Q: In a population, the frequency of allele $$A is$$ $$0.7$$ and the frequency of allele $$a is$$ $$0.3. $$According to Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes ($$Aa$$)?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Question 1

A dihybrid cross between two heterozygous pea plants (AaBb x AaBb) is performed. Assuming independent assortment and complete dominance, what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$9:3:3:1$$

Question 2

A woman with blood type O has a child with blood type O. Which of the following men could NOT be the father of the child?

Accepted Answer

A man with blood type AB

Question 3

In a testcross between a heterozygous tall pea plant (Tt) and a homozygous recessive dwarf plant (tt), what proportion of the offspring are expected to be tall?

Accepted Answer

$$0.5$$

Question 4

If two genes are linked and 20% of the gametes are recombinant, what is the map distance between the two genes?

Accepted Answer

$$20$$\ cM$

Question 5

A fruit fly with genotype $$w^+w ($$wild-type/red eyes) is crossed with a $$ww ($$white-eyed) fly. If the gene is X-linked and the female is heterozygous, what proportion of male offspring will have white eyes?

Accepted Answer

$$0.5$$

Question 6

A plant with genotype $$PpTt is $$self-fertilized. What is the probability that an offspring will be homozygous dominant for both traits?

Accepted Answer

$$\frac{1}{16}$$

Question 7

During meiosis I, homologous chromosomes separate. What is the ploidy of the resulting cells at the end of meiosis I in a diploid organism?

Accepted Answer

haploid

Question 8

A woman with genotype $$IAi ($$blood type A) and a man with genotype $$IBi ($$blood type B) have a child. What is the probability that the child will have blood type O?

Accepted Answer

$$0.25$$

Question 9

In a bacterial transformation experiment, DNA from a strain with genotype $$a^+b^- is $$added to a strain with genotype $$a^-b^+. If $$some progeny are $$a^+b^+$$, what process has occurred?

Accepted Answer

transformation

Question 10

A testcross is performed between a heterozygous fly for two genes (AaBb) and a homozygous recessive fly (aabb). If the genes are unlinked, what proportion of the offspring are expected to be double recessive (aabb)?

Accepted Answer

$$0.25$$

Question 11

A woman with an X-linked recessive disorder has children with a man who is unaffected. What is the probability that a son will be affected?

Accepted Answer

$$1.0$$

Question 12

In a pedigree, a trait appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

autosomal dominant

Question 13

A bacterial cell with the F+ phenotype can:

Accepted Answer

donate the F factor during conjugation

Question 14

If a gene is located 10 map units from the centromere and another gene is 30 map units away on the same chromosome, what is the expected recombination frequency between these two genes?

Accepted Answer

$$20\%$$

Question 15

A man with Klinefelter syndrome has which of the following karyotypes?

Accepted Answer

$$47,\ XXY$$

Question 16

A testcross is performed and the offspring phenotypes are: 259 hairless, 40 jointless, 391 jointless hairless, and 260 normal. Which of the following best describes the linkage arrangement of the two loci?

Accepted Answer

a. h/a; j/j

Question 17

Which of the following is a purine base found in DNA?

Accepted Answer

guanine

Question 18

In a population, the frequency of allele $$A is$$ $$0.7$$ and the frequency of allele $$a is$$ $$0.3. $$According to Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes ($$Aa$$)?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 19

A woman with genotype $$X^NX^n ($$carrier for an X-linked recessive disorder) and a man with genotype $$X^nY$$ have a child. What is the probability that a daughter will be affected?

Accepted Answer

$$0.25$$

Question 20

Which of the following statements about DNA replication is correct?

Accepted Answer

DNA strands are antiparallel

Genetics Study Guide: Mendelian Inheritance, Chromosome Theory, and Genetic Mapping

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