Punnett Square Practice Worksheet for genetics education.

Let’s solve this step by step.

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Question 1: Determine phenotype from genotype

We’re told:

- Purple flowers (P) are dominant to white (p)
→ So PP and Pp = purple, pp = white

- Hairy knuckles (H) dominant to non-hairy (h)
→ HH and Hh = hairy, hh = non-hairy

- Bobtails in cats are recessive (t), normal tails dominant (T)
→ TT and Tt = normal tail, tt = bobtail

So fill in:

PP → purple
Pp → purple
pp → white

HH → hairy knuckles
Hh → hairy knuckles
hh → non-hairy knuckles

TT → normal tail
Tt → normal tail
tt → bobtail

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Question 2: Classify genotypes as homozygous dominant, heterozygous, or homozygous recessive

Remember:
- Homozygous dominant = two capital letters (e.g., AA)
- Heterozygous = one capital, one lowercase (e.g., Aa)
- Homozygous recessive = two lowercase (e.g., aa)

So:

AA → homozygous dominant
gg → homozygous recessive
Pp → heterozygous
Ii → heterozygous
tt → homozygous recessive
TT → homozygous dominant

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Questions 3–5: Dog fur color cross

Given:
- Dominant allele F = grey fur
- Recessive allele f = black fur
- Female dog is heterozygous → so her genotype is Ff
- Male dog is homozygous recessive → so his genotype is ff

We need to set up a Punnett square.

Place male alleles on top: since he’s ff, both alleles are f and f

Place female alleles on side: she’s Ff, so F and f

Punnett Square:

```
| f | f
---------------------
F | Ff | Ff
---------------------
f | ff | ff
```

So offspring genotypes:

- Top left: Ff
- Top right: Ff
- Bottom left: ff
- Bottom right: ff

That’s 2 Ff and 2 ff out of 4 total.

So:

% of possible Genotypes:

FF: 0% (none have FF)
Ff: 50% (2 out of 4)
ff: 50% (2 out of 4)

% of possible Phenotypes:

Black fur = only ff → 50%
Grey fur = Ff (since F is dominant) → 50%

(Note: FF would also be grey, but there are none here.)

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Final Answer:

Question 1:

PP → purple
Pp → purple
pp → white

HH → hairy knuckles
Hh → hairy knuckles
hh → non-hairy knuckles

TT → normal tail
Tt → normal tail
tt → bobtail

Question 2:

AA → homozygous dominant
gg → homozygous recessive
Pp → heterozygous
Ii → heterozygous
tt → homozygous recessive
TT → homozygous dominant

Question 3:

% of possible Genotypes:
FF: 0%
Ff: 50%
ff: 50%

% of possible Phenotypes:
Black fur: 50%
Grey fur: 50%

Punnett Square setup:

Male parent alleles (top): f, f
Female parent alleles (side): F, f

Filled square:

Top row: Ff, Ff
Bottom row: ff, ff