SAC 3

Question 1

Define recessive

Answer 1

The trait that is not expressed but remains hidden in a heterozygous

Question 2

Define dominant

Answer 2

The trait that is expressed in a heterozygous condition.

Question 3

Define genotype

Answer 3

The inherited allele for genes from their parents. They are unable to be seen

Question 4

How to work out phenotype ratio

Answer 4

15 green : 4 albino

Divide by smallest number

15/4 : 4/4

3:1

Question 5

What is a Test cross

Answer 5

Test cross is used to discover original phenotype of organism. Cross dominant homozygous or dominant heterozygous phenotype with a homozygous recessive. As offspring shows recessive trait the individual must be heterozygous.

Question 6

How can you make a test cross more accurate

Answer 6

The larger the number of offspring the more reliable the results

Question 7

Advantageous phenotype (which would survive best in nature)

Answer 7

The green would as the white lack chlorophyll which is vital to help the plant photosynthesis and therefore produce energy

Question 8

Why would we study inheritance in barley and not human patterns

Answer 8

Plants are fast growing and more easier to produce large quantities
Plants are easier to observe as there are more clear distinctions between traits where humans is a lot more difficult
It is not ethical to experiment on humans as you would have to take samples from the participants and there would have to be a lot of willing participants to easily see inheritance

Question 9

Define phenotype

Answer 9

The visible expression of genetic makeup of an organism