Biology MCQ-01: ICMR JRF Entrance Exam Model Question Paper-1 with Answer & Explanations

Biology MCQ (Multiple Choice Questions in Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance)

ICMR JRF Model Question Paper
INDIAN COUNCIL OF MEDICAL RESEARCH


 Model Question Paper 01 (MCQ 01)


New: NET Life Sciences Dec 2015 Question Paper with Detailed Answer key

1. The average size of 70S ribosomes of prokaryotes are:

a.      ~ 200 Å
b.      ~ 250 Å
c.      ~ 290 Å
d.      ~ 303 Å

2. Which of the following is an example for chemolithotroph?

a.       Acidithiobacillus ferrooxidans
b.       Nitrosomonas

c.       Nitrobacter
d.      All of the above

3. Which of the following is an example for denitrifying bacteria?

a.       Nitrosomonas
b.       Nitrobacter

c.       Pseudomonads
d.      All of the above

4. Who introduced the group Archaea for a group of prokaryotes on the basis of phylogenetic analysis of 16S rRNA?

a.       Roger Stanier
b.       Carl Woese

c.       C. B. van Niel
d.      Theodor Escherich

5. Who discovered endoplasmic reticulum?

a.      Keith porter
b.      Konstantin Mereschkowsky

c.      Camillo Golgi
d.      George Emil Palade

6. Acrosome of sperm cell is a modified ________.

a.      Lysosome
b.      Peroxisome

c.      Golgi
d.      None of these

7. Calmodulin is a calcium-binding messenger protein of eukaryotic cells. A single calmodulin protein at a time can bind _______ Ca2+ ions.

a.      1
b.      2

c.      3
d.      4

8. The H – O – H bond angle of water molecule is ____________.

a.      103.5º
b.      104.5º

c.       105.5º
d.      109.5º

9. At a time a single water molecule can form _______ hydrogen bonds with other water molecules

a.      1
b.      2

c.      3
d.      4

10. pH below pI, amino acids will be___________.

a.      Cationic
b.      Anionic

c.       No charge
d.      Net charge zero

11. Which of the following is an example for a ribozyme?

a.      Transpeptidase
b.      Glutamyl transpeptidase

c.       Peptidyl transferase
d.      All of the above

12.  The nebenkern of Drosophila sperm cell is a modified ________.

a.      Nucleus
b.      Mitochondria

c.       Lysosome
d.      Golgi

13. Which of the following chromosomal aberration causes Patau syndrome in human?

a.      Trisomy 21
b.      Trisomy 13

c.       Trisomy 18
d.      Trisomy 8

14. The only antibody able to cross placenta to give passive immunity to the fetus _____.

a.      IgA
b.      IgE

c.       IgG
d.      IgM

15. Which of the following antibody is involved in allergic reactions?

a.      IgA
b.      IgE

c.       IgG
d.      IgM

16. Antibody present in tears and saliva is:

a.      IgA
b.      IgE

c.       IgG
d.      IgM

17. An autoimmune disease that affects the thyroid gland is _________

a.      Tay–Sachs disease
b.      Addison’s disease

c.      Graves’ disease
d.      Behçet’s disease

18. How many different types of gametes can be produced by an organism with genotype AaBBCCDdEe?

a.      4
b.      6

c.       8
d.      10

19. Weil–Felix test is used for the diagnosis of ________

a.       Rickettsial infection
b.       Pertussis

c.       Cholera
d.      African sleeping sickness

20. Phi X-175 is a ___________.

a.      ssRNA virus
b.      dsRNA virus

c.       ssDNA virus
d.      dsDNA virus

21. Diploid chromosome number of Pan troglodytes is

a.      42
b.      44

c.      46
d.      48

22. The 20 different amino acids in the protein are normally coded by:

a.      60 codons
b.      61 codons

c.      62 codons
d.      63 codons

23. Which of the following is the causative agent of fowl cholera?

a.       Vibrio cholera
b.       Escherichia coli

c.       Salmonella pullorum
d.       Pasteurella multocida

24. Which of the following amino acids is coded by maximum number of codons?

a.      Leucine
b.      Tryptophan

c.       Valine
d.      Alanine

25. Alu elements are

a.      Transposons
b.      Retroposons

c.       SINESs
d.      LINEs

26. For the construction of Ramachandran’s plot values of Psi and Phi are plotted. The value of Phi is the rotation angle around:

