Download Meiosis

Science Fact of the Day:
If the entire DNA from all nuclei in the human
body were to be arranged lengthwise, it would
measure 1,000 times greater than the distance
from the Earth to the Sun.
Bellwork: November 7
Copy the T-Chart below on a white
piece of paper and fill in the blanks.
Mitosis
•Involves ___ cell division
•Results in ___ genetically
identical cells
•Occurs only in _____ cells
•Creates _______ cells
(contains 2 sets of
chromsomes)
Meiosis
Objective: I will understand the
purpose of meiosis.
Language Objective: I will write
notes about meiosis and make a
Venn diagram of meiosis and
mitosis.
Chromosomes
Chromosomes are coiled
DNA located in the cell
nucleus.
An organism inherits one
chromosome from each
parent.
How many parents do you
have?
So you have ____ sets of
each chromosome.
2 copies of each
chromosome = homologous
chromosomes
A cell that contains 2 sets of homologous
chromosomes is said to be diploid.
2N = diploid cell.
Because N = number of chromosomes
Sexual Reproduction & Our Cells
On a cellular level, what happens
during sex?
Biologically speaking, what’s the
point of sex?
Sexual reproduction
combines DNA from 2
parents.
Gametes are sex cells, also
known as the sperm and
the egg.
When each parent forms
gametes (egg, sperm) in
their body, they can only
have 1 set of chromosomes
instead of 2.
During fertilization,
1 + 1 = 2 sets of
chromosomes.
When gametes (sex cells)
are formed, there must
be a process that
separates the two sets
of genes so that each
gamete ends up with
just one set.
Because gametes contain only 1 set of chromosomes they
are said to be haploid.
N = haploid
N= number of sets of chromosomes in the cell
Meiosis
Meiosis is a process in which
the number of chromosomes
per cell is cut in half through
the separation of homologous
chromosomes in a diploid
cell.
** Meiosis is how gametes
are produced**
Meiosis usually involves two divisions.
By the end of meiosis, the 1 diploid cell that entered
meiosis has become four haploid cells.
During Prophase I of meiosis, chromosomes line up to form
homologous pairs.
When crossing over occurs genetic material is exchanged
between the maternal and paternal sets of chromosomes
present in the cell.
Crossing over results in genetic variation.
Mom’s
chromosome
Dad’s
chromosome
Color and label the diagram
Crossing over
Result = genetic variation
Results of Meiosis
In male animals, the haploid gametes produced by
meiosis are called sperm.
In female animals, the haploid gametes produced by
meiosis are called eggs.
Mitosis vs. Meiosis
Mitosis results in two genetically identical diploid cells.
Mitosis is used for growth.
Meiosis results in four genetically different haploid cells.
Meiosis is used for gamete production and increased genetic variation.
Title the next section of your journal,
“Mitosis vs. Meiosis”.
Create a Venn diagram comparing and
contrasting the processes of mitosis and
meiosis. Consider the # of divisions, # of cells,
haploid/diploid, function in the body, etc.
Now let’s talk
about it…
Make sure
your diagram
contains
these
ingredients: