SOLVED PAPER OF LIFESCIENCE 26.09.2020

SOLVED PAPER OF LIFESCIENCE

1) Which one of the following is not a modification of a microscope?

(A) Phase contrast microscope

(B) Fluorescence microscope

(D) Dark-field microscope

2) In Drosophila melanogaster, sex is determined by:

(A) X and Y chromosomes (B) X/A ratio

3) Organelle found in plant seeds that oxidise stored lipids as source of carbon and energy for growth are:

(A) peroxisomes (B) chloroplasts (C) glyoxysomes (D) lysosomes

4) Which of the following represents mammalian mitotic cyclins ?

(A) Cyclins A and D (B) Cyclins B and D

5) The valency of Immunoglobulin M molecule is :

(A) 8 (B) 10 (C) 12 (D) 14

6) Bivalent formation and crossing over take place during :

(A) Zygotene (B) Pachytene (C) Diplotene (D) Leptotne

7) Induction of new blood vessels that invade the tumor and nourish it is known as:

(A) metastasis (B) neogenesIs (C) angiogenesis (D) extravasation

8) GLUT 1 is a well studied example of a protein that mediates :

(A) active transport (B) facilitated diffusion

9) Cadherins are a family of cell adhesion molecules dependent on :

(A) Ca2+ (B) K+ (C) Na+ (D) Mg2+

10) Cellulose is formed by repeated units of:

(A) glucose and galactose (B) galactose (C) glucose (D) fructose

11) The acetyl groups required for cytoplasmic fatty acid biosynthesis generated due to activity of:

(A) citrate lyase (B) citrate synthase

12. A non-competitive inhibitor:

(A) increases Km and V max both

(B) decreases Km and Increases V max

(D) Km remains unaltered, V max decreases

13) Which one of the following is not a proton pump ?

(A) NADH-Q reductase (B) Succinate-Q reductase

14) Two molecules of double stranded DNA have same length (1000bp) but differ in base composition. Molecule 1 contains 20% A+T, molecule 2 contains 60% A+T. Which molecule has a higher Tm and how many C

residues are there in molecule 2?

(A) 1; 400 (B) 1; 200 (C) 2; 400 (D) 2; 40

15) Which of the following does not involved in the lagging strand synthesis?

(A) RNaseA (B) Primase (C) Reverse Transcriptase (D) DNA Pol I

16) Which of the following does not inhibit translation?

(A) chloramphenicol (B) streptomycin (C) tetracycline (D) rifampicin

17) For a spontaneous reaction ΔG should be :

(A)positive (B) negative (C) equal to zero (D) may be negative or zero

18) There are three kinds of RNA polymerases (I, II, III) in eukaryotic cells, each specific for one class of RNA molecule (mRNA, tRNA and rRNA). Which of the following is a correct match?

(A) I-rRNA, II-tRNA (B) II-mRNA, III-rRNA

(C) I-rRNA, II-mRNA (D) I-tRNA, III-rRNA

19) Cold stress-induced increase in membrane fluidity is caused due to:

(A) increase in cholesterol

(B) increase in long chain fatty acids

(C) Increase in unsaturated fatty acids

(D) increase in sphingolipids

20) Which of the following statements is true?

(A) Intestinal cells have Na+/glucose antiporters

(B) Intestinal cells have Na+/amino acid symporters

(D) Cells have Na+/H+ symporters.

21)Which of the following is an osmoregulatory hormone in lower vertebrates?