a.      N – Cα bond
b.      Cα – C bond

c.      C – N bond
d.      N – H bond

27. Which of the following causes deviation in Hardy-Weinberg equilibrium in a population?

a.      Random mating
b.      Small population size

c.      Lack of selection pressure
d.      No mutation

28. Which of the following amino acids in a protein forms a ‘salt bridge’?

a.      Tyr – Phe
b.      Cys – Cys

c.       Lys – Glu
d.      Ala – Val

29. Bunchy top disease of banana is transmitted by the vector:

a.       Ferrisia virgata
b.       Aphis gossypii

c.       Thrips tabacci
d.       Pentalonia nigronervosa

30. The source of dwarfing genes in wheat is____

a.      Ganga 101
b.      Norin 10

c.      Dee-geo-woo-gen
d.      Sonalika

 


Biology MCQ-1: Biology/Life Science Multiple Choice Questions (MCQ) / Model Questions with answers and explanations for preparing ICMR JRF and CSIR JRF NET Life Science Examination and also for other competitive examinations in Life Science / Biological Science such as DBT JRF, GATE Life Science, GATE Biotechnology, ICAR, University PG Entrance Exam, JAM, GRE, Medical Entrance Examination etc. This set of practice questions for JRF/NET Life Science will help to build your confidence to face the real examination. A large quantum of questions in our practice MCQ is taken from previous year NET life science question papers. Please take advantage of our NET Lecture Notes, PPTs, Previous Year Questions and Mock Tests for you preparation. You can download these NET study material for free from our Slideshare account (link given below).


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Answers with explanations:

1. Ans. (a). ~ 200 Å

Average size of eukaryotic ribosome: 250Å – 300Å

2. Ans. (d). All of the above

Chemolithotrophs: microbes using inorganic substrate to obtain reducing power for dioxide fixation or ATP production through aerobic or anaerobic respiration.

Acidithiobacillus ferrooxidans uses Fe2+ ion (ferrous iron)

Nitrosomonas uses NH3 (ammonia)

Nitrobacter uses NO2− (nitrite)

3. Ans. (c). Pseudomonads

Clostridium, Paracoccus denitrificans and Thiobacillus denitrificans are the other denitrifying bacterial species.

Nitrosomonas, Nitrosococcus, Nitrobacter and Nitrococcus are nitrifying bacteria which feed on Ammonia to release nitrite first and then nitrate.

Rhizobia, Frankia, Azospirillum, Klebsiella pneumonia, Azotobacter vinelandii and Cyanobacteria are nitrogen fixing microbes.

Diazotroph: microbes of archaebacteria, bacteria and cyanobacteria which can fix atmospheric nitrogen.

icmr jrf exam model question paper by easybiologyclass

4. Ans. (d). Carl Woese

Roger Stanier: (student of C. B. van Niel), contributed to the taxonomy of bacteria and cyanobacteria.

C. B. van Niel: a microbiologist who for the first time explained the chemistry of photosynthesis. The general chemical formula of photosynthesis (2 H2A + CO2 → 2A + CH2O + H2O) was coined by him on the basis of his studies in purple sulfur bacteria and green sulfur bacteria in 1931.

Theodor Escherich: a pediatrician who discovered the bacterium Escherichia coli, which was named after him in 1919.

