Down’s syndrome is an example for
A) Aberration due to aneuploidy

1) B) Aberration due to polyploidy

C) Chromosomal mutation

D) Mutation in mitochondrial genes

The nucleotide sequence that stops transcription is
A) AUG

2) B) Shine-Dalgarno sequence

C) Stop codon

D) None of the above

The experimental laboratory bred animal deficient in thymus which are used for immunological research is
A) Sprague Dawley rats

3) B) Nu/nu mouse

C) BALB/c mouse

D) Bonobo monkeys

Which among the following is used in probiotic formulations to treat diarrhoeal diseases?
A) Lactobacillus species

4) B) Clostridium species

C) Escherichia coli

D) Enterococcus species

The major fatty acid found on royal jelly, which is used in the nutrition of larvae and adult queen honeybees, is
A) 10-hydroxy-2-decenoic acid

5) B) Arachidonic acid

C) Docosahexaenoic acid

D) Linoleic acid

According to the Ramachandran plot:
A) For a protein to be functional, all amino acids have to in the allowed regions i.e. in Quadrant I only.
B) For a protein to be functional, all amino acids have to be equally distributed within the allowed and disallowed regions i.e. between quadrants I and IV.
C) Glycine gives the least flexibility since it does not have a complex side chain.
D) The two torsion angles which describe the rotations of the polypeptide backbone around the bonds between N-Cα and Cα-C determine the structure of a protein

A person tries to lift a heavy object without success even though his muscles are fully extended. This type of muscle contraction is
A) Isotonic contraction

7) B) Fatigue

C) Distension

D) Isometric contraction

The rationale behind blue/white colony selection in rDNA technology is that
A) Bacteria carrying the inserted gene produce blue pigments while others do not.
B) Blue dye in the culture medium are decolourised by recombinant colonies.
C) Correct insertion of the gene inhibits the beta-galactosidase enzyme expressed by the lacoperon cassette.
D) Correct insertion of the gene disrupts alpha complementation of the lac- operon system.

Signet ring stage is characteristic of the trophozoites of the malarial parasite in its
A) Cycle of ROSS

9) B) Endo-erythrocytic cycle

C) Extra-corporeal phase

D) Pre-erythrocytic cycle

The botryoidal tissue is seen in
A) Nematomorpha

10) B) Cestoda

C) Nematoda

D) Hirudinea

Which among the following is a larval stage of Sacculina?
A) Veliger

11) B) Kentrogen

C) Tornaria

D) Trochophore

The minimum forest cover recommended for a stable ecosystem in India is
A) 17% of land area

12) B) 25% of land area

C) 33% of land area

D) 50 % of land area

The scientific name of ship worm is
A) Balanus

13) B) Balanoglossus

C) Teredo

D) Nereis

Which among the following is a viviparous animal?
A) Scoliodon

14) B) Echidna

C) Platypus

D) Salamander

The organ of insemination in penaeid species is
A) Conglobate gland

15) B) Utriculi majoris

C) Bursa copulatrix

D) Petasma

Identity the false statement with respect to the characteristic of the Nieuwkoop centre
A) The site of entry of the sperm has no bearing on the position of the Nieuwkoop centre.
B) Relocating the Nieuwkoop centre induces a new dorso/ventral axis.
C) Once the Nieuwkoop centre is formed, it overrides the role of the dorsal lip of the blastopore.
D) The Nieuwkoop Centre arises due to a gradient of nodal related proteins

The largest nesting sites of Olive Ridley turtles is
A) Coromandel coast in Sri Lanka
B) Gahirmatha Coast in Odisha
C) Galapagos Islands
D) Nancite Coast in Costa Rica

The largest nesting sites of Olive Ridley turtles is
A) Coromandel coast in Sri Lanka
B) Gahirmatha Coast in Odisha
C) Galapagos Islands
D) Nancite Coast in Costa Rica

Pesticide with very low biodegradation and strong affinity for fatty tissues is
A) Allerthrin

