BIOCHEM (161-328)

B. They agglutinate and plug small, ruptured vessels

. Platelets play an important role in hemostasis. Which of the following describes this role? A. They convert fibrinogen to fibrin B. They agglutinate and plug small, ruptured vessels C. They initiate fibrinolysis in thrombosis D. They supply fibrin stabilizing factor E. They supply proconvertin for thromboplastin activation

A. decreasing prothrombin production

A deficiency in vitamin K would affect blood clotting chiefly by: A. decreasing prothrombin production B. preventing the contraction of the clot C. preventing the reaction of thrombin with fibrinogen D. preventing the conversion of fibrinogen to fibrin E. preventing the conversion of prothrombin to thrombin

B. Xeroderma Pigmentosum

A genetic disease due to defective mechanisms for pyrimidine dimmers: A. Phenylketonuria B. Xeroderma Pigmentosum C. Albinism D. Ataxia telangiectasia E. Ehler's Danlos

A. Glycogen

A hormone which stimulates glycogenesis: A. Glycogen B. Glucagons C. Epinephrine D. Vasopressin

A. Lipase

A lipolytic enzyme capable of digesting dietary fat. A. Lipase B. Fatase C. Ptyalin D. Amylase

A. Retinal

A necessary precursor of visual pigment is: A. Retinal B. Retinol C. Ergosterol D. Cholecalciferol

C. ATP

A number of catabolic pathways are allosterically inhibited by an increase in the concentration of which of the following? A. ADP B. AMP C. ATP D. NAD+ E. Pyruvate

C. Tyramine

A substance found commonly in fermented foods that can be toxic when monoamine oxidase inhibitors are used: A. Adenosine diphosphate B. Adenosine triphosphate C. Tyramine D. Histidine E. Phenylalamine

B. Diabetes insipidus

Absence of anti-diuretic hormone in the body causes: A. Kidney failure B. Diabetes insipidus C. Diabetes mellitus D. Nephritis E. Hypertensive crisis

E. Oxaloacetic acid and α-ketoglutaric acid

Acids found in the citric acid (Krebs) cycle are: A. Glutamic acid and succinic acid B. Glucuronic acid and aspartic acid C. Oxaloacetic acid and aspartic acid D. Oxaloacetic acid and pyruvic acid E. Oxaloacetic acid and α-ketoglutaric acid

B. and increase in bleeding time due to lack of thrombin formation

Administration of heparin to a human results in symptoms similar to vitamin K deficiency in that both conditions result in: A. release of lipoprotein lipase to the blood and rapid clearance of chylomicrons B. and increase in bleeding time due to lack of thrombin formation C. retardation of fibrinogen synthesis by the liver D. elevated non-esterified fatty acids which chelate serum calcium, thus retarding blood clotting

D. reabsorbed into the portal circulation and reused

After functioning in the small intestines, the largest portion of bile salts are: A. excreted in the feces B. reabsorbed into the central lacteal C. destroyed by bacteria in the large intestines D. reabsorbed into the portal circulation and reused E. removed from the circulation by the kidneys and excreted in the urine

B. Ammonia

After prolonged acidosis, which of the following represents the nitrogenous product that is excreted in high amounts in the urine? A. Urea B. Ammonia C. Uric acid D. Creatinine E. Aspartic acid

A. Sodium balance

Aldosterone is normally associated with partial regulation of which of the following processes? A. Sodium balance B. Gluconeogenesis C. Lipid digestion D. Protein degradation E. Carbohydrate metabolism

E. Rapidly degraded

Amino acids that are not immediately incorporated into new protein are: A. Stored in the muscles B. Stored in the liver C. Recycled in the blood D. Stored in tissues E. Rapidly degraded

E. Recombinant DNA

An example of synthetic DNA: A. Replicated DNA B. GMO C. Gene D. Chromatin E. Recombinant DNA

A. Adrenal cortex

Androgens are produced in the testis and: A. Adrenal cortex B. Thyroid C. Adrenal medulla D. Pituitary E. Hypothalamus

A. Total G-C content of total DNA increasing

As DNA is denatured, each of the following events take place, except: A. Total G-C content of total DNA increasing B. UV light absorption increasing C. Complementary strands becoming random coils D. Base stacking becoming disrupted E. Hydrogen bond breaking

A. Transcription

Central Dogma concept wherein the RNA molecule is used as template for the synthesis of DNA molecule: A. Transcription B. Translation C. Mutation D. Coding

