BIO/BIOCHEM EXAM 10

Which of the following is the MOST plausible explanation for a patient experiencing hypoglycemia? A. Accidental self-injection of excess insulin B. Increased gluconeogenesis C. A 4-hour fast following a carbohydrate-rich meal D. Increased rate of glycogenolysis

A. Accidental self-injection of excess insulin

DCCD is a chemical that blocks the proton pore of ATP synthase. If treated with DCCD, which of the following is MOST likely to decrease in the actively respiring mitochondria of adult rat cardiac cells? A. H+ concentration within the intermembrane space B. ADP concentration within the matrix C. Oxygen consumption D. Chemiosmotic gradient across the inner membrane

C. Oxygen consumption

A couple trying to conceive without using IVF methods would MOST likely have their highest chance of pregnancy: A. early in the follicular phase of the menstrual cycle. B. after the onset of menses. C. during the luteal phase of the menstrual cycle. D. midway through the follicular phase of the menstrual cycle.

C. during the luteal phase of the menstrual cycle.

The bones in the front leg of an iguana and in the wing of a bat are evolutionary derived from their common ancestor. Based on this information, it can be concluded that they are: A. functionally similar. B. convergent. C. homologous. D. analogous.

C. homologous.

In skeletal myocytes, calcium is normally released from the sarcoplasmic reticulum after: A. the muscle begins to relax. B. myosin releases actin. C. the membrane depolarizes. D. physical damage to the muscle occurs.

C. the membrane depolarizes.

Patients with Ehlers-Danlos syndrome commonly suffer from hypermobile, unstable joints and fragile, easily bruised skin. Which of these loss-of-function mutations is most likely to cause Ehlers-Danlos syndrome? A. A mutation in actin B. A mutation in keratin C. A mutation in elastin D. A mutation in collagen

D. A mutation in collagen

Infection by the hepatitis C virus may result in chronic disease and permanent damage to the liver. If liver function is impaired, synthesis of which of the following molecules found in human blood and isolated in Experiment 1 would LEAST likely be affected in adults? A. Steroid hormones and antibodies B. VLDL, LDL, IDL, HDL, and chylomicrons C. Antibodies, fatty acids, and steroid hormones D. Antibodies only

D. Antibodies only

What role do histones and nucleosomes have in mitosis? A. They allow visible chromosomes to form prior to mitosis by linking pairs of sister chromatids. B. They cause the genetic variability that chromosomes require for mitotic splitting. C. They allow small coils of euchromatin to supercoil into large coils of heterochromatin. D. They facilitate mitosis by helping to supercoil nuclear DNA into chromosomes.

D. They facilitate mitosis by helping to supercoil nuclear DNA into chromosomes.

Which of the following would be the MOST ideal primer for the polymerase chain reaction? A. a primer with a high content of purines B. a primer with a high content of pyrimidines C. a primer with a high content of A and T D. a primer with a high content of G and C

D. a primer with a high content of G and C

BDNF is a plasma-soluble protein secreted after being manufactured in the endoplasmic reticulum. BDNF MOST likely: A. diffuses through the plasma membrane of target cells and, after binding to its receptor, acts directly on euchromatin to regulate transcription. B. frequently serves as a target in auto-immune diseases due to its close contact with dissolved immunoglobulins. C. contains external domains especially rich in V, W, and G residues. D. has its effect through binding receptors on the external leaf of the plasma membrane.

D. has its effect through binding receptors on the external leaf of the plasma membrane.

In aerobic organisms, glycolysis: A. is upregulated when blood glucose levels fall. B. directly supplies the citric acid cycle with acetyl-CoA. C. requires oxygen as the final electron acceptor. D. is inhibited by a high ratio of intracellular ATP : AMP.

D. is inhibited by a high ratio of intracellular ATP : AMP.

What is the purpose of an adjuvant? A. It acts as a transcription factor. B. It binds antibodies. C. It increases protection granted by vaccine of a host against pathogens. D. It causes dimerization of receptors.

