10.1 MEIOSIS

WHAT YOU WILL LEARN-The stages of meiosis-How chromosome number decreases during meiosis-How meiosis provides genetic variation

Cell Division and the Cell CycleFrank Gregariohttp://www.youtube.com/watch?v=Q6ucKWIIFmg&feature=em-share_video_user

http://www.youtube.com/watch?v=cs2cNLNMjN0Bill Nye Greatest Discoveries—CELL DIVISION

READING Q’s

CALCULATE- The approximate number of genes human cells have. Show your work.

-1500 x 46 = 69,000 genes

READING Q’s

IDENTIFY-Circle a pair of homologous chromosomes.

READING Q’s

IDENTIFY- How many chromosomes are in a human gamete.

a- 46 b- 23 c- 10

READING Q’s

LABEL- Circle the part of each chromosome that was swapped during crossover.

READING Q’s

IDENTIFY-During what phase the chromosome number reduced from 2n to n

-ANAPHASE I

READING Q’s

LABEL-Chromosome number for each phase (2n / n)

2n2n

n

n

READING Q’s

LIST-the phase in which the sister chromatids are pulled apart.

-ANAPHASE II

four

READING Q’s

COMPARE

two foursomatic

gametes

READING Q’s

IDENTIFY -underline the haploid daughter cell

READING Q’s

COMPARE

-How is chromosome inheritance different in

sexual reproduction-MEIOSIS- than in asexual reproduction -MITOSIS?

-half an organism’s chromosomes are inherited

from each parent.

GROUP WORK: APPLICATION NOTES

-As a group complete the application note sheet using your knowledge from the reading.

CHROMOSOMES and CHROMOSOME #

IDENTIFY: three characteristics that are the same in each member of a pair of homologous chromosomes

SAME DIFFERENT1- 1-2-3-

length

centromere positionposition of genes for same traits

DO NOT have exact version of each gene

MEIOSIS I / MEIOSIS II

IDENTIFY: the phases of MI and MII

PI T2 INTERPHASE

AIP2

TI A2 MI M2

MEIOSIS I / MEIOSIS II

COMPARE/CONTRAST: the phases of MI and M2PI-chromosomes condense/pair up-centrioles appear/spindle fibers form-homologous chromosomes pair up*crossing over occurs

MI-HC pairs line up at center*random assortment of HC

AI-homologous chromosomes separate

T1-each pole contains one of thepair of homologous chromosomes

P2-chromosomes condense/pair up-centrioles appear/spindle fibers form

M2-chromosomes line up at center

A2

-sister chromatids pulled apart

T2-cell divides into 4 different haploid cells

MEIOSIS I / MEIOSIS II

ANALYZE: the chart above to determine the phase when CROSSING OVER can occur.Mark a STAR on the correct phase

PROPHASE I

MEIOSIS I / MEIOSIS II

COMPARE: meiosis and mitosis by filling in the chart

1

1

4 different

2

1

2 identical2n-

diploidn-haploid

MEIOSIS I / MEIOSIS II

CATEGORIZE:

x

x

x

x

x

x

MEIOSIS I / MEIOSIS II

CATEGORIZE:

xx

xx

x

MEIOSIS I / MEIOSIS II

ORGANIZE: -info on how meiosis produces genetic variation

random arrangement of chromosome pairs @ equator

crossing over

SEXUAL v ASEXUAL REPRODUCTION

COMPARE: asexual reprod

genessexual reprod

genetic diversity

protists animals plants

mammals

SUMMARIZE

EXPLAIN how MEIOSIS and FERTILIZATION produce genetic variation during SEXUAL REPRODUCTION

Prophase 1-crossing over—switch pieces of genetic material Metaphase 1-random sorting of chromosomes lined up at equator increase genetic diversity

Fertilization -increases genetic variation further by combining genetic info from 2 different individuals

-only 1 sperm out of 1,000s will fertilize 1 egg