D1.1 DNA Replication

Question 1

What is Cell Division used for?

Answer 1

Growth or repair of tissues through cell replacement

Question 2

What makes DNA Replication Semi-Conservative?

Answer 2

As one double strand of DNA is replicated, for each new double strand produced, one strand contains the original DNA and the other contains newly synthesized DNA

Question 3

Role of Helicase & DNA Polymerase in DNA Replication

Answer 3

1. Eukaryotic DNA is supercoiled by being tightly wound around histones to form nucleosomes which helps package DNA and allows it to fit in the nucleus
2. Enzyme helicase unwinds double helix & separates the two DNA strands by breaking hydrogen bonds between bases
3. Enzyme DNA polymerase will move along separate strands to use as templates
4. DNA polymerase will begin building a new strand of DNA by attaching free nucleotides in a chain

Question 4

Polymerase Chain Reaction

Answer 4

Technique used to amplify small fragments of DNA

Question 5

PCR Reaction Chamber contains:

Answer 5

1. Free nucleoside triphosphates to synthesis new strands
2. Primers to allow replication to occur from desired point
3. Taq Polymerase cannot denature at high temperatures so it can continue to function in repeated cycles

Question 6

What is Taq Polymerase?

Answer 6

Special Heat Stable version of DNA polymerase

Question 7

Process of Thermal Cycling

Answer 7

1. Denaturation Phase (98C): DNA is heated enough to break hydrogen bonds that hold the strands together
2. Annealing Phase (60C): Short primer sequence will bond to complementary sequences
3. Extension Phase (72C): Taq polymerase replicates DNA using primer as a starting point

Question 8

Gel Electrophoresis

Answer 8

Technique used to separate & analyse DNA fragments based on their size & charge using an electric field and a gel matrix

Question 9

How does Gel Electrophoresis work?

Answer 9

It uses an electrical current to move molecules through a semisolid medium or gel and DNA molecules are separated by their size and amount of charge

Question 10

What are Restriction Endonucleases

Answer 10

Enzymes that cut the backbone of the DNA double helix at highly specific sequences which produces shorter DNA segments and distinctive fragment patterns

Question 11

Gel Electrophoresis Process

Answer 11

1. Samples with fragment of DNA are loaded into wells on one end of the gel
2. Gel is submerged in a buffer solution and an electric current runs through the gel
3. DNA travels through spaces within the gel
4. One or more wells is filled with a DNA ladder which contains DNA fragments with different lengths (Do not have colour, dyed)