The Purpose of Meiosis and
Mitosis
Bell work: Which one of Mr. Morgan’s parents does
he look more like? Does he look identical to either
one? Why?
1. What do you think the word
“diploid” might mean?
• Let’s break the word apart.
Di=Two
Ploid=copies
• We use the word diploid to describe a cell that
has two almost identical chromosomes. With the
exception of sex cells, almost all of a human’s
cells are diploid. We must have diploid cells to
function.
• In regards to a human we must have a pair of
chromosomes to function. With that in mind,
what is something that is paired that you might
use in your everyday life?
• Example: The tongs of a tweezers. There are
two of them and they must be almost
identical in order to function properly.
• Now, it’s your turn. Give me an example of
something that is diploid. Be ready to share
with the class
2. What do you think the word
“haploid” means?
• Let’s break the word apart.
• Hapl=single
Ploid=copies
• We use the word haploid to describe a cell that has
only one chromosome. In its single, halved form it
becomes called a chromatid. Haploid cells with their
chromatids are found in human sex cells (sperm and
egg cells). You started out as a combination of one
haploid cell from your mom and one haploid cell
from your dad.
• In regards to a human, a haploid cell must join
with another haploid cell to make a human.
With that in mind, what is something that
must be paired to make it functional?
• Example: A single shoe. A shoe must be paired with
another one to make the shoes functional.
• Now it’s your turn. Give me an example of
something that is haploid. Be ready to share it
with the class.
3. What does a diploid cell look like?
• Write in your own words one thing you know
about the word diploid.
• A diploid cell with one chromosome will look
like:
On your slates, draw what a diploid
cell with 3 chromosomes would look
like.
Diploid Cell With 3 Chromosomes
3
1
2
4. What does a haploid cell look like?
• Write in your own words one thing you know
about the word haploid.
• A haploid cell with one chromatid will look
like:
On your slates, what would a
haploid cell with 3
chromatids look like?
Haploid Cell With 3 Chromatids
1
2
3
On your slates, what
would a triploid cell
with one
chromosome look
like?
5. What do meiosis and mitosis look
like?
• Mitosis: starts with a diploid cell and ends
with 2 diploid cells.
• Based on the following description, what does
meiosis look like? Hint: fill in the chart. In this
case, consider the start cell to only have one
chromosome.
• Meiosis: begins with one diploid cell and ends
with 4 haploid cells.
6. What are the purposes of meiosis
and mitosis?
• Keep that flow chart in mind as you watch the
following video. Think about how meiosis and
mitosis look relates to what their purpose is. Answer
these questions.
• a.What is the purpose of mitosis?
• b.What is the purpose of meiosis?
Video:
http://www.youtube.com/watch?v=2aVnN4RePyI
In Class Assignment/Homework
• In class assignment: Looking at the flow chart
for meiosis and mitosis, how do the purposes
of each process relate to their end results.
Write 4-5 sentences relating form to function
for both meiosis and mitosis.
• *If you do not finish this in class, it will be
done as homework and turned in tomorrow.