Question 1

The human immunodeficiency virus (HIV)  is so named because it cripples the immune system by attacking and destroying helper T cells (TH cells) . What cell surface protein does the HIV virus most likely use to bind to and infect the TH cells?

Accepted Answer

A)   defensin
B)   MHC class I proteins
C)   CD4
D)   Toll-like receptor
E)   mannose-binding lectin proteinF)  membrane-attack complexG)  CD8H) C) and E)
I) C) and F)

Question 2

Something is terribly wrong with Beth and Steve's newborn baby girl. A biopsy of her kidneys reveals that the kidney nephrons all have extremely short Loops of Henle. What will be the ultimate fate of the baby?

Accepted Answer

A)   She may die because her kidneys cannot secrete K+ and H+ ions into the nephron tubule.
B)   She may die because her kidneys cannot filter urea out of the blood.
C)   She may die because her kidneys cannot reabsorb enough filtered water.
D)   She may die because her kidneys cannot reabsorb all the filtered sugars and amino acids.
E)   She will live because the kidneys of fish, amphibians and reptiles function perfectly well without any Loops of Henle.F) A) and E)
G) B) and E)

Question 3

What is a consequence of the fact that the chickenpox virus has a much lower mutation rate than the influenza virus?

Accepted Answer

A)   A chickenpox infection generally gives immunity against a repeat infection, but people can catch the flu every year.
B)   Chickenpox virus can reemerge decades later with the symptoms of shingles, while influenza is transient.
C)   Chickenpox virus can "hide out" as latent virus in nerve cell bodies, but influenza cannot.
D)   Chickenpox creates skin lesions, while influenza leads to body aches.E) A) and C)
F) A) and D)

Question 4

Different viruses have different properties that affect how the immune system responds to them, and consequently how vaccines must be developed.
-Every year a new version of the flu vaccine is made using a mixture of strains. The strains are chosen based on surveillance and analysis by experts from the FDA, WHO, and CDC. For other diseases however, such as varicella (chickenpox) , the same vaccine is used continually and repeated vaccinations are not necessary. What do you conclude is the important difference between the influenza virus and the varicella zoster virus with regards to vaccinations?

Accepted Answer

A)   Influenza virus has a much higher mutation rate than varicella, leading to frequent antigen changes in the coat proteins and a corresponding deficit of memory cells.
B)   Varicella is attacked by the innate immune system, while influenza is attacked by the acquired immune system.
C)   Influenza virus is transmitted through aerosol droplets in the air, while varicella can be transmitted via skin secretions.
D)   Macrophages and neutrophils can clear all varicella viruses from the body but are unable to do the same for the influenza virus.
E)   Influenza envelope proteins are bound by IgM, while varicella envelope proteins are bound by IgG.F) B) and C)
G) B) and D)

Question 5

You are researching an "orphan disease" with no available treatment. Your lab develops a drug that mimics a lipophilic hormone thought to be lacking in the disease, and you are looking for a pharmaceutical company to partner with to run a clinical trial. Based on the reaction from each team, which would you choose to work with?

Accepted Answer

A)   Company A: "What you've developed is wonderful, but we'll need to develop a delivery system to get the drug across the cell membrane."
B)   Company C: "We're interested in developing this drug - it could really help people. Do you know which genes the hormone regulates?"
C)   Company B: "Your new drug seems very promising. Do you know which G-protein coupled receptor it binds to?"D) All of the above
E) A) and B)

Question 6

Due to a mutation in a smooth muscle gene, the blood vessels in the skin of a certain strain of mouse become dilated when temperature falls below a certain point. Based on the likely outcome of this mutation, what precautions should the researchers take to maintain the health of their mice?

Accepted Answer

A)   The mouse room should be maintained at a cooler than normal temperature.
B)   The mouse room should be consistently maintained at a warm temperature.
C)   The mice will have weak muscles, and should be provided with exercise wheels.
D)   The mice will be susceptible to high blood pressure, and should not be provided with exercise wheels.E) A) and B)
F) A) and C)

Question 7

T cells binding to MHC class I-peptide complexes are responsible for acceptance or rejection of transplanted organs. To facilitate acceptance of the transplant, the ideal donor will have a close genetic relationship with the recipient -- even then, immune suppression drugs are often necessary. In a strange variation of this phenomenon, the endangered Tasmanian devil of Australia suffers from a devastating disease in which tumorous tissue is transmitted from animal to animal. What is the likely explanation for the lack of rejection of this transmissable tumor?