(A) Thyroxine (B) Malatonin (C) Prolactin (D) Epinephrine

22) "Mottled enamel" a condition which makes teeth particularly more resistant to decay is due to

(A) vitamin A excess (B) fluoride excess

23) Blue-light receptors in the plant are:

(A)Cryptochromes (B) Carotenoids(C) Cytochromes(D) Phytochromes

24) Echo location is characteristic of :

(A) Bats (B) Whates (C) Birds (D) Birds, whales and bats

25) Genes that are located at identical loci of homologous chromosomes are called:

(A) alleles (B) polygenes (C) homozygous (D) pseudogenes

26) The Okazaki fragments of the lagging strand of DNA template are joined by :

(A) DNA gyrase (B) DNA ligase (C) DNA polymerase (D) RNA primer

27) The name of chromosome map unit is :

(A)Inter locus distance (B) Cytomorgan

28) The basic unit of chromatin nucleosome consists of:

(A) H1A, H2B, H3, H4 histones and 200 bp of DNA

(B) H1, H2, H3, H4 histones and 180 bp of DNA

(C) H2A, H2B, H3, H4 histones and 140 bp of DNA

(D) DNA polymerase, DNA helicase and histones

29)The human hereditary disease associated with DNA repair is:

(A) Kleinfelter's syndrome (B) Haemophilia

30) A molecular technique that can be used to isolate contiguous regions of genomic DNA beginning with previously cloned DNA fragments that map near a gene of interest is called:

(A) chromosome walking (B) chromosome painting

31) Renewability,pluripotency and ability to differentiate are properties of:

(A) endocrine cells (B) endodermal cells (C) oocytes (D) stem cells

32) Exception to universal genetic code is seen in

(A) plasmids (B) viruses (C) mitochondria (D) transposons

33)Characteristics that have arisen as a result of common evolutionary descent are said to be :

(A)analogous (B) homologous (C) heterologous (D) heterogamous

34) The effect of natural selection may be countered by:

(A) gene flow (B) genetic drift (C) mutation (D) inbreeding

35)In a population of 100 persons, there are 30 personswith M blood group and 20 persons with N blood group. The gene frequency for M and N blood groups is :

(A) 0.20, 0.80 (B) 0.60, 0.40 (C) 0.20, 0.30 (D) 0.65, 0.45

36) Which of the following definitions correctly depicts "biological species" concept?

(A) A species is the most inclusive population of organisms that share a common fertilization system

(B) A species is a single lineage of population that maintains an identity separate from other such lineages

(C)Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups

(D) A species is the smallest unit of group of individuals sharing common ancestry

37) During the early stages of development, embryos of reptiles, birds and mammals look very similar. This suggests that reptiles, birds and mammals:

(A) have a common ancestor

(B) live in the same type of environment

(D) are no longer undergoing evolution

38) Speciation is more likely to occur in cases of :

(A) sympatry (B) allopatry (C) antipatry (D) panmixis

39) The ecosystem without stress is:

(A) highly productive (B) highly diverse and stable

40) A sustainable development practice involves

(A) control of pathogens using biopesticides

(B) reclamation of soils using chemical fertilizers

(D) use of fossil fuels

41) Which of the following ecosystems is represented by inverted pyramid of biomass?

(A) Forest (B) Grass land (C) Pond (D) Rhizosphere

42)The organism used for large scale production of vitamin B2 is

(A) Penicillium chrysogenum (B) Aspergillus niger

43) Assimilatory microbial SO₄ reduction occurs in:

(A)flowing water (B)surface water (C)atmosphere (D) water sediments

44) Bt toxin is active in the gut environment having

(A) alkaline pH (B) alkaline protease

45) Bentham and Hooker's system classifies :

(A) all tracheophytes (B) all seed plants

46) The group which contains all Cnidaria is :

(A) Obelia, Acetabularia, Hydra,Coral

(B) Hydra, Jellyfish, Rotifer, Coral

(D) Jellyfish, Ascon, Physalia, Sea Anemone

47) The common mushroom puffballs and truffles belong to the class of fungi

(A) Ascomycetes (B) Basidiomycetes

48) The biological name of common brewing and baking yeast is

(A) Candida albicans (B) Escherichia coli

49) A pair of halteres is seen in:

(A) Damsel fly (B) May fly (C) Butterfly (D) Fruit fly

50) Botanical gardens serve the purpose of ……conservation of plants.

(A) ex situ, ex vitro (B) in situ, ex vitro

51) Thar desert stretches to Indian states like :

(A) Rajasthan, Uttarakhand, Madhya Pradesh

(B) Rajasthan, Haryana, NCR

(D) Rajasthan, Punjab, Gujrat

52) Which of the following sequences indicates trend in the evolution of thallus in algae?

