Download Ch 6 Test C

Name ______________________________ Class __________________ Date ___________________
Heredity
Use the terms from the following list to complete the sentences below. Each term
may be used only once. Some terms may not be used.
heredity
traits
phenotype
genotype
haploid
gene
homologous
diploid
allele
1. In the second generation, recessive ______________________ reappear after
disappearing in the first generation.
2. The passing of traits from parents to offspring is called
______________________.
3. An organism’s appearance is its ______________________.
4. An organism’s inherited alleles together form its ______________________.
5. A cell, such as a sex cell, with only one set of unpaired chromosomes
is ______________________.
6. Chromosomes that carry the same set of genes, although they may have
different alleles, are ______________________ chromosomes.
UNDERSTANDING KEY IDEAS
Write the letter of the correct answer in the space provided.
_____ 7. How did Mendel ensure that the pea plants he studied would cross-pollinate and not self-pollinate?
a. He removed the seeds from one plant.
b. He removed the leaves from one plant.
c. He removed the flowers from one plant.
d. He removed the anthers from one plant.
_____ 8. Two forms of a gene, one from each parent, are called
a. alleles.
c. genotypes.
b. phenotypes.
d. genes.
_____ 9. The differences in the set of alleles that produce skin color in a population of corn snakes are called
a. organic difference.
c. genetic variation.
b. genetic variable.
d. organic variation.
Name ______________________________ Class __________________ Date ___________________
_____10. Some grasshoppers eat certain plants and consequently develop a yellow and black coloration because their genes are influenced by
a. their phenotype.
c. their external environment.
b. their mitochondria.
d. their internal environment.
_____11. If most human offspring receive 23 chromosomes from the mother,
how many chromosomes do they receive from the father?
a. 20
c. 46
b. 23
d. 78
12. Before Mendel performed experiments on heredity, what color did people
believe the offspring of a brown rabbit and white rabbit would be? Explain
why.
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13. Explain why Mendel used pea plants in his experiments on heredity.
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14. What happens to the genetic material from each parent before sexual reproduction can occur?
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CRITICAL THINKING
15. Describe what happens to homologous chromosomes when one diploid cell
becomes four haploid cells in the process of meiosis.
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Name ______________________________ Class __________________ Date ___________________
16. Assume that a single gene influences flower color and a single gene influences
seed color. What are the possible genotypes and phenotypes for flower color
and seed color in a cross between a plant that is true breeding for both
dominant purple flower color (P) and recessive yellow seed color (g) and a
plant that is true breeding for recessive white flower color (p) and dominant
green seed color (G)? What tool could be used to help determine these traits?
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INTERPRETING GRAPHICS
Use the Punnett square below to answer questions 17 and 18.
17. What is the function of
a Punnett square?
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18. The Punnett square shows a cross between a plant that is true breeding for
purple flowers and a plant that is true breeding for white flowers. What are the
phenotypes for this cross? Explain why.
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Name ______________________________ Class __________________ Date ___________________
CONCEPT MAPPING
19. Use the following terms to complete the concept map below:
trait
self-pollinate
first generation
dominant trait
cross-pollinate
true breeding
Name ______________________________ Class __________________ Date ___________________
Chapter Test C
1. traits
2. heredity
3. phenotype
4. genotype
5. haploid
6. homologous
7. D
8. A
9. C
10. D
11. B
12. Answers may vary. Sample answer: dark tan; Before Mendel performed his
experiments, people believed in blending inheritance, the idea that each trait of an
offspring is a mixture of traits of both parents.
13. Answers may vary. Sample answer: Mendel used pea plants in his experiments
because they grow quickly and there are many varieties; pea plants can self-pollinate,
so Mendel could grow true-breeding plants; and pea plants have a number of easy-topredict traits, such as flower color and seed shape.
14. Answers may vary. Sample answer: Before sexual reproduction occurs, the genetic
information from each chromosome is reduced by half in the process of meiosis.
15. Answers may vary. Sample answer: Diploid cells have homologous pairs of
chromosomes. Before meiosis, each chromosome of the homologous pair is copied.
The original chromosome and the copy, called a chromatid, join together. The pairs of
homologous chromosomes line up along the equator of the cell, and the homologous
pairs separate. The nucleus divides the first time. Each of the two cells contains one
member of the homologous chromosome pair. Then the chromatids separate, and the
two cells divide into four new haploid cells, each with half the number of
chromosomes present in the original cell.
16. If a single gene influences flower color and a single gene influences seed color, the
possible genotypes and phenotypes for this cross are: Pp, Pp, Pp, Pp, purple flowers
and Gg, Gg, Gg, Gg, green seeds. A Punnett square would be useful to help determine
these traits.
17. A Punnett square is used to predict the possible genotypes of offspring of a particular
cross.
18. All the offspring for this cross will have purple flowers. The dominant allele, written
as P, is for purple flowers, and only one dominant allele is needed to influence the
plant’s phenotype.
19. a. cross-pollinate, b. self-pollinate, c. first generation, d. true breeding, e. dominant
trait, f. trait