5. Ans. (a). Keith Porter: discovered ER in 1945

Ribosome was discovered by George Emil Palade in 1950. The term ‘ribosome’ was proposed by Richard B. Roberts in 1958

Chloroplast was probably discovered by Konstantin Mereschkowski in 1905

Golgi apparatus was discovered by Camillo Golgi in 1898

Mitochondria was discovered by Carl Benda in 1898

Lysosome was discovered by Christian de Duve in 1955

Peroxisome was discovered by J. Rhodin in 1954

Nucleolus was discovered by John Gurdon and Donald Brown in 1964

6. Ans. (c). Golgi.

Acrosome body of sperm cell is a modified Golgi apparatus containing hydrolyzing enzymes such as hyaluronidase and acrosin which hydrolyses the outer covering of the ovum called zona pellusida. Zona pellusida is a glycoprotein rich layer surrounding the plasma membrane of mammalian oocytes. There are four major zona pellucida glycoproteins (ZP1-4. ZP1, ZP3 and ZP4).  

Globozoospermia (sperm with globose head) is a disorder in males in which the Golgi apparatus is not transformed into the acrosome and thus causes male infertility.

7. Ans. (d). 4

Calmodulin is a highly conserved protein with 148 amino acids.  Each of the four EF-hand motifs of calmodulin can bind a Ca2+ ion. Ca2+ ion acts as second messenger in the cells.

Calsequestrin is another calcium binding protein.

Sarcoplasmic reticulum is a special smooth endoplasmic reticulum (SER) of myocytes and its specific functions is to store calcium.

8. Ans. (b). 104.5°

9. Ans. (d). 4

10. Ans. (a). Cationic

pH above pI amino acids will be anionic

pH at pI amino acids will be zitterionic (net charge zero)

11. Ans. (c). Peptidyl transferase

Peptidyl transferase enzyme is responsible for the peptide bond formation during protein synthesis in ribosome. It is not the protein part rather the enzymatic activity is provided by the rRNA of the large subunit of ribosome. Thus, it is functionally a ribozyme. This enzyme is the most important evidence supporting the RNA world hypothesis. In prokaryotes the 23S rRNA of 50S subunit and in eukaryotes 28S rRNA for 60S subunit of ribosome is responsible for the enzymatic properties. Antibiotic Chloramphenicol inhibits the peptidyl transferase activity by binding to the 23S rRNA of prokaryotic ribosome and inhibits protein synthesis.

Transpeptidase is a bacterial enzyme that cross link the peptidogylcan chains to form the rigid cell wall. Antibiotic penicillin inhibits bacterial cell division by inhibiting the enzyme transpeptidase.

12. Ans. (b). Mitochondria

13. Ans. (b) Trisomy 13

Trisomy 18 causes Edwards syndrome

Trisomy 21 causes Down syndrome

Trisomy 8 causes Warkany syndrome 2

Trisomy at sex chromosome: XXX – Triple X syndrome, XXY – Klinefelter syndrome

14. Ans. (c). IgG

15. Ans. (b). IgE

16. Ans. (a). IgA

17. Ans. (c). Graves’ disease

Tay–Sachs disease: a fatal autosomal recessive genetic disorder of deterioration of nerve cells in the early childhood. The disease is caused by the abnormal accumulation of gangliosides (a membrane lipid) in the nerve cells of brain.

Addison’s disease: An auto-immune disorder of endocrine system where the adrenal glands do not produce steroid hormone glucocorticoids and mineralocorticoids.

Behçet’s disease: An auto-inflammation disease of blood vessels leading to mucous membrane ulceration and ocular problems.

18. Ans. (c). 8

It can be easily calculated by a formula 2 raise to ‘n’, where ‘n’ is the number of heterozygous loci in the genotype.

Another example: Gametes produced by a genotype WWXxYyZz will be 2 raise to 3 = 2 x 2 x 2 8

19. Ans. (a). Rickettsial infection

20. Ans. (c). ssDNA virus

Phi X 174 is a bacteriophage, the first DNA genome sequenced organism (by Fred Sanger in 1977). The genome is a covalently closed [+] circular single stranded DNA with 5386 nucleotides coding for 11 proteins. Phi.X 174 is commonly used as a positive control in DNA sequencing experiments due to its small genome size.

