4.6.1.6 Genetic Inheritance

Question 1

What is a gamete?

Answer 1

• an organism’s reproductive cell
• egg in female and sperm in males
• has half the number of chromosomes (23)

Question 2

What is a chromosome?

Answer 2

• a structure found in the nucleus which is made up of a long strand of DNA

Question 3

What is a gene?

Answer 3

• a short section of DNA that codes for a protein, therefore contributes to a characteristic
• some characteristics are controlled by a single gene however many are the result of different genes interacting

Question 4

What are alleles?

Answer 4

• different forms of gene
• humans have two alleles for each gene as they inherit one from each parent

Question 5

What is a dominant allele?

Answer 5

• only one is needed for it to be expressed and for corresponding phenotype to be observed

Question 6

What is a recessive allele?

Answer 6

• two copies are needed for it to be expressed and for the corresponding phenotype to be observed

Question 7

What is homozygous?

Answer 7

• when both inherited alleles are the same

Question 8

What is heterozygous?

Answer 8

• when one of the inherited alleles is dominant and the other is recessive

Question 9

What is a genotype?

Answer 9

• the combination of alleles an individual has

Question 10

What is a phenotype?

Answer 10

• the physical characteristics that are observed in the individual

Question 11

What do family trees show?

Answer 11

• inheritance of different phenotypes over generations in the same family

Question 12

What does a single gene cross look at?

Answer 12

• probability of offspring of two parents having certain genotypes and phenotypes
• done using alleles and a Punnet square

Question 13

What do uppercase letters represent?

Answer 13

• dominant characteristics

Question 14

What do lowercase letters represent?

Answer 14

• recessive characteristics