B. Hormones

Chemical messengers produced by the endocrine glands: A. Genes B. Hormones C. Vitamins D. Enzymes

D. Antibiotics

Chemicals extracted from organism such as bacteria and can inhibit growth or destroy other microorganism: A. Vitamins B. Bacteria C. Hormone D. Antibiotics E. Both A and C

A. Jaundice

Condition wherein bile pigment is present in excess in the blood? A. Jaundice B. Hepatitis C. Cirrhosis D. Cystic fibrosis

A. Oxidation reduction

Cytochromes are useful in which reactions? A. Oxidation reduction B. Transamination C. Decarboxylation D. Hydrolysis E. Deamination

D. induction of dimerization by way of covalent bonds between adjacent thymine groups

DNA damage by ultraviolet light is due to: A. alkylation of the guanine in DNA B. excessive unwinding of the DNA molecule C. frequent replacement in the DNA molecule of purines by pyrimidines D. induction of dimerization by way of covalent bonds between adjacent thymine groups

B. Nucleus

DNA is primarily found in the: A. Cytosol B. Nucleus C. Mitochondria D. A and B E. B and C

E. Reverse transcriptase

DNA that is complementary to mRNA can be made using which of the following? A. a plasmid B. DNA ligase C. a retrovirus D. RNA polymerase E. Reverse transcriptase

B. Sucrose and saliva

Dental plaque arises primarily as a result of enzymatic reactions using which of the following? A. Sucrose and lipid B. Sucrose and saliva C. Glucose and saliva D. Glucose and protein

C. Cobalt

Each molecule of vitamin B12 contains an atom of: A. Potassium B. Copper C. Cobalt D. Nickel E. Zinc

C. Binds to intracellular receptors

Each of the following characterizes a peptide hormone, except: A. Stored in secretory granules B. Synthesized in a precursor form C. Binds to intracellular receptors D. Acts by generating a second messenger E. Usually transported unbound in plasma

D. Beta oxidation

Each of the following is expected to be active during fatty acid biosynthesis, except: A. Tricarboxylic acid cycle B. Pyruvate dehydrogenase C. Amino acid catabolism D. Beta oxidation E. Glycolysis

B. RNA polymerase

Each of the following is involved in gene cloning, except: A. DNA ligase B. RNA polymerase C. DNA polymerase I D. Restriction nucleases E. Reverse transcriptase

C. Mitochondria.

Enzymes concerned with the citric acid cycle are found in the: A. Nucleus B. Ribosomes. C. Mitochondria. D. Non - particulate cytoplasm

D. Mitochondria

Enzymes for electron transport reactions are most active and concentrated in which of the following structures of the animal cell? A. Nuclei B. Lysosomes C. Microsomes D. Mitochondria E. All of these

A. Cytoplasm

Enzymes that catalyze the anaerobic processes of carbohydrate metabolism are found predominantly in which part of a cell? A. Cytoplasm B. Membrane C. Cell wall D. Nucleus E. Mitochondria

D. Glycogen phosphorylase

Epinephrine causes an elevation in cAMP levels in muscle cells which in turn activate: A. ATPase B. Adenyl cyclase C. Glycogen synthetase D. Glycogen phosphorylase E. Glycogen phosphorylase phosphatase

D. Alkalosis

Excessive utilization of fats by the body as a source of energy during disturbances in carbohydrate metabolism can lead to all of the following conditions, except: A. Ketosis B. Acidosis C. Ketonuria D. Alkalosis

E. Pituitary glands

FSH and interstitial cell - stimulating hormones are produced by the: A. Islets of langerhands B. Thymus gland C. Thyroid glands D. Pineal gland E. Pituitary glands

D. Macrocytic anemia

Folic acid deficiency can lead to: A. Aplastic anemia B. Microcytic anemia C. Megaloblastic anemia D. Macrocytic anemia

B. dsDNA

Genetic information is stored and carried in all cells by: A. ssDNA B. dsDNA C. dsRNA D. sscDNA E. mRNA

A. Non - carbohydrate sources

Glucogenesis involves the formation of glucose from: A. Non - carbohydrate sources B. Pentose C. Aldohexose D. Ketohexose E. Polysaccharides

E. B and C

Gluconeogenesis is the formation of new glucose. The enzymes responsible for this are only confined to some organs, which includes: A. Muscles B. Liver C. Kidneys D. A and B E. B and C

B. Acetyl CoA

Glucose, amino acid and fatty acid enter the citric acid cycle by their conversion into: A. Pyruvate B. Acetyl CoA C. Malonyl CoA D. Palmitic acid

