Lecture 2

Question 0

meiosis

Answer 0

crossing over and independnt assortment and fertilization

Question 1

2 ways to get genetic variagtion

Answer 1

mutaion and sexual reproduction… mutation only way to get new information

Question 2

the production of haploid gametes

Answer 2

meiosis

Question 3

the fuiosn of haploid gametes

Answer 3

fertilization

Question 4

consequences of meiossi

Answer 4

genetic variation

Question 5

interphase

Answer 5

DNA synthesis and chromosomes replication phase

Question 6

seperation of homologous chromosome pairs, and reduction of the chromosome number by half

Answer 6

meiosis 1

Question 7

seperation of sister chromatids, also known as equational division

Answer 7

meiosis II

Question 8

major results of meiosis

Answer 8

increase in cell numbers sometimes, duaghter cells are not genetically identical, daugther cells are haploid, formation of gametes… compare to mitosis

Question 9

gametognesis

Answer 9

spermatogensis. oogenesis… produces sperm and eggs

Question 10

synapsis

Answer 10

pairing of homologous chromosmes

Question 11

crossing over

Answer 11

in meiosis

Question 12

meiosis requires

Answer 12

two consectutive cell divisions but only one cycle of DNA replication

Question 13

crossing over

Answer 13

1. once chromosome possesses the A and B allele
2. and the homologous chromosomes possesses the a and b allele
   DNA SYNTHESIS
3. DNA replication in the S phase produces identical sister chromatids
   CROSSING OVER
4. During crossing over in prophase I, segments of nonsister chromatids are exchanged.
   MEIOSIS I AND II
5. after meiosis I and II, each of the resulting cells carries a unique combination of alleles

Question 14

produces variation without crossing over

Answer 14

independent assortment… needs more than on pair of chromsomes… line up as homologous pairs in varies ways.

Question 15

reduction divison

Answer 15

meiosis I…. Diploid to haploid

Question 16

equational division

Answer 16

Meiosis II… haploid

Question 17

prophase I

Answer 17

Leptotne
zygotene
pachytene... synaptonemal complex
diplotene.. bivalent or tetrad, chiasmata
diakinesis

Question 18

leptotene

Answer 18

exteneded state, microscopically can’t be discerned as indviduals… thread like, very thin, each chormosome still two chromatids(replication has already occured)… start to condense…

Question 19

zygotene

Answer 19

start ot pair up, homologous chromsomses pair(synapsis).. synaptonemal complex forms, results in bivalents(tetrads)

Question 20

pachytene

Answer 20

thick… starting to condense.. shorter and thicker… crossing over begins

Question 21

synaptonemal complex

Answer 21

later like structure btw to chromosomes… alignment mechanims… if this does not work correctly duplicaiton and deletion occurs… equal crossing overs.

Question 22

diplotene

Answer 22

start to see tetrads(bivalents)

seee cross over points, chiasmata(pt where crossover occurs) are well defined

Question 23

diakinesis

Answer 23

cross over points start to move toward the end… homoloug pair and crossing over. termilalization occurs. spidle apparatus in place. nuclear memnbrane disrupted

Question 24

metaphase I

Answer 24

Centromeres DONOT divide, random alignment of homologus pairs of chromosomes along the metaphase plate

Question 25

prophase I

Answer 25

synopsis... pair up.

Question 26

anaphase I

Answer 26

move to opposite poles... not idintical bc of crossing over... haploid.... second mechanism of generating genetics variation in the newly formed gamates

Question 27

Telephase I

Answer 27

cytokinesis occurs, neclear membrane reforms. spinndle apparatus disassembles... HAPLOID.... INterkinesis...

Question 28

interkinesis

Answer 28

nucler membranes reform, spindle apparatus disassembles, chromsomes may uncoil to vaying degress... spindle usually breaks down.... no DNA synthesis takes place

Question 29

prophase II

Answer 29

chromsomes condense... each chromosmes has 2 chromatids... nuclear membrane disapears, each chromosmes has two chromatids ...e ach daughter cell has one complete set of chromosomes (haploid)

Question 30

metaphase II

Answer 30

chromosmes line up on equtorial plate... kinetochoroes face opposite poles...

Question 31

anaphase II

Answer 31

centromeres have split... sister chromatids seperate... chromosmes move to opposite poles... each consists of single chromatid

Question 32

telophase II

Answer 32

chromosmes uncoil, Four geneticall unique haploid cells!!! 4. is one compelte set... cytokinesis is complete. nuclear membre reforms.spindle aparatus disintigrates ... chromosomes arrive at the spindle poles.

Question 33

cytokinesis meiosis

Answer 33

the cytoplasm divides to produce tow cells, each having half the orginal number of chromosomes

Question 34

cohesion.

Answer 34

holds chromatids together during early parts of mitosis... break down allows sister chromatids to spearate during mitosis anaphase

Question 35

cohesion during meiosis

Answer 35

chromosomes arms holds homologous chromsomes together at chiasmata through metaphase I

Question 36

meiosis specific cohesions at centromere ...

Answer 36

keeps sister chromatids together during anaphase...

Question 37

the cohesion that protects anaphase of sister chromatids during meiosis is

Answer 37

shugoshin

Question 38

separase

Answer 38

kept inactive during interphase and early mitosis, breaks down cohesion at end of metaphase, breakse down meiosis-specific cohesion at centromere during end of metaphase II

Question 39

Keeps separase inactive during interphase and early mitosis

Answer 39

securin

Question 40

keeps sists kinetochores oriented toward same pole during metaphase i

Answer 40

monopolins

Question 41

48 mins

Answer 41

in lecture 2

Question 42

spermatogonia--->

Answer 42

...

Question 43

spermatogenesis... primordial germ cells

Answer 43

diploid... divide mitotically to produce dipoloid spermatogonia

Question 44

spermatogonia are

Answer 44

diploid can undergo repereated rounds of mitosis to produce more spermatogonia may initiate meiosis and enter into prophase I to give rise to primary spermatocyte

Question 45

Sour of genetica variation

Answer 45

mutation and sexual reproduction

Question 46

meiosis includes

Answer 46

crossing over and independent assortment and fertilization

Question 47

Spermatogonia-->

Answer 47

primary spermatocytes 2N

Question 48

primary spermatocytes 2N 1-->

Answer 48

secondary spermatocytes N 2... haploid, undergo meiosis II to produce haploid spermatids

Question 49

secondary spermatocytes 2.... N-->

Answer 49

4 spermatids N... haploid, differentiate into haploid sperm

Question 50

oogonia-->

Answer 50

2n primary oocytes.... arrests at diploteme of prophase I

Question 51

Primary ooctye 2N-->

Answer 51

seondary oocyte.... willl also divide off polar body... will go to 2nd metaphase that is ovulated and stop unless fertilized...

Question 52

secondary oocyte fertilized

Answer 52

ootid and polar body

Question 53

primary oocyte

Answer 53

lg ovum and small polar body, meiosis will not re