Sponge bob genetics | PDF - Free Printable

Let’s go step by step through each question to make sure we get everything right.

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Question 1: Write the phenotype (physical appearance) for each genotype.

We use the chart:

- Body Shape: Squarepants (S) is dominant, Roundpants (s) is recessive
- Body Color: Yellow (Y) is dominant, Blue (y) is recessive
- Eye Shape: Round (R) is dominant, Oval (r) is recessive
- Nose Style: Long (L) is dominant, Stubby (l) is recessive

Now match each:

(a) LL → both alleles are dominant for nose style → long nose ✔
(b) yy → both recessive for body color → blue body ✔
(c) Ss → one dominant allele for body shape → squarepants ✔
(d) RR → both dominant for eye shape → round eyes ✔
(e) Rr → at least one dominant → round eyes ✔
(f) ll → both recessive for nose → stubby nose ✔
(g) ss → both recessive for body shape → roundpants ✔
(h) Yy → at least one dominant for body color → yellow body ✔

All correct as written in the key.

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Question 2: Write the genotype(s) for each trait.

(a) Yellow body → can be YY or Yy → answer says “Yy YY” — that’s fine, but usually we write it as “YY or Yy”. Still acceptable.
(b) Roundpants → must be homozygous recessive → ss ✔
(c) Oval eyes → recessive → rr ✔
(d) Long nose → can be LL or Ll → answer says “LL or Ll” — good ✔
(e) Stubby nose → recessive → ll ✔
(f) Round eyes → can be RR or Rr → answer says “RR or Rr” ✔
(g) Squarepants → can be SS or Ss → answer says “SS or Ss” ✔
(h) Blue body → recessive → yy ✔

All correct.

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Question 3: Determine genotypes based on terms.

(a) Heterozygous round eyes → heterozygous means one of each allele → Rr ✔
(b) Purebred squarepants → purebred = homozygous dominant → SS ✔
(c) Homozygous long nose → homozygous dominant → LL ✔
(d) Hybrid yellow body → hybrid = heterozygous → Yy ✔

All correct.

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Question 4: SpongeBillyBob and SpongeGerdy genetics problem.

Given:
- Gerdy’s father: heterozygous squarepants → Ss
- Gerdy’s mother: roundpants → ss (since roundpants is recessive)

So cross: Ss x ss

Punnett square:

```
| s | s
----|-------|-------
S | Ss | Ss
----|-------|-------
s | ss | ss
```

Offspring: 50% Ss (squarepants), 50% ss (roundpants)

But the question says: “What is Gerdy’s genotype?” and the student wrote Ss

Wait — let’s think: Gerdy is described as a “cute squarepants gal”, so she has squarepants phenotype → which means she must have at least one S allele.

From her parents: father Ss, mother ss → possible offspring: Ss or ss.

Since Gerdy has squarepants, she cannot be ss → so she must be Ss.

✔ So Gerdy’s genotype is Ss — correct.

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(b) SpongeBillyBob is heterozygous for squarepants → that means Ss ✔

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(c) Cross Billy Bob (Ss) with Gerdy (Ss)

Punnett square:

```
| S | s
----|-------|-------
S | SS | Ss
----|-------|-------
s | Ss | ss
```

Student drew this correctly.

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(d) Possible genotypes: SS, Ss, ss
Phenotypes: Squarepants (SS, Ss), Roundpants (ss)

Student wrote:
G: SS, Ss, ss
P: Square, round → should say “Squarepants, Roundpants” but close enough.

Actually, better to write:
Genotypes: SS, Ss, ss
Phenotypes: Squarepants (for SS and Ss), Roundpants (for ss)

But since the student just listed them, it’s okay.

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(e) Probability of kids with squarepants?

From Punnett square: 3 out of 4 → SS, Ss, Ss → 3/4 = 75% ✔

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(f) Probability of kids with roundpants?

Only ss → 1 out of 4 → 25% ✔

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Everything checks out! The student’s answers are all correct.

Final Answer: All answers provided in the worksheet are correct. No corrections needed.