Accepted Answer

A)   Tumors are never targeted by T cells, unless they are caused by a viral infection.
B)   Tasmanian devils lack an adaptive immune system.
C)   Inbreeding in the small population has led to reduced genetic diversity and much-less variable MHC class I genes.
D)   MHC class I genes are unique to humans. Without them, the T cells have no way to distinguish self and non-self.E) A) and B)
F) None of the above

Question 8

Each nephron of the kidney consists of a long tubule and associated small blood vessels. Blood cells and plasma proteins are too large to enter with the glomerular filtrate. What is the correct path for the filtrate to follow through the nephron in the production of urine?

Accepted Answer

A)   Bowman's capsule  →\rightarrow→  distal convoluted tubule  →\rightarrow→  loop of Henle  →\rightarrow→  proximal convoluted tubule  →\rightarrow→  collecting duct
B)   Bowman's capsule  →\rightarrow→  proximal convoluted tubule  →\rightarrow→  loop of Henle  →\rightarrow→  distal convoluted tubule  →\rightarrow→  collecting duct
C)   Bowman's capsule  →\rightarrow→  loop of Henle  →\rightarrow→  proximal convoluted tubule  →\rightarrow→  distal convoluted tubule  →\rightarrow→  collecting duct
D)   Bowman's capsule  →\rightarrow→ collecting duct  →\rightarrow→  proximal convoluted tubule  →\rightarrow→  loop of Henle  →\rightarrow→ distal convoluted tubule
E)   collecting duct  →\rightarrow→  proximal convoluted tubule  →\rightarrow→  loop of Henle  →\rightarrow→  distal convoluted tubule →\rightarrow→ Bowman's capsule F) B) and E)
G) All of the above B

Question 9

You are a professor supervising first year medical students. One student is examining the adrenal gland of his cadaver. "Wow!" he exclaims, "This person must have had an endocrine problem. Their adrenal gland lacks any kind of duct connecting it to the bloodstream. The hormones could only have oozed out." How do you respond?

Accepted Answer

A)   "Look carefully and you will see the nerves that transport the hormones into the bloodstream."
B)   "Do you see signs of adrenal insufficiency, such as low fat stores or muscle degeneration?"
C)   "That's normal. The hormones ooze out and diffuse into nearby capillaries, which is why endocrine glands are sometimes called 'ductless glands'."
D)   "That makes their adrenal gland similar to an exocrine organ."E) All of the above
F) A) and C)

Question 10

Why don't hormones build up in the body over time?

Accepted Answer

A)   They are filtered out of the blood by lymph tissues.
B)   Hormone synthesis is subject to positive feedback regulation.
C)   They are deactivated or degraded by target cells after hormone-receptor binding.
D)   They do, but target tissues become desensitized over time.
E)   They are secreted from the body by exocrine glands.F) B) and C)
G) B) and E)

Question 11

Lampreys completely lack parathyroid glands. Suggest why these glands may be important for other vertebrates, but not for jawless fish.

Accepted Answer

A)   Because they are parasitic, lampreys get plenty of calcium from their hosts.
B)   Living in the ocean, they are surrounded by large amounts of sodium, chloride, and magnesium ions.
C)   Jawless fish employ a different system than other vertebrates to regulate blood sugar.
D)   Since they have a cartilaginous skeleton but not true bone, they have less need to regulate calcium levels.E) A) and D)
F) A) and C)

Question 12

Which of the following cells is matched to an incorrect function?

Accepted Answer

A)   plasma cells-secrete immunoglobulins
B)   neutrophil-important antigen-presenting cell
C)   natural killer cells-kill virus-infected and tumor cells
D)   macrophage-phagocytic cell
E)   monocyte-precursor of macrophageF) B) and E)
G) A) and E) B

Question 13

MHC class II cell surface proteins are found on what cells?