19) B) Organochlorines

C) Organophosphates

D) Pyrethroids

Cells that secrete spicules are known as
A) Desmocytes

20) B) Sclerocytes

C) Lophocytes

D) Archaeocytes

In ethology, Flehmen response is an act that
A) Results in maternal imprinting
B) Initiates courtship behaviour
C) Terminates courtship behaviour
D) Facilitates transfer of pheromones into the vomeronasal organ

The gene required for proper development of speech and language regions of the brain during embryogenesis is
A) LET 7 gene family

22) B) COX gene family

C) Forkhead (FOX) gene family

D) Calmodulin gene family

A phenomenon related to the transport of CO2 by the red blood cells is
A) Bohr effect

23) B) Warburg effect

C) Hamburger effect

D) Crabtree effect

In an ecosystem a community that is evolving towards its climax is termed as a ------ community
A) Ecotonic

24) B) Seral

C) Lotic

D) Pioneering

Assertion: Defective genes sometimes give an evolutionary advantage.
Reason 1: People with heterozygous genes for HbS escape death from malaria
Reason 2: People with the genes for cystic fibrosis escape death from cholera
A) The Assertion and both Reasons are true and both Reasons support the Assertion.
B) The Assertion is true but both the Reasons are wrong.
C) The Assertion is true and the Reason 1 alone is true and supports the Assertion.
D) The Assertion is true and Reason 2 alone supports the Assertion.

The enzyme activity of Taq polymerase is maximum at
A) 720 C and in the presence of Manganese ions.
B) 720 C and in the presence of Magnesium ions.
C) 720 C and in the presence of Zinc ions.
D) 940 C and in the presence of Magnesium ions

In man the odontoid process articulates with the
A) Skull

27) B) Acetabulum of the pelvic bone

C) Glenoid fossa of the scapula

D) Atlas

Which of the following describes the ninth vertebra of frog?
1. It is acoelus
2. The centrum has two concavities posteriorly and one concavity anteriorly.
3. The centrum has two convexities posteriorly and one convexity anteriorly.
4. The centrum has two convexities posteriorly and one concavity anteriorly.
5. Anterior zygapophyses are absent while the posterior zygapophyses are present.
A) 1, 3 and 5

28) B) 2 and 5

C) 1 and 3

D) 4 and 5

The Reissner’s membrane is a part of the
A) Visual system in fishes

29) B) Nasal cavity of mammals

C) Auditory system

D) Avian egg

According to the punctuated equilibrium hypothesis,
A) Speciation occurs only by cladogenesis in response to rapid geological changes.
B) One species gradually evolves into another depending on geological changes.
C) Species seen in fossil records are those which have become extinct due to unstable evolutionary changes.
D) Speciation occurs by phyletic gradualism

In aquaculture, raft culture is best suited for growing
A) Etroplus

31) B) Ostrea

C) Mytilus

D) Pinctada

The development of males in honey bees is an example of
A) Paternal imprinting

32) B) Apomixis

C) Arrhenotoky

D) Pseudo-arrhenotoky

The Aristotle’s lantern is the
A) Excretory system of echinoderms
B) Excretory system of trematodes
C) Protrusible 5-sided masticatory apparatus of a sea urchin
D) Protonephridia of Nemerteans

Which among the following is an invertebrate group represented only in the marine environment?
A) Crustacea

34) B) Cetacea

C) Hemichordata

D) Cnidaria

The pesticidal action of DDT is effected by
A) Shutting down Sodium ion channels
B) Opening up Sodium ion channels
C) Antifeedant activity
D) Destruction of intestinal wall

The pesticidal action of DDT is effected by
A) Shutting down Sodium ion channels
B) Opening up Sodium ion channels
C) Antifeedant activity
D) Destruction of intestinal wall

Albedo values indicate the contributions of an ecosystem to global warming. Consider the following ecosystems and identify the correct sequence according to decreasing albedo values.
1. Tundra; 2. Tropical evergreen forest; 3. Desert; 4. Prairies; 5. Taigas
A) 2, 4, 5, 3, 1