A. 2

Glycolysis produces ____ATPs: A. 2 B. 6 C. 36 D. 32

B. Somatotropin

Growth hormone is also known as: A. Thyrotropic hormone B. Somatotropin C. Gonadotropin D. Luteinizing hormone E. ACTH

B. 12

How many ATPs are produced for every acetyl CoA oxidized A. 10 B. 12 C. 14 D. 8 E. 6

A. 2

How many ATPs are produced in the conversion of one mole of FADH2 to FAD? A. 2 B. 3 C. 4 D. 12 E. 8

B. 3

How many ATPs are produced in the reduction of one mole of NAD to NADH? A. 2 B. 3 C. 4 D. 12 E. 8

B. 129

How many ATPs can one molecule of palmitic acid can be yielded via beta-oxidation? A. 128 B. 129 C. 130 D. 131 E. 132

C. Thyroxin and triiodothyronine

Hydrolysis of thyroglobulin liberates a number of iodinated compounds. Two are considered thyroid hormones. These are: A. Tyrosine and thyronine B. Tyrosine and diiodotyrosine C. Thyroxin and triiodothyronine D. Thyroxin and triiodotyrosine

C. Retention of phosphates by the kidneys

Hyperparathyroidism is marked by: A. Chronic tetany B. High blood calcium level C. Retention of phosphates by the kidneys D. Storage of excess minerals in the bones E. Increased irritability of excitable tissues

E. Oxidation of α-keto acids derived from amino acids

If protein is catabolized for energy, then MOST of the energy is derived from which of the following? A. Urea production B. Oxidative deamination C. Transamination reactions D. Cleavage of peptide bonds E. Oxidation of α-keto acids derived from amino acids

E. 5' UGC 3'

If the anticodon on transfer-RNA is 5'ACG3', then which of the following is its corresponding codon on messenger-RNA? A. 5' CGT 3' B. 5' CGU 3' C. 5' TGC 3' D. 5' UAG 3' E. 5' UGC 3'

B. 28%

If the molar percentage of A (adenine) in a native DNA specimen is 22%, then what is the molar content of G (guanine)? A. 22% B. 28% C. 44% D. 56% E. 78%

C. Translocate the growing peptide chain and to move the ribosome along the mRNA

In prokaryotic protein synthesis, the elongation factor G serves to: A. Form the initiation complex B. Facilitate the binding of Fmet tRNA C. Translocate the growing peptide chain and to move the ribosome along the mRNA D. Prevent the larger ribosomal subunits from binding with those that are smaller

D. 3 Hydrogen

In the DNA molecule, guanine on 1 strand is joined to cytosine on the complementary strand by which of the following bonds? A. Amide B. 1 Hydrogen C. 2 Hydrogen D. 3 Hydrogen E. Phosphodiester

D. Adenine will always pair with uracil

In the secondary structure of RNA: A. Adenine will always pair with thymine B. Cytosine will always pair with thymine C. Cytosine will always pair with uracil D. Adenine will always pair with uracil

E. Vasopressin - Peptide - Posterior pituitary

In which of the following combinations is the name of the hormone, its chemical type and its tissue of origin correctly matched? A. Aldosterone - Peptide - Pancreas B. Glucagon - Peptide - Adrenal cortex C. Epinephrine - Steroid - Adrenal medulla D. ACTH - Polypeptide - Adrenal cortex E. Vasopressin - Peptide - Posterior pituitary

A. Insulin

Inhibition of lipolysis, stimulation of protein synthesis and increased entry of glucose into muscles and adipose tissues are biologic actions of the hormone: A. Insulin B. Cortisol C. Glucagons D. Epinephrine E. Testosterone

B. Thyroxin

Iodine is primarily important in the biochemical synthesis of: A. ACTH B. Thyroxin C. Adrenalin D. Calcitonin E. Parathyroid hormone

D. All of the choices

It is a metabolic process occurring at the "cross roads: of metabolism (citric acid cycle): A. Anabolic B. Catabolic C. Amphibolic D. All of the choices

A. ATP

It is regarded as the universal biological energy currency: A. ATP B. GTP C. cAMP D. UTP E. cGMP

c. Gene

It is the entire genetic make up of an organism? A. Mutation B. Codon C. Gene D. Anti - codon E. Mammals

D. Stimulates testosterone production

Male luteinizing hormone: A. is not present B. has no effect C. Suppress testosterone production D. Stimulates testosterone production

