The induction of α-amylase synthesis in barley aleurone layers by gibberellin, given some statements about after the induction of GA into the aleurone layer, and allows some transcriptional gene function inside the nucleus such as;

a) GA-MYB is a negative regulator of α-amylase transcription

b) The sequence of the gibberellic acid response element (GARE) in the α-amylase gene promoter is similar to the DNA sequence to which MYB proteins bind.

c) Synthesis of GA-MYB mRNA begins to increase as early as 1 h after gibberellin treatment, preceding the increase in a-amylase mRNA by several  hours

d) A mutation in the GARE that prevents MYB binding also prevents  α-amylase expression.

e) GA-MYB can therefore be defined as a primary or early response gene, while the α-amylase gene is a secondary or late response gene

f) The secretory pathway requires GA stimulation of the calcium-calmodulin– independent pathway.

Which of the following statements is incorrect about this transcriptional gene?

#Question id: 869

#Unit 1. Structure and Function of Biomolecules

Which statements are correct regarding protein folding

A. Many molecular chaperones were first described as heat shock proteins (Hsp) because Their rate of synthesis is increased at elevated temperatures

B. The renaturation of a denatured protein in vitro may not entirely mimic the folding of a protein in vivo.

C. Molecular chaperones are essential proteins that bind to only partially folded polypeptide chains.

D. Molecular chaperones function to lift folding polypeptides out of the false minima in their folding funnel.

#Question id: 870

#Unit 1. Structure and Function of Biomolecules

Choose correct statements about ‘Protein Disulfide Isomerase’ in protein folding

A. Oxidized PDI catalyzes the rearrangement of a polypeptide’s non-native disulfide bonds via disulfide interchange reactions to yield native disulfide bonds.

B. Reduced PDI catalyzes the initial formation of a polypeptide’s disulfide bonds through the formation of a mixed disulfide.

C. Protein disulfide isomerase contains the conserved active site motif of Cys-Xaa-Xaa-Cys found in thioredoxin and shares a similar role to the Dsb family of proteins found in E. coli.

D. Under more reducing conditions with thiols in the active site the enzyme reshuffles disulfides (isomerase) in target proteins.

#Question id: 871

#Unit 1. Structure and Function of Biomolecules

According to ‘Energy–entropy phenomenon’ for protein folding correct combinations of possible conformations

#Question id: 872

#Unit 1. Structure and Function of Biomolecules

Which of the following statements is not true about HSP 70 family.

A. They have a molecular weight near 70,000 and are abundant in cells stressed by elevated temperature.

B. Bind to regions of unfolded polypeptides that are rich in hydrophilic residues

C. Hsp70 proteins not  block the folding of certain proteins that must remain unfolded untill they have been translocated across a membrane.

D.) It releases polypeptides in a cycle that uses energy from ATP hydrolysis.

#Question id: 873

#Unit 1. Structure and Function of Biomolecules

Intrinsically disordered proteins have properties that are distinct from classical structured proteins

A. Are characterized by sequences rich in certain polar and charged amino acids (Gln, Ser, Pro, Glu, Lys, Gly, and Ala)

B. Ordered proteins tend to participate in signaling and regulation, whereas Intrinsically disordered proteins are involved largely in catalytic reactions, transport processes, and structural functions.

C. Nearly half of all prokaryotic proteins contain long disordered segments, whereas only a few percent of eukaryotic proteins do.

D. Often adopt a specific secondary or tertiary structure when they bind to other molecules such as ions, organic molecules, proteins, and nucleic acids.

#Question id: 874

#Unit 1. Structure and Function of Biomolecules

Fates of misfolded proteins, according given figure