Bio Ch 10

Question 1

Meiosis

Answer 1

type of nuclear division that reduces the chromosome number from the diploid (2n) number to the haploid (n) number

Question 2

Diploid (2n) number

Answer 2

total number of chromosomes, which exists in 2 sets

Question 3

Haploid (n) number

Answer 3

half the diploid number, or a single set of chromosomes

Question 4

Gametes

Answer 4

reproductive cells (often the sperm and egg); usually have the haploid number of chromosomes

Question 5

Sexual reproduction

Answer 5

haploid gametes are produced during meiosis that subsequently merge into a diploid cell called a zygote

Question 6

Zygote

Answer 6

diploid cell formed by the union of 2 gametes; the product of fertilization

Question 7

Homologous chromosomes (homologues)

Answer 7

member of a pair of chromosomes that are alike and come together during synapsis during prophase of the first meiotic division

Question 8

Alleles

Answer 8

alternate forms of a gene

Question 9

Synaptonemal Complex

Answer 9

homologous chromosomes come together and line up side by side

Question 10

Synapsis

Answer 10

Process of forming synaptonemal complex

Question 11

Bivalent (tetrad)

Answer 11

2 homologous chromosomes that stay in close association during the 1st two phases of meiosis I; contains 4 chromatids

Question 12

Crossing-over

Answer 12

exchange of genetic material between non-sister chromatids of a bivalent during meiosis I

Question 13

Genetic recombination

Answer 13

process in which chromosomes are broken and rejoined to form novel combinations; in this way offspring receive alleles in combinations different from their parents

Question 14

Independent assortment

Answer 14

the homologous chromosome pairs separate independently (in a random manner)

Question 15

Fertilization

Answer 15

union of the male and female gametes

Question 16

Interkinesis

Answer 16

short rest period prior to beginning the second nuclear division (meiosis II); DNA replication does NOT occur because the chromosomes are already duplicated

Question 17

Spores

Answer 17

reproductive cells that develop into new multicellular structures without the need to fuse with another reproductive cell

Question 18

Alternation of generations

Answer 18

life cycle, typical of land plants, in which a diploid sporophyte alternates with a haploid gametophyte

Question 19

Life cycle

Answer 19

all the reproductive events that occur from one generation to the next similar generation

Question 20

Gametophyte

Answer 20

haploid generation

Question 21

Sporophyte

Answer 21

diploid generation

Question 22

Gametogenesis

Answer 22

production of gametes

Question 23

Spermatogenesis

Answer 23

in males, meiosis is a part of this, which occurs in the testes and produces sperm

Question 24

Oogenesis

Answer 24

in females, meiosis is a part of this, which occurs in the ovaries and produces eggs

Question 25

Secondary oocyte

Answer 25

in oogenesis, the functional product of meiosis I; becomes the egg

Question 26

Polar body

Answer 26

nonfunctional product of oogenesis produced by the unequal division of cytoplasm in females during meiosis; in humans 3 of the 4 cells produced by meiosis are polar bodies

Question 27

Nondisjunction

Answer 27

failure of chromosomes to separate; results in gain or loss of chromosomes

Question 28

Euploidy

Answer 28

the correct number of chromosomes in a species

Question 29

Aneuploidy

Answer 29

a change in the chromosome number resulting from nondisjunction during meiosis; seen in plants & animals; monosomy & trisomy are 2 aneuploid states

Question 30

Monosomy (2n - 1)

Answer 30

occurs when an individual has only one of a particular type of chromosome when they should have two

Question 31

Trisomy (2n + 1)

Answer 31

occurs when an individual has 3 of a particular type of chromosome when they should have two

Question 32

Karyotype

Answer 32

a visual display of the chromosomes arranged by size, shape, and banding pattern; may be performed to identify babies with Down syndrome and other aneuploid conditions

Question 33

Barr body

Answer 33

any additional X chromosomes become an inactive mass called this; provides a natural method for gene dosage compensation of the sex chromosomes and explains why extra sex chromosomes are more easily tolerated than extra autosomes

Question 34

Deletion

Answer 34

occurs when an end of a chromosome breaks off or when two simultaneous breaks lead to the loss of an internal segment

Question 35

Duplication

Answer 35

presence of a chromosomal segment more than once in the same chromosome

Question 36

Inversion

Answer 36

occurs when a segment of a chromosome is turned around 180 degrees

Question 37

Translocation

Answer 37

movement of a chromosome segment from one chromosome to another, nonhomologous chromosome