Question

1) There is one unit that is used both in the metric system and in other systems. Which of these units can be used in the metric system? a) pounds b) seconds c) miles d) gallon 2) During isolation of chromosomal DNA from onion cells, sodium dodecylsulphate (SDS) acts to: a) Dissolve membrane lipids b) Denature protein c) Ionize DNA molecules d) Both “A” and “B” are correct 3) Electrophoresis is used to a) Separate DNA fragments. b) identify DNA fragments. c) Purify DNA fragments. d) Both A and B e) Both A, B, and C 4) What does the electrophoresis apparatus consist of? a) Gel, buffer chamber and bench b) Buffer chamber and electrophoresis unit c) Electrophoresis unit and gel separator d) Power pack, gel, and electrophoresis unit 5) The function of a buffer in agarose gel electrophoresis is: a) to resist change in pH of solution. b) to act as a conductor of electric current c) to convert DNA into its linear form d) answers “A” and “B” are correct 6) What is your genotype for the Alu insert in your PV92 region if both copies of chromosome contain insert of 300 bases repeated sequence? a) homozygotes (-/-) b) heterozygous (+/-) c) homozygotes (+/+) d) pseudo heterozygous 7)  The substance used to separate the proteins from the DNA: a) sodium dodecyl sulphate b) salt c) ethanol d) water please answer the correct answer !

Answer 1

1. Correct option is second

SI system or metric system is used around the world. There are 7 basic units like metre (m), kilogram (kg), second (s), kelvin (K), amphere (A), mole (mol), candela (cd).

2. Correct option is d) both A and B are correct.

SDS stands for sodium dodecyl sulfate, is a solid anionic detergent that can solubilize the protien and lipids that frames the biological membranes. This will help the cell membrane to separate and expose the chromosome that contain DNA. SDS releaseDNA from histones and other DNA binding protiens by denaturing them. Hence correct option include both- dissolves membrane protiens and denatures protiens.

3. Correct option is e

Electrophoresis is the basic procedure used to separate DNA fragments based on their size and charge. DNA sample is allowed to run across the gel. Since DNA is negatively charged due to the presence of phosphate it run towards the positive charge. Thus smaller DNA fragments migrate faster and farther towards positive side and larger fragments migrate less distance and seen near to the wells. thus hey are separated according to their size. This basic separation method can be used to identify and purify DNA.

4. Correct option is d

An electrophoresis unit consists of power pack, gel and electrophoretic unit. Electrophoretic unit is a typically a plastic tank or box with cathode and anode at opposite ends. Gel used are agarose or polyacrilamide. Power is applied through the elecrophoretic unit to run DNA in the gel.

5. Correct option is d

Main function of buffer is it provides necessary ions to conduct electricity, maintains pH and maintains temperatue. it also keeps gel from melting.

6. sorry, don't know the correct answer.

7. correct option is a SDS. ( already explained in the 2nd question.)