Accepted Answer

A)   neutrophils only
B)   erythrocytes only
C)   macrophages, B cells and dendritic cells
D)   neutrophils and natural killer cells
E)   natural killer cells onlyF) B) and C)
G) None of the above

Question 14

Margaret had an unusual viral infection that damaged her posterior pituitary. Ever since, she has been excreting a large volume of dilute urine. The doctor tells Margaret that she has the disorder known as ____________.

Accepted Answer

A)   hypertension
B)   anti-diuresis
C)   atherosclerosis
D)   diabetes insipidus
E)   diabetes mellitusF) B) and C)
G) All of the above

Question 15

What cells directly stimulate the activity of other cells in the generation of an immune response?

Accepted Answer

A)   monocytes
B)   T cells
C)   plasma cells
D)   natural killer cells
E)   B cellsF) C) and E)
G) C) and D)

Question 16

Some scientists are trying to develop a vaccine that would prevent cancer. What is an important consideration?

Accepted Answer

A)   Since cancer cells have self-marking MHC molecules, they cannot be attacked by the immune system.
B)   Antigen selection would be critical, due to danger of the body's immune system attacking its own healthy tissue.
C)   The natural killer (NK)  cells already perform this function, which cannot be enhanced.
D)   It is not possible -- vaccines can only protect against viruses or bacteria.E) A) and B)
F) B) and C)

Question 17

You are an attending physician supervising a new resident. Together, you decide to treat a patient with a steroid drug. The resident administers the drug and watches the patient anxiously. "It's not working," he mutters. How do you respond?

Accepted Answer

A)   "Let's grab a cup of coffee and then check again. Activating the G-protein coupled receptor and its downstream kinase cascade can take several minutes."
B)   "Why don't you go on your rounds and come back? Steroid hormones need several hours to work, since they regulate gene expression. Transcription and translation take time."
C)   "You're right, it doesn't seem to be working. Let's increase the dose, since we need to achieve high steroid levels in the blood."
D)   "We forgot to administer the carrier protein to get the drug across the cell membrane. We can add that now."E) None of the above
F) A) and B) B

Question 18

Refer to the figure. What is the most likely concentration of the fluid in region E during moderate-volume urine production?

Accepted Answer

A)   5 mOsm
B)   300 mOsm
C)   700 mOsm
D)   1400 mOsm
E)   75 mOsmF) A) and D)
G) A) and C)

Question 19

About 180 liters of blood plasma is filtered into human nephrons per day and, of that amount, about 1.5-2 liters leaves the body as urine. Therefore, the percentage of plasma filtrate that leaves as urine each day is about _______.

Accepted Answer

A)   0.1-0.2 percent
B)   10-20 percent
C)   0.5-1.0 percent
D)   1-2 percent
E)   5-10 percentF)  20-50 percentG) All of the above
H) A) and C)

Question 20

When developing a monoclonal antibody-based test kit, great care must be taken to choose an antibody with the right binding properties. Imagine that you are developing a food-testing kit to specifically detect E. coli 0157:H7, a pathogenic serotype of E. coli that causes food poisoning. Choose the hybridoma line best suited for use in your test kit.

Accepted Answer

A)   1
B)   2
C)   3
D)   4
E)   5F) A) and E)
G) A) and D)

Exam 30: Maintaining Homeostasis

The human immunodeficiency virus (HIV) is so named because it cripples the immune system by attacking and destroying helper T cells (T_H cells) . What cell surface protein does the HIV virus most likely use to bind to and infect the T_H cells?

Correct Answer
verified

Something is terribly wrong with Beth and Steve's newborn baby girl. A biopsy of her kidneys reveals that the kidney nephrons all have extremely short Loops of Henle. What will be the ultimate fate of the baby?

Correct Answer
verified

What is a consequence of the fact that the chickenpox virus has a much lower mutation rate than the influenza virus?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Due to a mutation in a smooth muscle gene, the blood vessels in the skin of a certain strain of mouse become dilated when temperature falls below a certain point. Based on the likely outcome of this mutation, what precautions should the researchers take to maintain the health of their mice?

Correct Answer
verified

Correct Answer
verified

Each nephron of the kidney consists of a long tubule and associated small blood vessels. Blood cells and plasma proteins are too large to enter with the glomerular filtrate. What is the correct path for the filtrate to follow through the nephron in the production of urine?

Correct Answer
verified
B

Correct Answer
verified

Why don't hormones build up in the body over time?

