1. Cell Growth and Division

2. Cell Growth and Division
Cell division – when a cell produces two new daughter cells
Cell division is …
the process that allows young organisms to grow
replacement of injured and worn-out cells
or reproduction of single-celled organisms

3. Life Cycle of a Cell - Time Line
Interphase
Mitosis
(most of the cells life)
P M A T

4. Interphase Inter – meaning between Active time between cell divisions
Cell membrane
Interphase
Nucleolus
(ball of DNA)
Cytoplasm
Nuclear membrane
Nucleus
Inter – meaning between
Active time between cell divisions
Growing, making proteins or ATP, moving
Most of the cells life
At the end DNA is copied exactly (duplicated) to prepare for mitosis

5. Mitosis Cellular process of passing on DNA
DNA ( deoxyribonucleic acid) – code of cellular instructions
Mitosis occurs in four stages:
P – Prophase
M – Metaphase
A – Anaphase
T - Telophase

6. Prophase Pro – meaning before DNA forms strands called chromosomes
Cell membrane
Prophase
Centriole
Cytoplasm
Spindle fibers
Chromosomes
Pro – meaning before
DNA forms strands called chromosomes
Centrioles move to opposite sides of the nucleus
Nuclear membrane disappears
Long spindle fibers stretch between centrioles
Chromosomes attach to fibers

7. Metaphase Meta – meaning in the middle
Cell membrane
Metaphase
Centriole
Cytoplasm
Spindle fibers
Chromosomes
Meta – meaning in the middle
Chromosomes line up in the middle of the cell

8. Anaphase Ana – meaning up or away
Cell membrane
Anaphase
Centriole
Cytoplasm
Spindle fibers
Chromatid
Ana – meaning up or away
Looks like a tug-o-war of chromosomes
Doubled chromosomes separate
Fibers shorten
Single chromosomes (chromatids) move to opposite sides

9. Telophase Telo – meaning end Chromosomes reach opposite ends of cell
Cytoplasm
Cell membrane
Telophase
New nucleus
Nuclear envelope
Cytokinesis
Telo – meaning end
Chromosomes reach opposite ends of cell
Fibers disappear
Nuclear envelope forms around each new nucleus
New nuclei are identical to the parent nucleus
Cytoplasm and organelles move to either side
Cytokinesis – cell pinches in half

10. Daughter cells are identical to their parent cells
Two New Daughter Cells !!!
Daughter cells are identical to their parent cells

11. Meiosis Form of cell division that occurs in sex cells
Creates sex cells called gametes (sperm and eggs)
Also known as reduction division
During this process cells go through two divisions which reduces the number of chromosomes to half (haploid)

12. Meiosis – Why reduce the number of chromosomes?
This is important because sperm and eggs combine during fertilization to form a zygote
The sperm and the eggs each contribute half the number of chromosomes to create a whole (diploid), if they were not half the new organism would have too many chromosomes.

13. (Mitosis)