Restriction enzymes
a) are present in bacteria and are involved in host restriction system
b) cleave viral DNA inside bacterium
c) are enzymes involved in defence against bacteriophages
d) all of these *
Which substance forms approximately 20% of air?
1. Carbon dioxide
2. Nitrous oxide
3. Oxygen *
4. Hydrogen
In adult males, the percentage of water found in the body is:
1. 65%
2. 60%
3. 55%
4. 78% *
Nucleic acids consist of:
1. Organic molecules
2. Inorganic molecules
3. Inorganic salts
4. Hormones
Atmospheric pressure is important in the process of:
1. Blood flow
2. Micturition
3. Breathing *
4. Reproduction
The first Type II enzyme isolated was
a) Eco R1 *
b) Hind III
c) Bam HI
d) Sal I
Which of the following ions are required for the activity of Type II restriction enzymes
a) Ca 2+
b) Mg 2+ *
c) Cl 2+
d) Mn 2+
Typical type II restriction enzymes usually require only Mg2+ as a cofactor.
Nathen, Arber and Smith were awarded with Nobel prize for physiology and medicine in the year
a) 1970
b) 1974
c) 1978 *
d) 1980
The Nobel Prize in Physiology or Medicine 1978. The Nobel Prize in Physiology or Medicine 1978 was awarded jointly to Werner Arber, Daniel Nathans and Hamilton O. Smith “for the discovery of restriction enzymes and their application to problems of molecular genetics”
Which of the following statements are true regarding restriction enzymes
a) Type I and II enzymes cuts far away from the restriction sites
b) Type II cuts DNA within restriction sites
c) Eco R1 is a Type II restriction enzyme
d) all of these
