Why do cells divide?
Watch the lecture on mitosis by the “Penguin Prof” and fill out pages 1-5 as you watch:
http://www.youtube.com/watch?v=65SODTL_QsA
MITOSIS
Write down a few examples of when this basic type of cell division occurs:
1.
2.
3.
DNA Management
The DNA in a cell is ____ feet long. When the cell is not dividing, the DNA is in the
form of ____________________. When it is dividing, it is in the form of
______________.
Why is chromatin good for times when the cell is functioning normally, and why are
chromosomes good when the cell is dividing?
Overview of Mitosis:
Write a couple of sentences explaining what this diagram means.
When does the replication of DNA occur?
The Cell Cycle
List the 3 phases of the cell cycle that make up interphase: ______, _____, & ______.
List the two parts of the cell cycle that make up cell division: _______________ &
_________________.
1
Take notes on the diagram below, writing down what happens in the three phases of
interphase. Also write the names of the phases of mitosis.
Chromosomes
Label the structures 1 & 2 of the chromosome
on the far right.
Don’t worry about the different kind of microtubules
the Penguin prof talks about from 7:06-9:08. You
do not need to know about all these. We will call all
the different kinds of microtubules spindle fibers.
1 = _______________
2 = sister ___________
3 = short arm
4 = long arm
Pause the Penguin Prof:
Chromosomes are made up coiled up chromatin. Chromatin is DNA wrapped around
proteins called histones. Label the structures indicated by arrows using this word bank:
DNA
Histone
Chromatin
Chromosome
2
PHASES OF MITOSIS – restart the Penguin Prof
Prophase – take notes on the diagram below describing what occurs during this phase.
Label the centrosomes (same thing as the centrioles) and the nucleus.
Prometaphase – take notes on the diagram below describing what occurs during this
phase. All the different kinds of microtubules we will call the spindle fibers. Draw in
the spindle fibers as they did not copy well.
Metaphase – take notes on the diagram below describing what occurs during this phase.
Label the centrosomes (centrioles), the spindle fibers, and the chromosomes.
3
Anaphase – take notes on the diagram below describing what occurs during this phase.
Label the centrosomes and the spindle fibers. Draw a line that shows where the equator
is located.
Telophase – take notes on the diagram below describing what occurs during this phase.
Label the cleavage furrow and the nucleus of one of the newly formed cells.
How does the division of the cytoplasm of plant cells occur?
How long does it take for cells to divide?
An example of a type of cell that don’t divide at all once they reach maturity:
An example of a type of cells divides when stimulated:
An example of a type of cells that always divides:
4
HOW DO CELLS KNOW WHEN TO DIVIDE?
Take notes on what happens at each checkpoint on the cell cycle.
What happens in cell division that causes cancer?
CELL DIVISION IN PROKARYOTES
This is not in the video, get your info here: As they have no nucleus and only one long
circular chromosome, prokaryotes divide by making a copy of the chromosome, and the
membrane then pinching in to make two cells. This is called binary fission!!! Use this
information and the diagram below to answer these questions.
Label the two daughter cells in the diagram to the left.
Is binary fission sexual or asexual reproduction?
What kinds of cells reproduce through binary
fission?
5
MEIOTIC CELL DIVISION – Sexual Reproduction (making sperm & egg)
Watch this as an introduction: http://www.youtube.com/watch?v=kVMb4Js99tA
Then fill out the packet using Crash Course #13:
http://www.youtube.com/watch?v=qCLmR9-YY7o
What does meiosis explain?
Homologous chromosome pairs are:
• Most of your body cells (somatic cells) are diploid and contain _____ chromosomes.
But some cells are haploid and contain _____ chromosomes, these are ___________ and
_____________ cells.
• Meiosis starts with a diploid cell that duplicates its chromosomes, divides ________
times, creates _______ new cells, and all of the new cells are____________ from the
others!
Meiosis goes through the same stages of mitosis but twice! In the first division
homologous chromosomes separate, and in the second division sister chromatids separate.
DNA replicates in Interphase
The phases of meiosis are described on the next page:
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Stages of Meiosis
Prophase 1- Same as mitosis except for 2 additional steps:
Describe what is happening in the diagram below, use the terms crossing over &
recombination.
Describe what happens in each phase. Use the diagram below to help you:
Metaphase I Anaphase I Independent assortment!
Telophase I At this point, how many cells? ___ Are they diploid or haploid? ___________ Are they
identical? _______
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Second Meiotic Division
No DNA replication takes place. Using the diagram below to help you, describe what
happens in each phase:
Prophase II Metaphase II Anaphase II Telophase II At this point, how many cells? ___ Are they diploid or haploid? ___________ Are they
identical? _______
Explain how crossing over and independent assortment provide genetic variation.
And what is the advantage of genetic variation?
8
Using the information in the video and the diagram below, what is the difference between
the production of egg cells and the production of sperm cells?
9
Compare and Contrast Mitosis and Meiosis:
Mitosis
Meiosis
Purpose
Phases
Number of divisions
Number of daughter cells
Homologous chromosomes
pair?
Are daughter cells diploid
or haploid?
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Book Definition
Autosome
Any chromosome that is not
a sex chromosome
Binary
fission
Form of asexual reproduction
in single celled organisms by
which one cell divides into 2
equal cells
The repeating set of events in
the life of cell, consists of
interphase and cell division
The precursor of a new cell
wall that forms during cell
division and divides a plant
cell into two
An organelle that is
composed of two short
microtubules and that has an
active role in cell division
The region of the
chromosome that holds the
two sister chromatids
together during mitosis
One of the two strands of the
chromosome that becomes
visible cell division
The genetic material that
makes up chromosomes, a
complex of proteins and
DNA that are loosely coiled
A structure made of histone
proteins and DNA in
eukaryotes, and only visible
during cell division
Cell cycle
Cell plate
Centriole
Centromere
Chromatid
Chromatin
Chromosome
In my own words
How will I
remember it?
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Cleavage
furrow
Cytokinesis
Diploid
Haploid
Histone
Homologous
chromosoms
Nucleosome
Meiosis
Mitosis
The areas of the cell
membrane that pinches in
and eventually separates a
dividing cell into two new
cells, in animals.
The division of the
cytoplasm of a cell
A cell that contains two
haploid sets of chromosomes
Describes a cell or nucleus
that has only one set of
unpaired chromosomes
A type of protein molecule
found in the chromosomes of
eukaryotic cells but not
prokaryotic cells
Chromosomes that have the
same sequence of genes, the
same structure, and pair
during meiosis
One unit of DNA wrapped
around a histone, found in a
chromosomes
A process of cell division in
which the number of
chromosomes decreases by
half, which results in the
production of sex cells
In eukaryotic cells, a process
of cell division that forms
two new nuclei each of
which ahs the same number
of chromosomes as the
original cell
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