Description : The following are true about G proteins: a. they are first messengers b. when activated, the alpha subunit exchange GDP for GTP c. they are transmembrane signal receptor molecules d. vibrio cholerae secrets an exotoxin which makes G-proteins resistant to inactivation
Last Answer : when activated, the alpha subunit exchange GDP for GTP
Description : Adenylate cyclase is activated by (A) Insulin (B) Glucagon (C) Prostaglandin E1 (D) Ca2+ ions
Last Answer : Answer : B
Description : Cyclic AMP is formed from ATP by the enzyme adenylate cyclase which is activated by the hormone: (A) Insulin (B) Epinephrine (C) Testosterone (D) Progesterone
Last Answer : B
Description : Which of the following is activated by Cholera toxin? 1) Adenylate cyclase 2) Guanlyate cyclase 3) Peroxisome proliferator receptor (PPAR) gamma 4) Sodium/potassium ATPase 5) The glucose-sodium transporter
Last Answer : Answers-1 Cholera toxin activates adenylate cyclase with generation of cAMP.
Description : Binding of thyroxine to its receptors (A) Activates Adenylate cyclase (B) Activates guanylate cyclase (C) Activates a stimulatory G-protein (D) Increases transcription
Last Answer : Answer : D
Description : The nucleotide binding site of G-proteins is present on their (A) α-Subunit (B) β-Subunit α- and β- (C) γ-Subunit (D) δ-Subunit
Last Answer : Answer : A
Description : Which of the following statement(s) is/are true concerning cell membrane receptors? a. The largest family of cell surface receptors are the G-protein-linked receptors b. Activities of the ... through the use adenylate cyclase d. Tyrosine kinase receptors are considered G-protein-linked receptors
Last Answer : Answer: a, c All water-soluble regulatory molecules bind to the cell surface receptor proteins. Binding of the appropriate ligand evokes an intracellular signal which usually regulates ... are adenylate cyclase, which converts ATP to cAMP, and the polyphosphoinositide-specific phospholipase C
Description : Rod cells possess a trans-membrane protein which is (A) Adenylate cyclase (B) Transducin (C) Rhodopsin (D) B as well as C
Last Answer : Answer : C
Description : Insulin receptor is made up of (A) One α-and one β-subunit (B) Two α-and two β-subunit (C) Two, α two β-and two γ-subunit (D) One α, one β-one γ-and one δ-subunit
Description : The best understood intracellular messenger is cyclic AMP (cAMP). Which of the following statement(s) concerning this intracellular messenger is/are correct? a. Intracellular cyclic AMP is constantly ... of adenylate cyclase d. cAMP is the only cyclic nucleotide active as an intracellular messenger
Last Answer : Answer: a, b The prototypic intracellular messenger is cAMP. To function as a mediator, the concentration of cAMP must change rapidly. In resting cells, cAMP is continuously being degraded by ... produce cGMP. Intracellular calcium ions also serve as second messengers in a large number of cells
Description : cAMD is destroyed by (A) Adenylate cyclase (B) Phosphodiesterase (C) Synthetase phosphatase (D) Synthetase kinase
Description : Whcih of the following hormone does not activate adenylate cyclase? (A) Epinephrine (B) Glucagon (C) Parathyroid hormone (D) Insulin
Description : Binding of insulin to its receptor activates (A) Adenylate cyclase (B) Guanylate cyclase (C) Phospholipase C (D) Tyrosine kinase
Description : During phototransduction: a. hyperpolarisation occurs due to closure of the sodium channels b. 11-cis-retinal molecules are converted to all-trans-retinal c. transducin, a G protein converts GDP to GTP d. all above
Last Answer : all above
Description : Initiation of protein synthesis requires (A) ATP (B) AMP (C) GDP (D) GTP
Description : The first amino acyl tRNA approaches 40 S ribosomal subunit in association with (A) eIF-1A and GTP (B) eIF-2 and GTP (C) eIF-2C and GTP (D) eIF-3 and GTP
Description : G-proteins have a nucleotide binding site for (A) ADP/ATP (B) GDP/GTP (C) CDP/CTP (D) UDP/UTP
Description : During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.
Last Answer : (c) association of 30S mRNA with formyl-met- tRNA
Description : .During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.