B. III only

Most nitrogenous waste is converted to urea because: I. Ammonia and uric acid are toxic II. Urea is highly soluble III. Urea is non toxic A. I only B. III only C. II and III D. I and III E. I, II and III

E. Thyroid

Myxedema is a malfunction of which gland? A. Anterior pituitary B. Posterior pituitary C. Adrenal D. Parathyroid E. Thyroid

A. HCl

Pepsinogen is an example of zymogen which is inactive. Pepsinogen is activated by: A. HCl B. Enterokinase C. Ptyalin D. Lyases E. Trypsin

C. Two genes conferring resistance to different antibiotics

Plasmid vectors suitable for cloning have which of the following characteristics? A. Must be able to replicate synchronously with the host chromosome B. Several unique recognition sequences for one restriction enzyme C. Two genes conferring resistance to different antibiotics D. Large size to facilitate plasmid's entry into cells

D. Phosphorylation

Protein kinase regulate the activities of key enzymes through which of the following? A. Oxidation B. Hydrolysis C. Acetylation D. Phosphorylation E. Dephosphorylation

B. Pentose phosphate pathway

Ribose phosphate needed for nucleic acid synthesis can be derived from: A. Gluconeogenesis B. Pentose phosphate pathway C. Krebs' tricarboxylic acid cycle D. Decarboxylation of aromatic amino acids E. One-carbon transfer from tetrahydrofolate derivatives

C. Flow of pancreatic juice

Secretin functions in digestion of proteins by increasing: A. flow of bile B. Secretion of pepsin C. Flow of pancreatic juice D. Secretion of carboxypeptidase

B. Serum

Separates from cells when blood is coagulated: A. Fibrinogen B. Serum C. Plasma D. Thrombin

D. Growth hormone release inhibitor

Somastatin is also known as: A. Growth hormone B. HMG CoA Reductase C. Vasopressin D. Growth hormone release inhibitor E. Desmopressin

C. Albinism

Symptoms of photophobia/photosensitivity are most likely associated with which metabolic disorder? A. Phenylketonuria B. Alkaptonuria C. Albinism D. Maple syrup urine disease

C. Gangliosides

Tay-Sach disease is associated with an inborn error of metabolism involving a specific enzyme which normally degrades a particular molecule in the gray matter. This enzyme acts on which of the following? A. Polysaccharides B. Acylglycerols C. Gangliosides D. Fatty acids E. Proteins

D. Uric acid

The chief end product of purine metabolism: A. Carbon dioxide B. Ammonia C. Urea D. Uric acid

C. Kreb's Cycle

The common metabolic pathway: A. Glycolysis B. Beta oxidation C. Kreb's Cycle D. Glucogenesis

C. Acetyl CoA

The common product of carbohydrate, protein and fat catabolism is: A. Glucose B. Amino acids C. Acetyl CoA D. Fatty acids

B. GCTGGAACTAGCT

The complementary strand of CGACCTTGATCGA: A. TCGTTCCAGCTAG B. GCTGGAACTAGCT C. AGCAAGGTCGAAC D. ATCAAGGTCGATC

A. Acidosis

The condition that lowers the pH of the blood due to starvation is called ____: A. Acidosis B. Alkalosis C. Hyperglycemia D. Glycosuria

A. Gluconeogenesis

The conversion of an amino acid to sugar is A. Gluconeogenesis B. Glycolysis C. Glycogenesis D. Glycogenolysis E. Glucogenesis

C. the existence of multiple codons for each amino acid

The degenerate nature of the genetic code implies: A. a common tRNA for at least two amino acids B. that a remarkable degree of inaccuracy occurs in transcription C. the existence of multiple codons for each amino acid D. the existence of multiple species of ribosomes for control of messenger translation

A. Mouth

The digestion of carbohydrates begins in the _______ A. Mouth B. Stomach C. Small intestine D. Duodenum

B. Dehydrogenase

The enzymes involved in ethanol metabolism: A. Phosphorylase B. Dehydrogenase C. Lipase D. Ketase E. Thiokinase

A. Pyruvate

The final product of glycolysis is: A. Pyruvate B. Oxaloacetate C. Citrate D. Acetyl CoA

B. Tricarboxylic acid cycle

The final step in the complete metabolism of fat is carried out by means of: A. Anaerobic glycolysis B. Tricarboxylic acid cycle C. Reductive fixation of CO2 D. Hexose monophosphate shunt E. Krebs-Henseleit (urea) cycle

A. Phosphoric acid

The following are the components of DNA nucleosides, except: A. Phosphoric acid B. Sugar C. Adenine D. Cytosine E. Ribose

