Replication/Mutation/Variation &Evolution

Question 1

DNA replication
Process

Answer 1

• Provides an explanation for chromosomes replicating in prophase stage of mitosis

1.) DNA structure (double helix) unwinds to form ladder shape.
2.) 2 strands separate causing a complimentary base pair to separate as a result of H bonds breaking. These bonds are broken with the assistance of restriction enzymes.
3.) Base pairs of each strand exposed.
4.)Complimentary base pairs floating about in nucleus attach to exposed base pairs with the assistance of the enzyme DNA polymerase (helps make DNA)
5.) 2 new strands of DNA produced from original parent.

Question 2

Mutations

Answer 2

Is a change in the genetic material (DNA or Gene or Chromosome) and leads to variation.

Question 3

Mutation Causes

Answer 3

Inherited = low survival rate if harmful mutation.

Random/Spontaneous occurrence

Caused by a stimulus (Chemical/Radiation) resulting in a change ; known as a mutagenic agent. EG: Tobacco

Some Beneficial organisms adapt to survive where others are harmful, increase rate of cell replication = cancer.

Question 4

3 types of mutations

Answer 4

DNA : Structure of DNA altered
GENE : Sequence within a gene altered e.g albinism/ haemophilia
CHROMOSOME : Piece of its lost or turned around or gain or loss of a chromosome. e.g Down syndrome

Question 5

Causes of variation

Answer 5

-Sexual reproduction
-mutation
-environmental factors
-meiosis

Question 6

Advantage of variation

Answer 6

give rise to new genotypes

Question 7

Evolution

Answer 7

The genetic change in a species over a long period of time which gives rise to a new species within the family

Question 8

Who carried out the study of evolution

Answer 8

Darwin & Wallace

Question 9

What did the study of evolution involve?

Answer 9

Fossils, embryology, similar at anomy of many species all for general purpose and movement.