Biology (Breeding inheritance and engineering)

Question 1

What is the structure of DNA?

Answer 1

DNA is a double stranded, double helix molecule.

Question 2

Where is DNA found in the cell?

Answer 2

DNA is found in the nucleus of the cell. It is arranged as chromosomes.

Question 3

Define the term ‘gene’.

Answer 3

A gene is a section of a chromosome that codes for a particular characteristic e.g. hair colour.

Question 4

What is an allele?

Answer 4

An allele is an alternate form of a gene. E.g. if the gene is eye colour, the allele may be blue eyes, brown eyes, or green eyes.

Question 5

What causes variation within a species?

Answer 5

Variation within a species may be due to genetics or environmental factors.

Question 6

Describe the difference between dominant and recessive alleles.

Answer 6

Dominant alleles mask the effect of recessive alleles in heterozygous conditions.

Question 7

Distinguish between homozygous and heterozygous alleles.

Answer 7

Homozygous alleles are inherited alleles that are the same e.g. TT; Heterozygous alleles are inherited alleles that are different e.g. Tt.

Question 8

What is a genotype?

Answer 8

A genotype is the genetic makeup of an individual for a particular characteristic.

Question 9

What is a phenotype?

Answer 9

A phenotype is the observable characteristics of an individual.

Question 10

What is selective breeding?

Answer 10

Selective breeding is when humans choose parents to breed together with particular desirable characteristics.

Question 11

List the stages of selective breeding.

Answer 11

1. Select parents with desirable traits
2. Breed them together
3. Select offspring with desired traits for future breeding.

Question 12

What are some advantages of selective breeding?

Answer 12

1. Improved traits in offspring
2. Increased yield in crops and livestock
3. Disease resistance in plants and animals.

Question 13

What are some disadvantages of selective breeding?

Answer 13

1. Reduced genetic diversity
2. Increased risk of inherited diseases
3. Unintended consequences in traits.

Question 14

What is genetic engineering?

Answer 14

Genetic engineering is a process which involves changing the genes of an organism.

Question 15

List three characteristics that are genetically controlled.

Answer 15

1. Eye colour
2. Hair colour
3. Blood type.

Question 16

List three characteristics that are environmentally controlled.

Answer 16

1. Height
2. Weight
3. Skin colour.

Question 17

List three characteristics that are controlled by both genetics and the environment.

Answer 17

1. Intelligence
2. Personality traits
3. Health conditions.

Question 18

Fill in the blank: A _______ is an alternate form of a gene.

Answer 18

[allele]