Download 31 Mitosis- Growth, Maintenance, and Repair

31 Mitosis- Growth, Maintenance, and Repair
Biology B Pages 180-188
Name: ___________________ Date: _________ Period: _____________
All organisms (as far as we know) start out as a single celled
organism. For our purposes, all cells go through a cycle that includes
several basic steps:
1.) a living cell will get larger (that
is it usually gets slightly bigger)
This part of the cell cycle is called
the “G1” phase. See small cell becoming
“larger”
in pictures to the right
2.) The next phase is the “S” phase,
the genetic material duplicates. In
humans, we have 23 pairs or 46
chromosomes. During this phase the
cell makes a copy of each
chromosome (we briefly have 92
chromosomes).
Very small
piece of the
chromosome
Condensed
chromosome
Chromosomes make a copy of
themselves: (“S” phase)
Page 2 (Cont. #31 Biology B)
3.) The third part of the phase is when the cell is getting ready
to split into two cells -all the organelles replicate. This phase is called the
“G2” phase.
These first 3 steps taken together are often called “Interphase”!
4.) The last part of the cell cycle is the “Mitotic Phase” or the “M” phase.
This is where the two sets of DNA are
separated and two daughter cells are created
from one parent cell.
Daughter cells
Mitosis is used to:
1.) Repair: repair
damaged cells as in cuts,
scrapes, blood loss,
etc…see cut repair to
right.
In other words, cell
replication or mitosis
replaces injured or dead
cells with NEW cells.
Page 3 (Cont. #31 Biology B)
2.) Maintain: All cells have a life-span (that is how long they live). When
they die or start to malfunction, they are replaced by mitosis.
3.) Grow: All organisms start as a single cell (bacterial are only single
celled organisms and get a little larger before they divide). Multi-cellular
organisms (those that are made up of more than one cell) such as humans
start out as a zygote (see picture below) and undergo mitosis MILLIONS of
times in an effort to grow a larger organism that is more complex.
(The more
complex an
organism is, the
harder it is to
kill.)
Mitosis can be broken up into six basic stages/phases:
Interphase (see pages 1 and 2).
1.) Prophase- the chromosomes condense (become visible using a light
microscope) and start to move around
2.) Metaphase- the chromosomes line up in center of cell- in single file
3.) Anaphase- the chromatids separate (move to opposite sides of the cell
4.) Telophase- the chromosomes segregate (each set of chromosomes
begin forming walls around themselves- called nuclear membranes)
5.) Cytokinesis- two separate daughter cells form.
Page 4 (Cont. #31 Bio. B)
Complete the matching here and on scan-tron.
Column A
Column B
_____ 1.) Cell cycle phase where
A.) Go
organelles replicate
_____ 2.) Cell cycle phase where
chromosomes replicate
B.) G1
_____ 3.) Cell cycle phase where
cell grows bigger
C.) S
_____ 4.) Cell cycle phase where
one parent cell becomes two
daughter cells
D.) G2
E.) M
_____ 5.) Cell cycle phase where
each daughter cell gets an exact
copy of the chromosomes from
the parent cell
_______________________________________________________
Column A
Column B
_____ 6.) Mitosis phase where
A.) Prophase
chromosomes segregate
_____ 7.) Mitosis phase where
chromosomes move away from
each other to opposite sides
B.) Metaphase
_____ 8.) Mitosis phase where
chromosomes line up in single
file in the center of the cell
C.) Anaphase
_____ 9.) Mitosis phase where two
separate daughter cells are formed
D.) Telophase
_____ 10.) Mitosis phase where
chromosomes condense and start
moving around
E.) Cytokinesis
Date: _____________________________
Lesson Plant for Handout #31
Biology B
Objective: TLWD ability to list and explain the four different parts to the
cell cycle and list the five parts of the mitotic cycle when given handout #31.
Content: Cell cycle; G1, S, G1=”I”, M…. Mitotic cycle: Prophase,
Metaphase, Anaphase, Telophase, and Cytokinesis (PMAT-C)
NJCCCS: 5.3.12.A.4
Method: (8 pieces of yarn- two different colors).Yarn pieces as
chromosomes given out to all students and walk through the mitotic phases
making sure everyone is following along with each step at their desks- I
show the movement of the chromosomes on the overhead as I step through
phases.
Homework: Complete #31
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