Download Meiosis Packet

OHS
Unit 8 - Meiosis Packet
Ms. Leone
Name: _________________________________________
Period: ____________
Do NOT lose this packet! It contains all of your notes, worksheets, and study guides to be successful on
the test!
Concept
I know what the process of Meiosis is.
I know why Meiosis is important.
I know what the products of meiosis are.
I know what the term somatic cell is and I know
how many chromosomes are in every somatic
cell.
I know what the term gamete is and I know
how many chromosomes are in every gamete.
I know which types of sex cells males have and
which type females have.
I know what haploid means and the symbol to
describe it.
I know what diploid means and the symbol to
describe it.
I know what a zygote is and how it is made.
I know what oogenesis is and what it makes
I know what spermatogenesis is and what it
makes.
I know that there are two stages of meiosis.
I can draw each stage of meiosis one and write
down the key events.
I know what results after meiosis one.
I can draw each stage of meiosis two and write
down the key events.
I know what results after meiosis two.
I know what crossing over is and when it
occurs.
I know the difference between mitosis and
meiosis.
I can draw a chromosomes and label the sister
chromatids.
I know what is mean by homologous pair.
I HAVE NO
IDEA!
I get it but I need
help!
I totally get it!
Key Vocabulary in Meiosis Notes
Vocab. Word
Somatic Cell
Gamete
Homologous
Diploid
Book Definition
In My Own Words
Ms. Leone’s
Definition and
Example
Key Vocabulary in Meiosis Notes
Vocab. Word
Haploid
Oogenesis
Spermatogenesis
Zygote
Crossing Over
Book Definition
In My Own Words
Ms. Leone’s
Definition and
Example
A horse has a total of 64 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
5.
6.
7.
8.
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
9. Which cells have the N number?
10. Which cells have the 2N number?
A human has a total of 46 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
5.
6.
7.
8.
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
_______
9. Which cells have the N number?
10. Which cells have the 2N number?
A Kangaroo has a total of 16 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
5.
6.
7.
8.
A Spider Mite has a total of 4 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
9. Which cells have the N number?
10. Which cells have the 2N number?
5.
6.
7.
8.
______
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
_________
9. Which cells have the N number?
10. Which cells have the 2N number?
A Carp has a total of 104 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
5.
6.
7.
8.
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
9. Which cells have the N number?
10. Which cells have the 2N number?
A Coyote has a total of 78 chromosomes
1. Total # of chromosomes
2. Haploid # of chromosomes
3. Diploid # of chromosomes
4. # of chromosomes in somatic cells
5.
6.
7.
8.
# of chromosomes in gametes
N number
2N number
Pairs of chromosomes in a body cell
9. Which cells have the N number?
10. Which cells have the 2N number?
Meiosis Notes
What is meiosis?
 Every cell in the body make more cells through ______________________
o We call these cells __________________________
 The only cells in your body that are not produced by mitosis are __________________
o Gametes are ________________ and _______________ cells
o They are made through meiosis.
Meiosis (finally)
 Meiosis is ___________________________________________________________________________
____________________________________________.
o As a bonus, they use it to shuffle DNA around
o Start with 1 _____________ cell
o End with 4 _________________ cells
What is meiosis?
 WHY WOULD WE WANT TO CUT OUR CHROMOSOME NUMBER IN HALF?!
o So that when mom’s gamete and dads gamete join together you get a zygote with 46 chromosomes.
Mitosis Review
 Stages of mitosis
o _________________________________________
 Chromosomes condense
 Nuclear membrane disappears
o _________________________________________
 Chromosomes line up
o _________________________________________
 Chromosomes are pulled apart
o _________________________________________
 Nuclear membrane re-forms and cell pinches
 Chromosomes “dissolve”
 Makes 2 identical cells
Stages of Meiosis
 It happens in two steps: ________________________________ and ___________________________
 Meiosis 1 – similar to mitosis
o _________________________
o _________________________
o _________________________
o _________________________ and ________________________
 Meiosis II – Identical to mitosis
o _________________________
o _________________________
o _________________________
o _________________________ and _______________________
 Makes ____________________________________________________________________
Meiosis I (Reduction Division)
 Goal: ______________________________________________________________________________
 Prophase 1
o ________________________________________ condense
(this means we can see each individual
X)
o
o
o
_____________________________________________________________________________________
_______________
 Mom’s #1 and Dad’s #1, all the way through Mom’s #46 and Dad’s #46
________________________________
 An extra shuffling of the DNA
_________________________
 ______________________________________________________________________________
________________________________________________________
 Mom’s #1 and Dad’s #1 switch some pieces
 Leads to new genetic combinations that way you don’t look like your older or younger siblings.

Metaphase I
o ______________________________________ line up along the equator

Anaphase I
o ______________________________________ and move to opposite poles.
 Remember, at this point, mom and dads chromosomes are replicated,
that is why they look like X’s. Each part of the X is called a sister
chromatid.

