20
Minutes
31
Questions
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Marking
Q1. 1. A pea plant with round and yellow seeds (RrYy) is crossed with a pea plant with wrinkled and green seeds (rryy). What percentage of the offspring are expected to be Round and Green?
50%
25%
75%
100%
Q2. 2. A couple has three daughters. What is the probability that their fourth child will also be a daughter?
25% (1/4)
50% (1/2)
75% (3/4)
0% (It must be a son)
Q3. 3. A tall pea plant (genotype unknown) is crossed with a short (tt) pea plant. The offspring are 50% tall and 50% short. What was the genotype of the unknown tall parent?
TT
Tt
tt
TT or Tt
Q4. 4. In Mendel's dihybrid cross (RrYy x RrYy), what fraction of the F2 generation is expected to be homozygous for both recessive traits (rryy)?
9/16
3/16
1/16
6/16
Q5. 5. The fact that alleles 'T' (tall) and 't' (short) separate during gamete formation, so that each gamete receives only one, is explained by:
Law of Dominance
Law of Independent Assortment
Law of Segregation
Law of Variation
Q6. 6. If a gene 'A' (e.g., for axial flowers) controls the production of a functional protein, and gene 'a' (e.g., for terminal flowers) produces a non-functional protein, why is the 'Aa' plant axial?
The 'a' allele is destroyed by the 'A' allele.
The 'A' allele produces enough functional protein to show the trait.
The 'a' allele changes the 'A' allele.
Both alleles mix to form an intermediate protein.
Q7. 7. In a monohybrid cross (Tt x Tt), 120 offspring are produced. Approximately how many of these are expected to have the heterozygous genotype?
30
90
120
60
Q8. 8. Which of the following gamete combinations can be produced by a plant with the genotype RrYy (Round, Yellow)?
RY, Ry, rY, ry
RY, ry only
Rr, Yy
RRYY, rryy
Q9. 9. In humans, the sex of the child is determined by:
The mother's genetic contribution (X or X).
The father's genetic contribution (X or Y).
The autosomes inherited from both parents.
The size of the ovum at fertilization.
Q10. 10. In a dihybrid cross, the appearance of new combinations in the F2 generation (e.g., round-green, wrinkled-yellow) that were not present in the parents is due to:
Law of Dominance
Law of Independent Assortment
Linkage of genes
Mutation
Q11. 11. A student conducts a cross (Tt x Tt) and gets 100 plants. 70 are tall and 30 are short. This result:
Proves the 3:1 ratio is incorrect.
Is very close to the expected 3:1 ratio; the difference is due to chance/probability.
Means the 'tall' parent must have been 'TT'.
Suggests that 'short' (t) is the dominant trait.
Q12. 12. If a tall plant (TT) is crossed with a short plant (tt), what will be the genotypic ratio in the F2 generation (after self-pollinating the F1)?
1 (TT) : 1 (tt)
3 (Tall) : 1 (Short)
1 (TT) : 2 (Tt) : 1 (tt)
All Tt (100%)
Q13. 13. A man with blood type A (genotype I^A i) marries a woman with blood type B (genotype I^B i). Which blood type is impossible for their child?
Blood Type AB
Blood Type O
Blood Type A
All are possible
Q14. 13. (Revised) 'T' (Tall) and 't' (short) are different forms of the same gene. They are called:
Homologs
Genotypes
Phenotypes
Alleles
Q15. 14. In a dihybrid cross (RrYy x RrYy), what is the phenotypic ratio of Round seeds (dominant) to Wrinkled seeds (recessive), ignoring the color trait?
9:3:3:1
1:1
1:02:01
3:1
...and 16 more challenging questions available in the interactive simulator.