In mammalian cells, RNA editing
P. Can change the coding capacity of a gene after transcription
Q. Creates a stop codon in the middle of the apo-B mRNA in intestinal cells but not in liver cells
R. Usually makes many changes in each mRNA
S. Can change specific nucleotides by deamination

Which of the following is a prime example of a ribonucleoprotein enzyme, the catalytic activity of which (under non-physiological conditions), resides solely in its RNA component

A. Reverse transcriptase

B. Cytochrome c

C. Bacterial RNA polymerase

D. RNase P

Main functions of baffles in a bioreactor are
P. To prevent a vortex.
Q. To increase aeration.
R. To reduce interfacial area of oxygen transfer.
S. To reduce aeration rate.

A. P, Q

B. Q, R

C. R, S

D. P, S

All the following may be methods for the inhibition of microbial growth by antibiotics except

A. Antibiotics disrupt cell wall synthesis

B. Antibiotics interfere with cell membrane function

C. Antibiotics prevent the release of energy from ATP

D. Antibiotics inhibit the synthesis of protein

A feature common to almost all transmembrane proteins is

A. A phosphorylated exterior domain

B. A structure consisting almost exclusively of beta-sheets

C. An amino acid sequence rich in acidic residues

D. An alpha-helical region of about 20 to 25 hydrophobic amino acids