D. tRNA

The function of which of the following types of nucleic acid is to activate and select specific amino acids for protein synthesis? A. rRNA B. mRNA C. cDNA D. tRNA E. hnRNA

E. Cholecystokinin

The gallbladder is caused to contract by the hormone: A. Gastrin B. Secretin C. Pancreozymin D. Enterogastrone E. Cholecystokinin

B. Molisch Test

The general test for carbohydrates based on the dehydration of the sugar to form furfural derivatives when the sugar is treated with concentrated sulfuric acid producing a violet ring between two layers: A. Fehling's Test B. Molisch Test C. Benedict's Test D. Tollen's Test

C. liver glycogenolysis

The hyperglycemic effect of glucagon is mediated primarily through: A. the growth hormone B. muscle glycolysis C. liver glycogenolysis D. inhibition of cortisol action E. enhanced glucose reabsorption by renal tubules

C. cAMP

The intracellular, "second" messenger for many peptide and polypeptide hormones is: A. AMP B. ATP C. cAMP D. adenylate cyclase. E. a cytoplasmic receptor.

A. increased renal loss of phosphate

The low serum phosphate level in hyperparathyroidism is caused by: A. increased renal loss of phosphate B. decreased absorption of phosphate C. increased deposition of calcium phosphate in bone D. increased reabsorption of calcium phosphate from bone

D. B-DNA

The most abundant and most common form of DNA: A. A-DNA B. Z-DNA C. E-DNA D. B-DNA E. X-DNA

A. Viscosity

The most biologically important physiochemical property of connective tissue which is regulated by its mucopolysaccharide molecules is: A. Viscosity B. Buffering capacity C. Solubility in dilute acids D. Supersaturation with calcium ions

D. Ribose

The nucleic acids, RNA and DNA plays an important role in the biosynthesis of proteins. This sugar is: A. Glucose B. Sucrose C. Fructose D. Ribose

B. Accelerating the removal of calcium and PO4 -3 from the skeleton but not from the teeth

The parathyroid hormone acts in the body by: A. Decreasing absorption of calcium in the intestinal tract B. Accelerating the removal of calcium and PO4 -3 from the skeleton but not from the teeth C. Stimulating gluconeogenesis in the liver D. Decreasing the excretion of sodium and chloride E. All of the above

A. Malonyl CoA is an intermediate in synthesis

The pathway of extramitochondrial synthesis of even-numbered fatty acids differs from that of the catabolism of fatty acids in that: A. Malonyl CoA is an intermediate in synthesis B. Acyl carrier protein is needed in catabolism C. No flavoprotein enzymes are required for catabolism D. Propionyl CoA may serve as an intermediate in synthesis

C. Cytosol

The pentose phosphate pathway occurs in the _____ of liver, muscle and kidney A. Inner mitochondria B. Outer mitochondria C. Cytosol D. Ribosomes E. Tissues

C. Translation

The process by which genetic information flows from RNA to protein is: A. Mutation B. Replication C. Translation D. Transcription

D. Thyroglobulin

The protein precursor of thyroxine is: A. Ornithine B. Threonine C. Tryptophan D. Thyroglobulin

B. Silent mutation

The result of a point mutation that occurs when UCA (coding for serine) is converted to UCU (also coding for serine) is called: A. Nonsense mutation B. Silent mutation C. Misense mutation D. None of these

C. Replication, Transcription, Translatio

The steps of central states: A. Replication, Translation, Transcription B. Replication, Transcription, Transmission C. Replication, Transcription, Translatio D. Transcription, Translation, Replication

B. Bile acids

The substance responsible for the emulsion of fats is: A. Gastric acid B. Bile acids C. Pepsin D. Trypsin

A. Glycolysis

The term "anaerobic phase" of glucose oxidation is used to designate series of reaction known as: A. Glycolysis B. Glycogenesis C. Glycogenolysis D. Both A and B

A. Nonsense codon

The termination of synthesis of a polypeptide is believed to involve: A. Nonsense codon B. Anticodon-codon interaction C. tRNA which cannot bind amino acids. D. Hydrolysis of messenger RNA.

