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Life Sciences (GATE)

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Assertion (A): DMSO is used as a cryopreservant for mammalian cell cultures. Reason (R): It easily penetrates cells.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answers as under:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.


Correct Option: C
Explanation:

Correct answer. A is correct and R is incorrect. Dimethyl sulfoxide (DMSO) is used as a cryopreservant for mammalian cell cultures to protect cells from ice crystal induced mechanical injury. It protects cells by preventing crystallisation of water.

Which of the following is/are example(s) of derived protein structure databases?

  1. CATH
  2. PDB
  3. SCOP
  1. Only 2

  2. 1 and 2

  3. 1 and 3

  4. 2 and 3

  5. 1, 2 and 3


Correct Option: C
Explanation:

Correct answer. Structural Classification of Proteins (SCOP) database and CATH Protein Structure Classification are examples of derived protein structure databases.

Which of the following are computational tools for eukaryotic genomic sequences?

  1. AUGUSTUS
  2. Chemgenome
  3. GeneMark
  4. mGene
  1. 1 and 2

  2. 1 and 4

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4


Correct Option: B
Explanation:

Correct answer. AUGUSTUS is a program that predicts genes in eukaryotic genomic sequences. mGene is a computational tool for the genome-wide prediction of protein coding genes from eukaryotic DNA sequences.

Pyrrolidine-2-carboxylic acid is IUPAC name of

  1. alanine

  2. glutamine

  3. lysine

  4. proline

  5. valine


Correct Option: D
Explanation:

Pyrrolidine-2-carboxylic acid is IUPAC name of proline.

Arrange the following in correct sequence of signal transduction pathway:

  1. Hormone
  2. 7 TM receptor
  3. G protein
  4. cAMP
  5. PKA
  1. 1 → 2 → 3 → 4 → 5

  2. 1 → 3 → 2 → 4 → 5

  3. 1 → 4 → 3 → 2 → 5

  4. 5 → 2 → 3 → 4 → 1

  5. 5 → 4 → 3 → 2 → 1


Correct Option: A
Explanation:

Correct answer. Correct sequence of signal transduction pathway is Hormone → 7 TM receptor → G protein → cAMP → PKA. In the G protein associated signal cascade system, binding of hormone to a cell surface receptor, like the 7TM (a 7 transmembrane alpha helices) which is a part of G protein. This will activate production of second messengers like cAMP by the enzyme adenylate cyclase. The cAMP in turn binds and activates downstream signal proteins line cAMP dependent protein kinase A (PKA).

Which of the following statements are FALSE?

  1. Synteny refers to local conservation of gene order.
  2. The helix content of a protein can be determined using circular dichromism spectroscopy.
  3. In zinc finger proteins, the amino acid residues that coordinate zinc are cys and met.
  4. The production of secondary metabolites in plant cell cultures is enhanced by the addition of elicitors.
  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4


Correct Option: B
Explanation:

Correct answer. Both are false statements. Synteny refers to gene duplication from a common ancestor. This is the condition in which two or more gene loci are present on the same chromosome. During evolution, rearrangements may cause the loss of synteny, else it will be retained. Translocations can cause gain of synteny. In zinc finger proteins, the amino acid residues that coordinate zinc are cys and his. Zinc fingers coordinate zinc ions with a combination of cysteine and histidine residues. They can be classified by the type and order of these zinc coordinating residues (e.g. cys2his2, cys4, and cys6).

Which of the photoreceptors use FAD as chromophore?

  1. Phototropins
  2. Phytochrome
  3. Cryptochrome
  4. BLUF-proteins
  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4


Correct Option: E
Explanation:

The cryptochrome and the BLUF-proteins use flavin adenine dinucleotide (FAD) as chromophores.

Identify the false statements.

  1. Heat inactivation of serum is done to inactivate prions.
  2. Nude mice refer to transgenic mice.
  3. A humanised antibody is one in which the CDRs are from mouse and the rest is from human.
  4. B-lymphocytes originate from the bone marrow.
  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4


Correct Option: A
Explanation:

Correct answer. Both are false statements. Heat-inactivation (heating to 56°C for 30 minutes) of serum is done to inactivate complement, a group of proteins present in sera that are part of the immune response. A nude mouse is a laboratory mouse from a strain with a genetic mutation that causes a deteriorated or absent thymus, resulting in an inhibited immune system due to a greatly reduced number of T cells.

Which of the following drugs are used as skeletal muscle relaxants?

  1. Telenzepine
  2. Pancuronium
  3. Oxybutynin
  4. Tubocurarine
  1. 1 and 2

  2. 1 and 4

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4


Correct Option: D
Explanation:

Correct answer. Pancuronium is a non-depolarising neuromuscular blocking agent used to facilitate intubation and relax skeletal muscles. Tubocurarine is a toxic alkaloid and skeletal muscle relaxant in the category of non-depolarising neuromuscular-blocking drugs, used adjunctively in anesthesia to provide skeletal muscle relaxation during surgery or mechanical ventilation.

