41. Archea is considered as a separate group from bacteria and eukaryotes, based on
(A) genome sequence(B) 16S rRNA gene sequence(C) 23S rRNA gene sequence(D) EFTu sequence
Ans:16S rRNA gene sequence
42. Cholesterol contributes to which of the following properties of biological membranes?
(A) Membrane rigidity(B) Membrane fluidity(C) Membrane permeability(D) Membrane osmolarity
Ans: Membrane fluidity
At physiological condition (370C) increased amount of cholesterol will decrease membrane fluidity.
43. Active site of all serine proteases consists of
(A) Ser- Glu -Asp(B) Ser- Glu - Met(C) Ser-His-Asp(D) Ala-Glu-Met
Ans:The active site of the serine proteases consists of three key residues, Asp-His- Ser
44. Severe deficiency of which of the following vitamins leads to haemolytic anemia in animals ?
(A) Vit A(B) Vit E(C) Vit D(D) Vit K
- For more : Vitamins
45. The specific condition that occurs subsequent to the inhalation of carbon is referred to as
(A) Anthracosis(B) Pneumoconiosis(C) Siderosis(D) Acanthosis
- Anthracosis is nothing more than accumulation of carbon pigment from breathing dirty air.
- Coal worker's pneumoconiosis is a lung disease that results from breathing in dust from coal, graphite, or man-made carbon over a long period of time.
- Siderosis is the deposition of iron in tissue.
- Acanthosis - increasing the number of prickly epidermal cells in its germ layer, leading to thickening.
46. Which of the following processes occurs in the formation of disulfide bridge between two cysteine residues?
(A) Reduction of sulfhydral group(B) Electrostatic interaction(C) Oxidation of sulfhydral group(D) Hydrogen bond formation
Ans: Oxidation of sulfhydral group
- Disulfide bond is a covalent bond formed by the oxidation of sulfhydryl (-SH) groups (between two cysteine residues).
- Disulphide bonds are formed only in the oxidising environment of the endoplasmic reticulam as a result found primarily in extracellular and secreted proteins.
- Methionine is the other sulfur containing amino acid but cannot form S-S bond, due to lack of free SH group.
47. Regulation of fatty acid biosynthesis occurs at the enzymatic step catalyzed by
(A) carnitine acyltransferase I(B) acetyl CoA carboxylase(C) pyruvate carboxylase(D) citrate synthase
Ans: acetyl CoA carboxylase
- The enzyme involved in the first step of fatty acid synthesis.
- Carboxylation of Acetyl CoA to malonyl CoA
48. The symbiotic bacteria responsible for producing bio luminescence is
(A) Vibrio cholerae(B) Pseudomonas putida(C) Vibrio fischeri(D) Chromobacterium sp.
Ans: Vibrio fischeri
- Heterotrophic gram-negative bacteria often found in symbiotic association with Euprymna scolopes, a small shallow water squid.
- Vibrio fischeri is famous for its bioluminescence caused by five genes, luxCDABE, regulated by luxR and luxI.
- Soil bacterium.
- The first patented organism in the world.
- Used for bio remediation.
49. Independently folded functional unit of a protein is called a
(A) motif(B) fold(C) domain(D) module
- Domain: A part of protein that can fold function independently from rest of protein and may exist in different proteins Eg: Zinc finger Domain
- Motif are super secondary structures Eg: Helix –loop-Helix
50. When immature B cells mature in the bone marrow, they need to interact with
(A) stem cells present in the bone marrow(B) stromal cells and cytokines such as IL7(C) mature B cells present in the bone marrow(D) antigen presenting cells with different B cell epitopes presented on MHC II molecules
Ans: stromal cells and cytokines such as IL7
51. Conversion of glucose to glucose-6- phosphate requires energy. However, critically ill patients are treated with intravenous infusion of glucose rather than glucose -6-phosphate because
(A) glucose-6-phosphate is unable to enter into cells(B) glucose-6-phosphate is degraded very fast(C) exogenous glucose-6-phosphate is toxic to the cells(D) exogenous glucose-6-phosphate will competitively inhibit endogenous enzymes
Ans: A) glucose-6-phosphate is unable to enter into cells
- Glucose 6-phosphate is negatively charged and cannot cross the membrane. Only glucose can pass through glucose transporter protein (GLUT) on cell membrane
52. Which of the following properties is common to all cytoskeletal motor proteins like kinesins, dyneins and myosins?
(A) GTPase activity(B) ATPase activity(C) Actin binding domain(D) DNA binding domain
Ans: ATPase activity
53. The amino acid sequence of a novel membrane protein contains four immunoglobulin like domains and six fibronectin like repeats. This protein is most likely a
(A) hormone responsive ion channel(B) cell adhesion molecule(C) G-protein(D) transcription factor
Ans: cell adhesion molecule
54. A set of closely related genes or genetic markers that are inherited as a single unit is
(A) cistron(B) gene families(C) Haplotype(D) Haploid
- Haplotype: a group of genes, which is inherited together by an organism from a single parent
- Cistron :a nucleotide sequence coding for a functional polypeptide(gene)
- Haploid : A cell or organism of a species containing a set of chromosome normally found in gametes(Single set of chromosome)
- Gene families are groups of homologous genes that are likely to have highly similar functions.
55. Xth nerve is an example of
(A) mixed cranial nerve(B) sensory cranial nerve(C) spinal nerve(D) motor nerve
Ans: mixed cranial nerve.
56. Which among the following viruses is known for its antigenic variation?
(A) Rabies(B) Influenza(C) Yellow fever(D) Japanese encephalitis
57. Homology modelling can be used to predict the 3D structure of only
(A) paralogs(B) orthologs(C) xenologs(D) homologs
- Also known as comparative modelling of protein
- Comparative modelling uses the structural similarities between proteins by constructing a three dimensional structure based upon the known structure of the of one or more related proteins
58. Which of the following does not participate in the formation of antigen-antibody/ligand-receptor complexes?
(A) Hydrophobic bonds(B) Covalent bonds(C) Electrostatic interactions(D) Hydrogen bonds
Ans: Covalent bonds
- Strongest bond that is not suitable for reversible binding like ligand –receptor complex.
59. The enzyme used in SoLiD sequencing technology is
(A) sequenase(B) DNA polymerase(C) DNA Ligase(D) Taq Polymerase
Ans: DNA Ligase
- Sequencing by Oligonucleotide Ligation and Detection (SoLiD)
60. PRINTS database contains
(A) Single motifs(B) Multiple motifs(C) Single domains(D) Multiple domains
Ans: Multiple motifs
- PRINTS database: secondary database
- PRINTS is a compendium of protein fingerprints.
- A fingerprint is a group of conserved motifs used to characterize a protein family
- Single motif database: PROSITE
- PROSITE: first secondary database