Unit 3: Genetics

Question 1

What is a trait? Provide a distinguishing example.

Answer 1

Each variant for a characteristic

Example: Eye color is a characteristic. Blue, brown, grey, or green eyes are traits.

Question 2

What is a genotype?

Answer 2

Combination of alleles that an individual possesses for a specific gene

Question 3

What is a phenotype?

Answer 3

An organism’s observable characteristics

Example: Your looks

Question 4

What is hybridization?

Answer 4

Refers to the process of producing offspring by mating two parents.

Question 5

Name the list of generations in order.

Answer 5

P-Generation- Parental Generation
F1 Generation- Filial Generation
F2 Generation- Second Filial Generation

Question 6

What are alleles?

Answer 6

Alternative versions of genes

Examples: RR, rr, Rr

Question 7

What is a dominant allele/trait?

Answer 7

One variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene; indicates by capital letters

Question 8

What is a recessive allele/trait?

Answer 8

This is the variant of a gene that is overridden and whose effect is not visible in the phenotype; indicated by lowercase letters

Question 9

What is a recessive allele/trait?

Answer 9

This is the variant of a gene that is overridden and whose effect is not visible in the phenotype; indicated by lowercase letters

Question 10

What is a dominant?

Answer 10

One trait masks or overrides the effect of a different trait of the same characteristic; indicated by capital letters

Question 11

What is recessive?

Answer 11

This is the trait that is overridden and not visible in the phenotype; indicated by lowercase letters

Question 12

What is incomplete dominance?

Answer 12

Neither trait is truly dominant and so the phenotype is a mixture of the two traits; is always heterozygous

Question 13

What is partial dominance/codominance?

Answer 13

Both traits are dominant and both traits will become expressed in the phenotype; is always heterozygous

Question 14

What does homozygous mean?

Answer 14

Pair of identical alleles

Examples: BB (Homozygous Dominant), bb (Homozygous Recessive)

Question 15

What does heterozygous mean?

Answer 15

Pair of different alleles

Example: Bb

Question 16

What is the Punnett square?

Answer 16

Is a square diagram that is used to predict the genotypes of a particular cross or breeding experiment

Question 17

What are the first three steps of how to make and analyze a Punnett square?

Answer 17

1. Determine the genotype of the parents
2. Write down the “cross”
3. Draw the Punnett square

Question 18

What are the last four steps of how to make and analyze a Punnett square?

Answer 18

4. “Split” the parents’ genotypes into gametes on the outside of the Punnett square
5. Determine genotypes of offspring.
6. Summarize results (genotypes and phenotypes)

Question 19

In a Punnett square on the slides, what are the Y and G individually?

Answer 19

The genetic contributions of one parent and the other

Question 20

In a Punnett square on the slides, what are the YG’s collectively?

Answer 20

The offspring genotype possibilities

Question 21

How many alleles does an individual have for a gene?

Answer 21

Two each