Chapter 16

Front 1

2 types of cellular division

Back 1

mitosis (asexual), meiosis (sexual)

Front 2

How many chromosomes does asexual cellular division produce?

Back 2

maintains the normal number of chromosomes after divisions and is known as mitosis

Front 3

How many chromosomes does sexual cellular division produce?

Back 3

produces gametes with half the number of chromosomes and known as meiosis

Front 4

Asexual cellular division is

Back 4

mitosis

Front 5

sexual cellular division is know as

Back 5

meiosis

Front 6

Somatic cells divide and produce cells that are

Back 6

identical to the parent cell

Front 7

DNA is tightly wound around a series of ________ (______) that are found in the _________

Back 7

proteins, histones, nucleus

Front 8

genetic material is foun in a mass of intertwined strands known as

Back 8

chromatin

Front 9

During cellular division, chromatin condenses and forms a

Back 9

chromosome

Front 10

Central pinched region in a chromosome is the

Back 10

centromere

Front 11

humans have __ autosome pairs and a single pair of ___________

Back 11

22, sex chromosomes

Front 12

paired chromosomes are

Back 12

homologous

Front 13

homologous chromosomes carry the same

Back 13

genes

Front 14

Karyotyping

Back 14

a picture of the chromosomes is taken during metaphase

Front 15

After G2 phase the process of _________ begins in ______ cells

Back 15

mitosis, somatic

Front 16

at the end of interphase there are two ___________ sets of _________ present in the nucleus

Back 16

identical sets of DNA

Front 17

plant cells lack _________ but still form _________

Back 17

lack centrioles, still form spindle fibres

Front 18

how does cytokinesis occur in plant cells

Back 18

cell plate forms between two daughter nuclei and extends to form a new cell wall

Front 19

cells that are used in cloning must be

Back 19

totipotent

Front 20

define a totipotent cell

Back 20

able to become any cell in the body of an organism ( they are undifferentiated)

Front 21

clones are created from a ____ cell

Back 21

single

Front 22

5 steps to cloning

Back 22

1. Developing embryo at early stage is broken down to single cells

2. Nuclei from these cells are removed using a micropippette

3. Nuclei are injected into unfertilized egg cells (with the nucleus removed)

4. Egg cells are cultured in a lab

5. Blastulae are implanted into a recipient mother, which produces a number of cloned offspring

Front 23

cancer is ___________ cell ________

Back 23

uncontrolled, growth

Front 24

Normally cells divide

Back 24

to replace damaged cells

Front 25

Gametes have _____ the number of chromosomes as the rest of the body

Back 25

half (haploid)

Front 26

(n) is

Back 26

haploid

Front 27

(2n)

Back 27

is diploid

Front 28

meiosis is

Back 28

a two stage process where one diploid parent cell divides to create four non-genetically-identical haploid gametes

Front 29

Meiosis I is known as a reduction division because

Back 29

homologous pairs split-up, resulting in two haploid cells, each continaing on replicated pair of sister chromatids

Front 30

Process of meiosis II is _______ to mitosis

Back 30

identical

Front 31

Define nondisjunction

Back 31

the improper separation of chromatids in meiosis

Front 32

Characteristics of down syndrome:(2)

Back 32

- 47 chromosomes

- trisomy on 21st chromosome

Front 33

Turner syndrome characteristics: (2)

Back 33

- monosomy X

-female with 45 chromosomes

Front 34

Amniocentesis

Back 34

a needle is used to extract a sample of the amniotic fluid surrounding the fetus

Front 35

chronic villus smpling (CVS)

Back 35

extracted form the chorion of developing mebryo

Front 36

Spermatogenesis (2)

Back 36

- production of sperm cells

- occurs within the seminiferous tubules of the male testes

Front 37

What is oogenesis

Back 37

production of the ovum

Front 38

any zygote with a Y chromosome is

Back 38

male (XY)

Front 39

a zygote with two X chromosomes is

Back 39

female (XX)

Front 40

Diploid generation of a plant is called the

Back 40

sporophyte (spore-making body)

Front 41

sporophytes use_______________ to make __________ spores

Back 41

meiosis, haploid

Front 42

conifer trees are

Back 42

diploid sporophytes

Front 43

original cell

Back 43

parent cell

Front 44

new cell

Back 44

daughter cell

Front 45

chromosome is

Back 45

a length of DNA and its associated protein

Front 46

allele

Back 46

different form of the same gene occurring on homologous chromosomes

Front 47

chromtin

Back 47

long fibres that form chromosomes and contain, DNA, small amount of RNA, and proteins

Front 48

centromere

Back 48

the point at which two sister chromatids of a chromosome are joined and to which the spindle fibres attach during mitosis

Front 49

how many chromosomes do human somatic cells have ?

