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TLS Online TPP Program

#Question id: 4317

Which of the following functions does the product of the p53 gene carry out?

#SCPH01 Biochemistry

  1. It inhibits the cell cycle.

  2. It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.

  3. It causes cells to reduce expression of genes involved in DNA repair.

  4. It allows cells to pass on mutations due to DNA damage.

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TLS Online TPP Program

#Question id: 2285

#I Life Science/ Life Sciences Group – I-V

Assuming all other factors to be the same, electron microscopes have greater resolving power than light microscopes because.
TLS Online TPP Program

#Question id: 8924

#SCPH28 | Zoology

Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent?
1. Protostomes invade terrestrial environments.
2. Cambrian explosion occurs.
3. Deuterostomes invade terrestrial environments.
4. Vertebrates become top predators in the seas.
TLS Online TPP Program

#Question id: 10342

#SCPH05 I Biotechnology

Nitrate reductase is an important enzyme for nitrate assimilation. Given below some regulation of nitrate reductase activity through phosphorylation and dephosphorylation.

a) Light, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby activates the enzyme

b) In Dark, and Mg2+ stimulate a protein kinase that phosphorylates the same serine residues, which then interact with a 14-3-3 inhibitor protein, and thereby inactivate nitrate reductase

c) In Light, and Mg2+ stimulate a protein kinase that phosphorylates the serine residues, and thereby activate nitrate reductase

d) In Dark, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby inactivates the enzyme

Which of the following statements about regulation of nitrate reductase is correct?
TLS Online TPP Program

#Question id: 5584

#SCPH01 Biochemistry

Which one of the following provides rapid block to polyspermy during sea urchin fertilization?
TLS Online TPP Program

#Question id: 1599

#SCPH28 | Zoology

Name the class of MHC which is recognized by CD4 TH cell.