Bio-Chapter 8

Front 1

Living organisms reproduce by two methods

Back 1

-Asexual reproduction
-Sexual reproduction

Front 2

offsprings are identical to the original cell or organism and involves inheritance of all genes from one parent

Back 2

Asexual reproduction

Front 3

offspring are similar to parents but show variations in traits and involves inheritance of unique sets of genes from two parents

Back 3

Sexual reproduction

Front 4

the reproduction of cells

Back 4

cell division

Front 5

_ perpetuates life

Back 5

cell division

Front 6

Roles of Asexual reproduction

Back 6

-reproduction of an entire single-celled organism
-growth of a multicellular organism
-growth from a fertilized egg into an adult
-repair and replacement of cells in an adult

Front 7

Roles of Sexual reproduction

Back 7

sperm and egg production

Front 8

binary fission means

Back 8

"dividing in half"

Front 9

binary fission occurs in

Back 9

prokaryotic cells

Front 10

two identical cells arise from on cell

Back 10

binary fission

Front 11

steps in the binary fission process

Back 11

-a single circular chromosome duplicates and the copies begin to seperate from each other
-the cell elongates, and the chromosomal copies seperate further
-the plasma membrane grows inward at the midpoint to divide the cells

Front 12

_ composed of chromatin

Back 12

Eukaryotic chromosomes

Front 13

chromatin=

Back 13

DNA + proteins

Front 14

To prepare for division, the _ becomes highly compact and the _ are visible with a microscope

Back 14

chromatin
chromosomes

Front 15

Early in the divison process, chromosomes _

Back 15

duplicate

Front 16

Each chromosome appear as two _

Back 16

sister chromatids

Front 17

sister chromatids each contain

Back 17

identical DNA molecules

Front 18

sister chromatis are joined by a narrow region called the

Back 18

centromere

Front 19

cell cycle consists of two stages

Back 19

interphase
mitotic phase

Front 20

duplication of cell contents

Back 20

interphase

Front 21

division

Back 21

mitotic phase

Front 22

Interphase consist of

Back 22

-G1
-S
-G2

Front 23

growth, increase in cytoplasm

Back 23

G1

Front 24

duplication of chromosomes

Back 24

S

Front 25

growth, preparation for division

Back 25

G2

Front 26

mitosis inclues

Back 26

Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Cytokinesis

Front 27

_ often overlaps telophase

Back 27

cytokinesis

Front 28

_ is required to divide the chromosomes

Back 28

A mitotic spindle

Front 29

the mitotic spindle is composed of

Back 29

microtubules

Front 30

mitotic spindle is produced by

Back 30

centrosomes

Front 31

centrosomes are located in

Back 31

cytoplasm

Front 32

Centrosomes are responsible for

Back 32

-organize microtubule arrangement

Front 33

centrosomes contain a pair of _ animal cells

Back 33

centrioles

Front 34

Interphase in the cytoplasm

Back 34

-cytoplasmic contents double
-two centrosomes form

Front 35

Interphase in the nucleus

Back 35

-chromosomes duplicate during the S phase
-Nucleoli are visible

Front 36

sites of ribosomes assembly

Back 36

nucleoli

Front 37

Humans have _ chromosomes. By the end of interphase:
How many chromosomes are present in one cell?
how many chromatids are present in one cell?

Back 37

46
46
92

Front 38

Prophase in the cytoplasm

Back 38

-microtubules begin to emerge from centrosomes, forming the spindle

Front 39

Prophase in the nucleus,

Back 39

-chromosomes coil and become compact
-nucleoli disappear

Front 40

In prometaphase,

Back 40

-spindle microtubules reach chromosomes
-other microtubules meet those from the opposite poles
-the nuclear envelope disappears

Front 41

In prometaphase, when spindcle microtubles reach chromosomes, they

Back 41

-attach at kinetochores on the centromeres of sister chromatids
-move chromosomes to the center of the cell through associated protein motors

Front 42

In metaphase,

Back 42

-spindle is fully formed
-chromosomes align at the cell equator
-kinetochores of sister chromatids are facing the opposite poles of the spindle

Front 43

By end of metaphase,
how many chromosomes are present in one human cell?
how many chromatids are present in one human cell?

Back 43

46
92

Front 44

In anaphase,

Back 44

-sister chromatids seperate at the centromeres
-daughter chromosomes are moved to opposite poles of the cell
-kinetochore microtubules are shorten
-the cell elongates due to lenghtening of nonkinetochore microtubules

Front 45

By the end of Anaphase,
how many chromosomes are present in one human cell?
how many chromatids are?

Back 45

92
?

Front 46

In telophase,

Back 46

-the cell continues to elongate
-the nuclear envelope forms around chromosomes at each pole, establishing daughter nuclei
-chromatin uncoils
-nucleoli reappear
-the spindle disappears

Front 47

By the end of telophase,
-how many chromosomes are present in one nucleus wihtin the human cell?
-are the nuclei identical or different?

Back 47

46
?

Front 48

In cytokenesis,

Back 48

-cytoplasm is divided into seperate cells

Front 49

By the end of cytokinesis,
how many chromsomes are present in one human cell?
-how many chromatids are present in one human cell?

