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TLS Online TPP Program

#Question id: 1514

Following statements are regarding to multiple signaling pathways in vertebrate cells that regulate outer mitochondrial membrane permeability and apoptosis.

A. In healthy cells, the anti-apoptotic protein Bcl-2, or its homolog Bcl-xL, binds to Bak or Bax pro-apoptotic proteins, blocking the ability of Bak or Bax to oligomerize and form pores in the outer mitochondrial membrane.

B. The presence of specific trophic factors (e.g., NGF) leads to activation of their cognate receptor tyrosine kinases (e.g., TrkA) and inactivation of the PI-3 kinase–PKB (protein kinase B) pathway.

C. PKB phosphorylates Bad, and phosphorylated Bad forms a complex with a cytosolic 14-3-3 protein. This sequestered Bad is unable to bind to Bcl-2.

D. In the absence of trophic factors, nonphosphorylated Bad binds to Bcl-2, releasing Bax and Bak and allowing them to form oligomeric membrane pores and holes.

E. DNA damage or ultraviolet irradiation leads to induction of synthesis of the BH3-only Puma protein. Puma binds to Bak and Bax as well as to Bcl-2, allowing Bak and Bax to form oligomeric pores.

F. Removal of a cell from its substratum disrupts integrin signaling, leading to release of the BH3-only Bim protein from the cytoskeleton. Bim also binds to Bak and Bax to promote pore formation.

Which of the following is incorrect?

#Unit 4. Cell Communication and Cell Signaling

  1. A and C

  2. A, B, C and D

  3. C, E and F

  4. B only

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TLS Online TPP Program

#Question id: 12997

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the given reason is correct to minimize the repulsion in an α-helix
a) positively charged amino acids are often found near the amino terminus of the helical segment
b) negatively charged amino acids are often found near the amino terminus of the helical segment
c) positively charged amino acids are often found near the C-terminus of the helical segment.
d) negatively charged amino acids are often found near the C-terminus of the helical segment.
TLS Online TPP Program

#Question id: 12998

#Unit 1. Molecules and their Interaction Relevant to Biology

Match with appropriate bonding pattern

Helix typeHydrogen bonding
a. α-helix1. n, n+3
b. 310 helix2. n, n+5
c. π helix3. n, n+4
TLS Online TPP Program

#Question id: 12999

#Unit 1. Molecules and their Interaction Relevant to Biology

Proline and glycine both disturb the symmetry of α-helix which of the following are true regarding to these two amino acids
a) proline changes the orientation of hetropolymeric α-helix hence proline can be placed only as 1st amino acid residue near to C-terminus 
b) proline changes the orientation of polymeric α-helix hence proline can be placed only as 1st amino acid residue near to N-terminus
c) glycine disrupts the heteropolymeric α-helix by changing the helicity.
d) homopolymer of proline and glycine can form stable helix. 
TLS Online TPP Program

#Question id: 13000

#Unit 1. Molecules and their Interaction Relevant to Biology

Identify the correct statement regarding the structure
TLS Online TPP Program

#Question id: 13001

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is incorrect 
a) antiparallel β sheets are frequently found and they are quite more stable because of more no. hydrogen bond presence and linear H bonding pattern.
b) antiparallel β sheets are frequently found and they are quite more stable because of more no. hydrogen bond presence and having distorted H bonding pattern.
c) parallel β sheets are relatively less stable and mostly found in core of protein.
d) parallel β sheets are relatively more stable and mostly found in core of protein.
TLS Online TPP Program

#Question id: 13002

#Unit 3. Fundamental Processes

Where in a eukaryotic cell do you think you would find each of the following proteins residing when it is actively performing its function. Be as specific as you can in terms of subcellular location.
Match the following with the correct subcellular location;
Column 1Column 2
I) Polymerasesa) In the cytoplasm
II) Ribosomal proteinsb) Inside the plasma membrane.
III) DNA ligasec) In the mitochondrial matrix
IV) protein that allows ions to pass in and out of the celld) In the nucleus of cells
V) Activator proteine) Inside the nuclear membrane
VI) an enzyme in the Krebs/TCA cycle
VII) a protein that forms a channel through which mRNAs can be exported into the cytoplasm