Cell Division & Reproduction

Question 1

two main phases of the cell cycle

Answer 1

growth and division

Question 2

what happens in growth phases

Answer 2

interphase, cell makes new molecules, cell growth occurs, DNA replication

Question 3

what happens in division phase

Answer 3

division of the cell’s nucleus (mitosis) and cell division (cytokinesis)

Question 4

mitosis

Answer 4

the process by which nuclear material is divided during cell division

Question 5

interphase

Answer 5

the phase when the cell grows and prepares for cell division by duplicating its genetic material (DNA in chromatin replicates)

Question 6

stages of mitosis

Answer 6

prophase, metaphase, anaphase, telophase

Question 7

prophase

Answer 7

double chromatin strands shorten and thicken to form chromosomes
nuclear membrane and nucleolus disappear/disassemble
centrioles move to opposite poles of the cell
spindle fibers attach to the centromere of each chromosome

Question 8

metaphase

Answer 8

the tugging action of spindle fibres pulls the double stranded chromosomes into a line across the middle of the cell (equatorial or metaphase plate)

Question 9

anaphase

Answer 9

spindle fibres begin to contract and shorten, causing the centromere to be pulled apart
each single stranded chromosome moves to an opposite pole of the cell

Question 10

telophase

Answer 10

one complete set of chromosomes is now at each pole of the cell
spindle fibres begin to disappear
nuclear membranes begin to form around each set of chromosomes
nucleolus appears in each new nucleus
single stranded chromosomes start to uncoil to form chromatin
cytokinesis occurs forming two daughter cells

Question 11

cytokinesis in animals vs. plants

Answer 11

animals - cell membrane pinches in from the edges forming a cleavage furrow
plants - a new cell wall forms between 2 daughter cells forming a cell plate

Question 12

what is meiosis

Answer 12

a type of cell division that occurs in the reproductive organs, which produces sex cells called gametes (egg or sperm)

Question 13

haploid

Answer 13

containing only one copy of each type of chromosome

Question 14

diploid

Answer 14

cells containing two copies of each chromosome (one copy from each parent)

Question 15

homologous chromosomes

Answer 15

chromosomes that contain the same gene sequences but may not be made up of the same alleles

Question 16

allele

Answer 16

an alternate form of a gene

Question 17

crossing over

Answer 17

non-sister chromatids in a homologous pair exchange genes

happens in prophase I

Question 18

random assortment

Answer 18

the random alignment of homologous chromosomes along the equator during metaphase I

Question 19

zygote

Answer 19

a cell formed by the fusion of two gametes

Question 20

synapsis

Answer 20

the aligning of homologous chromosomes during prophase I

Question 21

spermatogenesis

Answer 21

the process of producing male gametes (sperm) in mammals

Question 22

oogenesis

Answer 22

the process of producing female gametes (eggs) in mammals

Question 23

monosomy

Answer 23

the loss of a chromosome as a result of non-disjunction

Question 24

trisomy

Answer 24

the gain of an extra chromosome as a result of non-disjunction

Question 25

prophase I

Answer 25

chromatin shortens and thickens
nuclear membrane breaks down and nucleolus disappears
centrioles move to opposite poles
spindle fibres form
homologous chromosomes pair up and cross over

Question 26

metaphase I

Answer 26

spindle fibers attach to the centromere of each chromosome

homologous chromosomes line up at the equator of the cell

Question 27

anaphase I

Answer 27

homologous chromosomes separate and move to opposite poles

Question 28

telophase I

Answer 28

does not occur in all cells

chromosomes uncoil and spindle fibres disappear

Question 29

prophase II

Answer 29

centrioles move to opposite poles
spindle fibres form
nuclear membrane breaks down

Question 30

metaphase II

Answer 30

single chromosomes line up at the equator

Question 31

anaphase II

Answer 31

one chromatid (of each chromosome) gets pulled to each pole

Question 32

telophase II

Answer 32

nucleus reassembles

cytokinesis occurs