Back 49

46
0

Front 50

Cytokinesis in animal cells

Back 50

- a cleave furrow forms from a contracting ring of microfilaments, interacting with myosin
-the cleavage furrow deepends to separate the contents into two cells

Front 51

Cytokinesis in plant cells

Back 51

-a cell plate forms in the middle from vesicles containing cell wall material
-the cell plate gows outward to reach the edges, dividing the contents into two cells
-each cell has a plasma membrane and cell wall

Front 52

Factors that affect cell division

Back 52

-presence of essential nutrients
-growth factors, proteins that stimulate division
-presence of other cells causes density-dependent inhibition
-contact with a solid surface; most cells show anchorage dependence

Front 53

_ escape controls on the cell cycle

Back 53

cancer cells

Front 54

cancer cells divide rapidly, often in the ansence of _

Back 54

growth factors

Front 55

cancer cells spread to other tissues thorugh the

Back 55

circulatory system

Front 56

growth is not inhibited by other cells and _ form

Back 56

tumors

Front 57

_ remain at the original site

Back 57

benign tumors

Front 58

_ spread to otherlocations by metastasis

Back 58

malignent tumors

Front 59

locatized tumors can be treated with _

Back 59

surgery or radiation

Front 60

_ is used for metastaic tumors

Back 60

chemotherapy

Front 61

_ is a process that converts diploid nuclei to haploid nuclei

Back 61

meiosis

Front 62

_ have two homologous sets of choromsomes

Back 62

diploid cells

Front 63

_ have one set of chormosomes

Back 63

haploid cells

Front 64

meiosis occurs in the sex organs, producing _

Back 64

gametes-sperm and and eggs

Front 65

_ is the union of sperm and egg

Back 65

fertilization

Front 66

the zygote has a _ chromosome number

Back 66

diploid
one set from each parent

Front 67

like mitosis, meiosis is preceded by _

Back 67

interphase

Front 68

in meiosis, chromosomes duplicate during

Back 68

S phase

Front 69

Unlike mitosis, meiosis has two divisions

Back 69

-during meiosis I, homologous chromosomes separate
-the chromosomes number is reduced by hald
-during meiosis II, sister chromatids separate
(chromosome numbers remain the same)

Front 70

In prophase I,

Back 70

-chromsomes coil and become compact
-homologous chromosomes come together as paris by synapsis
-tetrad
-nonsister chromatids exchange genetic material by crossing over

Front 71

each pair with four chromatids is called a

Back 71

tetrad

Front 72

crossing over genetic material by nonsister chromatids

Back 72

recombination

Front 73

At the end of prophase I,
how many chromosomes are present in one cell?
how many chromatids are present in one cell?

Back 73

46
92

Front 74

In metaphase I,

Back 74

tetrads align at the cell equator

Front 75

In Anaphase I,

Back 75

homologous pairs separate and move toward opposite poles of the cell

Front 76

At the ends of metaphase I,
how many chromosomes are present in one cell?
how many chromatids are present in one cells?

Back 76

46
92

Front 77

In telophase I,

Back 77

-duplicated chromosomes have reached the poles
-a nuclear envelope forms around chromosomes in some species
-each nucleus has the haploid number of chromsomes

Front 78

After telophase I and cytokinesis,
how many chromosomes are present in one human cell?
how many chromatids are present in one human cell?

Back 78

23
46

Front 79

In prophase II,

Back 79

-meiosis II follows meiosis without chromsome duplication
-each of the two haploid products enter meiosis II
-events in the nucleus during meiosis

Front 80

Events in the nucleus during meiosis II, prophase II

Back 80

chromsomes coil and become compact

Front 81

In metaphase II,

Back 81

duplicated chrosomes align at the cell equator

Front 82

In anaphase II,

Back 82

sister chromatids seperate and chromosomes move toward opposite poles

Front 83

In telophase II,

Back 83

-chromosomes have reached the poles of the cell
-a nuclear envelope forms around each set of chromosomes
-with cytokinesis, four haploid cells are produced

Front 84

after telophase II and cytokinesis,
how many chromosomes are present in one human cell?
how many chromatids are present in one human cell?

Back 84

23
0

Front 85

which characteristics are similar for mitosis and meiosis?

Back 85

one duplication of chromosome

Front 86

which characteristics are unique to meiosis?

Back 86

-two divisions of chromsomes
-pairing of homologous chromosomes
-exchange of genetic material by crossing over

Front 87

what is the outcome of mitosis?

Back 87

two genetically identical cells, with the same chromosome number as the original cell

Front 88

what is the outcome of meiosis?

Back 88

four geneticall different cell, with hald the chromsome number of the original cell

Front 89

the combination of each unique sperm with each unique egg increases genetic variability

Back 89

random fertilization

Front 90

Independent orientation at metaphase I

Back 90

-each pair of chromosomes independtly aligns at the cell equator
-there is an equal probability of the maternal or paternal chromosome facing a given pole
-the number of combinations for chromosomes packaged into gametes in 2n where n=haploid number of chromsomes

Front 91

_ can lead to genetic difference between gametes

Back 91

separation of homologous chromosomes

Front 92

homologous chromosomes may have different versions of _

Back 92

a gene at the same locus

Front 93

since homologues move to opposite poles during _, gametes will receive either the maternal or paternal version of the gene

Back 93

anaphase I

Front 94

_ is the production of new combinations of genes due to crossing over

Back 94

genetic recombinations

Front 95

crossing over involces exchange of genetic material between _

Back 95

homologous chromosomes

Front 96

nonsister chromatids join at a _

Back 96

chiasma, site of attachment and crossing over