Mitosis cell division review
Download
1 / 30

Mitosis/Cell Division Review - PowerPoint PPT Presentation


  • 65 Views
  • Uploaded on

Mitosis/Cell Division Review. A. B. C. D. E. Meiosis . Produces gametes or sex cells (sperm and egg cells) Occurs ONLY in the reproductive organs. Products of Meiosis = 4 new cells. AND. Divides the chromosome number in half. For Example: . Parent Cell. 4 daughter cells.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Mitosis/Cell Division Review' - harva


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

A

B

C

D

E


Meiosis

  • Produces gametes or sex cells (sperm and egg cells)

  • Occurs ONLY in the reproductive organs


Products of Meiosis = 4 new cells

AND

Divides the chromosome

number in half


For Example:

Parent Cell

4 daughter cells


2 Sets of Divisions

1st division is exactly like mitosis

except sister chromatids stay together


Before the 1st division takes

place DNA MUST replicate


Prophase I

  • Chromosomes condense

  • Homologous chromosomes pair together

  • Crossing over occurs



Metaphase I

  • Homologous pairs are moved to the equator (middle) of the cell


Anaphase I

  • Homologous pairs separate

  • Chromatids remain together

  • Genetic material has been recombined


Telophase I

  • Chromosomes gather at poles

  • Cytoplasm divides


2nd DIVISION BEGINS

DNA replication

DOES NOT

occur


Prophase 2

  • New spindles form around chromosomes

  • Crossing over – does not occur!


Metaphase 2

  • Chromosomes align along with equator (middle) of the cells


Anaphase 2

  • Sister chromatids (now called chromosomes) divide and move to opposite poles


Telophase 2

  • Chromosomes gather at the poles

  • Nuclear envelope forms and cytoplasm divides

4 new daughter cells, each genetically DIFFERENT, are formed and are all haploid


Sexual Reproduction

  • Haploid cells join to make diploid cells

  • Increase in genetic variation

  • Leads to change or evolution


Females: meiosis occurs before birth

Each month, one egg is matured

and released for possible fertilization

Males: meiosis begins at puberty

and continues until death


Asexual Reproduction

  • Single parents pass genes to offspring

    • Clones

    • Prokaryotes, yeast, hydra

    • Faster to produce offspring, but no genetic variation


GENETIC VARIATION

  • The chromosome a gamete will receive depends on the way it lines up at the equator

Independent

assortment


The Importance

  • Lead to the evolution of a species

  • Increase survival


CANCER

  • Cells have checkpoints to determine if they are healthy enough to divide

  • If those checkpoints are faulty, cells can divide and grow uncontrollable – can form a tumor and lead to cancer


What’s the problem

with more cells?

1.) Steal nutrients from healthy cells which eventually die



Causes of Cancer

  • Exposure to chemicals or toxins

  • Radiation

  • Viruses

  • Your Own Genetics


ad