Description : All the following statements about TSH are true except (A) It is a glycoprotein (B) It is made up of α- and β-subunits (C) Receptor recognition involves both the subunits (D) Its subunit is identical with those of FSH and LH
Description : Thyroid stimulating hormone is a dimer. The α-subunits of TSH, LH, FSH are identical. Thus the biological specificity must therefore be β subunit in which the number of amino acids is (A) 78 (B) 112 (C) 130 (D) 199
Description : Translocation of the newly formed peptidyl tRNA at the A site into the empty P site involves (A) EF-II, GTP (B) EF-I, GTP (C) EF-I, GDP (D) Peptidyl transferase, GTP
Description : In the process of elongation of chain binding of amino acyl tRNA to the A site requires (A) A proper codon recognition (B) GTP (C) EF-II (D) GDP
Description : The cofactors required for synthesis of adenylosuccinate are (A) ATP, Mg++ (B) ADP (C) GTP, Mg++ (D) GDP
Description : Coenzyme for phosphoenolpyruvate carboxykinase is (A) ATP (B) ADP (C) GTP (D) GDP
Description : Allsoteric activator of glutamate dehydrogenase is (A) ATP (B) GTP (C) ADP and GDP (D) AMP and GMP
Description : The mammalian DNA polymerase involved in error correction is (A) DNA polymerase α (B) DNA polymerase β (C) DNA polymerase γ (D) DNA polymerase δ
Description : Replication of nuclear DNA in mammals is catalysed by (A) DNA polymerase α (B) DNA polymerase β (C) DNA polymerase γ (D) DNA polymerase III
Description : Reverse transcriptase activity is present in the eukaryotic: (A) DNA polymerase α (B) DNA polymerase γ (C) Telomerase (D) DNA polymerase II
Description : The immediate parent of α, β and γ endorphins is (A) Pro-opiomelanocortin (B) β-lipotropin (C) ATCH (D) Lipoprotein
Description : In the insulin receptor, tyrosine kinase domain is present in (A) α-Subunits (B) β-Subunits (C) γ-Subunits (D) δ-Subunits
Description : Insulin binding sites are present on the (A) α-subunits of insulin receptor (B) β-subunits of insulin receptor (C) γ-subunits of insulin receptor (D) α-and β−subunits of insulin receptor
Description : All of the following can be formed from pro-opiomelanocortin except (A) α-and β-MSH (B) β-and γ-Lipotropins (C) α-and β-Endorphins(D) FSH
Description : Transferrin is a type of (A) Albumin (B) α-globulin (C) β1 globulin (D) γ-globulin MINERAL METABOLISM 203
Description : Characteristic absorption bands exhibited by ferrocytochrome: (A) α band (B) β band (C) α and β bands (D) α, β and γ bands
Description : Two molecules of vitamin A can be formed from 1 molecule of (A) α-Carotene (B) β-Carotene (C) γ-Carotene (D) All of these
Description : Precursor of Vitamin A is (A) α-Carotene (B) β-Carotene (C) γ-Carotene (D) All of these VITAMINS 121
Description : Amylase present in saliva is (A) α-Amylase (B) β-Amylae (C) γ -Amylase (D) All of these
Description : Instead of ester link plasmalogens possess an other link in position: (A) α (B) β (C) γ (D) None of these FATS AND FATTY ACID METABOLISM 93
Description : All the following are omega-6-fatty acids except (A) Linoleic acid (B) α-Linolenic acid (C) γ-Linolenic acid (D) Arachidonic acid
Description : Which of the following is omega-3 polyunsaturated fatty acid? (A) Linoleic acid (B) α-Linolenic acid (C) γ-Linolenic acid (D) Arachidonic acid
Description : When haemoglobin takes up oxygen there is a change in the structure due to the moving closer together of (A) β-chains (B) β-chains (C) γ-chains (D) α and γ chains
Description : Foetal haemoglobin contains (A) Two α and two γ chains (B) Two β and two γ chains (C) Both (A) and (B) (D) None of these
Description : All of the following statements about thioredoxin reductase are true except: (A) It requires NADH as a coenzyme (B) Its substrates are ADP, GDP, CDP and UDP (C) It is activated by ATP (D) It is inhibited by dADP
Description : The mRNA ready for protein synthesis has the ________ cap. (A) ATP (B) CTP (C) GTP (D) UTP
Description : The 2 energy rich compounds needed for protein biosynthesis are (A) ATP and GTP (B) ATP and UTP (C) ATP and CTP (D) ATP and TTP
Description : Elongation of a peptide chain involves all the following except (A) mRNA (B) GTP (C) Formyl-Met-tRNA (D) Tu, TS and G factors
Description : If α, β and γ are coefficients of linear, area l and volume expansion of a solid then
Last Answer : If α, β and γ are coefficients of linear, area l and volume expansion of a solid then (A) α:β:γ 1:3:2 (B) α:β:γ ... C) α:β:γ 2:3:1 (D) α:β:γ 3:1:2
Description : Radiations which is not emitted during radioactivity is – (1) α rays (2) β rays (3) γ rays (4) Cathode rays
Last Answer : (4) Cathode rays Explanation: Radioactivity is the process by which a nucleus of an unstable atom loses energy by emitting particles of ionizing radiation. It includes the emission of energetic alpha particles (α), beta particles (β), and gamma rays.
Description : Radioactive elements emit – (1) Radiowaves (2) Infrared waves (3) Ultraviolet waves (4) α, β and γ radiations
Last Answer : (4) α, β and γ radiations Explanation: The phenomenon of spontaneous emission of certain kinds of radiations by some elements is called radioactivity and the elements emitting such radiations are called ... the radioactive substances are separated in to three types, called a, b and g rays.