Bellwork 2-4-2014
1. Look at the two different populations of
organisms below:
a. Which one is asexual and which one is sexual?
b. Which one has variety and which once does not?
A
B
Missed work!!
• If you finish an assignment that was
incomplete when I put in homework grades,
turn it into the basket!
• All in class work can be completed for full
credit! Find a friend in the class if you are
missing a lot of work!
• Check grades
Vocab Review
• Chromosome – two chromatids put together, one
complete set of information
• Sister chromatids – make up a chromosome, half of
the information
• Homologous chromosomes – multiple pairs of
chromosomes (two chromatids each), some from
mom and some from dad
Exploring Meiosis I
• You will be exploring meiosis I on your own with
your NEW lab group today
• Following the guidelines at each lab bench, model
EACH step of meiosis with the colored beads and
chalk
• After each step, YOU MUST GET CHECKED and
then draw the step on your worksheet with
colored pencils
Your models
Chromatid
Chromosome
Replication 
**You will have 4
of these in total,
all different
colors!
Check your drawings!
Once you are done…
• Homework if not done in class…
– Describe the steps of meiosis using COMPLETE
SENTENCES
Bellwork 2-5-2014
1. At which stage in meiosis I does the exchange
of information on chromosomes occur?
2. How many cells does meiosis I create?
3. Are the products of meiosis I identical or is
there variety?
*Check grades
**Test-make-ups
Meiosis
Meiosis: Unit Vocabulary
meiosis
tetrad
haploid
diploid
somatic cell
homologous pair
gamete
zygote
crossing over
Prophase I and II
Metaphase I and II
Anaphase I and II
Telophase I and II
genetic recombination
sexual reproduction
asexual reproduction
independent assortment
Meiosis Video
• http://www.youtube.com/watch?v=wrxY4hjM
Dfk
How much information?
Whole set of DNA = 2n  Diploid
Half set = n  haploid
How to remember:
Half – Haploid
Di = 2
How much information?
n – haploid!
2n – diploid!
Talk with your neighbor:
Are chromatids haploid or diploid?
Are chromosomes (pair of sister chromosomes)
haploid or diploid?
Pre Interphase!
• Draw a circle on top of your worksheet and
label it pre-interphase
• What happens to chromatids
in pre-interphase to get the
results YOU drew in
interphase?
Interphase
DNA
replication
Draw and label the centrioles on your
Drawing
How much information?
2n!! Diploid
Prophase I
Tetrads form and
crossing over
occurs
Label the tetrads in
your picture &
where crossing
over happens
Prophase I
How much
information?
n or 2n??
2n - Diploid!!!
Tetrads & Crossing Over
Tetrads – close
association of sister
chromatids on
homologous
chromosomes
Crossing Over:
Homologous
chromosomes exchange
small pieces, resulting in
new chromosomes!
Crossing Over Must Happen
Perfectly!!!
What do we call the two pairs of chromosomes pictured?
Homologous Chromosomes!
Homologous Recombination I
• Where should the circled site on
Chromo1 recombine with Chromo2?
1
2
20
3
Oooops...
2
This is what happens in the mutation that causes color
blindness in males! Green opsin gene duplicated and
got changed somewhere along the way to sense more in
the red region.
Short end of the stick
22
http://www.blackwellpublishing.com/korfgenetics/figure.asp?chap=02&fig=Fig2-3
Metaphase I
metaphase
Homologous
chromosomes line
up at the
plate
How much info?
2n – Diploid!
Anaphase I
Homologous
chromosomes move to
opposite ends of the
cell
Independent
assortment occurs
creating new
combinations!
How much info?
2n – Diploid!
Independent Assortment
Chromosomes
from mom & dad
RANDOMLY move
to one side or the
other
Telophase I
Cell walls begin
to pinch inwards
How much info?
2n – Diploid!
(Cytokinesis I)
Two daughter
cells pinch off
Talk to your
neighbor…
How do they
compare to one
another?
n (haploid) or 2n
(diploid?
Why does genetic recombination
matter?
• Your turn!!! You will get two homologous
chromosomes with your partner that look like this…
Yellow:
White:
Red:
Green:
What traits do each
potential individuals have?
Why does genetic recombination
matter?
• Cross over at the indicated positions below
Yellow:
White:
Red:
Green:
Now what traits do each
potential individuals have?
Why does genetic recombination
matter?
• Cross over at the indicated positions below
Yellow:
White:
Red:
Green:
Now what traits do each
potential individuals have?
Bellwork 2-6-2014
1. If you missed the drawings for meiosis I, get
some colored pencils and copy it from your
neighbor. I will stamp it.
2. Get your sentences out from yesterday if I
didn’t stamp them yet.
3. Can you find my mistake from yesterday?
Extra credit to who figures it out first (hint: it
has to do with the amount of information in
one step but its not at the end of meiosis I!)
4. Get out your pink sheet and be ready to go
through meiosis II!
Announcements
• Tomorrow we will be walking through the gym
to see the science fair boards
• Test on meiosis next Wednesday
• Homework is coming on Monday! Don’t get
behind!
• Test make-ups
Once you are done…
• Write a sentence explaining the steps of
meiosis II! One sentence for each step.
