Missed Questions - Biochem 98'

The polymerase chain reaction is MOST useful for which of the following?

Preparing enzymes that synthesize nucleic acids
Isolating the genome of an organism
Amplifying a specific DNA sequence
Separating polyclonal antibodies
Synthesizing RNA from DNA

The enzyme catalyzing the rate-controlling step in the de novo synthesis of fatty acids is regulated allosterically by the positive modulator

ATP.
NADPH.
citrate.
cyclic AMP.
oxaloacetate.

Which of the following is required for vitamin D3 synthesis?

Decarboxylation in the liver
UV activation of precursors in skin
Metabolism by gut bacteria
Deamination in the kidney

Which of the following represents the normal substrate of thrombin?

Fibrin
Thrombospondin
Prothrombin
Thromboplastin
Fibrinogen

The anticaries effect of fluoride is LEAST related to which of the following?

Ion exchange
Decreased solubility
Facilitation of remineralization
Its presence during enamel formation
Activation of plaque polysaccharide hydrolysis

Which of the following types of bonds link amino acid residues to form proteins?

Amide
Anomeric
Epimeric
Hydrogen
Glycosidic

A mucin is which of the following types of proteins?

Simple protein
Phosphoprotein
Chromoprotein
Nucleoprotein
Glycoprotein

The tricarboxylic acid cycle is initiated by the condensation of which of the following two molecules?

Pyruvate and malate
NAD+ and oxaloacetate
NAD+ and oxalosuccinate
Acetyl coenzyme A and oxaloacetate
Acetyl coenzyme Aand oxalosuccinate

Both systemic and pulmonary circulations have the same

pulse pressure.
total capacitance.
diastolic pressure.
resistance.
flow rate.

Under strict anaerobic conditions, the catabolism of one glucose molecule would yield a net of

2 ATP and 2 lactic acid molecules.
4 ATP and 2 lactic acid molecules.
2 ATP and 2 pyruvic acid molecules.
4 ATP and 2 pyruvic acid molecules.

The ability to concentrate urine varies among animal species. The maximum urine concentration that can be produced by an animal is MOST closely related to which of the following?

Renal blood flow
Total number of nephrons
Glomerular filtration rate
Length of the loop of Henle
Diameter of the distal tubule

Each of the following appears in the glomerular filtrate in concentrations approximately equal to those in plasma EXCEPT one. Which one is this EXCEPTION?

Urea
Glucose
Amino acids
Steroid hormones
Plasma electrolytes

The clinical symptoms of dermatitis, diarrhea, and dementia suggest a deficiency in which of the following vitamins?

Retinol
Riboflavin
Tocopherol
Ascorbic acid
Niacin

Increased parasympathetic activity results in

decreased salivary secretion.
increased cardiac contractility.
decreased gastric motility and tone.
increased bronchiolar smooth muscle contraction.

A patient who has emphysema is MOST likely to exhibit which of the following changes in functional residual capacity (FRC) and compliance?

Increased FRC; increased compliance
Decreased FRC; no change in compliance
Increased FRC; no change in compliance
Decreased FRC; increased compliance
Decreased FRC; decreased compliance

Which of the following could be beneficial in reducing edema in the arms of women who have had radical mastectomy with removal of axial lymph nodes?

Hypertensive agents
Avoidance of all diuretic agents
Increase interstitial oncotic pressure
Decrease interstitial hydrostatic pressure
Administration of a plasma volume expander

Which of the following noncollagenous protein components BEST characterizes dentin matrix?

Laminin
Vimentin
Phosphophoryn
Osteonectin
Fibronectin

Coenzyme A participates in

formylation.
protein synthesis.
methionine activation.
activation of carboxyl groups

Which of the following do elastin and collagen have in common?

Easily stretched
Absence of proline
Disulfide crosslinking
Triple helix structure
About one-third glycine

The plasma osmolality decreases after infusion of

aldosterone.
vasopressin (ADH).
angiotensin II.
parathyroid hormone.
isotonic saline solution.

