D2.1 - Cell & Nuclear Division

Question 1

new cells are needed for …

Answer 1

growth, repair, reproduction

Question 2

cytokinesis

Answer 2

division of cytoplasm of cell to form two daughter cells

Question 3

cytokinesis in animals

Answer 3

cleavage furrow
contractile rings made of actic & myosin
pinch apart

Question 4

cytokinesis in plants

Answer 4

vesicles form in center to create new membrane
microtubule scaffold
each cell builds new cell wall

Question 5

equal cytokinesis

Answer 5

parent cell equally divides into 2 daughter cells

Question 6

unequal cytokinesis

Answer 6

possible as long as new cell receives nucleus and mitochondria

Question 7

ex of unequal cytokinesis

Answer 7

yeast budding & oogenesis

Question 8

budding in yeast

Answer 8

asexual reproduction
nucleus eplicates & divides
new cell wall to separate

Question 9

oogenesis

Answer 9

egg cell production
meiosis has 2 cell divisions
produces one viable oocyte
3 polar bodies

Question 10

role of mitosis and meiosis in eukaryotes

Answer 10

cells must replicate the nucleus before division to prevent unnucleated cells

Question 11

unnucleated cells cannot …

Answer 11

synthesize proteins

Question 12

role of mitosis

Answer 12

produces 2 identical daughter cells = diploid
all cells have identical copy of genome

Question 13

role of meiosis

Answer 13

produces 4 genetically unique cells = haploid
half of chromosomes needed for gamete
random assortment of genes

Question 14

prerequisite for mitosis & meiosis

Answer 14

DNA replication

Question 15

chromosome

Answer 15

structures that consist of 2 identical chromosomes held together by cohesin loops

Question 16

what happens to DNA prior to cell division

Answer 16

dna is elongated, replicated and condensed into chromosomes

Question 17

supercoiling

Answer 17

dna wrapped around histone proeins, which then link together

Question 18

process of condensation and moement of chromosomes

Answer 18

cytoskeleton microtubules disassembled to form spindle

spindle microtubules link with kinetechore on cetromere

kinetochore act as microtubule motor

remove microtubule, shorten spindle, move chomatids apart

Question 19

phases of mitosis

Answer 19

PMAT
prophase
metaphase
anaphase
telophase

Question 20

what happens prior to mitosis

Answer 20

interphase

Question 21

interphase process

Answer 21

DNA in chromatid form
growth, normal cell function
synthesis (replication) of DNA

Question 22

prophase process

Answer 22

chromosomes condense
spindle microtubule assemble
nuclear membrane dissolves

Question 23

metaphase process

Answer 23

microtubules attach to centromere
chromosomes align in center

Question 24

anaphase process

Answer 24

cohesin loops are cut
tension from spindles pull
chromosomes move towards pole
separation

Question 25

telophase

Answer 25

new membrane forms chromosomes decondense back to chromatin happens same time as cytokinesis

Question 26

homologous chromosomes

Answer 26

diploid 2n cells one from each parent same genes in same location different alleles

Question 27

diploid cells

Answer 27

2n, come in pairs produced by mitosis ex: stomata cells

Question 28

haploid cells

Answer 28

n, not in pairs produced by meiosis gamete cells

Question 29

gametes are produced by ...

Answer 29

meiosis

Question 30

process of gamete production due to meiosis

Answer 30

chromosome number reduced by half dna replicated 2 cell divisions

Question 31

phases of meiosis

Answer 31

meiosis 1 prophase 1 metaphase 1 anaphase 1 telophase 1 meiosis 2 prophase 2 metaphase 2 anaphase 2 telophase 2

Question 32

anaphase 1 vs anaphase 2 in meiosis

Answer 32

anaphase 1: homologous chromosomes split anaphase 2: sister chromatids split

Question 33

product of meiosis

Answer 33

4 haploid daughter cells

Question 34

nondisjunction def

Answer 34

failure of chromosomes to separate

Question 35

result of disjunction

Answer 35

gametes with too many or too few chromosomes results in cell death

Question 36

down syndrome cause

Answer 36

trisomy 21, 3 copies of 21st chromosome

Question 37

meiosis impact on genetics

Answer 37

source of variation due to production of unique haploid daughter cells

Question 38

bivalent

Answer 38

pair of homologous chromosomes

Question 39

synapsis in meiosis

Answer 39

formation of bivalent

Question 40

chiasma

Answer 40

point of crossing over between homologous chromosomes

Question 41

crossing over in meiosis

Answer 41

exchange of alleles between nonsiter chromatids of homologous chromosomes

Question 42

random orientation

Answer 42

alignment of chromosomes is random (metaphase 1&2) different alignments will pproduce different combinations of alleles

Question 43

steps of meiosis

Answer 43

dna replication --> meiosis 1 --> sytokinesis --> meiosis 2 --> cytokinesis

Question 44

when does crossing over of bivalent homologous chromosomes occur

Answer 44

meoisis 1, prophase 1 Does NOT occur in meiosis 2

Question 45

meiosis 1 steps

Answer 45

prophase 1: crossing over metaphase 1: homologous pairs align at equator anaphase 1: separation of homologous chromosomes telophase 1: ends w 2 haploid cells

Question 46

meoisis 2 steps

Answer 46

prophase 2: similar to mitosis, no crossing over metaphase 2: sister chromatids align at equator anaphase 2: separation of sister chromatids telophase 2: ends w 4 haploid cells

Question 47

why is mitosis important

Answer 47

for growth, repair damaged cells tissue

Question 48

a chemical colchine disrupts formation of microtubules, discuss influence of mitosis

Answer 48

lack of microtubule formulation disrupts metaphase, preventing attachment of microtubule to centromere, prohibits occurence of anaphase, homologous pairs will not separate

Question 49

parent cell has 24 chromosomes, how many chromatids does it have

Answer 49

47

Question 50

compare cytokinesis b/w animal and plant cells

Answer 50

animals: contractile rings made of actic & myosin form cleavage furrow and pinch apart plants: versicles form in center to create cell wall, microtubule scaffold separates cells