(1). ssRNA Virus: Coronaviridae (SARS), Picornaviridae, Rabdoviridae (Rabies)

(2). dsRNA virus: Reoviridae (Rotavirus)

(3). ssDNA virus: Geminiviridae, Microviridae, Parvoviridae, Phi X 174

(4). dsDNA virus: Baculoviridae, Papovaviridae, Polydnaviridae, Adenoviridae, Herpesviridae, Phage T4, Poxviridae and Phycodnaviridae.

21. Ans. (d). 48

Pan troglodytes is the scientific name of common chimpanzee. Both Fossils evidence and DNA sequencing showed that chimpanzees are the sister group of modern human evolutionary lineage.

22. Ans. (b). 61 codons

There are a total of 64 codons (43), among which three codons are stop codons, they are UAA, UAG and UGA and they are sometimes called as ochre, amber and opal respectively.

23. Ans. (d) Pasteurella multocida

24. Ans. (a). Leucine

Leucine, Serine and Arginine have maximum number of codons. All these three amino acids have six codons. Methionine and Tryptophan are with least number of codon; both of these amino acids have only one codon; Methionine is coded by AUG and Tryptophan is coded by UGG.

25. Ans. (c).  SINESs

Alu elements are a class of repetitive sequence in the human genome, is so named because they are first characterized the restriction endonuclease Alu from Arthrobacter luteus. Alu elements are about 300 bp long and thus they are included in the short interspersed elements (SINEs) class of repetitive DNA.

LINEs: Long interspersed elements are retro-transposons present in many eukaryotic genome.

Retro-transposons: a class of transposable elements in the genome which undergo transposition via RNA intermediate and reverse transcriptase enzyme (copy paste mechanism of transposition).

Transposons (transposable element, TE) are jumping genes which change its position in the genome, first described by Barbara McClintock.

26. Ans. (a). N – Cα bond

Phi (ϕ) bond: N – Cα bond

Psi (ψ) bond: Cα – C bond

27. Ans. (b). Small population size

Hardy–Weinberg principle: “The relative frequencies of various kinds of genes and alleles in a large and randomly mating (panmictic) population tend to remain constant from generation to generation in the absence of mutation, selection and gene flow”.

Hardy–Weinberg equilibrium is effective in a population with the following characteristics:

If the evolutionary forces are absent (mutation, selection, drift)

The population is large

Its individuals have random mating

Each parent produces roughly equal number of gametes

The gametes produced by the mates combine at random and the gene frequency remain constant

The above mentioned points are the evolutionary forces in a population

Thus it should be noted that a population in Hardy-Weinberg equilibrium do not show evolution.

28. Ans. (c). Lys – Glu

Salt bridge is formed by the interaction between the acidic group in the R group of Aspartate or Glutamate (acidic amino acids) with the basic group in the R group of Lysine or Arginine (basic amino acids)

29. Ans. (d). Pentalonia nigronervosa

30. Ans. (b). Norin 10

Norin 10 is a semi dwarf wheat variety of Japan. Rht1 and Rht2 (Rht stands for Reduced height) are two important dwarf genes obtained from this variety. Both of these genes are effectively utilized in modern plant breeding programs of wheat.

Sonora 64, a wheat variety extensively cultivated in India during green revolution was actually a hybrid of Norin 10.

Dee-geo-woo-gen is a semi dwarf variety of rice arised by the spontaneous mutation in Taiwanese strain or rice called woo-gen. Sd1 is a semi dwarf gene isolated from Dee-geo-woo-gen is used as a source of dwarf allele for rice breeding programs.

Sonalika is a high yielding wheat variety, extensively cultivated during green revolution in India.


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