Which of the following is necessary for de novo synthesis of cholesterol?

NA+
NADH
NADP+
NADPH
FADH2

Which of the following changes in lung compliance and vital capacity would be observed in the absence of pulmonary surfactant?

increase lung compliance; increase vital capacity
increase lung compliance; decrease vital capacity
increase lung compliance; no change vital capacity
decrease lung compliance; increase vital capacity
decrease lung compliance; decrease vital capacity

Which of the following represents a decrease in the frequency of action potentials in an afferent neuron despite a constant stimulus intensity?

Refraction
Potentiation
Perception
Adaptation
Accommodation

Which of the following is a typical finding for a normal 23-year-old man?

Hematocrit of 45%
Venous blood with pH of 7.2
White blood cell count of 10,000/mm3
Red blood cell count of 7,000,000/mm3
Pulse pressure equivalent to 80 mm Hg

Plasmid vectors suitable for cloning have which of the following characteristics?

Must be able to replicate synchronously with the host chromosome
Several unique recognition sequences for one restriction enzyme
Two genes conferring resistance to different antibiotics
Large size to facilitate plasmid's entry into cells

In relative insulin insufficiency, acetyl CoA is usually channeled into

ketone-body formation.
cholesterol synthesis.
fatty-acid synthesis.
gluconeogenesis.
the Krebs cycle.

After prolonged acidosis, which of the following represents the nitrogenous product that is excreted in high amounts in the urine?

Urea
Ammonia
Uric acid
Creatinine
Aspartic acid

Sodium fluoride inhibits glycolysis by affecting which of the following?

Amylase
Enolase
Phosphatase
Phosphorylase

Hyperventilation alters the acid-base balance of arterial blood by

increasing C02 and increasing pH.
increasing C02 and decreasing pH.
decreasing CO2 and decreasing pH.
decreasing CO2 and increasing pH.

Which of the following collagen synthesis post-translational events occurs extracellularly?

Glycosylation
Hydroxylation
Intermolecular cross-linkage
Disulfide bond formation

If the pH becomes lower than the isoelectric point of a protein, then how will the protein respond in an electrophoretic system? It will

become denatured.
migrate to the negative pole.
migrate to the positive pole.
remain stationary and unchanged.
separate into its different monomeric forms.

Triglyceride absorbed into the lymphatic system is transported to the liver as which of the following?

Very low density lipoprotein
Low density lipoprotein
Chylomicrons
Liposomes
Micelles

Epinephrine causes an elevation in cAMP levels in muscle cells which in turn activate

ATPase.
adenyl cyclase.
glycogen synthetase.
glycogen phosphorylase.
glycogen phosphorylase phosphatase.

Acromegaly is due to an excessive production of which of the following?

Thyrotropin
Gonadotropin
Somatotropin
Adrenocorticotropin

Intravenous injections of KCl solution would increase the secretion of which of the following?

Insulin
Cortisol
Calcitonin
Aldosterone
Parathyroid hormone

Pieces of dog parotid gland and pancreas are transplanted under the skin of the donor animal. After re-establishment of circulation, ingestion of food will result in secretion from which of the following?

Parotid and pancreatic transplants
The fragment of the pancreas only
The fragment of the parotid only
Neither fragment

Which of the following conditions is indicated during isovolumetric ventricular contraction of the heart?

All valves are open.
All valves are closed.
The aortic and pulmonary valves are open and the mitral and tricuspid valves are closed.
The aortic and pulmonary valves are closed and the mitral and tricuspid valves are open

Which of the following controls the excitability of the muscle spindle?

Load on the muscle
Gamma efferent system
Alpha efferent discharge
Length of the extrafusal fibers

Which term of the Michaelis-Menten equation, can be determined from the y intercept of a Lineweaver-Burk plot?

v
Vmax
Km
[S]

How many anomeric carbons are present in a fructose molecule?

0
1
2
5
6