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MEIOSIS Q2 WK3 D2 Meiosis MEIOSIS Q2 WK3 D2 Meiosis

MEIOSIS Q2 WK3 D2 Meiosis - PowerPoint Presentation

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MEIOSIS Q2 WK3 D2 Meiosis - PPT Presentation

Meiosis is the type of cell division by which germ cells eggs and sperm are produced One parent cell produces four daughter cells Daughter cells have half the number of chromosomes found in the parent cell ID: 927733

chromosomes meiosis homologous cells meiosis chromosomes cells homologous amp cell http genetic variation cross haploid set sex spindle org

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Presentation Transcript

Slide1

MEIOSIS

Q2 WK3 D2

Slide2

Meiosis

Meiosis is the

type of

cell division by which

germ cells

(eggs and sperm)

are produced.

One parent cell produces

four

daughter cells.

Daughter cells have half the number of chromosomes found in the parent cell

Slide3

Meiosis

During meiosis, DNA replicates

once

, but the nucleus divides

twice

.

There are 2 parts to Meiosis:

Meiosis 1

Meiosis 2

The 4 new daughter cells have variation of the parent DNA; this is genetic variation

Slide4

Meiosis Terminology

Karyotype: Arranging of chromosomes from largest to smallest; pairing up the homologous chromosomesAutosomes: All non-sex chromosomes

; (#1-22 for humans)

Sex Chromosomes:

Chromosomes that determine the sex

of an organism (#23 for humans)

Set (n):

# of different chromosomes.

REMEMBER:

Haploid = 1set, Diploid= 2 sets

Slide5

Amniocentesis

Slide6

Karyotype of a human

Is this person male or female?

How many sex chromosomes are present?

How many autosome chromosomes are present?

How many homologous

pairs

of chromosomes are present?

Slide7

Background on Meiosis

Meiosis involves 2 divisions of the nucleusMeiosis 1 & Meiosis 2Meiosis STARTS with HOMOLOGOUS CHROMOSOMESHomologous Chromosomes: They are

similar in shape, size & genetic content

Slide8

Meiosis 1: 1st Division of Meiosis

Prophase I: Chromosomes condense, nuclear envelope breaks, homologous chromosomes pair at ends.

***Cross-Over:

Part of chromatid on 1 homologous chromosome exchanges with the other chromosome

***

DRAW ME

This is

Genetic variation

Slide9

Meiosis 1: 1st Division of Meiosis

Metaphase I: Homologous chromosomes move to center of the cell by the spindle fibers.

Anaphase I

:

Homologous chromosomes separate

and move to opposite poles

,

BUT sister chromatids stay together.

A set of chromosomes moves to each pole

Telophase I

:

The spindle fibers disappear, cells begin to cleave;

still, two sets of chromosomes are at opposite poles

Slide10

Meiosis 1

Slide11

End of Meiosis I

Once Meiosis I is complete, cytokinesis occurs and the cell splits into 2 haploid cells. These 2 cells enter Meiosis II

Slide12

Meiosis I: STOP & THINK

1. What is the purpose of Meiosis?2. Describe genetic variation

3. Explain purpose of karyotyping

4. Explain cross-over

5. What major event occurs in Anaphase I ?

6. Are the daughter cells haploid or diploid? Explain

Slide13

Any questions

on Meiosis I

?????

Slide14

Meiosis I: Videohttp://www.youtube.com/watch?v=D1_-mQS_FZ0

Slide15

Meiosis II

Prophase II: A new spindle forms around the chromosomes (no longer HOMOLOGOUS CHROMOSOMES)Metaphase II: Chromosomes line up at center & spindle fibers attach to centromere

Anaphase II:

Centromeres split,

chromatids move to opposite poles of cell

Telophase II:

Nuclear envelope forms around each set of chromosomes

& spindles retracts, cell begins cytokinesis

Slide16

Result of Meiosis II

4 HAPLOID cells form as a result of Meiosis IIHaploid = cell containing 1 set of chromosomes

Slide17

Meiosis II: 2nd

division of Meiosis

Slide18

Prophase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Slide19

Metaphase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Slide20

Telophase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Slide21

Meiosis I & II Venn Diagram

Meiosis I

Meiosis II

Slide22

Meiosis Booklet

1. Everyone needs 3 sheets of blank paper

2.

Fold each one hotdog style

3.

Cut straight up the fold

(You should have 6 long sheets, only use 5)

4.

Label each square with the phases of meiosis the same as the mitosis booklet

Slide23

Meiosis Review Questions

What type of cells are used in Meiosis? Give examples of these cells.2.

Meiosis is used in sexual reproduction.

E

xplain the process of “cross-over”

3. Draw homologous chromosomes going through cross-over.

4.Meiosis

is divided into two parts, why?

5

. Define “Haploid”

6

. Compare and Contrast Meiosis to Mitosis.

In your notebook!

Slide24

Mitosis & Meiosis

Comparison Worksheet 

http://www.pbs.org/wgbh/nova/baby/divi_flash.html

http://www.usoe.k12.ut.us/curr/science/sciber00/7th/genetics/sciber/animatin.htm

Slide25

Meiosis & Genetic Variation

Q2 WK4 D2

Nov. 5

th

, 2013