Top 30 Genetics Quiz
Top 30 Genetics Quiz
Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms. Though heredity had been observed for millennia, Gregor Mendel, Moravian scientist and Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically.
1. Gregor Mendel used pea plants to study
- a. flowering.
- b. gamete formation.
- c. the inheritance of traits.
- d. cross-pollination.
Answer:- {C} the inheritance of traits.
2. Offspring that result from crosses between true-breeding parents with different traits
- a. are true-breeding.
- b. make up the F2 generation.
- c. make up the parental generation.
- d. are called hybrids.
Answer:- {D} are called hybrids.
3. The chemical factors that determine traits are called
- a. alleles.
- b. traits.
- c. genes.
- d. characters.
Answer:- {C} genes.
4. Gregor Mendel concluded that traits are
- a. not inherited by offspring.
- b. inherited through the passing of factors from parents to offspring.
- c. determined by dominant factors only.
- d. determined by recessive factors only.
Answer:- {B} inherited through the passing of factors from parents to offspring.
5. When Gregor Mendel crossed a tall plant with a short plant, the F1 plants inherited
- a. an allele for tallness from each parent.
- b. an allele for tallness from the tall parent and an allele for shortness from the short parent.
- c. an allele for shortness from each parent.
- d. an allele from only the tall parent.
Answer:- {B} an allele for tallness from the tall parent and an allele for shortness from the short parent.
6. The principle of dominance states that
- a. all alleles are dominant.
- b. all alleles are recessive.
- c. some alleles are dominant and others are recessive.
- d. alleles are neither dominant nor recessive.
Answer:- {C} some alleles are dominant and others are recessive.
7. When Gregor Mendel crossed true-breeding tall plants with true-breeding short plants, all the offspring were tall because
- a. the allele for tall plants is recessive.
- b. the allele for short plants is dominant.
- c. the allele for tall plants is dominant.
- d. they were true-breeding like their parents.
Answer:- {C} the allele for tall plants is dominant.
8. A tall plant is crossed with a short plant. If the tall F1 pea plants are allowed to self-pollinate,
- a. the offspring will be of medium height.
- b. all of the offspring will be tall.
- c. all of the offspring will be short.
- d. some of the offspring will be tall, and some will be short.
Answer:- {D}some of the offspring will be tall, and some will be short.
9. The principles of probability can be used to
- a. predict the traits of the offspring produced by genetic crosses.
- b. determine the actual outcomes of genetic crosses.
- c. predict the traits of the parents used in genetic crosses.
- d. decide which organisms are best to use in genetic crosses.
Answer:- {A} predict the traits of the offspring produced by genetic crosses.
10. In the P generation, a tall plant is crossed with a short plant. The probability that an F2 plant will be tall is
- a. 50%.
- b. 75%.
- c. 25%.
- d. 100%.
Answer:- {B} 75%.
11. Organisms that have two identical alleles for a particular trait are said to be
- a. hybrid.
- b. homozygous.
- c. heterozygous.
- d. dominant.
Answer:- {B} homozygous.
12. In the Punnett square shown in Figure 11-1, which of the following is true about the offspring resulting from the cross? (Tt x TT)
- a. About half are expected to be short.Tt, T T*TT=T TT Tt-T TT Tt
- b. All are expected to be short.
- c. About half are expected to be tall.
- d. All are expected to be tall.
Answer:- {D} All are expected to be tall.
13. The genotypic ratio of the offspring in Figure 11-1 is:
- a. 2TT:2Tt
- c. 1TT:2Tt:1tt
- b. 2tall:2short
- d. 3tall:1short
Answer:- {A} 2TT:2Tt
14. The phenotypic ratio of the offspring in Figure 11-1 is:
- a. 2TT:2Tt
- b. 2tall:2short
- c. 1TT:2Tt:1tt
- d. 4 tall
Answer:- {D} 4 tall
15. A Punnett square shows all of the following EXCEPT
- a. all possible results of a genetic cross.
- b. the genotypes of the offspring.
- c. the alleles in the gametes of each parent.
- d. the actual results of a genetic cross.
Answer:- {D} the actual results of a genetic cross.
16. If you made a Punnett square showing Gregor Mendel’s cross between true-breeding tall plants and true-breeding short plants, the square would show that the offspring had
- a. the genotype of one of the parents.
- b. a phenotype that was different from that of both parents.
- c. a genotype that was different from that of both parents.
- d. the genotype of both parents.
Answer:- {C} a genotype that was different from that of both parents.
17. What principle states that during gamete formation genes for different traits separate without influencing each other's inheritance?
- a. principle of dominance
- b. principle of independent assortment
- c. principle of probabilities
- d. principle of segregation
Answer:- {B} principle of independent assortment
18. How many different allele combinations would be found in the gametes produced by a pea plant whose genotype was RrYY?
- a. 2
- b. 4
- c. 8
- d. 16
Answer:- {A} 2
19. If a pea plant that is heterozygous for round, yellow peas (RrYy) is crossed with a pea plant that is homozygous for round peas but heterozygous for yellow peas (RRYy), how many different phenotypes are their offspring expected to show?
- a. 2
- b. 4
- c. 8
- d. 16
Answer:- {A} 2
20. Situations in which one allele for a gene is not completely dominant over another allele for that gene are called
- a. multiple alleles.
- b. incomplete dominance.
- c. polygenic inheritance.
- d. multiple genes.
Answer:- {B} incomplete dominance.
21. A cross of a red cow (RR) with a white bull (WW) produces all roan offspring (RRWW). This type of inheritance is known as
- a. incomplete dominance.
- b. polygenic inheritance.
- c. codominance.
- d. multiple alleles.
Answer:- {C} codominance.
22. The number of chromosomes in a gamete is represented by the symbol
- a. Z.
- b. X.
- c. N.
- d. Y.
Answer:- {C} N
23. If an organism’s diploid number is 12, its haploid number is
- a. 12.
- b. 6.
- c. 24.
- d. 3.
Answer:- {B} 6.
24. Gametes have
- a. homologous chromosomes.
- b. twice the number of chromosomes found in body cells.
- c. two sets of chromosomes.
- d. one allele for each gene.
Answer:- {D} one allele for each gene.
25. Gametes are produced by the process of
- a. mitosis.
- b. meiosis.
- c. crossing-over.
- d. replication.
Answer:- {B} meiosis.
26. What is shown in Figure 11-3? (Figure 11-16 in your book)
- a. independent assortment
- b. anaphase I of meiosis
- c. crossing-over
- d. Replication
Answer:- {C} crossing-over
27. Chromosomes from tetrads during
- a. prophase of meiosis I.
- b. metaphase of meiosis I.
- c. interphase.
- d. anaphase of meiosis II
Answer:- {A} prophase of meiosis I.
28. What happens between meiosis I and meiosis II that reduces the number of chromosomes?
- a. Crossing-over occurs.
- b. Metaphase occurs.
- c. Replication occurs twice.
- d. Replication does not occur.
Answer:- {D} Replication does not occur.
29. Unlike mitosis, meiosis results in the formation of
- a. diploid cells.
- b. haploid cells.
- c. 2N daughter cells.
- d. body cells.
Answer:- {B} haploid cells.
30. Unlike mitosis, meiosis results in the formation of
- a. two genetically identical cells.
- b. four genetically different cells.
- c. four genetically identical cells.
- d. two genetically different cells.
Answer:- {B} four genetically different cells.