fundamentals of genetics chaptest_a

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Modern Biology 65 Chapter Test

Fundamentals of GeneticsComplete each statement by writing the correct term or phrase in the space provided.

1. When two members of the F1 generation are crossed, the offspring are

referred to as the generation.

2. Parents with genotypes Pp and pp can produce offspring of genotypes

and .

3. Crossing two pea plants heterozygous for flower color should produce a

phenotypic ratio of in the offspring.

4. Mendel allowed each variety of garden pea to -

for several generations. This ensured that each plant

in the P generation was - for

a particular trait.

5. The genotypic ratio expected when two Pp plants are crossed is

.

In the space provided, write the letter of the term or phrase that best completeseach statement or best answers each question.

______ 6. When two different alleles occur together, the one that is expressed iscalleda. dominant. c. recessive.b. phenotypic. d. superior.

______ 7. An organism that has inherited two of the same alleles of a gene fromits parents is for that trait.a. hereditary c. homozygousb. heterozygous d. a mutation

______ 8. The law of segregation states thata. alleles of a gene separate from each other during gamete formation.b. different alleles of a gene can never be found in the same organism.c. each gene of an organism ends up in a different gamete.d. each gene is found on a different molecule of DNA.

Name Class Date

Chapter Test AAssessment



Name Class Date

Fundamentals of Genetics, Chapter Test A continued

______ 9. The probability of a coin toss yielding heads isa. 0.25 b. 0.50 c. 1.00 d. 0.00

______10. The law of independent assortment applies only to genes that area. codominant.b. located on different chromosomes or are far apart on the same

chromosome.c. located on the same chromosome.d. dominant.

Refer to the figure below, which shows a cross between two rabbits, to answerquestions 11–14. In rabbits, black fur (B) is dominant over brown fur (b).

______11. The device illustrated above, which is used to organize genetic analysis, is called aa. Mendelian box. c. genetic graph.b. Punnett square. d. phenotypic paradox.

______12. The fur in both of the parents in the cross isa. black. c. homozygous dominant.b. brown. d. homozygous recessive.

______13. The phenotype of the offspring indicated by Box 3 would bea. brown.b. a mixture of brown and black.c. black.d. The phenotype cannot be determined.

______14. The genotypic ratio (BB : Bb) of the F1 generation would bea. 1:1. b. 3:1. c. 1:3. d. None of the above

______15. The first step in Mendel’s garden pea experiments was toa. remove the stamens of flowers on the plants.b. cross-pollinate two P generation plants with contrasting traits.c. allow each plant variety to self-pollinate for several generations.d. allow the F1 generation to self-pollinate.

______16. Which ratio of dominant to recessive phenotypes did Mendel find inhis F2 generation?a. 1:3 b. 3:1 c. 2:1 d. 4:1

Bb � Bb

1 2

43

B

B

b

b



Name Class Date

Fundamentals of Genetics, Chapter Test A continued

______17. When a cross between a red flower and a white flower yields pink offspring, the trait isa. dominant. c. incompletely dominant.b. recessive. d. codominant.

______18. Black fur is dominant over brown fur in rabbits. White and gray furexhibit incomplete dominance. How can you find out the genotype of a rabbit with black fur?a. Mate the black rabbit with a white rabbit.b. Mate the black rabbit with a another black rabbit.c. Mate the black rabbit with a gray rabbit.d. Mate the black rabbit with a brown rabbit.

In the space provided, write the letter of the description that best matches theterm or phrase.

______19. allele

______20. pollination

______21. trait

______22. genotype

______23. phenotype

Read each question, and write your answer in the space provided.

24. What approximate ratio of plants expressing contrasting traits did Mendelcalculate in his F2 generation of garden peas? What steps did he take tocalculate this ratio?

25. Describe Mendel’s two laws of heredity.

a. an organism’s genetic makeup

b. pollen grains are transferred to the stigma

c. an organism’s appearance

d. genetically determined variant of a characteristic

e. alternative form of a gene

23. In asexual reproduction, a single par-ent passes copies of all of its genes toeach of its offspring. In contrast, insexual reproduction, two parents eachform reproductive cells (gametes) thathave one-half the number of chromo-somes. These gametes join to form adiploid offspring.

24. Animal cells lack cell walls. In animalcells, the cytoplasm is divided when a cleavage furrow pinches the cell inhalf. In plant cells, the Golgi apparatusforms vesicles that fuse in a line alongthe center of the cell and form a cellplate. A new cell wall then forms oneach side of the cell plate.

25. Each chromosome is a single moleculeof DNA wrapped tightly around histones.The DNA-histone coils are coiled further to pack the DNA into a chromosome.

Cell ReproductionChapter Test B (Advanced)1. e 5. d2. g 6. b3. h 7. f4. a 8. c9. cell cycle

10. DNA synthesis11. interphase12. microtubules13. cancer14. copied15. b 20. b16. a 21. a17. c 22. c18. d 23. d19. c 24. c25. A prokaryote would have a circular

molecule of DNA attached to the innersurface of the plasma membrane. Aeukaryote would contain the followingstructures at some stage of cell division:nucleus, centrosome, mitotic spindle,kinetochore fibers, polar fibers, indi-vidual rod-shaped chromosomes,nucleolus, and other organelles.

26. Meiosis results in haploid cells. Thecells produced during meiosis differgenetically from the original cell.

27. Diagrams should include G1, S, G2, M(mitosis), and C (cytokinesis) phases.

28. Spermatogenesis yields four sper-matids. Oogenesis yields one egg celland three polar bodies.

29. Independent assortment is the randomseparation of the homologous chromo-somes. It results in genetic variation.

30. a. metaphase (3); b. cytokinesis (6); c. prophase (2); d. telophase (5); e. interphase (1); f. anaphase (4); g. mitosis; two diploid cells are produced

Fundamentals of GeneticsChapter Test A (General)1. F2

2. Pp and pp

3. 3:14. self-pollinate, true-breeding5. 1:2:16. a 15. c7. c 16. b8. a 17. c9. b 18. d

10. b 19. e11. b 20. b12. a 21. d13. c 22. a14. d 23. c24. Mendel calculated an approximate 3:1

ratio of contrasting traits. He derivedthis ratio by counting plants express-ing each type of trait he was compar-ing. Using division, he found that theratio of plants expressing the domi-nant trait to plants expressing therecessive trait was about 3:1.

25. The law of segregation states that thetwo factors for a trait are separatedduring the formation of gametes. Thelaw of independent assortment statesthat the factors for two different traitsseparate independently of one anotherduring the formation of gametes. Wenow know that this is true only whenthe genes for the two traits are locatedfar apart on the same chromosome oron separate chromosomes.


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