(A) Ethylene(B) Auxins(C) Cytokinin(D) Abscisic acid
For more Phytohormones (Plant hormones)
22. Which one of the following is an example of structural chromosomal aberration?
(A) Edward’s syndrome(B) Down’s syndrome(C) Turner’s syndrome(D) Cri-du-chat syndromeAns: Cri-du-chat syndrome
- Karyotype :46,XY, del(5)(p25)
- Short arm deletion of 5
For more: Human Genetic Disorder
23. A mammalian cell has an outstretched double stranded DNA of 1.2 meter which duplicates in 4hrs. If it duplicates at the rate of 20μmeter/min, how many origins of replication are there in the DNA?
Length of dsDNA=1.2 m=1.2x106 um
Rate of duplication=20um per minute
Time taken for duplication (if there is single ori)= 1.2x106/20um=60000min=1000hrs
Actual time taken=4hrs
No. of ori required to complete duplication in 4 h=1000/4=250 origins
24. Which of the following cells secrete Eselectins?
(A) Eosinophils(B) Endothelial cells(C) Microglial cells(D) Epithelial cells
Ans: Endothelial cells
- The Selectin family is comprised of three members, E-Selectin, L-Selectin, and P-Selectin.
- E-selectin (endothelial leukocyte adhesion molecule-1 (ELAM-1)is expressed on inflamed endothelial cells in response to treatment with inflammatory cytokines.
- L-Selectin (Leukocyte Selectin)is expressed constitutively on a wide variety of leukocytes. Human P-Selectin (GMP-140, LECAM-3, PADGEM, CD62P) is expressed by activated platelets and endothelial cells.
25.'Weak calf syndrome' in pregnant cows at 80-125 days of gestation period is caused by
(A) BVD virus(B) Pseudorabies virus(C) IBR Virus(D) MCF virus
Ans:Bovine Viral Diarrhea (BVD)Virus
26. Which of the following is/are selective media for Vibrio cholerae?
(A) Thayer –Martin medium(B) Cefoxitin cycloserine fructoseagar(C) Skirrow’s medium(D) Thiosulfate-citrate-bile-sucrose agar
- Thiosulfate-citrate-bile salts-sucrose agar - isolation of pathogenic vibrios.
- Thayer-Martin Selective Agar -selective isolation of Neisseria species.
- Cycloserine Cefoxitin Fructose Agar (CCFA) - isolation and identification of Clostridium.
- Skirrow's medium - suitable for growing Campylobacter fetus and Brucella spp.
27. Which one of the following microscopic techniques is best suited to visualize the topology and distribution of transmembraneprotein of a cell membrane?
(A) Scanning electron microscopy(B) Transmission electron microscopy(C) Freeze-fracture electron microscopy(D) Thin-section electron microscopy
Ans:C) Freeze fracture electron microscopy
- For more : Microscopy Techniques
28.Bovine keratitis is caused by
(A) Morexella bovis(B) Bordetella pertosis(C) Staphylococcus(D) Bacteroides
Ans: Moraxella bovis
29. A novel type II restriction enzyme has been isolated from a thermophilic bacteria. This restriction endonuclease recognizes 5’ATAANNNTTAT3’ (N= any nucleotide) and cuts after third ‘A’ in the above sequence. What is the fate of DNA after restriction digestion ?
(A) a 3 nucleotide long 5´ overhang(B) a 7 nucleotide long 5´ overhang(C) a 4 nucleotide long 5´ overhang(D) a 3 nucleotide long 3´ overhang
Ans: is (A) a 3 nucleotide long 5´ overhang.
For answering this question, we should know exactly what is Type II restriction enzyme?
- Only Type II restriction enzymes are used in rDNA technology as it can cut DNA at specific sequences called restriction sites or recognition sequences.
- Recognition sequences of type II restriction enzymes are palindromes with rotational symmetry. This point should be in mind to answer this question
- Recognition sequence in the question is 5’ATAA-NNNTTAT3’ cleaves after 3rd A.
