mitosis/meiosis

Question 1

prokaryotes divide by

Answer 1

binary fission

Question 2

what do chromosomes look like in bacteria?

Answer 2

single circular chromosome

Question 3

how do bacteria replicate their DNA?

Answer 3

from ORI sequence- create double strand- form septum, pinch in, voila! 2 daughter cells

Question 4

eukaryotes have what kind of chromosomes (shape)

Answer 4

linear

Question 5

unlike bacteria, chromosomes exist in ___ pairs

Answer 5

homologous

Question 6

definition mitosis

Answer 6

chromosomal process that ensures each daughter cell gets exact, correct copy of genetic information

Question 7

at what phase of mitosis do chromosomes become visible in light microscope

Answer 7

prophase

Question 8

define DNA packing

Answer 8

Positively charged Histone proteins neutralize the negative charge on DNA

Question 9

what is the beads on a string model?

Answer 9

Octamers of histone “core” proteins (nucleosomes) wrap DNA around themselves, giving it the appearance of “beads on a string”

Question 10

when would you see the most condensed form of DNA

Answer 10

metaphase, on sister chromatids

Question 11

what does 30 mm fiber refer to

Answer 11

the arrangement of packed nucleosomes and DNA

Question 12

when would distinct chromosomes be visible

Answer 12

M phase of mitosis

Question 13

4 phases of cell cycle

Answer 13

G1, G2 S, M,

Question 14

what phase are non dividing cells in? can you give an example?

Answer 14

G0. liver cell

Question 15

Interphase is what 3 phases

Answer 15

G1 + G2 + S

Question 16

G1

Answer 16

rapid growth and metabolic activity of mitosis

Question 17

G2

Answer 17

growth and preparation for cell division

Question 18

S phase

Answer 18

DNA replication and growth

Question 19

what kind of phase are neurons always in?

Answer 19

G0 - nondividing

Question 20

what significant event happens in S phase?

Answer 20

synthesis of DNA

Question 21

describe a replication fork and when you’d find it

Answer 21

in S phase, as you replicate DNA, you go from single strand -> double strand. as this is happening, bidirectionally, you get a replication bubble and fork

Question 22

Kinetochore

Answer 22

Kinetochore structures (made of proteins) are the attachment sites for microtubules at the centromere regions

Question 23

telomeres

Answer 23

ends of chromatids/chromosomes

Question 24

what do you call DNA in the replicated form

Answer 24

‘sister chromatids’

Question 25

how do you identify chromosomes for a karyotype?

Answer 25

based on their band patterns, gleaned from electrophoresis. line up from largest-\>smallest

Question 26

name for non-sex cells

Answer 26

somatic cells

Question 27

what phase of mitosis is essentially a reverse of prophase

Answer 27

telophase- rebuild nuclear envelope, recondense

Question 28

when would DNA convert back to regular old chromatin?

Answer 28

after cytokinesis

Question 29

what does the nucleus do in interphase?

Answer 29

1. Ribosomal RNA being copied from RNA into DNA form to assemble a ribosome

Question 30

what happens in interphase nucleus that would affect the chromatin?

Answer 30

ex- inactive B cell (in lymphocyte) and it has a lot of heterochromatin. After it is activated to participate in immune response, the gene pattern changes and now we have a lot of euchromatin instead of heterochromatin

Question 31

\_\_\_ are the intermediate filaments that support the inside of nuclear envelope

Answer 31

nuclear lamins

Question 32

\_\_ chromosomes are in each cell during mitosis

Answer 32

46

Question 33

kinetochore complex

Answer 33

centrosome + microtubule site of attachment

Question 34

what's the pac-man complex?

Answer 34

to move the chromosome towards the poles for anaphase, the kinetochore complex 'eats' the microtubules- aka depolymerizes the tubulin in the microtubules

Question 35

aster fibers and who has them

Answer 35

1. only animals have aster fibers 2. they are a type of mitotic spindle that are unattached microtubules hanging off the centriole

Question 36

do plant cells have centrioles?

