10.1 meiosis what you will learn -the stages of meiosis -how chromosome number decreases during...
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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
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