Chapter 6: Meiosis and Mendel

Question 1

somatic cells

Answer 1

also called body cells, make up most of your body tissues and organs

Question 2

gametes

Answer 2

sex cells – ova in the female, and spermatozoa in the male. Contain DNA which can be passed onto offspring

Question 3

homologous chromosomes

Answer 3

two chromosomes, one inherited from each parent, that have the same length, general appearance, and copies of the same genes

Question 4

autosomes

Answer 4

chromosome pairs 1 through 22, contain genes for characteristic not directly related to the sex of an organism

Question 5

sex chromosomes

Answer 5

directly control the development of sexual characteristics, in humans X and Y

Question 6

sexual reproduction

Answer 6

the fusion of two gametes that results in offspring which are a genetic mixture of both parents

Question 7

fertilization

Answer 7

the actual fusion of an egg and a sperm cell

Question 8

diploid (2n)

Answer 8

a cell which contains two copies of each chromosome; one from each parent

Question 9

haploid (n)

Answer 9

a cell which has only one copy of each chromosome

Question 10

meiosis

Answer 10

a form of nuclear division that divides a diploid cell into haploid cells

Question 11

gametogenesis

Answer 11

production of gametes through meiosis and other changes that produce a mature cell

Question 12

sperm

Answer 12

the male gamete

Question 13

egg

Answer 13

the female gamete

Question 14

polar bodies

Answer 14

the products of female meiosis besides the egg, which contain little more than DNA and are eventually broken down

Question 15

traits

Answer 15

distinguishing characteristics that are inherited

Question 16

genetics

Answer 16

study of biological inheritance patterns and variation in organisms

Question 17

purebred

Answer 17

a line of organisms which becomes genetically uniform

Question 18

cross

Answer 18

the mating of two organisms

Question 19

law of segregation

Answer 19

Mendel’s first law;
- organisms inherit two copies of each gene, one from each parent
- genes segregate during gamete formation, and organisms donate only one copy of each gene in their gametes

Question 20

gene

Answer 20

a piece of DNA which provides a set of instructions to a cell to make a certain protein

Question 21

allele

Answer 21

any of the alternative forms of a gene that may occur a specific locus

Question 22

homozygous

Answer 22

two of the same alleles at a specific locus

Question 23

heterozygous

Answer 23

two different alleles at a specific locus

Question 24

genome

Answer 24

all of an organism’s genetic material

Question 25

genotype

Answer 25

the genetic makeup of a specific set of genes

Question 26

phenotype

Answer 26

the physical characteristics of an individual organism

Question 27

dominant

Answer 27

the allele which is expressed when two different alleles or two dominant alleles are present

Question 28

recessive

Answer 28

allele that is only expressed when two copies are present

Question 29

Punnett square

Answer 29

a grid system for predicting all possible genotypes resulting from a cross

Question 30

monohybrid cross

Answer 30

crosses that examine the inheritance of only one specific trait

Question 31

test cross

Answer 31

a cross between an organism with an unknown genotype and an organism with the recessive phenotype

Question 32

dihybrid crosses

Answer 32

crosses that examine the inheritance of two different traits

Question 33

law of independent assortment

Answer 33

Mendel's second law; allele pairs separate independently of each other during gamete formation

Question 34

probability

Answer 34

the likelihood that a particular event will happen

Question 35

crossing over

Answer 35

exchange of chromosome segments between homologous chromosomes during prophase I of meiosis I

Question 36

genetic linkage

Answer 36

genes located close together tend to be inherited together