Cell Cycle - PowerPoint PPT Presentation

About This Presentation
Title:

Cell Cycle

Description:

They grow and divide! The process of cells growing and dividing is known as the cell cycle. Why do cells need to do this? Hmmm Cell cycle cells growing and ... – PowerPoint PPT presentation

Number of Views:509
Avg rating:3.0/5.0
Slides: 27
Provided by: pco57
Category:
Tags: cell | cycle

less

Transcript and Presenter's Notes

Title: Cell Cycle


1
Cell Cycle
2
How do cells make more cells?
  • They grow and divide!
  • The process of cells growing and dividing is
    known as the cell cycle.
  • Why do cells need to do this? Hmmm
  • Cell cycle cells growing and dividing

3
Stages of Cell Cycle
  • There are 3 stages
  • Interphase
  • Mitosis
  • Cytokinesis
  • All of the cell cycle occurs in the nucleus!

4
Parts to know
  • We need to understand some parts of the cell
    before we begin looking at each step.
  • Centrioles
  • Chromatin
  • DNA
  • Chromosomes

5
Centrioles
  • Come in pairs
  • Look like a macaroni noodle or barreled shape
  • Found in the cytoplasm
  • Like to hang out at the north pole of the cell
  • They are orange here

6
Centrioles
7
Chromatin
  • Definition Mass of genetic material composed of
    DNA and proteins.
  • Chromatin is located in the nucleus of a cell.
  • During mitosis (2nd stage), chromatin condenses
    to form chromosomes.

8
DNA in Chromatin
  • I mentioned that chromatin
  • is made of DNA.
  • What is DNA?
  • DNA, or deoxyribonucleic acid, is the hereditary
    material in humans and almost all other
    organisms.
  • Most DNA is located in the cell nucleus.
  • So, chromatin is composed of DNA and chromatin
    condenses to form chromosomes.

9
Chromosomes
  • Once again chromatin is composed of DNA and
    chromatin condenses to form chromosomes.
  • What are chromosomes?
  • It is a single piece of coiled DNA

10
Chromosomes
11
Structure of Chromosome
The centromere acts like a button. It keeps the
2 chromatids together making the double rod X
structure.
12
Stage 1- Interphase
  • Interphase Growth Phase
  • This is the period where the cell grows and
    prepares for division.  It is divided into three
    parts
  • G1 The cell grows
  • S The cell replicates its chromosomes (DNA).
  • G2 The cell replicates its organelles and
    prepares for division.

13
Stage 1- Interphase
  • During interphase, the chromosomes are not
    visible.  They are uncoiled.  When the DNA is in
    this uncoiled form its called chromatin. 
  • The reason its uncoiled is this allows it to be
    copied more easily.

14
Stage 1- Interphase
  • The cell spends most of its life in the
    interphase stage.

15
Visit Stage 1- Interphase
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • Now the cell is ready to divide. Next stage

16
Stage 2 - Mitosis
  • Mitosis Division of the Nucleus
  • This is divided into four steps
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase

17
Stage 2 MitosisStep 1 Prophase
  • Chromatin condenses to form chromosomes
  • Centrioles move to opposite ends of cell
  • Nuclear envelope starts to break down.

18
Visit Mitosis Step 1 Prophase
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • Time to move to the next step of mitosis

19
Stage 2 MitosisStep 2 Metaphase
  • The chromosomes line up in the MIDDLE of the
    cell.
  • The centrioles are at north south poles.
  • MMMMetaphase..MMMMiddle

20
Visit Mitosis Step 2 Metaphase
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • Time to move to the next step of mitosis

21
Stage 2 MitosisStep 3 Anaphase
  • Remember the centromeres
  • that act like a button and hold
  • the chromosomes together?
  • Well, not anymore. The centromeres break.
  • Thus, the chromosome is seperated and becomes two
    chromatids again.
  • Each chromataid moves
  • to opposite ends of cell.
  • AAAnaphaseAAAway

22
Visit Mitosis Step 3 Anaphase
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • Time to move to the last step of mitosis

23
Stage 2 MitosisStep 4 Telophase
  • A new nuclear envelope has formed around each
    region of chromosomes
  • TTTwo Nucleus(Nuclei)TTTelophase

24
Stage 2 Mitosis.Step 4 Telophase
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • The last step of mitosis.

25
Stage 3 - Cytokinesis
  • cyto- (cell) and kinesis (motion, movement)
  • Cytokinesis is the process in which the cytoplasm
    of a single eukaryotic cell is divided to form
    two daughter cells.

26
Stage 3 - Cytokinesis
  • http//www.phschool.com/atschool/phsciexp/active_a
    rt/cell_cycle/index.html
  • A look at the last stage of the cell cycle.
Write a Comment
User Comments (0)
About PowerShow.com