(A) Unicellular →Heterotrichous→Colonial → Filamentous

(B) Unicellular →Filamentous →Heterotrichous →Colonial

(D) Unicellular →Filamentous →Colonial → Heterotrichous

53) Dendrocronology deals with determination of age of a tree with:

(1) Diffused porous wood (2) Ring porous wood

(3) Heart ring porous wood (4) Sap wood

(A) 1 and 3 (B) 2 and 3 (C) 1 and 4 (D) 2 and 4

54) The immediate products of meiosis in megaspore mother cell are:

(A) Eggs (B) Megaspores

55) 'Reserpine' a therapeutically active compound used for hypertension and epilepsy is obtained from :

(A) Roots of Rauwolfia serpentine (B) Roots of Glycyrrhiza glabra

56) In plants first step in the synthesis of sulfur containing organic compounds is reduction of sulfate. Which of the following amino acids is synthesized in this process?

(A) Methionine (B) Cysteine (C) Glutamine (D) Glycine

57) Lolium is a long day plant, which of the following light treatments will result in flowering in this plant?

(A) Red -- Far Red (B) Far -- Red Red--Far Red

58) Allopolyploids eventually give rise to amphidiploids. These can be easily recognized by looking at their:

(A) Morphological characters (B) Karyotype

59) In animal kingdom, there are animals who show true and false body segmentation. Animals characterized by the presence of coelom and segmentation of the body belong to the phylum:

(A)Rotifera (B)Annelida (C)Platyhelminthes (D) Echinodermata

60) During last few centuries, our earth has seen considerable extinction of fauna and flora.However, scientists came across some species, thought to have been extinct by chance. The living fossil Latimeria chalumnae is an example of:

(A) Lung fish (B) Placoderm (C) Lobe-finned fish (D) Xiphosuran

61) If gonadotropin releasing hormone was to be secreted in large amounts and at a constant rate rather than in a pulsatile manner, one of the following would happen :

(A) Secretion of luteinising hormone would increase at first and then decrease

(B) Secretion of luteinizing hormone would

(D) Ostradiol secretion in a female would be continuously high.

62) Prevention of polyspermy of an egg predominantly contributed by a process is called :

(A) Acrosome reaction (B) Cortical granule breakdown

63) In amphibians, the embryonic gene expression does not begin during cleavage in early embryos. The maternal mRNAs are translated. Whereas at later stages there is induction of embryonic gene expression. This phenomenon is called:

(A) Maternal-paternal transition (B) Mid-blastula transition

64) Mimicry is exhibited by harmless colubrid snakes which resemble the poisonous snakes of the genus, Elaps in having beautiful body colouration of alternating red and black bands.

(A) Protective (B) Mullerian (C) Warning (D) Batesian

65) A period of arrested development in the life cycle of some insect pests is known as:

(A) Ecdysis (B) Diastasis (C) Diapause (D) Pupa

66) Typha angustata grows abundantly in/on:

(A) Mountain plateaus (B) Wetlands

67) Completion of the life cycle of the malarial parasite Plasmodium requires two hosts because:

(A)After passing through the pre-erythrocytic and erythrocytic cycles in its human host, the parasite requires low ambient temperature for further development. Therefore it enters second host, the mosquito.

(B) There are too many parasites in the human blood. Therefore, a transfer to the second host becomes necessary.

(C) The infected person starts taking medicines which prevents further development. Hence a transfer to a second host becomes necessary.

(D) The person develops resistance to the parasite by the time the erythrocytic cycle starts. Therefore another host is required.