• HOMEWORK IF NOT DONE IN CLASS!
Bellwork 2-7-2014
1. Have your sentences from meiosis I out if
they have not been stamped yet as well as
meiosis II sentences
2. Have pink sheet with drawings out for
meiosis I and II to be stamped
3. Work on the questions at the end of your
pink meiosis packet for bellwork. This will
be stamped WHEN YOUR DONE!
Bellwork 2-10-2014
1. What is the difference between a
homologous chromosome pair and a
chromosome?
2. What is a tetrad?
3. Have sentences from meiosis II out to be
stamped
4. Have green science fair sheet out to be
stamped if I didn’t stamp it Friday
Announcements
• Meiosis quiz Wednesday
• Essential question
• Drawing and binder check TODAY!
PRE - INTERPHASE
INTERPHASE
PROPHASE
Tetrad= 2 homologous
chromosome pairs (one from
mom in each, one from dad
in each): 4 chromatids
Crossing over
occurs between
homologous pairs
METAPHASE 1 (middle)
ANAPHASE 1 (apart)
Homologous chromosome
pairs line up
Spindles attach to chromosomes
TELOPHASE 1
Almost two cells
CYTOKINESIS
PROPHASE II
METAPHASE II
Spindles
attach to
chromatids
ANAPHASE II
Chromatids separate
TELEPHASE II &
CYTOKINESIS
Prophase II
Beginning with the
end products of
meiosis II
Chromosomes are
condensed and
prepare for another
division
No crossing over!!
n or 2n? 2n - Diploid!!
Metaphase II
Chromosomes line
up at the
metaphase plate
More similar to
mitosis this time
Not homologous
pairs any longer
n or 2n? 2n - Diploid!!
Anaphase II
Chromatids
move to either
end of the cell
n or 2n?
2n - Diploid!!
Telophase II
Chromatids
separate to
individual cells
n or 2n?
n - haploid!!
(Cytokinesis)
Individual cells form
n or 2n?
Talk with your neighbor:
How do the cells
compare to each other?
How do they
compare to the
products of meiosis I?
What do we call these cells?
These cells are called
gametes  they can be
Eggs (from females) or
Sperm (from males)
n or 2n?
They are haploid!!!
Get half of information
from mom, half from
dad
Fertilization – Making babies!
Sperm
+
Zygote
Egg
=
Human Chromosomes!
How many pairs?
23
How many
chromosomes?
46
How many sex
chromosomes?
2
How many undergo meiosis? All of them!
Chromosome vs. Chromatid and how
they are used
Meiosis I
Products:
Amount of info:
Spindles attach to:
What is divided:
Crossing over?
vs.
Meiosis II
Products:
Amount of info:
Spindles attach to:
What is divided:
Crossing over?
Funny Meiosis Video
• http://www.youtube.com/watch?v=iCL6d0Ow
Kt8
Vocab activity
• You and a partner will get a sheet of card stock
to draw a stage of meiosis I or II.
• You MUST label all parts of your drawing
(homologous chromosomes, centrioles, cell
pinching, metaphase plate etc.)
• When you and your partner/s are done,
present to the class
Binder Check
Bellwork (4 stamps)
Notes
• Meiosis I and meiosis II notes (hand written)
Homework/worksheets/labs
• Green variation activity with colors
• Pink meiosis packet with all drawings and stamps
• Green science fair worksheet
• Meiosis I and II sentences (handwritten)
Homework 1-10-2014
• Orange meiosis worksheet – due tomorrow!
Tuesday
• Put homework and notes packet together and
take home to study!
Bellwork 2-11-2014
1. What is being separated in meiosis I?
a. Chromosomes
b. Homologous chromosomes
2. What is being separated in meiosis II?
a. Chromosomes
b. Homologous chromosomes
3. What is the difference in the amount of
information from meiosis I to meiosis II?
Presentations
• Present your stage of meiosis I or II
Slate Quiz!
• Look at the pictures on the following slides &
name the stage of meiosis!
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Charades!
Unit Packet
• Notes on top (meiosis I and meiosis II)
• Homework/worksheets/labs on bottom
– Green variation activity
– Pink meiosis packet
– Green science fair worksheet
– Meiosis I and II sentences (handwritten)
– Orange homework multiple choice worksheet
– Yellow questions packet  add tomorrow!
Work on yellow sheet
• Last 10 minutes…
• Finish the first page (front and back) of the
yellow sheet as your ticket out the door.
Bellwork 2-12-2014
1. Grab an article by the door, read it for
bellwork and answer the following
questions…
a. What was the main point the article was trying to
make?
b. Hypothesize how this might be possible given
what we have learned so far.
Work on yellow sheet
• Work on the second sheet (front and back) of
the yellow sheet
• You have 10 minutes
Turn in unit packets and bellwork
• Add yellow sheet to unit packet and turn into
basket
• Add up bellworks (6 stamps) and write at the
top
Unit Packet
• Notes on top (meiosis I and meiosis II)
• Homework/worksheets/labs on bottom
– Green variation activity
– Pink meiosis packet
– Green science fair worksheet
– Meiosis I and II sentences (handwritten)
– Orange homework multiple choice worksheet
– Yellow questions packet