37) B) 1, 3, 5, 4, 2

C) 2, 5, 4, 3, 1

D) 3, 4, 5, 2, 1

The five kingdom classification and the three domain system were proposed by ----- and ----- respectively.
A) Hugo-de Vries & Carl Woese
B) Robert Whittaker & Carl Woese
C) Charles Linnaeus & Carl Woese
D) Charles Darwin & Charles Linnaeus

Class switching is the process by which
A) B-cells and T-cells differentiate in the bone marrow.
B) Different types of antibodies are produced by the same T-cell.
C) Different types of antibodies are produced by the same B-cell.
D) Pluripotent stem cells in the bone marrow change their potency and form blood and immune cells.

The term “survival of the fittest” was coined by
A) Charles Darwin

40) B) Hebert Spencer

C) Jeane Baptiste Lamark

D) Alfred Russell Wallace

In a cladogram
A) The leaves denote clades, the nodes denote synapomorphs, the branches denote plesiomorphs and the length of the root denotes the evolutionary distances.
B) The leaves denote plesiomorphs, the nodes denote evolutionary distances, the branches denote synapomorphs and the length of the clades denotes evolutionary distances.
C) The leaves represent individual species, the nodes denote points of divergence, the branches denote lines of descendance and the length of the branches denote the evolutionary distances.
D) The leaves denote extant species, the nodes denote extinct species, the branches denote divergence and the length of the clades denote evolutionary distances.

Which among the following is used for DNA barcode analyses?
A) Genes for cyclo-oxygenase

42) B) Genes for cytochrome oxidase

C) Genes for LOX

D) Genes from the sex chromosomes.

The Lee–Boot effect is a phenomenon concerning the
A) Suppression or prolongation of oestrous cycles of mature mice, when females are housed in groups and isolated from males.
B) Suppression or prolongation of oestrous cycles of mature mice, when males are housed in groups and isolated from females.
C) Suppression or prolongation of oestrous cycles of mature mice, when females are housed in groups
D) None of the above

The difference between eukaryote and prokaryote mRNA is
A) Prokaryote mRNA has introns, while eukaryote mRNA has no introns.
B) Translation of mRNA into proteins occurs simultaneous with transcription in eukaryotes while it takes place separately in prokaryotes.
C) The eukaryote mRNA has a cap and a polyA tail while the prokaryote mRNA has no such parts.
D) Translation of mRNA in prokaryotes does not require ribosomes, while in eukaryotes, translation occurs in ribosomes.

The international consortium for molecular taxonomy is
A) Linnaean society

45) B) IUCN

C) COBOL

D) ICZN

In mammals, the embryonic mesoderm gives rise to
A) Liver, pancreas and urinary bladder.
B) Trachea, lungs and the thyroid
C) Brain, spinal cord and notochord
D) Dermis, bone and connective tissue.

Which among the following is caused by a single nucleotide polymorphism?
A) Haemophilia

47) B) Sickle cell anaemia

C) Down’s syndrome

D) Cri-du-chat syndrome

Which among the following is true?
A) Prokaryotes lack mitochondrial mechanisms and hence depend only on NADPH as the energy currency.
B) Prokaryotes lack mitochondria, but have mitochondrial mechanisms which are capable of producing ATP.
C) Prokaryotes depend on fermentation pathways because they are incapable of producing ATP.
D) Prokaryotes have fully evolved mitochondria capable of producing ATP.

In taxonomy, according to the Law of Priority,
A) When giving scientific names to animals the name of the genus should have priority beforethe species name.
B) When a new species is discovered, priority should be given to the name of the person who first described it.
C) The first properly published name of a species or genus takes precedence over any subsequently published one
D) A name once given to an organism should never be changed

Which among the following is a Gram positive bacterium?
A) Saccharomyces cerevisiae

50) B) Escherichia coli

C) Lactobacillus lactis

D) Haemophilus influenzae

51) The following statements are made with reference to DNA replication

• Camptothecin causes intrastrand and inter- strand crosslinks in DNA, leading to stalling of replication forks.
• Prevention of reinitiation of DNA replication during the same cell cycle is mediated by
regulating the loading of the initiator complex ORC.
• A glu → ala mutation in the nucleotide building pocket of DNA polymerase III could lead to the incorporation of ribonucleotides in the extending DNA chain.

