Miscommunication and Misunderstanding: Eisenhower, IRBMs ...
Why do cells Divide? For Growth Development Repair Reproduction Larger cells: - can...
-
Upload
oswin-wilcox -
Category
Documents
-
view
216 -
download
0
Transcript of Why do cells Divide? For Growth Development Repair Reproduction Larger cells: - can...
CELL DIVISION
Why do cells Divide?
For Growth Development Repair Reproduction
Larger cells:
- can miscommunication with DNA
- have trouble processing information
- struggle to exchange materials
across the membrane (SA:V)
Cell Division
Two Types of reproductionAsexual Reproduction
○ Genetically identical offspring from a single parent’s cells dividing
Sexual Reproduction○ Fusion of sex cells from 2
individuals
Advantages of Reproduction Types Asexual: Survival Strategy for single celled
organismsOffspring are genetically identical to parent.Occurs rapidly under favorable conditions.Lower energy input
Sexual: Survival Strategy for multi-cellular organismsOffspring are genetically varied from parentAn advantage in environments that change
frequentlyHigher energy input
Cell Division
A single cell divides into 2 daughter cells
The Cell Cycle
A Series of steps a cell goes through
Growth of the cell / parts Synthesis of new DNA Division of the cell
Cell Division
The Beginning of the Cycle is called Interphase G1- intense growth and making of
new proteins and organelles S - new DNA is synthesized so 2
copies of the chromosomes exist G2 – Preparation and replicating
organelles
The Cell Cycle
A Series of steps a cell goes through:
-growth, preparation, division
B. Prokaryotes:
- asexual reproduction called
binary fission
C. Eukaryotes
- Four phases: G1, S, G2, and M
The Cell Cycle
The Second Stage in the cycle is Mitosis
(division of nucleus and cytoplasm)
III. Chromosomes
A. Packages of DNA (genetic information) that is bundled together.
centromere
chromatids
Duplicated chromosome
Chromosomes (cont.)
B. Prokaryotes-Contain single, circular chromosome.
Bacterial chromosome plasmids
Chromosomes (cont)C. Eukaryotes
-contain multiple chromosomes
-Chromatin -DNA is generally
wrapped around proteins called
histones.
Counting Chromosomes
Chromosomes can have one or two sets of DNA.
Count chromosomes by counting the number of centromeres
a. Mitosis
Prophase –
1. genetic material
condenses
2. chromosomes become
visible
3. spindle starts to form
4. nuclear envelope
disappears
Mitosis (cont.)
Metaphase –
1. Duplicated chromosomes line up in middle
2. Spindle fibers connect to centromeres
Mitosis (cont)
Anaphase –
1. Sister chromatids separate and move to opposite ends of the cell
Mitosis (cont)
Telophase
1. Condensed chromosomes begin to spread out into chromatin.
2. Nuclear envelope
re-forms
b. Cytokinesis
-division of the cytoplasm
-splits parent cell into identical 2 daughter cells
Cytokinesis (cont)Animal Cells: membrane pinches inward
Plant Cells: cell plate develops from inside
Cell Division Animation
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_cell_cycle_works.html