B. 6 to 8

The total net ATP produced in aerobic glycolysis is ________ ATPs per mole of hexose, depending on which shuttle predominates in the transport of NAD/NADH. A. 4 to 6 B. 6 to 8 C. 4 to 8 D. 8 to 10

D. Acetyl coenzyme A and oxaloacetate

The tricarboxylic acid cycle is initiated by the condensation of which of the following two molecules? A. Pyruvate and malate B. NAD+ and oxaloacetate C. NAD+ and oxalosuccinate D. Acetyl coenzyme A and oxaloacetate E. Acetyl coenzyme A and oxalosuccinate

C. mRNA

The type of RNA molecule that brings amino acids to the site of protein synthesis is: A. rRNA B. aRNA C. mRNA D. tRNA E. dsRNA

A. mRNA

The type of RNA which serves as template for the amino acid sequence being synthesized: A. mRNA B. tRNA C. rRNA D. ssDNA E. dsDNA

E. Glycine, proline, and hydroxyproline

The unique amino acid composition of collagen is reflected in the high content of: A. Valine, threonine, and lysine B. Desmosine, glycine, and proline C. Cysteine, hydroxylysine, and proline D. Cysteine, tyrosine, and phenylalanine E. Glycine, proline, and hydroxyproline

A. Okazaki Fragment

These are discontinuous stretches in which the lagging strand is initially synthesized during DNA replication: A. Okazaki Fragment B. Enhancer C. Primer D. Opener E. DNA Ligase

C. Zymase

This is a fermenting enzyme that causes the conversion of monosaccharide into alcohol and carbon dioxide. A. Carboxylase B. Invertase C. Zymase D. Convertase

A. Marasmus

This is also known as protein-calorie malnutrition. It is a state resulting from the chronic deficiency of calories, which can occur even in the presence of adequate intake of protein: A. Marasmus B. Obesity C. Hemochromatosis D. Kwashiorkor

A. IgG

This is the most abundant immunoglobulin in the blood. A. IgG B. IgA C. IgM D. IgE E. IgD

C. Succinyl CoA to succinate

This is the only reaction coupled with substrate level phosphorylation in the TCA. A. Citrate to isocitrate B. Isocitrate to alpha - ketoglutarate C. Succinyl CoA to succinate D. Succinate to fumarate

D. Succinate to fumarate

This is the only reaction in TCA that involves FAD/FADH2? A. Citrate to isocitrate B. Isocitrate to alpha - ketoglutarate C. Succinyl CoA to succinate D. Succinate to fumarate

B. Isomerism

This refers to aldose - ketose interconversion: A. Tautomerization B. Isomerism C. Mutarotation D. Conjugation

B. Elongation

This step repeats until reaching a stop codon: A. Transcription B. Elongation C. Translation D. Termination

D. Lactic acid

This substance accumulates in the muscle as a result of vigorous exercise: A. Lactulose B. Amino acid C. Glycogen D. Lactic acid

A. Nonsense mutation

This type of mutation occurs when the codon containing the changed base may become a termination codon: A. Nonsense mutation B. Silent mutation C. Misense mutation D. None of these

D. is released in response to signals from the hypothalamic-anterior pituitary complex

Thyroid hormones, glucocorticoids and gonadal steroids are similar in that each A. is derived from cholesterol B. is derived from amino acids C. acts on only one target organ or tissue D. is released in response to signals from the hypothalamic-anterior pituitary complex E. is released in response to signals from the hypothalamic-posterior pituitary complex

B. RNA from DNA

Transcription is the cellular process of making: A. new DNA B. RNA from DNA C. proteins from amino acids by way of RNA D. none of the above

B. Glucagon and epinephrine

Two hormones which act similarly to increase glycogen and lipid breakdown as well as cyclic AMP synthesis are: A. Insulin and calcitonin B. Glucagon and epinephrine C. Aldosterone and testosterone D. Parathyroid hormone and glucagon.

D. Glucose - 6 - phosphatase

What enzyme in gluconeogenesis is employed to bypass the hexokinase reaction, which is the interconversion of glucose to glucose - 6 - phosphate? A. Pyruvate carboxylase B. PEP carboxykinae C. Fructose biphosphatase D. Glucose - 6 - phosphatase

E. UGA

What is the anti - codon in tRNA that corresponds to the codon ACF in mRNA? A. UGC B. TGC C. GCA D. CGU E. UGA

A. The ability of certain anticodons to pair with codons that differ at the third base

What is wobble? A. The ability of certain anticodons to pair with codons that differ at the third base B. An error in translation induced by streptomycin C. A mechanism that allows for a peptide extension in the 50s sub-unit of the ribosome D. Thermal motions leading to local denaturation of the DNA double helix

D. Point mutation

When only one base is replaced in the DNA sequence, the mutation is said to be a: A. Frame shift mutation B. Deletion C. Inversion D. Point mutation E. Translocation