A mutation in the gene encoding Topoisomerase II could lead to entanglement of DNA daughter strands during replication.

Which one of the following options represents all correct statements ?
• A, B and C only
• B, C and D only
• A, C and D only
• C and D only

52) Mitochondrial protein synthesis is of prokaryotic origin. Following statements are being made about the ribosomes from bacteria and mitochondria:

• The bacterial ribosome consists  of small and large subunits of 30S and 50S respectively, whereas in mitochondria of mammals these subunits are of 28S and 39S
• In the bacterial ribosomes the RNA: protein ratio is about 2:1 whereas in mitochondria ribosomes this ratio is usually 1:2
• Both the bacterial and mitochondrial ribosomes consist of 30S and 50S subunits
• Both the bacterial and mitochondrial ribosomes consist of RNA and protein in the ratio of 1:1

Choose the option that represents all correct statments.

• A and B only
• B and C only
• C and D only
• A and D only

53) Following statements were made about imprinting in the human genome.

• Imprinting control centre (IC) harbors part of the SNRPN gene.
• Imprinting of genes in an individual cannot be tissue specific.
• Sperms and eggs exhibit identical pattern of genome methylation, except in the sex chromosomes.
• At imprinted loci, expression depends on the parental origin.

Select the option with all the correct statements.

• A and D
• B and D
• A and C
• B and C

During cytokinesis, a small GTPase, RhoA, localizes to the equatorial membrane above
the spindle midzone. The localization/activity of RhoA is potentially modulated by:

• Aurora B kinase
• PLK1 kinase
• MKLP1 kinesin
• ATM and ATR

Which one of the following combination contains all correct statments ?
• A, B and D only
• A, B,C and D only
• B, C,D and E only
• A, C and D only

55) Given below are a few statements about nuclear transport

• RanGTP levels are higher in the nucleus than in the cytoplasm.
• Nuclear import receptors can shuttle between the nucleus and cytoplasm.
• NTF2 transports RanGDP into the cytosol.
• Export of mRNA is not directly dependent on Ran.
• tRNA and miRNA export is mediated by exportins.

Which one of the following combinations contains all correct statements ?

• A, B, C, D only
• B, C, D only
• A, B, D, E only
• A, C, E only

56) Which one of the following is valid with respect to, one step growth experiment developed by Ellis and Delbruck in 1939?

• The reproduction of large phage population is synchronized.
• A culture is directly developed by inoculation of single bacterial colony from the agar plate into the liquid medium.
• Involves only a single step of overnight culture development followed by inoculation of a fresh medium with 1% inoculum.
• Only a single carbon source such as glucose is used in the medium

57) Following statements were made aboutchromosome cohesion during mitosis and meiosis?

• Though cohesin is important for pairwise alignment of the chromosomes on the mitotic spindle, it is not important for the generation of tension across the centromere.
• Cohesin binds to the chromosome even before the initiation of the S-phase.
• In fission yeast, centromere-specific localization of Moa1 and Rec8 regulates the orientation of kinetochores at meiosis-I.

• Cohesin exhibits uniform distribution/ localization pattern across the chromosomal length.
• Polo/Cdc5 is a positive regulator of Separase, an endopeptidase that facilitates opening of the cohesin ring.

Which one of the following combination contains all correct statments ?

