Monohybrid & Test Cross Practice WS 1A - Honors Biology worksheet featuring a monohybrid cross diagram of pea plants and genetics questions.

I'll work through each question step by step, solving the genetics problems carefully.

Questions 1-5: Monohybrid Cross with Pea Plants

Looking at the diagram:
- P₁ generation: Short pea plant × Tall pea plant
- F₁ generation: All tall pea plants
- F₂ generation: 3 tall : 1 short

Question 1: The single trait being considered is plant height (tall vs. short).

Question 2: In the F₁ generation, all plants are tall. In the F₂ generation, there's a mix of both tall and short plants (3 tall to 1 short ratio).

Question 3: Mendel called the observed trait in F₁ the dominant trait, and the trait that seemed to disappear was called the recessive trait.

Question 4:
- Phenotype of F₁: All tall plants
- Genotype of F₁: All heterozygous (Tt) - they have one allele from each parent

Question 5: The trait for shortness seems to "skip a generation" because it's recessive. In the F₁ generation, all plants have one dominant allele (T) which masks the recessive allele (t). The short trait only appears in F₂ when an offspring receives two recessive alleles (tt) - one from each heterozygous parent.

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Question 6: Dogs - Wire-haired (W) dominant over smooth hair (w)

Cross: Homozygous wire-haired male (WW) × Female with smooth hair (ww)

Let me create the Punnett square:

| | W | W |
|---|---|---|
| w | Ww | Ww |
| w | Ww | Ww |

Genotypes: All Ww (100% heterozygous)
Phenotypes: All wire-haired (100%)
Ratio: 100% wire-haired or 4:0 or 1:0

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Question 7: Rabbits - Short hair (L) dominant over long hair (l)

Cross: Two heterozygous rabbits (Ll × Ll)

Let me create the Punnett square:

| | L | l |
|---|---|---|
| L | LL | Ll |
| l | Ll | ll |

Genotypes:
- 1 LL : 2 Ll : 1 ll
- Or: 25% LL, 50% Ll, 25% ll

Phenotypes:
- Short hair (LL and Ll): 3 out of 4 = 75%
- Long hair (ll): 1 out of 4 = 25%
- Ratio: 3 short hair : 1 long hair

Final Answer:
1. Plant height (tall vs. short)
2. F₁: all tall; F₂: mixture of tall and short (3:1 ratio)
3. Dominant and recessive
4. Phenotype: all tall; Genotype: Tt (heterozygous)
5. Because shortness is recessive and requires two recessive alleles (tt), which only occurs in F₂ when both parents contribute the recessive allele
6. Genotypes: all Ww; Phenotypes: all wire-haired; Ratio: 100% wire-haired (or 4:0)
7. Genotypes: 1 LL : 2 Ll : 1 ll; Phenotypes: 3 short hair : 1 long hair