68) Ability to taste phenylthiocarbamide (PTC) in human beings is controlled by a single gene, the tasters being either TT or Tt and non-tasters being tt. Suppose in a population of 'human beings, different genotypes are represented by ratio 0.50 TT: 0.20 Tt : 0.30 tt (The gene frequencies will be T = 0.60, t = 0.40). If population attains equilibrium, one would expect the genotypic ratios as :

(A) 0.50 TT : 0.20 Tt : 0.30 tt (B) 0.36 TT : 0.48 Tt : 0.16 tt

69) Exposure of an organism to carcinogens often results in mutagenesis. This leads to alterations in important growth regulatory genes. Carcinogens are therefore identified by:

(A) Ames test (B) Commet assay

70) Viruses generally infect only one or a few particular species. This is called:

(A) Host restriction (B) Host range (C) Cell specificity (D) Viral range

71) The disaccharide that does not react with Benedict's reagent is:

(A) Sucrose (B) Lactose (C) Maltose (D) Isomaltose

72)Lampbrush chromosomes in frog oocytes exhibit an index of amplification of:

(A) rRNA (B) mRNA (C) tRNA (D) snoRNA

73) State which of the following statements is correct in case of population analysis

(A) The rare allele is represented predominantly in heterozygotes particularly as it becomes rare

(B) The rare allele is always under selection

in a single generation of random mating

(D) The maximum heterozygotes frequency of cannotexceed 0.75

74) Activation of formation of different kinds of microfilament like actin network and actin bundles (stress fibers) are caused by cell signaling mediated by a particular protein family member. Which of the following is involved in formation of stress fibers?

(A) cdc 42 (B) Rac (C) Rho (D) Both Rho and Rac

75) In mammals, sex is determined by presence or absence of Y chromosome. The search for sex determining genes has led to identification of Hy, bkm, zfy as testes determining gene. Recently, identified Sry gene, a putative sex determining gene has one of the following propertiesassigned:

(A) DNA binding protein expressed in genital ridge at 8.5 dpc

(B) Zn finger protein expressed in testes

(D) Leads to sex transformation from males to females

76) The stimulation of microbial decomposition of recalcitrant compounds by the addition of microorganisms specific for its degradation is termed as:

(A) Biostimulation (B) Bioaugmentation

(C) Biotransformation (D) Bioconversion

77)Chromosome walking technique relies on:

(A) Genomic libraries (B) cDNA libraries

78) During G2 phase of cell cycle, cyclin B is synthesized and it forms a complex with CDK. This complex, called MPF, is crucial for the cells to enter mitosis. However, there is an extensive regulation of activity of MPF. There are kinases and phosphatases which take part in for conversion of an inactive MPF to an active MPF that initiates mitosis, there are the following possibilities:

(1) Phosphorylation of CDK by Wee1 kinase

(2) Phosphorylation of CDK by CAK

(3) Dephosphorylation of CDK inhibitory site by CDC 25

(4) Dephosphorylation by PTEN

Which of the following is correct?

(A) 1 and 2 (B) 1 and 3 (C) 2 and 3 (D) 2 and 4

79) Principle of holocoenotic environment means:

(A) Every factor affects every other factor in an ecosystem

(B) Only one factor affects every other factor in an ecosystem

(D) All the factors affect only one factor in an ecosystem

81) Last few years humans have seen rapid degradation of ecosystems. This has led global pressure on conservation of fauna and flora. In this direction the trees and shrubs are planted on all unused and fallow land to provide fuelwood, fodder etc. thereby reducing pressure on existing forests. For example, unused farmlands, community land, road and rail sides etc. are planted with suitable indigenous and/or exotic tree species. This is known as:

(A) Forest plantations (B) Social forestry

81) The frequency with which spontaneous mutations arise in a normal diploid population is:

(A) 10-8 (B) 10-2 (C) 10-12 (D) 10-3

82) A student examined two different groups of cells and made the following observations:

Trait

Cell I

Cell II

Cell wall

Ribosomes

Nucleus

photosynthesis

Respiration

Present

Absent

Present

Absent

Present

These observations support which of the following conclusions:

(A) Cell I is more complex in its organization than cell II

(B) Cell I is a prokaryote

(D) Both cell I and II are plant cells

83) A sigmoidal plot of substrate concentration versesvelocity indicates:

(A) Michaelis-Menten kinetics (B) Competitive inhibition

84) E. coli is used as a faecal pollution indicator. The water giving positive results for the presence of E. coli is declared non-potable or unfit for drinking. Which of the following is the most correct explanation for the above strategy?