• A, B and D only
• A, C and E only
• B, C and D only
• B, C and E only

The following statements are being made to define the Michaelis constant(KM) It is
• Independent of enzyme concentration in[E] and substrate concentration[S}
• equal to dissociation constant when the [ES] complex disassociates more rapidly than product formation
• equal to dissociation constant when product formation is more Rapid than [ES] Complex dissociation
• An intrinsic property of an enzyme and does not depend on Ph, temperature and ionic strength

• A and B only
• A, B and D only
• C and D only
• A and D only

Fluorescence microscope that requires photoactivatable probes to obtain superresolution
is
• Structured illumination microscope (SIM)
• dSTORM – stochastic optical reconstruction microscopy dSTORM
• Stimulated emission depletion microscopy (STED)
• Laser scanning confocal microscope

Widal test, a widely used serological test for enteric fever, is a type of
• precipitation reaction
• agglutination reaction
• complement fixation test
• immunofluorescence detection

For nuclear spin of spin quantum number (I=½ ) processing in a magnetic field at a larmor frequency of 300 MHz the wavelength of incident radiation required to excite the nuclear spins must be approximately
• 1 nm
• 1 cm
• 1 m
• 10 m

Which one of the following options represents a combination of terms that are matched INCORRECTLY?
• ddNTPs : Chain termination
• South Western blot: Physical interaction between DNA and proteins
• 5’ -3’ exonuclease activity : Proofreading polymerase for PCR
• Yeast two hybrid system: Interaction between proteins

Which one of the following regions of the target gene is NOT used for making an RNAi construct to knock down its expression?
• .5’ UTR of the mature transcript
• 3’ UTR of the mature transcript
• Exonic region
• Intronic region

Which one of the following statements is
correct?
• If a transgenic plant heterozygous for an insert segregates into 1:1 ratio for the transgenic phenotype on backcrossing then it contains two unlinked copies of the insert.
• ANOVA allows a plant breeder to test whether measurements from three or more treatments show statistically significant differences.
• Comparative genomics allows scientists to identify regions of collinearity but not synteny between different species.

• For genetic mapping of a quantitative trait in plants, an RIL mapping population comprising of individuals
that are heterozygous at most loci is preferred

Which one of the following combinations of terms is matched INCORRECTLY?
• Nanopore: DNA sequencing
• Pyrosequencing: Protein primary structure
• Homologous recombination: chloroplast transformation
• SSRs: Co-dominant markers SSRs

Select the correct statement related to phylogeny of primates.
• Lemurs are more closely related to lorises than to gibbons.
• Orangutans are closer to lorises than to gibbons.
• Tarsiers are the same as old-world monkeys.
• Humans are closer to new world monkeys than to orangutans

67) Consider the following four geological periods.

• Quaternary
• Cretaceous
• Jurassic
• Cambrian

Which one of the following options represents the correct arrangement of these geological periods from earliest to recent:
• A-B-D-C,
• D-C-B-A
• C-B-D-A
• B-A-C-D

68) Given below are statements on ‘living fossils’. Select the correct statements.

• Living fossils are impressions ofextant organisms in old rocks.
• Living fossils show high morphological divergence from fossil records.
• Living fossils are always an evolutionary link between two classes of organisms.
• Living fossils are organisms that have remained unchanged for millions of years.

Consider the following ecosystems
• Tropical rain forests
• Open ocean
• Algal beds and Coral reefs
• Marshes and Swamps

69) Which one of the following options represents these ecosystems in increasing order of their contribution to annual world net primary production?

Which one of the following gases is present in the stratosphere at a concentration higher than its concentration in troposphere?
• Nitrogen
• Oxygen
• Ozone
• Carbon dioxide

71) Which of the following combinations would best characterize the dominant phase of the life cycle of a pteridophyte?

• Diploid gametophyte
• Haploid gametophyte
• Diploid sporophyte
• Haploid sporophyte

What is the pattern of cleavage observed in mammals?
• Radial
• Spiral
• Rotational
• Bilateral

73) Eukaryotes are classified into 5-6 super groups based on phylogenomic studies. Which one of the following statements about eurkaryotic supergroups is FALSE?

• Fungi and animals are more closely related to each other than eithergroup is to plants.
• Amoebozoa and opisthokonts are unikonts.
• Land plants and green algae belongto Archaeplastida.
• Alveolates and amoeba belong to same super group.

