Topic 6: Heredity and Predicting Inheritance

Question 1

What is inheritance?

Answer 1

• the transfer of genetically determined characteristics from 1 generation to the next

Question 2

What is genetics the study of?

Answer 2

• inheritance

Question 3

What are alleles?

Answer 3

• genes occupying the same locus on homologous chromosomes

Question 4

What are the two types of alleles?

Answer 4

• homozygous and heterozygous

Question 5

What does homozygous mean?

Answer 5

• both alleles express the same version of a trait
  ex. blonde hair (bb), black hair (BB)

Question 6

What does heterozygous mean? (2)

Answer 6

• different alleles of the same gene
• alleles code for different expressions of the same trait
  eg. Bb

Question 7

What is a genotype?

Answer 7

• catalogue of a person’s genes (genetic makeup)

Question 8

What is a phenotype?

Answer 8

• expression of genotype (genes) to give observable characteristics
  ex. black hair

Question 9

What is a dominant allele?

Answer 9

• expressed in phenotype regardless of other allele
• ex. BB or Bb - dominant allele eg. black hair

Question 10

What is a recessive allele?

Answer 10

• expressed in phenotype only if present on both alleles
• ex. bb is blonde hair

Question 11

What is the purpose of a Punnett Square? (2)

Answer 11

• determines the probability of inheritance
• predicts offspring genotype and phenotype

Question 12

Does a Punnett Square always turn out to be true?

Answer 12

• no, it only determines the probability of having those traits on offspring
  ex. if you have a 25% chance of blonde hair, it does not guarantee that 1/4 kids will be blonde