Question

bikini bottom genetics 2
use your knowledge of genetics to complete this worksheet.

1. use the information for spongebob’s traits to write the phenotype (physical appearance) for each item.

trait	dominant gene	recessive gene
body color	yellow (y)	blue (y)
eye shape	round (r)	oval (r)
nose style	long (l)	stubby (l)

(a) ll-
(b) yy-
(c) ss-
(d) rr -
(e) rr-
(f) ll-
(g) ss-
(h) yy -

1. use the information in the chart in #1 to write the genotype (or genotypes) for each trait below.

(a) yellow body -
(b) roundpants -
(c) oval eyes -
(d) long nose -
(e) stubby nose -
(f) round eyes -
(g) squarepants -
(h) blue body -

1. determine the genotypes for each using the information in the chart in #1.

(a) heterozygous round eyes -
(b) purebred squarepants -
(c) homozygous long nose -
(d) hybrid yellow body -

1. one of spongebob’s cousins, spongebillybob, recently met a cute squarepants gal, spongegerdy, at a local dance and fell in love. use your knowledge of genetics to answer the questions below.

(a) if spongegerdy’s father is a heterozygous squarepants and her mother is a roundpants, what is her genotype? complete the first punnett square to show the possible genotypes.
based on your results, what would gerdy’s genotype have to be?
(b) complete the second punnett square to show the possibilities that would result if billy bob & gerdy had children.
note: spongebillybob is heterozygous for his squarepants shape.
(c) what is the probability of kids with squarepants? %
(d) what is the probability of kids with roundpants? %

Explanation:

Step1: Analyze Question 3(a)

Heterozygous means having two different alleles. For round eyes, dominant is \( R \), recessive is \( r \). So heterozygous round eyes would be \( Rr \).

Step2: Analyze Question 3(b)

Purebred (homozygous) squarepants. Squarepants is dominant (\( S \)), so purebred is \( SS \).

Step3: Analyze Question 3(c)

Homozygous long nose. Long nose is dominant (\( L \)), so homozygous is \( LL \).

Step4: Analyze Question 3(d)

Hybrid (heterozygous) yellow body. Yellow is dominant (\( Y \)), blue is recessive (\( y \)), so hybrid is \( Yy \).

Step5: Analyze Question 4(a)

Father: heterozygous squarepants (\( Ss \)), Mother: roundpants (\( ss \)). Punnett square:

	\( S \)	\( s \)
\( s \)	\( Ss \)	\( ss \)

Gerdy is squarepants, so her genotype is \( Ss \) (since \( ss \) is roundpants, and she is squarepants gal).

Step6: Analyze Question 4(b)

Billy Bob: heterozygous squarepants (\( Ss \)), Gerdy: \( Ss \). Punnett square:

	\( S \)	\( s \)
\( s \)	\( Ss \)	\( ss \)

Step7: Analyze Question 4(c)

From Punnett square in 4(b), squarepants genotypes: \( SS, Ss, Ss \) (3 out of 4). Probability: \( \frac{3}{4} \times 100 = 75\% \).

Step8: Analyze Question 4(d)

Roundpants genotype: \( ss \) (1 out of 4). Probability: \( \frac{1}{4} \times 100 = 25\% \).

Answer:

Question 3:

(a) \( Rr \)
(b) \( SS \)
(c) \( LL \)
(d) \( Yy \)

Question 4:

(a) Gerdy's genotype: \( Ss \)
(c) Probability of squarepants kids: \( 75\% \)
(d) Probability of roundpants kids: \( 25\% \)