74) The basic difference between direct repair and base excision repair is

• Direct repair restores the original structure of altered nucleotide without replacement, while in base excision repair the section of DNA containing the distortion is removed, the correct base is added and resealed.
• In direct repair, homologous recombination repairs the broken region while base excision repair restores original structure of altered nucleotide by modification.
• Direct repair restores original structure by non-homologous end joining without using homologous template while in base excision repair the section of DNA containing the distortion is repaired by using homologous recombination.
• In direct repair, an exonuclease, a DNA polymerase and a ligase are used, while in base excision repair a translesion polymerase that bypasses the bulky lesions is used by the cell.

Human polydactyly traits having extra fingers or toes are caused by a dominant allele. In a screening it was found that out of 42 individuals having an allele for polydactyly, only 38 of them were polydactylus. Which of
the following is the correct interpretation of the observation?
• The penetrance of polydactyly is estimated to be 90%
• The expressivity of polydactyly is 90%
• This is an example of variable expressivity
• The polydactyly trait is showing complete penetrance

A fly with apricot coloured eye was crossed with a sepia eyed fly of opposite sex. In F1 all flies were wild type. The genes responsible for the two phenotypes were
• Allelic
• non-allelic
• Pseudo-allelic
• paralogous genes

77) DNA was isolated from a strain of bacterium with genotype a+ b+ c+ d+ e+ and transformed into a bacterial strain ab-c- d-. The transformants were tested for the presence of the donated genes. The contransformed genes were found as follows: a+ abd b+; c+ and e+; d+ and c+;b+ and d+

• a b c d e
• a c b e d
• a b c e d
• a b d c e

78) Which one of the following is not present in the filtration slit diaphragm?

• NEPH1
• Paxillin
• Nephrin
• NEPH2

79) The dark current in retina is due to

• Closing of Na+ channels in the outer segment of photoreceptors
• Opening of K+ channels in the inner segment of photoreceptors
• Opening of Na+ channels in the outer segment of photoreceptors
• Closing of K+ channels in the outer segment of photoreceptors

80) Which one of the following is used in organification of tyrosine residues in thyroglobulin protein, during thyroid hormone biosynthesis?

• Iodine
• Reduced iodine
• Oxidized iodine
• Hydrogen iodide

81) Dirigent proteins predominantly play an important role in biosynthesis of:

• Lignans
• alkaloids
• Terpenoids
• amino acids

82) Photochemically generated ATP is consumed in which one of the following phases of Calvin- Benson cycle?

• Only carboxylation
• Only regeneration
• Carboxylation and reduction
• Reduction and regeneration

Which of the following ‘R’ gene products do not contain NBS-LRR domain?
• RPS2 protein of Arabidopsis
• Xa1 protein of rice
• N protein of tobacco
• Mlo protein of barley

In a transplantation experiment, the area of presumptive ectoderm from an early frog gastrula was transplanted to a region of the newt gastrula destined to become parts of the mouth. The resulting salamander larvae had frog like mouth parts (frog tadpole suckers) instead of balancers as observed during development of wild type newt embryo.
This is an example of

• Determination
• Genetic specificity of interaction
• Regional specificity of interaction
• Autonomous specification

85) In which of the following stages of Arabidopsis embryogenesis do the visible distinctions between the adaxial and abaxial tissues of the cotyledons become initially apparent?

• Globular stage
• Zygotic stage
• Torpedo stage
• Mature stage

86) During normal development of sea urchin, β-catenin accumulates predominantly in the micromeres, which are fated to becomeendoderm and mesoderm. If GSK- 3 is blocked  in the developing embryo:

• β-catenin accumulation in the nuclei of large micromeres will be inhibited leading to formation of ectodermal ball.
• β-catenin will accumulate in the nuclei of all blastula cells leading to an ectodermal ball.
• β-catenin will accumulate in the nuclei of all blastula cells leading to animal cells getting specified as

• β-catenin which accumulate in the nuclei of large micromeres will be inhibited leading to animal cells getting specified as endoderm and mesoderm

87) Which one of the following statements with respect to development in amphibians is correct?

