Question

name____ period__ date__ spongebob and bikini bottoms genetics worksheet scientists at bikini bottoms have been investigating the genetic makeup of the organisms in the community. use the information provided and your knowledge of genetics to answer each question. 1. for each genotype below, indicate whether it is a heterozygous (he) or homozygous (ho). tt__ rb__ dd__ ff__ ff__ dd__ dd__ rr__ tt__ bb__ bb__ ff__ a. which of the genotypes in #1 would be considered purebred? b. which of the genotypes in #1 would be hybrids? 2. determine the phenotype for each genotype using the information provided about spongebob. yellow body - color is dominant to blue. yy__ yy__ yy__ a round shape is dominant to a square. rr__ rr__ rr__ 3. for each phenotype, give the genotypes that are possible for patrick. a tall head (t) is dominant to a short (t). tall =__ short =__ pink body color (p) is dominant to yellow (p). pink body =__ yellow body =__ 4. spongebob squarepants recently met spongesusie roundpants at a dance. spongebob is homozygous recessive for his square shape, but spongesusie is heterozygous for her round shape. create a punnett - square to show the possibilities that would result if spongebob and spongesusie had children. hint: read question #2! a. list the possible genotypes and phenotypes for their children. g:__ p:__ b. what are the chances of a child with a square shape?__ out of__ or__% c. what are the chances of a child with a round shape?__ out of__ or____%

Explanation:

Step1: Define heterozygous and homozygous

Heterozygous has two different alleles, homozygous has two identical alleles.

Step2: Classify genotypes in question 1

• TT: Homozygous (Ho) as both alleles are T.
• Rb: Not a valid genotype notation in standard genetics.
• DD: Homozygous (Ho) as both alleles are D.
• Ff: Heterozygous (He) as alleles are different (F and f).
• tt: Homozygous (Ho) as both alleles are t.
• dd: Homozygous (Ho) as both alleles are d.
• Dd: Heterozygous (He) as alleles are different (D and d).
• rr: Homozygous (Ho) as both alleles are r.
• Tt: Heterozygous (He) as alleles are different (T and t).
• Bb: Heterozygous (He) as alleles are different (B and b).
• BB: Homozygous (Ho) as both alleles are B.
• FF: Homozygous (Ho) as both alleles are F.

Step3: Identify pure - bred genotypes (homozygous)

A. The pure - bred genotypes (homozygous) from question 1 are TT, DD, tt, dd, rr, BB, FF.

Step4: Identify hybrid genotypes (heterozygous)

B. The hybrid genotypes (heterozygous) from question 1 are Ff, Dd, Tt, Bb.

Step5: Determine phenotypes in question 2

• For body color:
• YY: Yellow (dominant phenotype as Y is dominant over y).
• Yy: Yellow (dominant phenotype as Y is present).
• yy: Blue (recessive phenotype as only y alleles are present).
• For shape:
• RR: Round (dominant phenotype as R is dominant over r).
• Rr: Round (dominant phenotype as R is present).
• rr: Square (recessive phenotype as only r alleles are present).

Step6: Determine possible genotypes for phenotypes in question 3

• For head height:
• Tall: TT or Tt (as T is dominant for tall).
• Short: tt (as only recessive alleles for short).
• For body color:
• Pink body: PP or Pp (as P is dominant for pink).
• Yellow body: pp (as only recessive alleles for yellow).

Step7: Create Punnett square for question 4

Let R represent the dominant allele for round shape and r represent the recessive allele for square shape. Sponge - Bob is rr (homozygous recessive) and Sponge - Susie is Rr (heterozygous).

	R	r
r	Rr	rr

Step8: List genotypes and phenotypes for question 4A

A. G (Genotypes): Rr, rr. P (Phenotypes): Round, Square.

Step9: Calculate probabilities for question 4B and 4C

B. Chances of a child with a square shape (rr): 2 out of 4 or 50%.
C. Chances of a child with a round shape (Rr): 2 out of 4 or 50%.

Answer:

1.

• TT: Ho; Rb: Invalid; DD: Ho; Ff: He; tt: Ho; dd: Ho; Dd: He; rr: Ho; Tt: He; Bb: He; BB: Ho; FF: Ho
• A. TT, DD, tt, dd, rr, BB, FF
• B. Ff, Dd, Tt, Bb

2.

• YY: Yellow; Yy: Yellow; yy: Blue; RR: Round; Rr: Round; rr: Square

3.

• Tall: TT, Tt; Short: tt; Pink body: PP, Pp; Yellow body: pp

4.

• A. G: Rr, rr; P: Round, Square
• B. 2 out of 4 or 50%
• C. 2 out of 4 or 50%