- Then the complementary sequence is 3’TATT NNN-AATA5’ (-)restriction site
- Upon restriction we get the sequence as 5’ATAA and NNNTTAT3’
3’TATT NNN AATA5’
- Overhang means single stranded unpaired region.
30. Xenopsylla cheopis is the vector for
(A) Indian tick typus(B) Epidemic typus(C) Plague(D) Kala azar
Male Xenopsylla cheopis -This flea is the primary vector of plague.
31. Elevation of intracellular inositol triphosphate (IP3) results in the release of Ca2+ from which of the following organelles?
(A) Mitochondria(B) Smooth endoplasmic reticulum(C) Peroxisome(D) Golgi-complex
Ans: (B) Smooth endoplasmic reticulum
- Second messengers include IP3, DAG, cAMP, cGMP
32. Testosterone hormone necessary for spermatogenesis is secreted by
(A) sertoli cells(B) leydig cells(C) spermatozoa(D) cowpers gland
Ans: (B) leydig cells
33. When Hfr strain of E. coli is crossed with F- strain, recombinants obtained are
(A) always F+(B) always HFr+(C) rarely F+(D) rarely HFr+
Ans: rarely F+
- In bacteria, transfer of genetic material (DNA) from one bacterium (donor) to another (recipient) takes place through three methods i.e., Transformation, Transduction and Conjugation.
- Conjugation was discovered in 1942 by Lederberg and Tatum.
- During conjugation DNA is transferred from donor cell to a recipient cell through a conjugation canal formed between them.
- The donor cells posses a small circular DNA (plasmid) called F factor ( fertility factor or sex factor). The F factor can exist in two states: the autonomous states (F+)and the integrated state(Hfr). Bacteria without F factor is refererred as F-.
- F+x F- = F+, F- becomes F+
- Hfr x F- =F- remain F- as usually F factor may not be transferred, where as some bacterial genes of Hfr may integrate into the F- genome during conjugation.
34.The mouse model for type II diabetes mellitus is
(A) NZB mouse(B) SCID mouse(C) Nude mouse(D) NOD mouse
Ans: NOD mouse
- NZB Mouse as a Model for Chronic Lymphocytic Leukemia
- Nude mouse - immuno deficient mice
- NOD: The mouse model for type Idiabetes mellitus
- Nagoya-Shibata-Yasuda (NSY) specifically the mouse model for type II diabetes mellitus
35. In which of the following cases, the enzyme substrate complex is irreversible in nature?
(A) Competitive inhibition(B) Non-competitive inhibition(C) Un-competitive inhibition(D) Both competitive and non-competitive inhibition
Ans: Un-competitive inhibition
36. Replication of papillomavirus is restricted to
(A) epithelial cells(B) nerve cells(C) fibroblasts(D) reticulo-endothelial cells
Ans: epithelial cells
37. Which of the following is a lipid with a signal transducing activity?
(A) Phosphatidyl serine(B) Phosphatidyl ethanolamine5(C) Phosphatidyl inositol 4,5-bisphosphate(D) Phospholipase A2
Ans:Phosphatidyl inositol 4,5-bisphosphate
38. Which one of the following techniques is used for the evaluation of phylogenetic trees?
(A) Null hypothesis(B) Bootstrapping(C) Chi-square(D) Probability
39. NiceProt is
(A) Protein sequence database(B) Derived Protein database(C) Protein sequence view(D) Nucleotide sequence view
Ans:Protein sequence view
NiceProt View of Swiss-Prot
40. Which of the following chemotherapeutic drugs has neurotoxicity?
(A) Vincristine(B) Cyclophosphamide(C) Anthracyclines(D) Adriamycin
- Anthracyclines attack cancer cells by multiple mechanisms, inhibiting replication and damaging cells in ways that promote cell death.
- Cyclophosphamide (CP), an alkylating agent is one of the widely used cytostatic drugs.
- Adriamycin (Doxorubicin) is an anthracycline antibiotic isolated from streptomyces peucetius. Adriamycin prevents DNA replication.