(A) Faecal E .coli is extremely pathogenic

(B) Presence of E. coli also means the presence of pathogens

(C)E. coli and enteropathogens both enter water through faecal matter

(D) E. coli grows much faster than most enteropathogens

85) Two statements I and II are given below:

Statement I: Some vaccines when administered protect the recipient from the specific infection for long periods.

Statement II: Antibodies induced by some antigens are stable enough to persist, in body for long, periods.

(A) Both the statements are incorrect

(B) Both the are correct and statement II is the cause ofstatement I

(C) Statement I is correct, but the statement II is incorrect

(D) Statement II is correct, but statement I is incorrect

86) Although pancreas is the site of storage of proteolytic enzymes; these enzymes do not act on pancreatic tissues because:

(A) They are inactivated

(B) They are not released from pancreas

(C) They are in the form of pro-enzymes

(D) Their substrate is absent in pancreas

87)The tertiary structure of proteins is stabilized by various interactions. Which is the weakest interaction of the following?

(A) Hydrogen bond (B) Hydrophobic interactions

(C) Van der Waals interactions (D) Covalent bond

88) Which of the following sugar pucker favours Zconformation of DNA ?

(A) 2’-OH steric hindrance (B) Anti-G and C 2'-endosugar

(C) Syn G and C 3'-endosugar (D) G4 DNA quartet

89) The sequence in which the following electron carriers

are organised in electron transport chain is :

(A) Ubiquinone, cytochrome a + a3, NADH dehydrogenase

(B) Cytochrome a + a3 ubiquinone, NADH dehydrogenase

(C) NADH dehydrogenase, ubiquinone, cytochrome a ,a3

(D) NADH dehydrogenase, cytochrome a + a3, ubiquinone

90)In a single substrate reaction competitive inhibitor was added to examine the effect on Km and V max. Which of the following equations will be correct?

91) An amino acid contains no ionizable groups in its side chain (R). It is titrated from pH 0 to 14. Which of the following ionizable state is not observed during the entire titration in the pH range 0 to 14?

92) Which of the following tissues utilize ketone body acetoacetate as a source of energy during prolonged starvation?

(A) Brain (B) Liver (C) Skeletal muscle (D) Lung

93) Hibernating animals can maintain their body temperature during hibernation period. This is made possible by :

(A) Maintaining the BMR at low level

(B) Coupling oxidative phosphorylation to ATP synthesis

(C) Uncoupling oxidative phosphorylation from ATP synthesis

(D) Catabolising muscle proteins

94) Maple syrup disease is a result of genetic defect in metabolism of:

(A) Sulphur containing amino acids (B) Branched chain amino acids

95) Which of the following is not a feature of transcription factors?

(A) glycosylation domain (B) zinc finger motif

96) There are many compounds that are known to be inhibitors of mitochondrial electron transport chain (ETC). Which of the following is not an inhibitor of ETC?

(A)Rotenone (B)Antimycin A (C)Sodium azide (D)Dinitrophenol

97) Coding strand in ds-DNA is:

(A) identical in sequence to transcribed RNA

(B) complementary in sequence to transcribed RNA

(C) identical to sense strand of DNA

(D) identical in sequence to ORF alone

98)Non-homologous nucleotide sequences in two DNA molecules could be visualised using:

(A) Heteroduplex techniques (B) Fluorescent in-situ hybridisation

99) RNA type C tumor viruses are negative strand viruses and amplify copy number of their genome by using an enzyme encoded by them, which is:

(A) RNA replicase (B) RNA polymerase

(C) RNA dependent DNA polymerase (D) RNA helicase

100) For precise quantification of differential gene expression at mRNA level for a gene 'X' which of the following methods will be used?

(A) Western blot (B) Real time PCR

(C) RT-PCR (D) Northern blot

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SOLVED PAPER OF LIFESCIENCE 26.09.2020

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