fig. 13-1. fig. 13-3b technique pair of homologous replicated chromosomes centromere sister...

Fig. 13-1

Fig. 13-3b

TECHNIQUE

Pair of homologousreplicated chromosomes

Centromere

Sisterchromatids

Metaphasechromosome

5 µm

Fig. 13-4

Key

Maternal set ofchromosomes (n = 3)

Paternal set ofchromosomes (n = 3)

2n = 6

Centromere

Two sister chromatidsof one replicatedchromosome

Two nonsisterchromatids ina homologous pair

Pair of homologouschromosomes(one from each set)

Fig. 13-7-1Interphase

Homologous pair of chromosomesin diploid parent cell

Chromosomesreplicate

Homologous pair of replicated chromosomes

Sisterchromatids Diploid cell with

replicated chromosomes







Meiosis I

Homologouschromosomesseparate

1

Haploid cells withreplicated chromosomes







Meiosis I


1

Haploid cells withreplicated chromosomes

Meiosis II

2 Sister chromatidsseparate

Haploid cells with unreplicated chromosomes

Fig. 13-8

Prophase I Metaphase I Anaphase ITelophase I and

CytokinesisProphase II Metaphase II Anaphase II Telophase II and

Cytokinesis

Centrosome(with centriole pair)

Sisterchromatids Chiasmata

Spindle

Homologouschromosomes

Fragmentsof nuclearenvelope

Centromere(with kinetochore)

Metaphaseplate

Microtubuleattached tokinetochore

Sister chromatidsremain attached


Cleavagefurrow

Sister chromatidsseparate Haploid daughter cells

forming

Metaphase I

Fig. 13-8a

Prophase I Anaphase I Telophase I andCytokinesis



Spindle




Metaphaseplate




Cleavagefurrow

Fig. 13-8b

Prophase I Metaphase I



Spindle


Metaphaseplate




Fig. 13-8c

Anaphase ITelophase I and

Cytokinesis



Cleavagefurrow

Fig. 13-8d

Prophase II Metaphase II Anaphase II Telophase II andCytokinesis


forming

Fig. 13-8e

Prophase II Metaphase II

Fig. 13-8f

Anaphase IITelephase II and

Cytokinesis


forming

Fig. 13-9MITOSIS MEIOSIS

MEIOSIS I

Prophase I

Chiasma

Homologouschromosomepair

Chromosomereplication

Parent cell

2n = 6


Replicated chromosome

Prophase

Metaphase Metaphase I

Anaphase ITelophase I

Haploidn = 3

Daughtercells of

meiosis I

AnaphaseTelophase

2n 2n

Daughter cellsof mitosis

n n n n

MEIOSIS II

Daughter cells of meiosis II

SUMMARY

Meiosis

Occurs during interphase before meiosis I begins

Two, each including prophase, metaphase, anaphase, andtelophase

Occurs during prophase I along with crossing overbetween nonsister chromatids; resulting chiasmatahold pairs together due to sister chromatid cohesion

Four, each haploid (n), containing half as many chromosomesas the parent cell; genetically different from the parentcell and from each other

Produces gametes; reduces number of chromosomes by halfand introduces genetic variability amoung the gametes

Mitosis

Occurs during interphase beforemitosis begins

One, including prophase, metaphase,anahase, and telophase

Does not occur

Two, each diploid (2n) and geneticallyidentical to the parent cell

Enables multicellular adult to arise fromzygote; produces cells for growth, repair,and, in some species, asexual reproduction

Property

DNAreplication

Number ofdivisions

Synapsis ofhomologouschromosomes

Number ofdaughter cellsand geneticcomposition

Role in theanimal body

Fig. 13-9a

MITOSIS MEIOSIS

MEIOSIS I

Prophase I

Chiasma


Homologouschromosomepair


2n = 6

Parent cell

Prophase

Replicated chromosome

Metaphase Metaphase I

Anaphase ITelophase I

Haploid n = 3

Daughter cells ofmeiosis I

MEIOSIS II

Daughter cells of meiosis II

nnnn

2n2n

Daughter cellsof mitosis

AnaphaseTelophase

Fig. 13-9b

SUMMARY

MeiosisMitosisProperty

DNAreplication

Number ofdivisions

Occurs during interphase beforemitosis begins

One, including prophase, metaphase,anaphase, and telophase

Synapsis ofhomologouschromosomes

Does not occur

Number ofdaughter cellsand geneticcomposition

Two, each diploid (2n) and geneticallyidentical to the parent cell

Role in theanimal body

Enables multicellular adult to arise fromzygote; produces cells for growth, repair,and, in some species, asexual reproduction

Occurs during interphase before meiosis I begins

Two, each including prophase, metaphase, anaphase, andtelophase

Occurs during prophase I along with crossing overbetween nonsister chromatids; resulting chiasmatahold pairs together due to sister chromatid cohesion

Four, each haploid (n), containing half as many chromosomesas the parent cell; genetically different from the parentcell and from each other

Produces gametes; reduces number of chromosomes by halfand introduces genetic variability among the gametes

Fig. 13-11-1

Possibility 1 Possibility 2

Two equally probablearrangements ofchromosomes at

metaphase I

Fig. 13-11-2



metaphase I

Metaphase II

Fig. 13-11-3



metaphase I

Metaphase II

Daughtercells

Combination 1 Combination 2 Combination 3 Combination 4

Fig. 13-12-1Prophase Iof meiosis

Pair ofhomologs

Nonsisterchromatidsheld togetherduring synapsis


Pair ofhomologs


Chiasma

CentromereTEM


Pair ofhomologs


Chiasma

Centromere

Anaphase I

TEM


Pair ofhomologs


Chiasma

Centromere

Anaphase I

Anaphase II

TEM


Pair ofhomologs


Chiasma

Centromere

Anaphase I

Anaphase II

Daughtercells

Recombinant chromosomes

TEM

Fig. 13-UN1

Prophase I: Each homologous pair undergoessynapsis and crossing over between nonsisterchromatids.

Metaphase I: Chromosomes line up as homolo-gous pairs on the metaphase plate.

Anaphase I: Homologs separate from each other;sister chromatids remain joined at the centromere.

Fig. 13-UN2

F

H

Fig. 13-UN3

fig. 13-1. fig. 13-3b technique pair of homologous replicated chromosomes centromere sister...

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