Chapter 14: Part 1

Question 1

Mendel used the scientific approach to identify

Answer 1

two laws of inheritance

Question 2

Mendel discovered two basic principles of heredity by breeding garden peas in carefully planned experiments

Answer 2

• Law of Segregation

- Law of Independent Assortment

Question 3

What Mendel called a “heritable factor”

Answer 3

is what we now call a gene

Question 4

Character

Answer 4

A heritable feature that varies among individuals (such as flower color) is called a

Question 5

Trait

Answer 5

Each variant for a character, such as purple or white color for flowers, is called a

Question 6

advantages of using peas

Answer 6

• Short generation time
• large numbers of offspring
• Mating could be controlled; plants could be allowed to self-pollinate or could be cross pollinated.

Question 7

true-breeding

Answer 7

plants that produce offspring of the same variety when they self- pollinate

Question 8

hybridization

Answer 8

Mendel mated two contrasting, true- breeding varieties

Question 9

P generation

Answer 9

true-breeding parents

Question 10

F1

generation

Answer 10

The hybrid offspring of the P generation

Question 11

F2 generation

Answer 11

When F1 individuals self-pollinate or cross- pollinate with other F1 hybrids, it produces F2

Question 12

When Mendel crossed contrasting, true-breeding white- and purple-flowered pea plants,

Answer 12

all of the F1 hybrids were purple

Question 13

When Mendel crossed the F1 hybrids, many of the F2 plants had purple flowers,

Answer 13

but some had white

Question 14

Mendel discovered a ratio of 3:1

Answer 14

purple to white flowers, in the F2 generation

Question 15

dominant trait

Answer 15

purple flower

Question 16

recessive trait

Answer 16

white flower

Question 17

The factor for white flowers was not diluted or destroyed

Answer 17

because it reappeared in the F2 generation

Question 18

First *alternative versions of genes

Answer 18

account for variations in inherited characters

Question 19

First* : Ex. the gene for flower color in pea plants exists in two versions,

Answer 19

one for purple flowers and the other for white flowers

Question 20

allele

Answer 20

alternative versions of a gene

Question 21

Alleles are simply variations in a

Answer 21

gene’s nucleotide sequence

Question 22

gene resides at a specific locus

Answer 22

on a specific chromosome

Question 23

• Second: for each character, an organism

Answer 23

inherits two alleles, one from each parent

Question 24

The two alleles at a particular locus may be identical,

Answer 24

as in the true-breeding plants of Mendel’s P generation

Question 25

he two alleles at a locus may differ

Answer 25

as in the F1 hybrids

Question 26

*Third: if the two alleles at a locus differ, then one (the dominant allele) determines the organism’s appearance, and

Answer 26

he other (the recessive allele) has no noticeable effect on appearance

Question 27

Third:

Answer 27

Ex., F1 plants had purple flowers because the allele for that trait is dominant

Question 28

*Fourth (the Law of Segregation): the two alleles for a heritable character separate (segregate) during

Answer 28

gamete formation and end up in different gametes

Question 29

Thus, an egg or a sperm gets only

Answer 29

1 of the 2 alleles that are present in the organism

Question 30

This segregation of alleles corresponds to the distribution of homologous chromosomes

Answer 30

to different gametes in meiosis

Question 31

So the Law of Segregation says the 2 alleles for

Answer 31

each gene

separate during gamete formation