Download Chapter 5: CELL GROWTH & DIVISION

BIG IDEA: (P.128)
CELLS HAVE THEIR OWN LIFE CYCLE THAT
INCLUDES REPRODUCTION, GROWTH &
REGULATION, WHICH ALLOWS ORGANISMS
TO CARRY OUT LIFE FUNCTIONS AND GROW.
What might happen to your body that would cause a normal cell to respond
by dividing?
Injury… infection…
developmental changes… or
maintenance……
BACKGROUND INFOAll cells that make up the BODY are known as SOMATIC cells. (hair, skin, bones)
In humans, they all contain 46 chromosomes.
Cells with a FULL set of chromosomes are called DIPLOID (2n)
SPERM & EGG are unique cells called GAMETES or GERM CELLS.
In humans, they contain 23 chromosomes each.
Cells with HALF a set of chromosomes are called HAPLOID. (n)
ZYGOTE-
very first BODY cell…sperm & egg unite
THE CELL CYCLE (P. 130)
INTERPHASE
The cell cycle has 4 main stages:
Gap 1- (G1) normal cell functions, rapid growth
Synthesis ( S) – copies DNA
Gap 2 (G2)- continue normal functions and growth
Mitosis (M) – mitosis and cytokinesis
CELL SIZE IS LIMITED (P. 132)
Cells have upper and lower size limits.
Cells too small would not have room for necessary
organelles.
Cells too large would be limited by ratio of surface
area to volume.
Materials could not move sufficiently across cell.
See fig. 1.3, p. 133
*To maintain a suitable cell size, growth and division
must be coordinated.
5.2 MITOSIS AND CYTOKINESIS
It’s ALL about the CHROMOSOMES!!
Chromosome- one long continuous thread of DNA that consists of
numerous genes and information.
gene- smallest unit of DNA that codes for a protein and trait
Fun fact- If stretched out straight, end to end, the DNA in ONE cell
would be about 10 feet long!
How does it fit inside your cells?
chromosomes TIGHTLY condense and wrap around
proteins.
STATES OF DNA: (P. 135)
1. Chromatin2. Chromosome3. Chromatid-
Centromere-
STAGES OF MITOSIS (P.136)
Remember: Before the cell can divide it must go through INTERPHASE
STAGES OF MITOSIS : P.M.A.T.
1.PROPHASE- NUCLEAR ENVELOPE DISAPPEARS
- CHROMATIN CONDENSES INTO CHROMOSOMES
- MITOTIC STRUCTURES FORM: SPINDLES & CENTRIOLES
PROPHASE VIDEO
STAGES OF MITOSIS : P.M.A.T.
2. METAPHASE-
- CHROMOSOMES LINE UP IN MIDDLE ALONG EQUATOR
- SPINDLES ATTACH TO
CENTROMERES
METAPHASE VIDEO
STAGES OF MITOSIS : P.M.A.T.
3.
ANAPHASE
- SISTER CHROMATIDS SEPARATE
ANAPHASE VIDEO
STAGES OF MITOSIS : P.M.A.T.
4. TELOPHASE:
IDENTICAL CHROMOSOMES ARE AT OPPOSITE POLES OF CELL
NUCLEAR MEMBRANES REAPPEAR
MITOTIC STRUCTURES DISAPPEAR
TELOPHASE VIDEO
CYTOKINESIS:
WHEN THE CYTOPLASM COMPLETELY DIVIDES
INTO 2 CELLS & COMPLETES THE FULL STAGE
OF THE CELL CYCLE.
CYTOKINESIS DIFFERS IN PLANTS & ANIMALS
Cell furrow
Cell plate
REGULATION OF CELL CYCLE (P.140)
INTERNAL & EXTERNAL FACTORS REGULATE THE CELL CYCLE
EXAMPLES: Chemical & Physical Signals
The cell cycle has checkpoints that respond to feedback signals
CANCER
When regulation of the cell cycle is disrupted……
…..cells divide out of CONTROL!
Clumps of cancer cells = tumors
BenignMalignant-
BINARY FISSION
*PROKARYOTES- carry out a simpler & quicker mode of division
*remember they are less complex with NO ___________.
End result is similar: both mitosis and binary fission form 2 daughter
cells that are identical to the parent cell.
ASEXUAL REPRODUCTION
ADVANTAGES
DISADVANTAGES
STEM CELLS P. 150
Stem cells- unique type of BODY cells that can divide & renew
themselves for long period of time and differentiate into specialized
cells.
Adult Stem Cellspartially undifferentiated, can be found all over the body
Embryonic Stem CellsUndifferentiated cells in a 3-5 day embryo, can become any type of cell.
REVIEW MITOSIS:
P.M.A.T.