Unit 5: Chapter 13

Question 1

during meiosis, _____ _____ are paired

Answer 1

homologous chromosomes

one from maternal parent and one from paternal parent

Question 2

homologous chromatids exchange genetic material during what process

Answer 2

crossing over

Question 3

heredity

Answer 3

the transmission of traits from one generation to the next

Question 4

genetics

Answer 4

the scientific study of heredity and variation

Question 5

genes

Answer 5

segments of DNA

Question 6

gametes

Answer 6

sperm and egg cells

Question 7

asexual reproduction

Answer 7

one parent produces genetically identical offspring by mitosis (not meiosis)

Question 8

a haploid has how many chromosomes

Answer 8

23

Question 9

a diploid has how many chromosomes

Answer 9

46

Question 10

each human somatic cell has how many chromosomes arranged in pairs

Answer 10

46

Question 11

homologues

Answer 11

each set two chromosomes that pair up

one from each parent

each carries genes that control the same characteristics

Question 12

sister chromatids

Answer 12

two identical parts that make up one chromosome

Question 13

meiosis ensures that each gamete receives one complete ______

Answer 13

haploid set of chromosomes

Question 14

a cell with one set of chromosomes is called a

Answer 14

haploid

for humans, 23 chromosomes

gametes are haploid cells

Question 15

a cell with two set of chromosomes

Answer 15

diploid

humans: 46

somatic cells

Question 16

female homologous pair of chromosomes

Answer 16

XX

Question 17

males homologous pair of chromosomes

Answer 17

XY

Question 18

autosomes

Answer 18

the 22 pairs of chromosomes that don’t determine sex

Question 19

fertilization

Answer 19

the fusing of gametes

forms diploid

ultimately forms zygote

Question 20

similarity between meiosis and mitosis

Answer 20

both are preceded by the replication of chromosomes

Question 21

3 differences between meiosis and mitosis

Answer 21

during meiosis:

2 sets of cell divisions
4 daughter cells instead of 2
each daughter cell is a haploid

Question 22

four phases of meiosis 1

Answer 22

prophase 1
metaphase 1
anaphase 1
telophase 1

Question 23

what happens during meiosis 1

Answer 23

homologous chromosomes separate

results in two haploid daughter cells with replicated chromosomes

Question 24

what happens in meiosis 2

Answer 24

sister chromatids separate

results in four haploid daughter cells with nonreplicated chromosomes

Question 25

what happens during interphase (before meiosis 1)

Answer 25

chromosomes are replicated to form genetically identical sister chromatids this new chromosomes replicates, forming two centrosomes

Question 26

which stage of meiosis is the longest

Answer 26

prophase 1

Question 26

what happens during prophase 1

Answer 26

chromosomes condense each pair of chromosomes forms a tetrad, or a group of four chromatids synapsis and crossing over

Question 27

synapsis

Answer 27

during prophase 1 homologous chromosomes loosely pair up align gene by gene

Question 28

crossing over

Answer 28

prophase 1 nonsister chromatids exchange DNA segments

Question 29

metaphase 1

Answer 29

tetrads line up at the metaphase plate, with one chromosome facing each pole microtubules from both poles attach to the kinetochores of both chromosomes of each tetrad

Question 30

anaphase 1

Answer 30

pairs of homologous chromosome separate one chromosome moves towards each pole the sister chromatids remain attached at their centromere during this process

Question 31

telophase 1 and cytokinesis

Answer 31

animal cells: cleavage furrow forms plant cells: cell plate forms NO chromosome replication

Question 32

prophase 2

Answer 32

spindle apparatus forms chromosomes move towards metaphase plate

Question 33

metaphase 2

Answer 33

sister chromatids are arranged on metaphase plate no longer genetically identical kinetochores of sister chromatids attach to microtubules from opposite poles of cell

Question 34

anaphase 2

Answer 34

sister chromatids separate and move towards opposite poles

Question 35

telophase 2 and cytokinesis

Answer 35

chromosomes arrive at opposite poles nuclei form and chromosomes de-condense cytoplasm is separated by cytokinesis

Question 36

what is the result of meiosis?

Answer 36

4 daughter cells each has a haploid set of unreplicated chromosomes (because of crossing over)

Question 37

three mechanisms that contribute to genetic variation

Answer 37

independent assortment of chromosomes crossing over random fertilization

Question 38

independent assortment of chromosomes

Answer 38

homologous pairs of chromosomes are randomly oriented during metaphase 1 so any pair of chromosomes can be sorted into the daughter cells regardless of what happens to other pairs

Question 39

random fertilization

Answer 39

any sperm can fuse with any unfertilized egg