C. It increases protection granted by vaccine of a host against pathogens.

GTP is best classified as a member of which class of biological molecules? A. Amino acids B. Peptides C. Nucleotides D. Nucleic acids

C. Nucleotides

Which of the following cell types performs functions in the central nervous system analogous to Schwann cells? A. Chondrocytes B. Microglia C. Oligodendrocytes D. Ependymal cells

C. Oligodendrocytes

Which of the following structures develop from the mesoderm of the gastrula? I. Lungs II. Red blood cells III. Cardiac muscle A. II B. I, II C. II, III D. I, II, III

C. II, III

DNA polymerase has a significantly lower error rate than RNA polymerase for nucleotide incorporation. Which of the following statements best explains this phenomenon? A. DNA polymerase contains a proof-reading domain, while RNA polymerase does not. B. RNA is less stable than DNA, and this instability makes it much harder for RNA polymerase to proofread the sequence. C. The rate of nucleotide incorporation is much faster in RNA polymerase than DNA polymerase. D. DNA polymerase reads the DNA template in a 3' to 5' direction while RNA polymerase reads the DNA template in a 5' to 3' direction.

A. DNA polymerase contains a proof-reading domain, while RNA polymerase does not.

Which of the following statements is FALSE regarding transcription and post-transcriptional modifications in eukaryotes? A. There is one RNA polymerase that transcribes different classes of genes. B. Termination is dictated by a terminator sequence. C. Transcription occurs in the nucleus. D. In eukaryotes, spliceosomes remove introns.

A. There is one RNA polymerase that transcribes different classes of genes.

The unfolded proteins that accumulate in response to ER homeostatic disruption MOST likely: A. exhibit disrupted tertiary structure due to a lack of proper covalent bond formation. B. exhibit disrupted secondary structure due to a lack of proper disulfide bond formation. C. exhibit disrupted secondary structure due to a lack of proper hydrophobic interactions. D. exhibit disrupted primary structure due to a lack of proper peptide bond formation.

A. exhibit disrupted tertiary structure due to a lack of proper covalent bond formation.

Newly formed chylomicrons involved in the transport of intestinally absorbed lipids immediately pass from cells of the duodenum into: A. lacteals contained within intestinal villi. B. capillaries perfusing intestinal villi. C. lacteals passing through the serous lining of the abdominal cavity. D. capillaries supplying the muscular layer of the duodenum.

A. lacteals contained within intestinal villi.

Given the role of the reaction in cellular respiration, what is the most likely Eº value for the reduction of oxygen to water? A. 0.02 V B. 0.82 V C. -0.02 V D. -0.82 V

B. 0.82 V

Which of the following will most likely cause low blood glucose levels? A. A hormone-secreting tumor in the alpha cells of the pancreas B. A hormone-secreting tumor in the beta cells of the pancreas C. A lesion to the beta cells of the pancreas D. A hormone-secreting tumor in the thyroid gland

B. A hormone-secreting tumor in the beta cells of the pancreas

A thyroid storm is an acute, life-threatening, hypermetabolic state induced by excessive release of thyroid hormones with a 90% mortality rate in adults. It is observed that the hypermetabolic rate causes the release of thyroid hormone which then further elevates the metabolic rate. This cycle indicates what kind of mechanism may be the cause? A. Negative-feedback loop B. Positive-feedback loop C. Negative-forward loop D. Positive-forward loop

B. Positive-feedback loop

Signaling through TLR4 occurs when a ligand brings two TLR4 molecules together in a process called ligand-induced dimerization. TLR4 as a homodimer then recruits proximal adaptor molecules, leading to a phosphorylation cascade that ultimately results in NF-kB import into the nucleus. NF-kB ultimately results in the change of cellular proteins, leading to a pro-inflammatory phenotype. What type of molecule is NF-kB most likely to be? A. Translation factor B. Transcription factor C. Protease D. Kinase

B. Transcription factor

In a metabolic analysis experiment, researchers subjected fatty acid samples to β-oxidation. Mass spectrometry performed on the resulting products would reveal: A. glucose. B. acetyl-CoA. C. pyruvate. D. succinate.

B. acetyl-CoA.

All of the following are functions of insulin EXCEPT: A. increasing glycogen synthesis. B. increasing gluconeogenesis. C. increasing glucose uptake by liver and muscles. D. decreasing proteolysis.

B. increasing gluconeogenesis.

Localized radiation therapy of the thyroid will most likely affect another endocrine gland that has which of the following characteristics? A. It consists of multiple cell types secreting a number of different steroid hormones. B. High calcium stimulates the release of its major hormone product. C. Hyperactivity of the gland can cause osteoporosis. D. It synthesizes its hormone from cholesterol ester using enzymes found in the smooth endoplasmic reticulum and mitochondria.

C. Hyperactivity of the gland can cause osteoporosis.