Match the column – I (amino acid) with column – II (single letter code) and select the correct option.

 
Column – I Column – II
A. Glutamine 1. K
B. Lysine 2. Q
C. Tryptophan 3. W
D. Tyrosine 4. Y
  1. A - 3, B - 4, C - 2, D - 1

  2. A - 2, B - 1, C - 3, D - 4

  3. A - 2, B - 3, C - 1, D - 4

  4. A - 3, B - 2, C - 1, D - 4

  5. A - 3, B - 1, C - 4, D - 2


Correct Option: B
Explanation:

Correct answer. Single letter code for glutamine is Q. Single letter code for lysine is K. Single letter code for tryptophan is W. Single letter code for tyrosine is Y.

Assertion (A): Gram-positive bacteria are generally resistant to complement-mediated lysis. Reason (R): Thick peptidoglycan layer in gram-positive bacteria prevents insertion of membrane attack complex into the inner membrane.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answers as under:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.


Correct Option: A
Explanation:

It is the correct answer. A and R both are correct and R is the correct explanation of A. Gram-positive bacteria are generally resistant to complement-mediated lysis because thick peptidoglycan layer prevents insertion of membrane attack complex into the inner membrane.

An example of a program for DNA sequence assembly is

  1. ProDom

  2. Phrap

  3. PHYLIP

  4. Pfam

  5. PROSITE


Correct Option: B
Explanation:

Phrap is a widely used program for DNA sequence assembly. It is a DNA sequence assembler and finishing tools from the UW Genome Center.

Match the column – I (structures of cells) with column – II (relative functions) and select the correct option.

 
Column – I
Column – II
A. Cytoplasmic membrane 1. Mineral storage of cells
B. Ribosome 2. Protein synthesis
C. Inclusion body 3. Tough, heat resistance structure that helps bacteria survive in adverse conditions
D. Endospore 4. Regulation of substance transport into and out of cells
  1. A - 1, B - 2, C - 3, D - 4

  2. A - 2, B - 1, C - 4, D - 3

  3. A - 4, B - 2, C - 1, D - 3

  4. A - 3, B - 2, C - 4, D - 1

  5. A - 4, B - 3, C - 2, D - 1


Correct Option: C
Explanation:

Correct answer. The cell membrane (also known as the plasma membrane or cytoplasmic membrane) is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells Ribosomes are small, electron-dense particles not enclosed in membrane and are located in the cytosol. Ribosomes are involved in protein synthesis. Inclusion bodies are the transitory residents of the cytoplasm not involved in cell metabolism and do not survive cell division. They comprise mainly accumulated metabolites, lipid droplets and pigments and are sporadically distributed in body cells. An endospore is dormant, tough, and non-reproductive structures produced by certain bacteria from the Firmicute phylum, that help bacteria survive in adverse conditions.

Match the column – I (antibiotics) with column – II (mechanism of action) and select the correct option.

 
Column – I Column – II
A. Bacitracin 1. DNA Synthesis Inhibitors
B. Tetracyclines 2. Protein Synthesis Inhibitors
C. Metronidazole 3. Folic Acid synthesis inhibitors
D. Sulfonamides 4. Inhibits cell wall synthesis
  1. A - 3, B - 4, C - 2, D - 1

  2. A - 2, B - 3, C - 4, D - 1

  3. A - 4, B - 2, C - 1, D - 3

  4. A - 3, B - 2, C - 4, D - 1

  5. A - 3, B - 1, C - 4, D - 2


Correct Option: D
Explanation:

 Belladonna contains the chemical substance atropine which indeed affects the pupils in the manner described. Paclitaxel is a mitotic inhibitor used in cancer chemotherapy. It was discovered in a US National Cancer Institute program at the Research Triangle Institute in 1967 when Monroe E. Wall and Mansukh C. Wani isolated it from the bark of the Pacific yew tree, Taxus brevifolia and named it taxol.

Assertion (A): Hyposecretion of somatotropin hormone (STH) causes Simond’s disease. Reason (R): STH is secreted by posterior lobe of pitutary.

Directions: In the following question, there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answers as under:

1. A and R both are correct and R is the correct explanation of A.
2. A and R both are correct and R is not the correct explanation of A.
3. A is correct and R is incorrect.
4. A is incorrect and R is correct.
5. A and R both are incorrect.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.


Correct Option: C
Explanation:

Correct answer. A is correct and R is incorrect. Hyposecretion of somatotropin hormone (STH) causes Simond’s disease. STH is secreted by anterior lobe of pitutary.

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