Telophase I
o ________________________ partially reform around two nuclei.
o _____________________________ occurs between meiosis I and II
Meiosis II
 We have now achieved _____________________________________
o This means each of the ___________________________________________________
o However, ________________________________________ need to be separated.
 A second round of division pulls the chromosomes apart
o Just like in mitosis
 Meiosis II is virtually identical to mitosis
Meiosis II
 ___________________________
o Chromosomes condense and nucleus/nucleolus disappear
 ___________________________
o Chromosomes line up in the middle of the cell
 __________________________
o Sister chromatids separate to opposite sides of the cell
 ___________________________ and _____________________________
o 4 new cells, each with 23 chromosomes are made
A Review of Meiotic Cell Division
The cells of all green plants and animals have a set or characteristic number of chromosomes. This full
characteristic number is termed diploid or 2N. In humans, the 2N is 46. Each one of the pairs of chromosomes comes
from one parent. The pairs of like chromosomes is termed homologous chromosomes. The homologous chromosomes
are alike in shape and function.
Half the normal number is called haploid or N. In a haploid cell, there are no paired chromosomes. The haploid
number of a human sex cell (gamete) is 23.
During sexual reproduction, there is a union of two gametes (egg + sperm). This union forms a cell called a
zygote. The zygote will have the normal number of chromosomes (diploid). 23 of the zygotes chromosomes will come
from mom and 23 will come from dad.
1. A cell with a 2N number of chromosomes is called _____________________________________
2. A cell with an N number of chromosomes is called _____________________________________
3. Sexual reproduction involves specialized sex cells also called _____________________________
4. These specialized sex cells have a _____________________________ number of chromosomes.
5. The purpose of meiosis is ______________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
6. During the first meiotic division, crossing over occurs. What is crossing over? ____________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
7. After the second meiotic cell division, what percentages of the original chromosomes are in each cell?
___________________________________________________________________________________________
8. If a cell had 140 chromosomes as its 2N number, after both stages of meiosis, each of the 4 daughter cells would
have how many chromosomes? ____________________________________________________
9. The process of sperm formation is called _____________________________________________
10. The process of egg formation is called _______________________________________________
11. In sperm formation, ___________________ equal sized sperm are formed. Each sperm has
________________________ number of chromosomes.
12. In egg formation, ____________________ egg(s) is/are formed. Each egg has a ___________________________
number of chromosomes.
13. What do we call the three other, in viable eggs, in egg formation? ______________________________________
14. How does a zygote form? ______________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
15. How many chromosomes does a zygote have? __________________________
Cell Reproduction: Mitosis vs. Meiosis
The chart below shows the steps of mitosis and meiosis in the correct order. Complete the chart by answering the
questions beside the diagrams.
Mitosis
Meiosis
Questions
A. Where are the chromosomes located?
B. How many chromosomes are present in each cell?
C. What happens to the chromosomes in each picture?
D. What part has disintegrated?
E. Where in the cell have the chromosomes moved to?
F. What helps move the chromosomes? (Hint: they are made by
the centrioles).
G. In mitosis, what begins to form around the chromosomes? Is
this happening in meiosis?
H. How many cells are present in mitosis?
I. How many chromosomes do the cells in mitosis have?
J. What happens in meiosis at this point?
K. Did the chromosome replicate again?
L. How many cells are formed in meiosis?
M. How many chromosomes does each of those cells have?
1. In the exercise above, are the chromosomes paired up in the new cells?
2. How does the process of meiosis differ from mitosis?
In humans, 46 chromosomes are present in each somatic (body) cell and 23 chromosomes are in each gamete (sex cell).
In the chart below, fill in the number of chromosomes in each type of cell, whether that cell is a somatic cell or a
gamete, and the process used to make the cell (mitosis or meiosis).
Cell Type
Number of Chromosomes in Cell
Somatic Cell or Gamete?
Process Used to Make Cell
Stomach
Liver
Sperm
Heart
Egg
Complete the chart below by checking the process of cell division in which each step occurs.
Step of the Process
Two new cells are formed from each original cell.
Four new cells are formed from each original cell.
Replication of chromosomes occurs.
Crossing over occurs between homologous chromosomes.
Cells with a reduced number of chromosomes are formed.
Cells with the same number of chromosomes as the original cell are formed.
Process results in the formation of egg or sperm.
Process results in the formation of somatic cells.
Each original cell divides only once.
Each original cell divides twice.
Chromosomes move to the center of the cell.
Mitosis
Meiosis
Meiosis Study Guide
1. What are the products of meiosis? Think in terms of how many cells are made, whether the cells are
haploid or diploid, and whether or not the cells are identical or not.
2. Gamete cells are __________________________________ and somatic cells are
__________________________________.
3. Crossing over takes place in what stage of meiosis?
4. What is another term for meiosis?
5. When sperm and egg join, a __________________________ is formed.
6. Describe how Spermatogenesis and Oogenesis are different.
7. A human has 46 chromosomes, write how many chromosomes are in each type of cell:
a. Egg
b. Sperm
c. Somatic Cell
d. Zygote
e. Haploid cell
f. Diploid Cell
8. Which part of meiosis is the same as mitosis, meiosis I or meiosis II? Explain how they are similar.
9. Why is crossing over important?
10. Which process of meiosis is performed specifically by females? Males?
11. During meiosis when is the only time that chromosomes are replicated?
12. What process produces somatic cells?
13. Describe in your own terms what homologous chromosomes are.
EXTRA NOTES
EXTRA NOTES
EXTRA NOTES
EXTRA NOTES