D. Vitamin D

Which among the following vitamins may cause extensive vasoconstriction and elevated blood pressure and calcinosis of soft tissues when taken in excess? A. Vitamin A B. Vitamin B3 C. Vitamin B6 D. Vitamin D

D. Night blindness

Which among the items listed below best associated to vitamin A? A. Sunshine vitamin B. Beri-beri C. Pyridoxine D. Night blindness E. Bleeding problems

C. Aldosterone

Which hormone can regulate the level of blood sodium level? A. Corticosteroid B. Cortisol C. Aldosterone D. Sterol

C. Fat

Which is not a product of hydrolysis of nucleotide? A. N - base B. Sugar C. Fat D. Phosphate E. A, B, and D only

E. Site-specific endonucleases

Which of the following BEST describes restriction enzymes? A. Exonucleases B. Topiosomerases D. Non-specific endonucleases C. Enzymes that degrade RNA E. Site-specific endonucleases

C. Stabilize DNA in a compact form

Which of the following BEST describes the major function of histones? A. Unwind DNA B. Activate genes C. Stabilize DNA in a compact form D. Remove exons during RNA splicing. E. Stabilize RNA during transcription

B. It increases the H2O permeability of the collecting ducts and the distal tubules

Which of the following BEST explains the primary action of anti - diuretic hormone? A. It decreases the activity of the Na-K pump in the distal tubule B. It increases the H2O permeability of the collecting ducts and the distal tubules C. It decreases the pore size of the distal tubules and the collecting ducts D. It decreases the glomerular filtration rate E. It inhibits the action of glutaminase

E. Phosphodiester

Which of the following bonds link the monomeric units of nucleic acids? A. Ionic B. Peptide C. Thioester D. Glycosidic E. Phosphodiester

A. Fe+2

Which of the following compounds is NOT involved in coagulation of blood? A. Fe+2 B. Ca+2 C. Prothrombin D. Fibrinogen E. Thromboplastin

B. Liver disease

Which of the following conditions are associated with increase blood ammonia levels? A. Reye's syndrome B. Liver disease C. Neuropathy D. Dermatitis E. Streptococcal infection

A. Malabsorption

Which of the following conditions are usually measured via the D-xylose test? A. Malabsorption B. Brain tumor C. Glucose metabolism D. Renal dysfunction E. Thyroid function

A. They activate specific genes

Which of the following describes the principal mechanism by which glucocorticoids stimulate their target cells? A. They activate specific genes B. They activate initiation factors for protein synthesis C. They increase the intracellular Ca++ concentration D. They allosterically modify adenylate cyclase activity E. They bind to cell membrane receptors and activate adenylate cyclase

C. Glucose-6-phosphatase

Which of the following enzymes is essentially absent from normal mammalian muscle? A. Glucokinase dehydrogenase B. Phosphorylase C. Glucose-6-phosphatase D. Glucose-6-phosphate isomerase E. Glucose-6-phosphate

D. Glucose - 6 - phosphatase

Which of the following enzymes is present only in the liver and kidney and not in the muscle? A. Pyruvate carboxylase B. PEP carboxykinase C. Fructose biphosphatase D. Glucose - 6 - phosphatase

A. Amino Acyl-tRNA synthetase

Which of the following enzymes or processes ensures that the correct amino acid is incorporated for a particular codon during protein synthesis? A. Amino Acyl-tRNA synthetase B. Ribosomal protein synthesis C. Post-transcription splicing D. RNA synthetas E. Helicase

E. Ligase

Which of the following enzymes seals nicks in DNA? A. Exonuclease B. Endonuclease C. DNA polymerase D. RNA polymerase E. Ligase

B. Estrogen

Which of the following generates a slowly developing long-term response in target tissues by binding to an intracellular receptor? A. Glucagon B. Estrogen C. Prolactin D. Growth hormone E. Parathyroid hormone

A. Insulin

Which of the following hormones does NOT induce activation of adenylate cyclase? A. Insulin B. Glucagon C. Epinephrine D. Parathyroid hormone

E. Relaxin

Which of the following hormones is NOT synthesized from cholesterol? A. Progesterone B. Testosterone C. Estradiol D. Cortisol E. Relaxin

E. Follicle-stimulating hormone

Which of the following hormones is a polypeptide? A. Epinephrine B. Testosterone C. Progesterone D. Triiodotyronine E. Follicle-stimulating hormone

C. Calcium

Which of the following ions is involved in blood clotting? A. Iron B. Sodium C. Calcium D. Potassium

