Start Meiosis -- Lecture 8

Question 1

cytokinesis (what is it)

Answer 1

process of dividing 1 cell into 2

Question 2

cytokinesis in animal cells:

animal cells use a ___

Answer 2

contractile ring

Question 3

cytokinesis in animal cells:

___ use a contractile ring

Answer 3

animal cells

Question 4

cytokinesis in animal cells:

contractile ring is composed of

Answer 4

actin microfilaments

myosin motor proteins

Question 5

cytokinesis in animal cells:

in the contractile ring, ___ and ___ contract rapidly to pinch cell in 2, forming a cleavage furrow

Answer 5

actin microfilaments

myosin motor proteins

Question 6

cytokinesis in animal cells:

in the ___, actin microfilaments and myosin motor proteins contract rapidly to pinch cell in 2, forming a cleavage furrow

Answer 6

contractile ring

Question 7

cytokinesis in animal cells:

in the contractile ring, actin microfilaments and myosin motor proteins contract rapidly to pinch cell in 2, forming a ___

Answer 7

cleavage furrow

Question 8

cytokinesis in plants:

vesicles (definition)

Answer 8

membrane-bound delivery vehicles

Question 9

cytokinesis in plants (steps)

Answer 9

1) vesicles accumulate in middle of cell
2) vesicles bring the necessary material to form a temporary structure called a cell plate
3) cell plate goes thru a series of biochemical changes and becomes the cell wall

vesicles in middle –> cell plate –> cell wall

Question 10

chromosome terminology:

In human cells: in G1: there are 46 one-chromatid ___

Answer 10

chromosomes

Question 11

chromosome terminology:

In human cells: in G1: there are ___ one-chromatid chromosomes

Answer 11

46

Question 12

chromosome terminology:

In human cells: in G1: there are 46 ___-chromatid chromosomes

Answer 12

one

Question 13

chromosome terminology:

In ___ cells: in G1: there are 46 one-chromatid chromosomes

Answer 13

human

Question 14

chromosome terminology:

the chromosomes are in ___: 1 from Mom, 1 from Dad

Answer 14

pairs

Question 15

chromosome terminology:

each pair chromosomes are referred to as ___ or ___

Answer 15

homologs

homologous chromosomes

Question 16

chromosome terminology:

homologous chromosomes are very similar but ___

Answer 16

slightly different

Question 17

chromosomes revisited:

homologous chromosomes contain same ___ but have slightly different ___

Answer 17

genes

DNA sequences

Question 18

chromosomes revisited:

before DNA replication, each homolog has ___ chromatid

Answer 18

1 chromatid

Question 19

chromosomes revisited:

after DNA replication, each homolog has ___

Answer 19

2 chromatids

Question 20

ploidy (definition)

Answer 20

of homologs of each chromosome in a cell

Question 21

diploid (definition)

Answer 21

has 2 homologs of each chromosome – 1 from each parent

2n

Question 22

haploid (definition)

Answer 22

have 1 homolog of each chromosome

n or 1n

Question 23

polyploid (definition)

Answer 23

have 3 or more homologs of each chromosome

Question 24

diploid cells (2n):

46 one-chromatid chromosomes

how many homologous pairs?

Answer 24

23

Question 25

haploid cells (n): 23 one-chromatid chromosomes how many homologous pairs?

Answer 25

none

Question 26

mitosis vs. meiosis: mitosis (definition)

Answer 26

a eukaryotic cell divides and makes a clone of itself each new cell has the same # of chromosomes as the original cell

Question 27

mitosis vs. meiosis: meiosis (definition)

Answer 27

a eukaryotic cell divides each new cell has 1/2 the # of chromosomes as the original cell

Question 28

mitosis vs. meiosis: why would a eukaryote go thru meiosis?

Answer 28

reproduction

Question 29

meiosis enables reproduction

Answer 29

each parent is diploid (46 one-chromatid chromosome) thru meiosis, their gametes are haploid (23 one-chromatid chromosomes) gametes fuze into zygote, a 1-celled embryo, which is diploid (46 one-chromatid chromosomes)

Question 30

gametogenesis (definition)

Answer 30

making sperm and egg cells

Question 31

spermatogenesis results in...

Answer 31

results in 4 viable haploid sperm cells

Question 32

spermatogenesis (process)

Answer 32

1, primary spermatocyte (diploid) thru meiosis becomes... 4, mature sperm cells (haploid)

Question 33

oogenesis results in...

Answer 33

results in 1 viable egg cell and 3 nonviable egg cells called polar bodies (all haploid)

Question 34

polar bodies

Answer 34

3 of the 4 egg cells produced in oogenesis which are nonviable

Question 35

oogenesis (process)

Answer 35

1, primary oocyte (diploid) thru meiosis becomes... 4 egg cells (haploid) 1 viable egg cell and 3 polar bodies (nonviable egg cells)

Question 36

meiosis overview (meiosis I): beginning of the process

Answer 36

cell in G1: - 4 one-chromatid chromosomes --> 1 diploid cell S-phase: - 4 two-chromatid chromosomes --> 1 diploid cell ``` Meiosis I (first of 2 cell divisions): - homologous pairs segregate into different cells --> 2 haploid cells ```

Question 37

meiosis overview (meiosis I): after meiosis I

Answer 37

there are 2 haploid cells, each w/ 2 two-chromatid chromosomes

Question 38

meiosis overview (meiosis I): which meiosis is called reduction division?

Answer 38

meiosis I

Question 39

meiosis overview (meiosis I): why is meiosis I called reduction division?

Answer 39

because the chromosome # is less

Question 40

meiosis overview (meiosis II): meiosis II (the 2nd of 2 cell divisions) -- what happens?

Answer 40

chromatids separate and segregate into different cells

Question 41

meiosis overview (meiosis II): after meiosis II

Answer 41

4 cells each w/ 2 one-chromatid chromosomes --> haploid