective delivery of 02 chan is possible with a closed system.

C. The circulatory flud is also the interstitial fluid.

Which of the following statements concerning an open circulatory system is true? • A. A heart is not required to pump the circulatory fluid. • B. An open circulatory system has higher blood pressure and is less energy efficient than a closed system. • C. The circulatory fluid is also the interstitial fluid. • D. The circulatory fluid does not require respiratory pigments for 02 transport. • E. The lower pressures provide for more effective delivery of 02 chan is posssble with a closed system.

C. The circulatory fluid is also the interstitial fluid.

Why are measles vaccinations effective? • 1. They cause the inflamination asponse resuling in the production of antibodies that cogulf the measles vius if it enters the body • B, They cause an immune response resuhung sa the producion of cytotose Toells that ruman in the blood attacang sil mruses that enter the body • C. They cause an immune response resiling in the producton of memory B cells the provide a raped response il the indradual is sabsequeatly safected by the measles varos • D. They cause the infammation response resulting in the production of memory T cell that provide a limited response i infecho by the meles virus.

C. They cause an immune response resiling in the producton of memory B cells the provide a raped response il the indradual is sabsequeatly safected by the measles varos

A(n) is an animal that has a relatively variable body temperature, whereas a(n) is an animal that maintains a relatively stable body temperature. • A. Endotherm; ectotherm • B. Ectotherm; endotherm • C. Homeotherm; poikilotherm • D. Poikilotherm; homeotherm • F. Ectotherm; poikilotherm

D. Poikilotherm; homeotherm

Which of the following would increase the rate of heat exchange between an animal and its environment? A. Feathers of fur • B. Vasoconstriction near the skin • C. Blubber or a fat layer under the skin • D. Wind blowing across the body surface • E. All of the above

D. Wind blowing across the body surface

Yearly vaccination of humans for influenza viruses is necessary because: • A. of an increase in immunodeficiency disease. • B. the flu can generate anaphylactic shock. • C. surviving the flu one year exhausts the immune system to nonresponsiveness the second year. • D. rapid mutation in flu viruses alters the surface proteins. • E. memory cells are not formed upon exposure to the flu virus

D. rapid mutation in flu viruses alters the surface proteins.

Compare an animal with a gastrovascular cavity to an animal with a tube-type digestive system. What is(are) the major advantages) of having a tube? • A. It allows the animal to consume a sccond meal while the first is being digested. • B. It permits development of specialized enzymes and concentration of digestive juices in different regions. • C. It permits more time for enzymatic action. • D. Additional physical cutung and grinding of the food bolus is made possible • E. All of the above are advantages.

E. All of the above are advantages.

If the atrioventricular node (AV node) were surgically removed from the heart without disrupting signal transmission to the Purkinje fibers, what would happen? • A. No apparent effect on hcart activity would be observed. • B. Only the ventricles would contract. • C. The heart rate would decrease, • D. Only the atria would contract. • E. Atria and ventricles would contract at approximately the same time.

E. Atria and ventricles would contract at approximately the same time.

Fluid is forced out of systemic capillaries at the arteriolar end because: • A. The blood pressure is less than that of the interstitial fluid. • B. The osmotic pressure of the interstitial fluid is greater than that of the blood • C. The osmotic pressure of the interstitial fluid is greater than the blood pressure. • D. The osmotic pressure of the blood is greater than the hydrostatic pressure of the interstitial fluid • E. The blood pressure is greater than the osmotic pressure of the blood.

E. The blood pressure is greater than the osmotic pressure of the blood.

Some nutrients are considered "essential" in the diets of certain animals because: • A. Only those animals use the nutrients. • B. Those nutrients are subunits of important polymers. • C. Those nutments are necessary coenzymes. • D. Only some foods contain those nutrients. • E. Those nutrients cannot be synthesized by the animal.

E. Those nutrients cannot be synthesized by the animal.

A given volume of blood flowing through an area of large surface area (as at a capillary bed) will have _ speed compared to areas of smaller surface area (as arteries and veins). • A. Higher • B. Lower

b. lower

If some problem made your helper T' cells ineffective, what might be affected? • A. the cell-mediated immune response (cytotoxic T' cells, etc.) • B. the humoral immune response (B cells, etc.) • C. both might be affected • D. neither would be affected

c. both might be affected

The inflammatory response includes all of the following except: • A. release of histamine by mast cells • B. temperature increase • C increased blood flow • D. phagocytosis • E. blood vessel constriction

e. blood vessel constriction