D. Hyaluronidase

Which of the following is MOST likely to promote depolymerization of extracellular matrix? A. Cortisone B. Collagenase C. Chymotrypsin D. Hyaluronidase

D. UGA

Which of the following is a STOP Codon? A. AUG B. CGC C. GGA D. UGA E. CCC

D. Acetoacetate

Which of the following is a ketone body? A. Glycerol B. Glucagon C. Acetyl CoA D. Acetoacetate E. Phosphatidycholine

B. To enhance cell permeability to glucose

Which of the following is a principal action of insulin? A. To mobilize lipid deposits B. To enhance cell permeability to glucose C. To decrease cell permeability to glucose D. To conserve glucose by breaking down amino acids

E. All are correct features of DNA structure

Which of the following is correct about the Watson-Crick model of DNA? A. The backbone of each DNA strand is a repeating sugar-phosphate polymer B. The strands of DNA are anti-parallel, spiraling around the helix axis in opposite directions C. The sequences of bases in the two strands are determined by hydrogen bonding between adenine and thymine or guanine and cytosine D. The sugar involved in the backbone structure is deoxyribose E. All are correct features of DNA structure

D. NADPH

Which of the following is necessary for de novo synthesis of cholesterol? A. NAD+ B. NADH C. NADP+ D. NADPH E. FADH2

D. All of these

Which of the following is/are the main goals of Pentose Phosphate Pathway? A. Produce ribose - 5 - Phosphate for nucleotide synthesis B. Produce NADPH and NADP for fatty acid and steroid biosynthesis C. To interconvert pentose and hexoses D. All of these E. A and B only

A. Glucokinase

Which of the following liver enzymes, absent from other tissues, gives the liver an advantage over other cells in taking up glucose after a meal? A. Glucokinase B. Aldolase C. Hexokinase D. Enolase E. Glucose-6-phosphatase

B. Phosphorylation of phosphorylase b to phosphorylase a

Which of the following mechanisms operates in liver cells to regulate breakdown of glycogen? A. Zymogen activation B. Phosphorylation of phosphorylase b to phosphorylase a C. Induction of phosphorylase b by an inducer D. Inhibition of adenylate cyclase

E. B and C

Which of the following occur(s) in the cytosol? A. TCA B. Glycolysis C. PPP D. A and B E. B and C

E. Adenosine triphosphate

Which of the following represents the chemical substance that is the immediate source of energy for muscle contraction? A. Glycogen B. Acetyl CoA C. Lactic acid D. Creatine phosphate E. Adenosine triphosphate

C. Separated strands are able to re-associate

Which of the following represents the consequence of the fact that DNA strands are complementary? A. Hairpin loop structures can be generated B. They will always have identical sequences C. Separated strands are able to re-associate D. They cannot get back together once separated

E. Fibrinogen

Which of the following represents the normal substrate of thrombin? A. Fibrin B. Thrombospondin C. Prothrombin D. Thromboplastin E. Fibrinogen

C. I, II, III and IV

Which of the following statements is (are) true about insulin: I. Insulin is a hormone II. Insulin is a protein III. Produced by the beta cells of the pancreas IV. Insulin is rapidly distributed throughout extracellular fluid A. I, III and IV only B. I and II only C. I, II, III and IV D. I, II and IV

D. A segment of the polypeptide chain is removed

Which of the following takes place as proinsulin is converted to insulin? A. Disulfide bonds are formed B. Disulfide bonds are broken C. The polypeptide chain is lengthened D. A segment of the polypeptide chain is removed

A. Thrombocytopenia

Which of the following terms describes a reduced number of platelets? A. Thrombocytopenia B. Leukopenia C. Leukocytosis D. Thrombophlebitis E. Thrombocytosis

C. Ninhydrin test

Which of the following tests is specific for the presence of free amino acid groups? A. Biuret tests B. Hopkin's Cole test C. Ninhydrin test D. Xanthoproteic test E. Sakaguchi test

C. Ascorbic acid

Which of the following vitamins is essential for the normal elaboration and maintenance of bone matrix, cartilage, and dentin? A. Niacin B. Vitamin E C. Ascorbic acid D. Pantothenic acid

D. Fats

Which substance yields the largest number of calories per gram? A. Carbohydrates B. Proteins C. Minerals D. Fats E. Vitamins

B. Niacin

Which vitamin can be used in the management of hyperlipidemia: A. Thiamine B. Niacin C. Riboflavin D. Panthothenic acid