miosis

Question 1

heredity

Answer 1

the transmission of traits from one
generation to the next

Question 1

genetics

Answer 1

the scientific study of heredity and
variation

Question 2

how is variation demonstrated

Answer 2

demonstrated by the differences in
appearance that offspring show from parents and siblings

Question 3

genes

Answer 3

the units of heredity, and are made
up of segments of DNA

Question 4

gametes

Answer 4

sperm and egg

Question 5

locus

Answer 5

a specific location on a certain chromosome where a specific gene is located

Question 6

clone

Answer 6

a group of genetically identical
individuals from the same parent

Question 7

asexual reproduction

Answer 7

one parent produces genetically identical offspring by mitosis

Question 8

sexual reproduction

Answer 8

two parents give rise to offspring that have unique combinations of genes inherited from the two parents

Question 9

somatic cells

Answer 9

not gametes

Question 10

karyotype

Answer 10

an ordered display of the pairs of chromosomes from a cell

Question 11

homologous chromosomes/homologs

Answer 11

two chromosomes in a pair that are the same length and carry genes controlling the same inherited characters

Question 12

sex chromosomes

Answer 12

x and y

Question 13

autosomoes

Answer 13

the 22 pairs of chromosomes that do not determine sex

Question 14

diploid cell

Answer 14

a cell with two sets of chromosomes

Question 15

what does each replicated chromosome consists of

Answer 15

two identical sister chromatids

Question 16

haploid

Answer 16

a gamete (sperm or egg) contains a single set of chromosomes,

Question 17

meiosis

Answer 17

produces gametes

Question 17

fertilization

Answer 17

the union of gametes (the sperm and the egg)

Question 18

zygote

Answer 18

a fertilized egg

Question 19

what 2 cell divisions does meiosis take place in

Answer 19

meiosis 1 and 2

Question 20

meiosis 1

Answer 20

results in two haploid daughter cells
with replicated chromosomes; it is called the reductional division

Question 21

reductional division

Answer 21

results in two haploid daughter cells
with replicated chromosomes

Question 22

meiosis 2

Answer 22

results in four haploid daughter
cells with unreplicated chromosomes; it is called the equational division

Question 23

equational division

Answer 23

results in four haploid daughter cells with unreplicated chromosomes

Question 24

meiosis phases

Answer 24

- Prophase I – Metaphase I – Anaphase I – Telophase I and cytokinesis

Question 25

synapsis

Answer 25

homologous chromosomes loosely pair up, aligned gene by gene

Question 26

crossing over

Answer 26

nonsister chromatids exchange DNA segments

Question 26

chiasmata

Answer 26

X-shaped regions where crossing over occurred

Question 27

tetrad

Answer 27

what each pair of chromosomes forms (a group of 4 chromatides)

Question 28

metaphase 1

Answer 28

tetrads line up at the metaphase plate, with one chromosome facing each pole, microtubules from one pole are attached to the kinetochore of one chromosome of each tetrad microtubules from the other pole are attached to the kinetochore of the other chromosome

Question 29

anaphase 1

Answer 29

pairs of homologous chromosomes separate, one chromosome moves toward each pole guided by the spindle apparatus, sister chromatids remain attached at the centromere and move as one unit toward the pole

Question 30

Telophase I and Cytokinesis

Answer 30

in the beginning of telophase I, each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids, cytokinesis usually occurs simultaneously, forming two haploid daughter cells, in animal cells, a cleavage furrow forms; in plant cells, a cell plate forms, no chromosome replication occurs

Question 31

meiosis 2 phases

Answer 31

– Prophase II – Metaphase II – Anaphase II – Telophase II and cytokinesis

Question 32

prophase 2

Answer 32

a spindle apparatus forms, in late prophase II, chromosomes (each still composed of two chromatids) move toward the metaphase plate

Question 33

metaphase 2

Answer 33

the sister chromatids are arranged at the metaphase plate, because of crossing over in meiosis I, the two sister chromatids of each chromosome are no longer genetically identical, the kinetochores of sister chromatids attach to microtubules extending from opposite poles

Question 34

anaphase 2

Answer 34

the sister chromatids separate, the sister chromatids of each chromosome now move as two newly individual chromosomes toward opposite poles

Question 35

telophase 2 and cytokynesis

Answer 35

In telophase II, the chromosomes arrive at opposite poles, nuclei form, and the chromosomes begin decondensing, cytokinesis separates the cytoplasm, at the end of meiosis, there are four daughter cells, each with a haploid set of unreplicated chromosomes each daughter cell is genetically distinct from the others and from the parent cell

Question 36

cohesions

Answer 36

protein complexes that allows sister chromatids of a single chromosome to stay together through meiosis I

Question 37

three mechanisms contribute to genetic variation

Answer 37

- Independent assortment of chromosomes - Crossing over - Random fertilization

Question 38

when does crossing over begin

Answer 38

very early in prophase I, as homologous chromosomes pair up gene by gene

Question 38

recombinant chromosomes

Answer 38

are what crossing over produces, which combine genes inherited from each parent

Question 39

what does crossing over contribute to

Answer 39

genetic variation by combining DNA from two parents into a single chromosome