genetic diagrams

Question 1

What does “P” stand for in a genetic cross?

Answer 1

Parent generation.

Question 2

What does “F1” stand for?

Answer 2

First filial (offspring) generation.

Question 3

What does “F2” stand for?

Answer 3

Second filial (offspring) generation.

Question 4

What is a Punnett square used for?

Answer 4

To predict the possible genotypes and phenotypes of offspring.

Question 5

What do capital letters (e.g., T) represent in genetics?

Answer 5

Dominant alleles.

Question 6

What do lowercase letters (e.g., t) represent?

Answer 6

Recessive alleles.

Question 7

What happens during meiosis in genetic crosses?

Answer 7

Alleles separate, forming gametes with only one allele from each parent.

Question 8

How do you determine offspring genotypes?

Answer 8

By using a Punnett square to combine parental alleles.

Question 9

What is the expected genotype ratio when two heterozygous parents (Tt × Tt) are crossed?

Answer 9

1 TT : 2 Tt : 1 tt.

Question 10

What is the expected phenotype ratio in the same cross (Tt × Tt) if T is dominant?

Answer 10

3 tall : 1 short.

Question 11

If one parent is TT (homozygous dominant) and the other is tt (homozygous recessive), what will be the genotype of all F1 offspring?

Answer 11

Tt (heterozygous).

Question 12

What is the phenotype of all F1 offspring in this TT × tt cross?

Answer 12

All tall

Question 13

If a trait has 4 possible genotypes and only 1 of them results in a particular phenotype, what is the probability of that phenotype appearing?

Answer 13

1 in 4 or 25%.

Question 14

What is the probability of a heterozygous (Tt) and a homozygous recessive (tt) cross producing a short offspring?

Answer 14

50% (2 out of 4 offspring will be tt).