Chapter 14: Genetics

Question 1

What is a character?

Answer 1

The heritable feature that varies among individuals

Question 2

What is a trait?

Answer 2

Each variant for a character such as a color

Question 3

What is hydridization?

Answer 3

Two contrasting varieties that breed

Question 4

What is the p generation?

Answer 4

The true breeding parents

Question 5

What is the f1 generation?

Answer 5

The hybrid offspring of the p generation

Question 6

What are alleles?

Answer 6

The alternative versions of a gene

Question 7

How many alleles does an organism inherit?

Answer 7

2 from each parent

Question 8

What is the dominant allele?

Answer 8

Determines the organisms appearance

Question 9

What is the recessive allele?

Answer 9

The allele that has no noticeable appearance on organism

Question 10

What is the law of segregation?

Answer 10

The two alleles for a heritable character separate during gamete formation and end up in different gametes

Question 11

What are monohybrids?

Answer 11

Heterozygous for one character

Question 12

What is a mono hybrid cross?

Answer 12

A cross between heterozygous

Question 13

What is the law of independent assortment?

Answer 13

each pair of alleles segregates independently of each other pair of alleles during gamete formation

Question 14

What is complete dominance?

Answer 14

When phenotypes of the heterozygous and dominant homozygote are identical

Question 15

What is incomplete dominance?

Answer 15

When the phenotype of f1 hybrids is somewhere between the phenotypes of two parental varieties

Question 16

What is codominance?

Answer 16

Two dominant alleles affect the phenotype in separate ways

Question 17

What are carriers?

Answer 17

Heterozygous individuals who carry recessive alleles but are phenotypically normal

Question 18

What do we mean when we use the terms monohybrid cross and dihybrid cross?

Answer 18

A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.

Question 19

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

Answer 19

Traits are inherited in discrete units and are not the results of “blending.”

Question 20

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

Answer 20

8

Question 21

The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?

Answer 21

different possible assortment of chromosomes into gametes

Question 22

Mendel continued some of his experiments into the F2 or F3 generation to _____.

Answer 22

observe whether or not a recessive trait would reappear

Question 23

Which of the following statements about independent assortment and segregation is correct?

Answer 23

The law of independent assortment requires describing two or more genes relative to one another.

Question 24

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

Answer 24

HT

Question 25

Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that

Answer 25

traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1

Question 26

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?

Answer 26

All of the genes controlling the traits behaved as if they were on different chromosomes.

Question 27

Mendel’s observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

Answer 27

anaphase I of meiosis

Question 28

Mendel’s second law of independent assortment has its basis in which of the following events of meiosis I?

Answer 28

alignment of tetrads at the equator

Question 29

Why did the F1 offspring of Mendel’s classic pea cross always look like one of the two parental varieties?

Answer 29

One allele was dominant