Correct Answer
verified

Lampreys completely lack parathyroid glands. Suggest why these glands may be important for other vertebrates, but not for jawless fish.

Correct Answer
verified

Which of the following cells is matched to an incorrect function?

Correct Answer
verified
B

MHC class II cell surface proteins are found on what cells?

Correct Answer
verified

Margaret had an unusual viral infection that damaged her posterior pituitary. Ever since, she has been excreting a large volume of dilute urine. The doctor tells Margaret that she has the disorder known as ____________.

Correct Answer
verified

What cells directly stimulate the activity of other cells in the generation of an immune response?

Correct Answer
verified

Some scientists are trying to develop a vaccine that would prevent cancer. What is an important consideration?

Correct Answer
verified

You are an attending physician supervising a new resident. Together, you decide to treat a patient with a steroid drug. The resident administers the drug and watches the patient anxiously. "It's not working," he mutters. How do you respond?

Correct Answer
verified
B

Refer to the figure. What is the most likely concentration of the fluid in region E during moderate-volume urine production?

Correct Answer
verified

About 180 liters of blood plasma is filtered into human nephrons per day and, of that amount, about 1.5-2 liters leaves the body as urine. Therefore, the percentage of plasma filtrate that leaves as urine each day is about _______.

Correct Answer
verified

Correct Answer
verified

Exam 30: Maintaining Homeostasis

The human immunodeficiency virus (HIV) is so named because it cripples the immune system by attacking and destroying helper T cells (TH cells) . What cell surface protein does the HIV virus most likely use to bind to and infect the TH cells?

Correct AnswerverifiedShow Answer

Something is terribly wrong with Beth and Steve's newborn baby girl. A biopsy of her kidneys reveals that the kidney nephrons all have extremely short Loops of Henle. What will be the ultimate fate of the baby?

Correct AnswerverifiedShow Answer

What is a consequence of the fact that the chickenpox virus has a much lower mutation rate than the influenza virus?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Due to a mutation in a smooth muscle gene, the blood vessels in the skin of a certain strain of mouse become dilated when temperature falls below a certain point. Based on the likely outcome of this mutation, what precautions should the researchers take to maintain the health of their mice?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Each nephron of the kidney consists of a long tubule and associated small blood vessels. Blood cells and plasma proteins are too large to enter with the glomerular filtrate. What is the correct path for the filtrate to follow through the nephron in the production of urine?

Correct AnswerverifiedB

Correct AnswerverifiedShow Answer

Why don't hormones build up in the body over time?

Correct AnswerverifiedShow Answer

Lampreys completely lack parathyroid glands. Suggest why these glands may be important for other vertebrates, but not for jawless fish.

Correct AnswerverifiedShow Answer

Which of the following cells is matched to an incorrect function?

Correct AnswerverifiedB

MHC class II cell surface proteins are found on what cells?

Correct AnswerverifiedShow Answer

Margaret had an unusual viral infection that damaged her posterior pituitary. Ever since, she has been excreting a large volume of dilute urine. The doctor tells Margaret that she has the disorder known as ____________.

Correct AnswerverifiedShow Answer

What cells directly stimulate the activity of other cells in the generation of an immune response?

Correct AnswerverifiedShow Answer

Some scientists are trying to develop a vaccine that would prevent cancer. What is an important consideration?

Correct AnswerverifiedShow Answer

You are an attending physician supervising a new resident. Together, you decide to treat a patient with a steroid drug. The resident administers the drug and watches the patient anxiously. "It's not working," he mutters. How do you respond?

Correct AnswerverifiedB

Refer to the figure. What is the most likely concentration of the fluid in region E during moderate-volume urine production?

Correct AnswerverifiedShow Answer

About 180 liters of blood plasma is filtered into human nephrons per day and, of that amount, about 1.5-2 liters leaves the body as urine. Therefore, the percentage of plasma filtrate that leaves as urine each day is about _______.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The human immunodeficiency virus (HIV) is so named because it cripples the immune system by attacking and destroying helper T cells (T_H cells) . What cell surface protein does the HIV virus most likely use to bind to and infect the T_H cells?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
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Correct Answer
verified

Correct Answer
verified

Correct Answer
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B

Correct Answer
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Correct Answer
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Correct Answer
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