Genetic Variation

Question 1

What does DNA stand for?

Answer 1

Deoxyribose Nucleic Acid.

Question 2

What are the DNA bases and their pairs?

Answer 2

DNA bases;
- Adenine (A)
- guanine (G)
- Cytosine (C)
- Thymine (T)
DNA pairs;
- (A) + (T)
- (G) + (C)

Question 3

Why is DNA important?

Answer 3

• DNA contains the instructions for an organism to develop, survive and reproduce. Each DNA sequence that contains instructions to make a protein is known as a gene.
• The size of a gene can vary greatly, ranging from about 1000 bases to 1 million bases in humans.

Question 4

What is the purpose of DNA sequencing?

Answer 4

• DNA sequencing determines the order of the four chemical ‘bases’ that make up the DNA molecule.
• It tells scientists the kind of genetic information carries by a particular DNA segment.

Question 5

What is variation?

Answer 5

• Causes by random assortment and crossing over during meiosis.
• Further variations arise due to random fertilisation during reproduction.
• Individuals of a species are similar but rarely identical.

Question 6

What does ‘Recombination’ refer to?

Answer 6

The rearrangement of DNA sequences by the breakage and rejoining of chromosomes or chromosome segments. It also describes the consequences of such rearrangements.

Question 7

What does ‘Random fertilisation’ refer to?

Answer 7

Any of the genetically unique sperm generated by the male may fertilise the genetically unique egg produced by the female to create a variation.