Back 49

46

Front 50

autosome is

Back 50

a chromosome other than a sex chromosome , human somatic cells have 22 pairs

Front 51

are sex chromosomes homologous ?

Back 51

no

Front 52

homologous chromosomes carry the same

Back 52

genes at the same location

Front 53

are homologous chromosomes identical ?

Back 53

no they carry different forms or alleles of the same gene

Front 54

cell that contains homologous chromosomes is a

Back 54

diploid

Front 55

cells that contian unpaired chromosomes

Back 55

haploid

Front 56

most of the somatic cells life is spent in what stage ?

Back 56

growth

Front 57

3 phases of interphase ?

Back 57

G1, S phase G2

Front 58

G1 phase: (3)

Back 58

- called Gap 1

- cell grows quickly

- organelle replication

Front 59

S (Synthesis) phase: (2)

Back 59

- DNA in the chromatic replicates to create a second identical set of DNA

- the identical chromosomes (sister chromatids) are joined at the centromere

Front 60

G2 phase: (3)

Back 60

- Gap 2 or Growth 2

- lets the cell rebuild its reserves of energy to prep for division

- manufactures proteins and other molecules required for division

Front 61

interphase ends when the cell begins

Back 61

the process of nuclear division (mitosis)

Front 62

meiosis

Back 62

cellular process that produces haploid gametes from diploid cells in the ovaries and testes

Front 63

mitosis

Back 63

division of genetic material and the contents of the cell's nucleus into two complete and separate sets, results in a daughter cell receiving the exact number of chromosomes and genetic make-up as the parent

Front 64

cytokinesis

Back 64

separation of cytoplasm and organelles and the formation of two daughter cells

Front 65

cell cycle made up of two main stages

Back 65

growth and division

Front 66

3 important functions of mitosis and cytokinesis

Back 66

1. growth

2. maintenance

3. repair

Front 67

When does DNA replication occur in interphase ?

Back 67

S phase

Front 68

first phase of mitosis

Back 68

prophase

Front 69

prophase (5)

Back 69

- chromatin condenses into tightly packed chromosomes

- nuclear membrane breaks down releasing the chromosomes into the cytoplasm

- nucleous disappears

- centrioles move apart to opposite poles of cell

- spindle appartus forms between them

Front 70

Metaphase (2)

Back 70

- spindle fibres guide chromosomes to the equator

- spindle fibres attach to the centromere so that one sister chromatid faces the opposite pole and vice versa

Front 71

Anaphase (4)

Back 71

- centromere splits apart and the sister chromatids separate from one another

- spindle fibres linked to the centromeres shorten and sister chromatids are pulled to opposite poles

- at the same time, other microtubuoles in the spindle apparatus lengthen and push poles of the cell away from each other

- one complete diploid set of chromosomes gathered at each pole of the elongated cell

Front 72

Telophase

Back 72

- chromatids begin to unwind into chromatin

- spindle fibres break down

- nuclear membrane forms

- nucleolus forms within each new nucleus

Front 73

What happens during cytokinesis in animal cells? (2)

Back 73

- an indentation forms in the cell membrane along the cell equator --> till cell pinched in two

- cytoplasm and organelles divide equally between the two halves of the cell

Front 74

2 key outcomes of meiosis

Back 74

1. reduction division: produces daughter cells with fewer chromosomes

2. recombination: have different combinations of genes

Front 75

what is synapsis and when does it occur?

Back 75

aligning of homologous chromosomes side-by-side during prophase I in meiosis `

Front 76

tetrad

Back 76

homologous pair formed during prophase I of meiosis // is a pair of sister chromatids synapsed with another pair of sister chromatids

Front 77

Prophase I: (2)

Back 77

- each pair of homologous chrom. align side by side (synapsis)

- homologous chromosomes pair up and create tetrads

Front 78

Metaphase 1:

Back 78

- spindle fibre from one pole attaches to one pair of sister chromatids in the tetrad and a spindle fibre from the opposite pole attaches to the other

- spindle fibres guide the tetrad to the equator

- chromosomes do not line up single file like mitosis, they line up as homologous pairs

Front 79

difference between metaphase in mitosis and metaphase I in meiosis?

