981. Which of the following mineral is involved in protein metabolism and oxidation reactions?
A. Molybdenum
B. Manganese
C. Magnesium
D. calcium

982. Which of the following mineral deficiency may result into impaired growth and development, skin lesions and loss of appetite?
A. Zinc
B. Cobalt
C. Iron
D. Magnesium

983. Which of the following is not a function of iron?
A. Oxygen transport
B. Immune function
C. Brain function
D. Gene regulation

984. Consumption of which nutrient leads to the multiplication of oral bacteria?
A. Fat
B. Carbohydrate
C. Protein
D. Fluoride

985. In an SDS-PAGE
A. proteins are denatured by the SDS
B. proteins have the same charge-to-mass ratio
C. smaller proteins migrate more rapidly through the gel
D. all of the above

986. Proteins can be visualized directly in gels by
A. staining them with the dye
B. using electron microscope only
C. measuring their molecular weight
D. none of these

987. In SDS-PAGE, the protein sample is first
A. treated with a reducing agent and then with anionic detergent followed by fractionation by electrophoresis
B. fractionated by electrophoresis then treated with an oxidizing agent followed by anionic detergent.
C. treated with a oxidizing agent and then with anionic detergent followed by fractionation by electrophoresis
D. none of the above

988. Electrophoresis of histones and myoglobin under non-denaturing conditions (pH = 7.0) results in
A. both proteins migrate to the anode
B. histones migrate to the anode and myoglobin migrates to the cathode
C. histones migrate to the cathode and myoglobin migrates to the anode
D. both proteins migrate to the cathode

989. In isoelectric focusing, proteins are separated on the basis of their
A. relative content of positively charged residue only
B. relative content of negatively charged residue only
C. size
D. relative content of positively and negatively charged residue

990. In a gel filtration column
A. smaller proteins enter the beads more readily
B. large proteins elute first
C. both (a) and (b)
D. large proteins enter the beads more readily