BIO 190 lAB Quiz #10 Cell Division Mitosis and Meiosis

what is the purpose of mitosis

growth and to increase the number of cells

the majority of a cells life is spent in ______

interphase

what are the 3 periods of interphase

G1, S, G2

what happens during the G 1 phase

the cell grows larger

what happens during the S phase

replication occurs

what happens during the G 2 phase

the cell prepares to divide

what is it called when the cytoplasm divides

cytokinesis

the purpose of meiosis is

sexual reproduction

as a result of meiosis the number of chromosomes in each daughter cell called a ______ is _______

gamete is halved

at fertilization when male and female gametes fuse the chromosome number of the resulting ______ is restored to normal number

zygote

when a cell prepares to enter mitosis the chromosomes _______

condense into a tight coil

sister chromatids are connected by a

centromere

what is the apical meristem

meristems in the rapidly growing regions if the tip of the stem and roots

key features during interphase

distinct nucleus is available

2 or more nucleoli

nuclear envelope in tact

key features in prophase

condensing chromosomes

spindle fibers appear

nuclear envelope disappears

key features of metaphase

sister chromosomes line up in middle

spindle fibers attach to sister chromatids

key features in anaphase

sister chromatids separate (now called chromosomes again) and move towards opposite poles of the cell

key features of telophase

chromosomes reached opposite ends of poles

chromsomes decondense

spindle disappears

nuclear envelope reforms

key features of cytokinesis

typically starts while cell is in telophase

in plants a new cell plate forms

in animals a cleavage furrow forms

allium root tip

grid-like cells, all have nucleus, some undergoing mitosis

when a sperm fertilizes an ovum in an animal the resulting ___ begins a series of rapid divisions called cleavage

zygote

whitefish blastula

the cells we observed that were fertilized

somatic body cells in humans have _______ chromosomes

46

but there are only 23 different kinds of chromosomes

you have 2 of each kind (one from your mom and one from your dad) these are called homologous pairs

the number of different kinds of chromosomes, 23 in humans is referred to as

haploid (n) number of chromosomes

the total number of chromosomes in humans is 46 which is _____

diploid 2n

in mitosis a diploid parent cell produces _____________

2 diploid daughter cells

in meiosis a diploid parent cell produces _____________4 haploid daughter cells

the 4 haploid daughter cells produced my meiosis are __________

gametes

sperm in males

ova in females

the overall life cycle involves meiosis which _____ the number of chromosomes followed by restoration of the full set of chromosomes by fertilization in sexual reproduction

halves

Meiosis 1: Prophase 1

DNA condenses

each homologous pair of chromosomes pair resulting is a pair of sister chromatids called a tetrad

the nuclear envelope disappears

Meiosis 1: Metaphase 1

the tetrads line along the equator

the centrosome for one homologous in the tetrad attach to the spindle fibers

the centromere for the other attaches to the spindle fibers facing the other pole of the cell

meiosis 1: anaphase 1

the tetrad separates

one replicated chromosomes moves towards one side, the other on the other side

Meiosis 1: Telophase 1 and Cytokinesis

each pair of sister chromatids reaches its pole

cytokinesis occurs

in humans there are now 2 cells each with 23 chromosomes in the paired sister chromatid form

Meiosis 2: Prophase 2

chromosomes remain in sister chromatid form

chromosomes condenses

meiosis 2: metaphase 2

the centromere for each sister chromatid attaches to the spindle fibers facing one pole of the cell

sister chromatids migrate to the equator and line up with the centromeres

meiosis 2: anaphase 2

sister chromatids separate and move toward opposite poles

Meiosis 2: Telophase 2 and Cytokinesis

chromosomes reach opposite ends of the cell

nuclear envelope reforms

chromosomes unwind into chromatin

cytokinesis takes place

there are now 4 haploid daughter cells

independent assortment

during metaphase 1 when tetrads align along the equator of the cell with one homologue facing one pole and one with the other there is no rule that governs how they segregate. its random

the number of chromosome combination is dependent on the number of chromosomes in the organism

crossing over

introducing different allele combinations to the gametes

reshuffles some of the allele on the chromosomes to produce new combos of alleles

nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

spermatogenesis

meiosis of male gametes

produces sperm

occurs in testes

spermatogonia

diploid cells that give rise to gametes via meiosis

spermatids

four haploid cells that are formed when a diploid reproductive cell divides meiotically

the production of ova

oogenesis

meiosis of female gametes that occurs in the ovaries

the diploid female reproductive cell ________ does not undergo mitosis after the embryonic period therefore women are born with a finite number of potential ova

oogonium

the diploid oogium enlarges to a

primary oocyte

the secondary oocyte is released from the ovary during

ovulation

oocytes are housed in the

ovarian follocies

graffian follicles

process of gamete production in males vs females

males: spermatogenesis

females: oogenesis

the diploid repreductive cell destined to become a gamete in make vs female

male: spermatogonium

female: oogonium

gamete production occurs in

the ovaries or testes

males produce _____ viable gametes per meiotic division

4 viable sperm

females produce _____ viable gametes per meiotic division

1 viable egg