Cellular Reproduction

Chromosomes

Contain genetic information – DNA

DNA is arranged in segments called genes Determine

characteristics, or traits Humans have 46

chromosomes in their cells – 23 from each parent

Chromosomes

Exist as chromatin prior to cell division - relaxed form of DNA in the cell’s nucleus

Chromosomes

Sister chromatids: Each half of the X, contains identical copies of DNA

Centromere: at the center of the chromosome where the sister chromatids attach

HUMAN CHROMOSOMES

The Cell Cycle

Cells reproduce by growing and dividing

WHY?? Cell division

prevents the cell from becoming too large

To replace other cells

For asexual reproduction

To allow multicellular organisms to grow

3 Main Stages:

InterphaseMitosis

Cytokinesis

The Cell Cycle

Interphase

G1: The cell is growing, carrying out normal cell functions, and preparing to replicate DNA. Occurs immediately after the cell divides.

S: The cell copies its DNA in preparation for cell division.

G2: The cell prepares for the division of its nucleus.

Mitosis Process that

divides the nucleus of one cell into two nuclei

Purpose is to create two daughter cells with identical genetic information

Each daughter cell receives the exact same # and type of chromosomes, it’s like photocopying the cell!

Prophase

Beginning phase, the longest phase

Chromatin tightens, or coils, into chromosomes

In this phase the chromosomes are shaped like an X

Nuclear envelope disappears

Centrioles migrate to poles

Spindle fibers form

Metaphase

Changing phase, one of the shortest stages

Chromosomes are pulled to center of cell and lined up

Ensures there are accurate copies of the chromosomes

Anaphase

Anew phase The spindle

fibers pull the sister chromatids apart into two identical chromosomes

The chromosomes are pulled to opposite ends of the cell

Telophase

Ending phase Chromosome

s reach the poles of the cell and begin to unwind

Two new nuclear membranes begin to form

Nuclei reappear

It’s not over yet!

Cytokinesis

Towards the end of mitosis, the cell undergoes cytokinesis

This divides the cytoplasm

The cytoplasm is pinched (the furrow)

Creates two new cells

Animal Cell - Mitosis

Interphase

                                              

              

Prophase

                                             

               

Metaphase

                                              

              

Anaphase

                                             

               

Telophase

                                              

              

Interphase

                                             

               

Plant Cell - MitosisInterphase

                                                   

         

Prophase

                                                  

          

Metaphase

                                                   

         

Anaphase

                                                  

          

Telophase

                                                   

         

Interphase

                                                  

          

Chromosomes

The Cell Cycle

The Cell Cycle

InterphaseProphaseMetaphaseAnaphaseTelophaseCytokinesis

I Pray More At The Church!

Cell Cycle Regulation

The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong.

Abnormal Cell Cycle

CANCER: the uncontrolled growth and division of cells

Cancer cell can kill an organism by crowding out normal cells, resulting in the loss of tissue function

Cancer

THE CANCER CELL CYCLE IS MUCH FASTER THAN THE NORMAL CELL CYCLE:

Interphase: 120 minutes

Prophase: 60 minutes Metaphase: 10

minutes Anaphase: 3 minutes Telophase: 12 minutes

CHICKEN STOMACH CELLS

Interphase: 16 minutes

Prophase: 15 minutes Metaphase: 2 minutes Anaphase: 1 minute Telophase: 3 minutes

http://www.youtube.com/watch?v=IeUANxFVXKc

Causes

The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations.

Inherited Carcinogen

s Radiation

Apoptosis

Programmed cell death

Cells going through this apoptosis actually shrink and shrivel in a controlled process

Cell Death

Stem Cells

Unspecialized cells that can develop into specialized cells when under the right conditions