Back 79

- in metaphase in mitosis , chromosomes line up single file

Front 80

Anaphase I: (4)

Back 80

- spindle fibres shorten and cause homologous chromosomes to separate from one another

- homologues move to opposite poles

- centromeres do not split like in mitosis

- results in a single chromosome (made of two sister chromatids) from each pair moves to each pole of the cell

Front 81

Difference between anaphase I and anaphase

Back 81

centromeres not split

Front 82

telophase I (3)

Back 82

- chromosomes begin to uncoil and spindle fibres disappear

- cytoplasm divided, nuclear membrane forms around each group of homologous chromosomes

- two cells formed (haploid)

Front 83

each cell that enters Meiosis II is ____________ but consists of __________ chromosomes. At the end of meiosis II the ______ cells are still _________ but contain _________ ________ chromosomes>

Back 83

haploid, replicated, daughter, haploid, single, unreplicated

Front 84

independent assortment

Back 84

orientation of homologous chromosomes is independent

Front 85

crossing over

Back 85

process by which non-sister chromatids exchange genes during prophase I of meiosis

Front 86

nondisjunction

Back 86

failure of homologous chromosomes pairs or sister chromatids to separate during meiosis I and II properly

Front 87

nondisjunction in anaphase I

Back 87

when homologous chromosome pair do not separate to opposite poles, instead one entiire pair is pulled toward the same pole

Front 88

nondisjunction in anaphase II

Back 88

when sister chromatids do not separate to opposite poles, instead both sister chromatids are pulled toward the same pole

Front 89

monosomy

Back 89

when one chromosome is lost due to nondisjunction

Front 90

trisomy

Back 90

gain of an extra chromosome

Front 91

spermatogenesis starts with a diploid germ cell called a

Back 91

spermatogonium

Front 92

spermatogonia divides by mitosis to from tow daughter cells, one replenishes the spermatogonia cell population and the other develops into a

Back 92

primary spermatocyte

Front 93

primary spermatocyte undergoes _______ to form two __________ spermatocytes

Back 93

meiosis I, secondary

Front 94

secondary spermatocytes undergo __________ to form four ________

Back 94

meiosis II, spermatids

Front 95

steps in oogenesis (2)

Back 95

- oogenesis starts with diploid germ cell and divides with mitosis to form two primary oocytes

- every month after puberty one primary oocyte undergoes meiosis

Front 96

asymmetrical cytokinesis

Back 96

unequal division of the cytoplasm that occurs during cell division to form an egg during oogenesis

Front 97

in oogenesis the cell that receive most of the cytoplasm is called the ? the cell that receives less it the?

Back 97

secondary oocyte -- polar body

Front 98

when does DNA replication occur in mitosis?

Back 98

during interphase before nuclear division

Front 99

number of divisions in mitosis

Back 99

one

Front 100

number of daughter cells in mitosis and their characteristics

Back 100

2, diploid // identical to parents

Front 101

how many divisions are in meiosis ?

Back 101

2

Front 102

when does synapsis occur in meiosis ?

Back 102

Prophase I

Front 103

how many daughter cells produced in meiosis and their characteristics ?

Back 103

4, haploid, not identical to parent cell

Front 104

asexual reproduction

Back 104

reproduction that requires only one parent, produces genetically identical offspring

Front 105

sexual reproduction

Back 105

reproduction involving meiosis, gamete formation and fertilization

Front 106

budding

Back 106

new organism develops as outgrowth of the body of the parent (asexual)

Front 107

vegetative reproduction

Back 107

new plant grows from a modified stem (asexual)

Front 108

fragmentation

Back 108

new organisms is created from a portion of a parent organism (asexual)

Front 109

parthenogenesis

Back 109

unfertilized egg develops into an adult (asexual)

Front 110

sporophyte

Back 110

diploid generation of a plant that produces haploid spores through the process of meiosis that develop without fertilization into a gametophyte

Front 111

gametophyte

Back 111

haploid generation, produces male and female gametes that fuse at fertilization to form a diploid sporophyte

Front 112

3 advantages of sexual reproduction

Back 112

1. adaptation due to variation

2. competition reduced to to diversity

3. opportunity to replace and repair damaged chromosomes

Front 113

3 advantages of asexual reproduction

Back 113

1. quick, doesn't need another parent

2. less energy

3. maximize chances that individual offspring will survive