Question

15 multiple choice 1 point
in a flower having multiple blooms on a stem is dominant to having a single stem. if you cross a two pure breeding flowers one with the recessive phenotype and one with the dominant phenotype, what ratio would describe genotypes the f2 generation?
1 homozygous dominant : 1 homozygous recessive : 1 heterozygous
0 homozygous dominant : 1 homozygous recessive : 3 heterozygous
1 homozygous dominant : 1 homozygous recessive : 2 heterozygous
16 multiple choice 1 point
if two parents with heterozygous blood types, one with type a blood and one with type b blood, have an offspring, what is the probability of the offspring having type o blood?
0%
25%
50%
75%

Explanation:

For Question 15:

Step1: Define parental genotypes

Let dominant allele = $D$, recessive allele = $d$. Pure breeding dominant: $DD$; pure breeding recessive: $dd$.

Step2: Find F1 generation genotype

Cross $DD \times dd$: All F1 offspring are $Dd$ (heterozygous).

Step3: Cross F1 to get F2

Cross $Dd \times Dd$. Punnett square gives genotypes: $DD$, $Dd$, $Dd$, $dd$.

Step4: Count genotype ratios

1 homozygous dominant ($DD$) : 1 homozygous recessive ($dd$) : 2 heterozygous ($Dd$)

Step1: Define parental genotypes

Heterozygous Type A: $I^A i$; heterozygous Type B: $I^B i$.

Step2: Set up Punnett square

Gametes from Type A: $I^A$, $i$; Gametes from Type B: $I^B$, $i$.
Offspring genotypes: $I^A I^B$, $I^A i$, $I^B i$, $ii$.

Step3: Calculate Type O probability

Type O = $ii$, which is 1 out of 4 possible genotypes. Probability = $\frac{1}{4} = 25\%$

Answer:

1 homozygous dominant : 1 homozygous recessive : 2 heterozygous

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For Question 16: