Ch' 10, Cell Growth and Division Ch' 11, Meiosis sec' 114

1
Ch. 10, Cell Growth and DivisionCh. 11, Meiosis
(sec. 11-4)

• Ch. 10
• Cell Growth- why do cells divide instead of
  continue to grow?
• Cell Division Cell Cycle and when a cell
  divides, Mitosis
• Regulation of the Cell Cycle- how its
  controlled, what happens when its out of control
• Ch. 11
• Phases of Meiosis
• Comparing Mitosis and Meiosis

2
Cell Growth
Section 10.1 Cell Growth
Im out of control!
Too Big!
Just right
TooSmall

• How do organisms grow? Do their cells get
  bigger? Or do they make more cells?
• Answer Make more cells!!!
• There is a limit to how big cells can grow!
• Getting bigger does 2 things
• Places more demands on DNA
• Makes it harder to move molecules across a cells
  membrane

Box 1
Box 2
3
Surface Area to Volume Ratio
Bigger is NOT better!
Volume (V) 1 x 1 x 1 1 cm3 (length x width x
height)
More surface area! Good!
Ratio of SA to V 6/1 61
SA 3 x 3 x 6 54 cm3
Less surface area! Bad!
V 3 x 3 x 3 27 cm3
Ratio of SA to V 54/27 21
4
Whats the solution to this traffic problem?
5
Cell Division
Im too fat
daughter
daughter
Mommy?

• When a cell divides, the 2 cells that result are
  called daughter cells
• Cell Division process by which a cell divides
  into 2 new daughter cells
• Before cell division, the cell replicates, or
  makes copies of all of its DNA
• Solves the 2 problems with cell growth
• New daughter cells get one complete set of
  genetic information- they get their own complete
  genetic library
• No more problems with SA to V ratio because
  daughter cells has an increased ratio of SA to V
  because their volume overall is reduced (one cell
  dividing into two makes both cells smaller)

Box 8
Box 9
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Cell Division
Section 10-2

• In Eukaryotes (you!), cell division occurs in 2
  main stages
• Mitosis division of the cells nucleus
• Cytokinesis division of the cytoplasm

Box 11
(Sy-toh-kih-NEE-sis)
7
Chromosomes
chromatid

• When a cell isnt in the process of dividing,
  chromosomes are not visible because they are
  spread out within the nucleus.
• However, when cell division is beginning, the
  chromosomes condense into compact, visible
  structures we can see in a microscope.
• Before cell division occurs, each chromosome is
  copied, or replicated, and the identical copies
  are called sister chromatids (KROH-muh-tids)

replication
Yo! Sis!
LYLAS!
Centromere
Box 16
Sister chromatid
Sister chromatid
Box 15
8
The Cell Cycle
Box 17

• The Cell Cycle is a series of events that cells
  go through as they grow and divide
• 1. Cell grows
• 2. Cell prepares for division
• 3. Cell divides to form 2 daughter cells (each
  daughter cell will begin the cell cycle again)

9
Cell Cycle Phases
Box 20
I
G1 phase
I
M
M phase
S phase
I
G2 phase
10
Mitosis

• Interphase then.
• Mitosis has 4 phases
• 1. Prophase
• 2. Metaphase
• 3. Anaphase
• 4. Telophase

I then ..PMAT
Box 25
Interphase is NOT part of Mitosis!!!!! Remember
that!
11
Mitosis
Interphase cell grows and replicates its DNA
and centrioles.
Box 26
Interphase
Centrioles
Chromatin
Nuclear envelope
12
Interphase cell grows and replicates its DNA
and centrioles.
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down
Box 27
Interphase
Spindle forming
Prophase
Centrioles
Centromere
Chromatin
Nuclear envelope
Chromosomes (paired chromatids)
13
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down.
Interphase cell grows and replicates its DNA
and centrioles.
Interphase
Spindle forming
Prophase
Centrioles
Centromere
Centriole
Chromatin
Nuclear envelope
Chromosomes (paired chromatids)
Spindle
Centriole
Metaphase
Box 28
Metaphase chromosomes line up across the center
of the cell, each chromosome is connected to a
spindle fiber at its centromere
14
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down.
Interphase cell grows and replicates its DNA
and centrioles.
Interphase
Spindle forming
Prophase
Centrioles
Centromere
Centriole
Chromatin
Nuclear envelope
Chromosomes (paired chromatids)
Spindle
Centriole
Individual chromosomes
Metaphase
Box 29
Anaphase sister chromatids separate into
individual chromosomes and move apart
Metaphase chromosomes line up across the center
of the cell, each chromosome is connected to a
spindle fiber at its centromere
Anaphase
15
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down.
Interphase cell grows and replicates its DNA
and centrioles.
Interphase
Spindle forming
Prophase
Centrioles
Centromere
Centriole
Chromatin
Nuclear envelope
Chromosomes (paired chromatids)
Spindle
Centriole
Telophase
Individual chromosomes
Metaphase
Nuclear envelope reforming
Anaphase sister chromatids separate into
individual chromosomes and are moved apart
Anaphase
16
Interphase cell grows and replicates its DNA
and centrioles.
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down.
Interphase
Spindle forming
Prophase
Centrioles
Centromere
Centriole
Chromatin
Nuclear envelope
Chromosomes (paired chromatids)
Spindle
Cytokinesis
Centriole
Telophase
Individual chromosomes
Metaphase
Nuclear envelope reforming
Anaphase sister chromatids separate into
individual chromosomes and are moved apart
Anaphase
Telophase chromosomes gather at opposite ends
of the cell and lose their distinct shapes- 2 new
nuclear envelopes form
17
Prophase chromatin condenses into chromosomes,
centrioles separate, spindle forms, nuclear
envelope breaks down.
Interphase cell grows and replicates its DNA
and centrioles.
Cytokinesis cytoplasm pinches in half, each
daughter cell has an identical set of duplicate
chromosomes
Interphase
Prophase
Ithen PMAT
Cytokinesis
Metaphase
Metaphase chromosomes line up across the center
of the cell, and each is connected to a spindle
fiber at its centromere
Telophase chromosomes gather at opposite ends
of the cell and lose their distinct shapes- 2 new
nuclear envelopes form
Telophase
Anaphase
Anaphase sister chromatids separate into
individual chromosomes and are moved apart
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Prophase
Interphase
Metaphase
Cytokinesis
Anaphase
Telophase
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Cell Cycle Tree Map
Cell Cycleincludes..
Mitosisis divided into
Interphaseis divided into
G1 phase
S phase
G2 phase
Telophase
Prophase
Metaphase
Anaphase
And thenCytokinesis