Exercise 7

Question 1

Define the term genotype

Answer 1

2. Genotype refers to the two genes or gene combination of an individual. An individual receives one gene from each parent for every characteristic.

Question 2

What Is an allele

Answer 2

3. An allele is an alternate form of a gene. Alleles have the same position on a pair of chromosomes and affect the same trait. Autosomal alleles appear in pairs and one of each pair of alleles is inherited from each parent.

Question 3

4. How is a dominant allele designated? How is a recessive allele designated?

Answer 3

4. A dominant allele is designated by an upper case letter. Example - A A recessive allele is designated by a lower case letter. Example - a

Question 4

5. Explain what is meant by dominant genotype.

Answer 4

5. A dominant genotype means that at least one dominant allele is present. To display a dominant characteristic an individual has to have only one dominant allele. A dominant allele masks the expression of the recessive allele.

Question 5

6. Explain what is meant by recessive genotype.

Answer 5

6. A recessive genotype means that two recessive alleles or genes are present. To display a recessive characteristic and individual has to have inherited a recessive allele from each parent.

Question 6

7. What is meant by the term heterozygous?

Answer 6

7. Heterozygous means that the homologous pair of chromosomes carry a different allele for a characteristic. In other words, the instructions for a characteristic inherited form each parent is different.

Question 7

What Is meant by the term homozygous

Answer 7

8. Homozygous means that the homologous pair of chromosomes carry the same gene or allele for a characteristic. In other words, the instructions for a characteristic inherited from each parent is the same.

Question 8

What Are the three genotype possibilities

Answer 8

9. The three possibilities in determining the genotype are:
   two dominant alleles – homozygous dominant genotype – AA
   two recessive alleles – homozygous recessive genotype– aa
   one dominant allele and one recessive allele –heterozygous dominant genotype - Aa

Question 9

10.Define the term phenotype.

Answer 9

10. Phenotype is the physical appearance of an individual.

Question 10

12.Brown eyes (B) are dominant to blue eyes (b). What are the chances, that a heterozygous brown-eyed woman and a blue-eyed man would have a blue-eyed child?

Answer 10

The chance of this couple having a blue-eyed child is 50%

Question 11

What does the term inheritance mean?

Answer 11

1. Inheritance is the transfer of characteristics (genes) from one generation to another.