Question

1 for each genotype below, write whether it is homozygous dominant (hd), homozygous recessive (hr), or heterozygous (he).
rr ____ dd __ pp ____
bb ____ ss __ ee ____
ff ____ ee __ bb ____
2 for each genotype below, determine the phenotype.
curly hair is dominant, straight hair is recessive
hh ____________________
hh ____________________
hh ____________________
3 for each phenotype below, determine the genotype (hint: two letters)
being able to roll your tongue is dominant (r). not being able to roll your tongue is recessive (r).
______ can roll your tongue (homozygous)
______ can roll your tongue (heterozygous)
______ cannot roll your tongue

Explanation:

Problem 1: Classify Genotypes (HO, HR, HE)

• Homozygous Dominant (HO): Two identical dominant alleles (e.g., \( AA \)).
• Homozygous Recessive (HR): Two identical recessive alleles (e.g., \( aa \)).
• Heterozygous (HE): One dominant and one recessive allele (e.g., \( Aa \)).

Step 1: Analyze \( Rr \)

\( Rr \) has one dominant (\( R \)) and one recessive (\( r \)) allele → HE

Step 2: Analyze \( Dd \)

\( Dd \) has one dominant (\( D \)) and one recessive (\( d \)) allele → HE

Step 3: Analyze \( Pp \)

\( Pp \) has one dominant (\( P \)) and one recessive (\( p \)) allele → HE

Step 4: Analyze \( bb \)

\( bb \) has two identical recessive alleles → HR

Step 5: Analyze \( SS \)

\( SS \) has two identical dominant alleles → HO

Step 6: Analyze \( EE \)

\( EE \) has two identical dominant alleles → HO

Step 7: Analyze \( FF \)

\( FF \) has two identical dominant alleles → HO

Step 8: Analyze \( Ee \)

\( Ee \) has one dominant (\( E \)) and one recessive (\( e \)) allele → HE

Step 9: Analyze \( Bb \)

\( Bb \) has one dominant (\( B \)) and one recessive (\( b \)) allele → HE

Problem 2: Determine Phenotypes (Hair Type)

• Dominant allele (\( H \)) = Curly hair; Recessive allele (\( h \)) = Straight hair.
• \( HH \) (homozygous dominant) → Curly.
• \( Hh \) (heterozygous) → Curly (dominant allele expressed).
• \( hh \) (homozygous recessive) → Straight.

Problem 3: Determine Genotypes (Tongue Rolling)

• Dominant (\( R \)) = Can roll; Recessive (\( r \)) = Cannot roll.
• Homozygous dominant: Two identical dominant alleles → \( RR \).
• Heterozygous: One dominant, one recessive → \( Rr \).
• Homozygous recessive: Two identical recessive alleles → \( rr \).

Final Answers:

Problem 1:

\( Rr \): HE
\( Dd \): HE
\( Pp \): HE
\( bb \): HR
\( SS \): HO
\( EE \): HO
\( FF \): HO
\( Ee \): HE
\( Bb \): HE

Problem 2:

\( HH \): Curly hair
\( Hh \): Curly hair
\( hh \): Straight hair

Problem 3:

Can Roll (Homozygous): \( RR \)
Can Roll (Heterozygous): \( Rr \)
Cannot Roll: \( rr \)

Answer:

• Dominant (\( R \)) = Can roll; Recessive (\( r \)) = Cannot roll.
• Homozygous dominant: Two identical dominant alleles → \( RR \).
• Heterozygous: One dominant, one recessive → \( Rr \).
• Homozygous recessive: Two identical recessive alleles → \( rr \).

Final Answers:

Problem 1:

\( Rr \): HE
\( Dd \): HE
\( Pp \): HE
\( bb \): HR
\( SS \): HO
\( EE \): HO
\( FF \): HO
\( Ee \): HE
\( Bb \): HE

Problem 2:

\( HH \): Curly hair
\( Hh \): Curly hair
\( hh \): Straight hair

Problem 3:

Can Roll (Homozygous): \( RR \)
Can Roll (Heterozygous): \( Rr \)
Cannot Roll: \( rr \)