Answer 36

no

Question 37

kinetochore microtubules

Answer 37

mitotic spindle running 'pole to kinetochore'. found in both plant and animal cells

Question 38

polar microtubules

Answer 38

mitotic spindle running pole to pole. found in both plants and animals

Question 39

what proteins perform the cleavage taking telephase to cytokinesis?

Answer 39

actin filaments + myosin motors act to contract the cleavage furrow until the cell pinches off

Question 40

reduction divsiion

Answer 40

stage of meiosis I , anaphase I, where the pairs of chromosomes separate (3 replicated chromes on each side of cell) centromeres have NOT split. this is the stage where the cell finally goes from 46-\> 23 chromosomes

Question 41

in anaphase II, how many chromosomes are at each pole

Answer 41

23

Question 42

when does synapse occur?

Answer 42

meiosis : in prophase I- line up with homologous chromosomes, crossing over occurs @ chiasmata

Question 43

what are the 2 parts of anaphase

Answer 43

anaphase A: chromosomes pulled poleward anaphase B: poles pulled apart

Question 44

when in mitosis does gene activity resume?

Answer 44

telophase

Question 45

when in mitosis does nucleolus reappear?

Answer 45

telophase

Question 46

phragmoplast

Answer 46

1. instead of pinching in, plants create a cell plate in the middle of cell 1. grouping of small vesicles produced in the golgi that move along microtubules to the middle of cell 2. new golgi/ER complex in replicating plant cell is the phragmoplast

Question 47

when you enter prophase I of meiosis, are chromosomes already replicated?

Answer 47

yes

Question 48

when in meiosis does crossing over occur

Answer 48

prophase I

Question 49

what event precludes crossing over

Answer 49

synapse

Question 50

The Thompson seedless grape is triploid, with three copies of each chromosome. Which phase of the cell cycle would you expect triploid cells to be unable to complete.

Answer 50

homologous chromosomes must pair in meiosis I. Triploid cells would be unable to complete meiosis I.

Question 51

The stage of meiosis where cells become haploid

Answer 51

Separation of homologous pairs occurs at anaphase I. Even though each chromosome has two chromatids, the total number of chromosomes is 23 for humans after anaphase I of meiosis I. Recall that the number of chromosomes is determined by the number of centromeres

Question 52

name the 3 mitotic spindle fibers

Answer 52

1. aster fibers 2. pole to pole fibers 3. pole to kinetochore fibers

Question 53

telocentric

Answer 53

centromere hangs out at end of chromosome

Question 54

name for when centromere is in middle of chromosome

Answer 54

metacentric

Question 55

name for when centromere is at top of chromosome

Answer 55

acrocentric

Question 56

when would gene expression happen

Answer 56

interphase

Question 57

of centrioles present in metaphase

Answer 57

4; 2 at each end (count each guy as its own!)

Question 58

number of chromosomes/chromatids present at metaphase 2

Answer 58

chromosomes: n chromatids: 2n

Question 59

chromosomes / chromatids: anaphase 2

Answer 59

46, 46

Question 60

chromosomes/chromatids: metaphase I

Answer 60

2n, 4n

Question 61

chromosomes/chromatids: prophase I

Answer 61

2n, 4n

Question 62

chromosomes/chromatids prophase II

Answer 62

n, 2n

Question 63

mitosis: # chromosomes/chromatids in metaphase

Answer 63

2n, 4n

Question 64

how does division in binary fission work

Answer 64

•split in two between plasma membrane attachment sites (involves forming a septum and pinching-in)

Question 65

specific structure to which microtubules attach

Answer 65

kinetochore

Question 66

test cross (who vs who?)

Answer 66

SsYy x ssyy

Question 67

amount dna division versus prophase

Answer 67

1:2 (you get sister chromatids in prophase, 2x the DNA!)

Question 68

how many chromatids are present in anaphase?

Answer 68

0. they are all replicated, no single chromatids