EOCT practice Domain III: Genetics

1. What is the diploid chromosome number in a human

body cell?

A. 23

B. 32

C. 44

D. 46

2. The gene for red/green colorblindness in humans is recessive and primarily affects males. It must be

located onA. the X chromosome

B. the Y chromosome

C. both the X and Y chromosomes

D. either the X or Y chromosome

3. Which of the following shows how information is transformed

to make a protein?

A. DNA → RNA → protein

B. gene → chromosome → protein

C. cell respiration → ATP → protein

D. ATP → amino acid → protein

4. The genetic disorder trisomy 21 (Down syndrome) is caused

by what genetic event?

A. crossing-over

B. nondisjunction

C. base pair substitution

D. frame-shift location

5. Pea plants have seeds that are either round or wrinkled. In this cross RR x Rr, what will be the phenotypic ratio of the

offspring?

A. 50% RR and 50% Rr

B. 25% RR, 50% Rr, and 25% rr

C. 50% round seeds and 50% wrinkled seeds

D. 100% round seeds

R = Round Seedsr = Wrinkled Seeds

6. The process by which the order of bases in messenger RNA (mRNA)

codes for the order of amino acids in a protein is called

A. translation

B. transcription

C. replication

D. nondisjunction

7. A gene that is sex-linked is BEST described as which of the

following?

A. It results in all male offspring.

B. It results in all female offspring.

C. It is located on the X chromosome.

D. It is located inside the mitochondria.

8. Which of the following correctly shows the shape of

a DNA molecule?

9. The observed trait that appears in an organism as a result of its genetic

makeup is called the organism’sA. allele

B. genotype

C. phenotype

D. karyotype

10. Why is it important for the cells of multicellular organisms

to undergo mitosis?

A. Mitosis allows for reproduction with male and female gametes.

B. Mitosis increases variation within an organism.

C. Mitosis produces cells that are different from the original dividing cell.

D. Mitosis produces identical cells to the original dividing cell.

11. Which of the following correctly lists the phases of the cell cycle

starting with interphase?

A. 4, 1, 2, 3, 6, 5

B. 4, 6, 1, 5, 2, 3

C. 4, 1, 6, 3, 5, 2

D. 4, 1, 5, 6, 3, 2

12. How many chromosomes are contained in a human male

gamete cell?

A. 11

B. 23

C. 34

D. 46

13. The genetic code in DNA is represented by unique codons that

represent a specific amino acid. Which of the following represents a codon?

A. G

B. TA

C. GCGC

D. CAU

14. The cell shown below is undergoing mitosis. The daughter chromosomes are moving toward opposite poles of the cell.

Which phase of mitosis is shown to the right?A. anaphase

B. metaphase

C. prophase

D. telophase

15. Two organisms, each with genotype AaBb, are crossed. The

expected phenotypic ratio in the F1 generation is expected to be

A. 4:4:4:4

B. 7:6:2:1

C. 8:4:2:2

D. 9:3:3:1

16. In rabbits, albinism (b) is recessive to normal brown coloration (B). When an albino female was

crossed with a brown male, they produced 4 brown offspring and 1 albino. What was the genotype of the

male parent?

A. bb only

B. Bb only

C. BB only

D. BB or Bb

17. In protein synthesis, translation is the process that

directly results in the

A. production of amino acid chains

B. manufacture of mRNA

C. copying of one DNA molecule into two molecules

D. movement of protein from one cell to another

18. Information on mRNA is used to make a sequence of amino

acids into a protein by which of the following processes?

A. replication

B. translation

C. Transcription

D. transference

19. What is a source of genetic variation?

A. mutation

B. adaptation

C. replication

D. transcription

20. ATG is a DNA triplet that codes for an amino acid. Which mRNA

codon will pair with the ATG triplet?

A. ATG

B. GTU

C. TAC

D. UAC

21. Which of the following is the correct base-pairing rule for DNA?

A. A-U; C-G

B. A-G; T-C

C. A-T; G-C

D. A-C; T-G

22. A mutagenic factor that can alter DNA by the loss of a chromosome

segment is known as

A. translocation

B. crossing over

C. deletion

D. nondisjunction

23. In Mendel’s experiments with a single trait, the trait that disappeared in the first

generation and reappeared in the next generation is called the

A. homozygous trait

B. dominant trait

C. recessive trait

D. heterozygous trait

24. Changes to an organism’s DNA can cause unexpected traits to be expressed in its offspring. DNA in an individual’s gametes will most likely be

altered before being passed to offspring if exposed to

A. x-rays

B. loud sounds

C. magnetic fields

D. extreme temperatures

25. Agricultural companies have developed the ability to control the genetic characteristics of their crops. Genetic engineering techniques have been

used to produce all of the following effects EXCEPT

A. grow salt-tolerant crop plants

B. decrease harvesting time

C. make crop plants resistant to disease

D. decrease soil nitrogen levels

Answers 21-25

A. C

B. C

C. C

D. A

E. D

26. In fruit flies, the gray body color (G) is dominant to the ebony body color (g). What is the genotypic ratio of the offspring of a cross between a heterozygous gray female and an

ebony male?

A. 25% Gg, 75% ggB. 50% Gg, 50% ggC. 75% gray, 25% ebonyD. 100% gray

27. The process of meiosis produces gametes. How does this process increase reproductive variability?

A. Different combinations of alleles are produced.

B. Each allele from the parent cell forms a separate gamete.

C. Each pair of genes undergoes crossing-over with different genes.

D. The two genes are passed on to a daughter cell, resulting in new traits.

28. DNA and RNA are nucleic acids. A characteristic of RNA is

that it

A. remains in the chromosomes in the nucleus

B. is involved in translating information in DNA into proteins

C. undergoes crossing-over during meiosis

D. is replicated during the process of mitosis

Answers 1-5

A. D

B. A

C. A

D. B

E. D

Answers 6-10

A. A

B. C

C. D

D. C

E. D

Answers 11-15

A. C

B. B

C. D

D. A

E. D

Answers 16-20

A. B

B. A

C. B

D. A

E. D

Answers 26-28

A. B

B. A

C. B