• Gastrulation begins with the invagination of bottle cells, followed by coordinated involution of the mesodermal precursors and the epiboly of the prospective ectoderm.
• The organizer induces the Nieuwkoop centre
• The organizer is formed by the accumulation of β-catenin
• In the absence of BMP inhibitors ectodermal cells form neural tube BMP

A breakthrough in cancer therapy is expected
where T- cells are taken from a patient are modified in the laboratory to attack cancer cells before reinfusion in the patient. These T cells are called

• cancer associated receptor T cells
• chimeric antigen-receptor T cells
• chimeric B and T cell
• cancer antigens recognition T cells

The cytoplasmic domain of the receptor of
which of the following proteins does NOT
function as tyrosine kinase?

• Epidermal growth facto
• Platelet derived growth factor
• Insulin
• Asialoglycoprotein

90) Which of the following is the causative agent of filariasis?

• Listeria monocytogenes
• Cryptococcus neoformans
• Francisella tularensis
• Brugiya malayi

91) Which one of the following combinations represents the major protein or protein complex involved in chromatin condensation in yeast and human, respectively?

• HP1 and SIR Complex HP1
• SIR complex and HP1 SIR
• HP1 and Su(var)
• SIR complex and Su(var) SIR

92) Which one of the following proteins is essential for both the initiation of DNA replication as well as the continued advance of the replication fork?

• ORC
• Geminin
• Cdc45
• Cdc6

93) All of the following statements about bacterial transcription termination are true EXCEPT

• some terminator sequences require Rho protein for termination.
• inverted repeat and ‘T’ rich nontemplate strand define intrinsic terminators.
• Rho-dependent terminators may possess inverted repeat elements.
• Nus A is necessary for intrinsic transcription termination.

94) Some cells possess peptides which contain D- form of amino acids. How do they arise?

• These peptides are produced by ribosomes by incorporating Damino acids at specific positions
• Ribosome makes peptides with L-amino acids only. However, some of the amino acids in the peptides are replaced by D- amino acids by a pathway that involves excision of the L- amino acids

• The peptides with the D-amino acids are produced in a ribosome independent manner.
• Peptides with D-amino acids exist only in archeae where they are made by the presence of racemase

95) In bacteria many of the tRNA genes do not contain the CCA sequence found at the 3’ end of tRNA. In this context which one of the following statements represents the correct explanation?

• In these tRNAs amino acylation occurs at the 3’ end of the tRNA irrespective of the presence of the - CCA sequence.
• CCA sequence is added to these tRNA transcripts in a DNA template-independent manner.
• These tRNAs exploit the process of trans- splicing to include a CCA sequence at their 3’ end.
• The absence of CCA sequence occurred only in the last common ancestor (LCA) during the course of evolution and the current day tRNA genes always possess a sequence to encode the CCA end of the tRNA.

96) Iron-sulphur clusters [Fe-S] are the key prosthetic groups that carry electrons in all of the below EXCEPT

• NADH - CoQ reductase
NADH - CoQ
• Succinate – CoQ reductase

•   Cytochrome C oxidase
• CoQH2 –Cytochrome C reductase
CoQH2

97) The movement of proteins bigger than 50 kDa across the nuclear envelope requires

• Sec 61
• Tom 20
• Importin β
• Tim 44

98) In eukaryotic cells, covalently attached lipids help to anchor some water soluble proteins to the plasma membrane. One group of cytosolic proteins are anchored to the cytosolic face of membrane by a fatty acyl group (e.g.myristate or palmitate). These groups are generally covalently attached towhich amino acids present at the N-terminus of the polypeptide chain?

• Glycine
• Tyrosine
• Serine
• Lysine

Progression across G1/S boundary followed by entry into S-phase is promoted by the
activation of which one of the following protein complexes

• Cdk4/Cyclin D
• Cdk2/Cyclin E
• Cdk4,6/Cyclin
• Cdk4,6/Cyclin D, E

100) How many hydrogen bonds involving the backbone CO and NH can be observed in an α-helix consisting of 15 amino acid residues?