Genetics

Question 1

State what is meant by an allele.

Answer 1

Different forms of the same gene are called alleles.

Question 2

Name the type of allele that will always produce a characteristic in an organism.

Answer 2

Dominant alleles. These are said to be “expressed” in the organism.

Question 3

State how many copies of recessive allele are needed for it to be expressed.

Answer 3

You need two copies of a recessive allele for the characteristic to be expressed in the organism.

Question 4

Can characteristics be predicted and if so, how?

Answer 4

Yes , scientists are able to carry out a genetic cross which shows what an organisms offspring will look like.

Question 5

Complete:
Different forms of the same gene known as- - - will always be expressed if they are present.
- - alleles will only be expressed if two copies are present.

Answer 5

Different forms of the gene are known as - ALLELES -. -DOMINANT- alleles will always be expressed if they are present. - RECESSIVE- alleles will only be expressed if two copies are present.

Question 6

In mice-
white fur = recessive black fur = dominant

state the following fur colours:
BB
bb
Bb

Answer 6

BB- black
bb- white
Bb- black

Question 7

Use a punnet square to work out the freckles of the offspring. Freckles are dominant characteristics.
Mother - FF
Father - Ff

Answer 7

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