Sexual reproduction
Sponsored Links
This presentation is the property of its rightful owner.
1 / 53

Sexual Reproduction PowerPoint PPT Presentation


  • 82 Views
  • Uploaded on
  • Presentation posted in: General

Sexual Reproduction. Cellular Reproduction. There are 2 types of reproduction: Asexual Reproduction Sexual Reproduction. Cellular Reproduction. Asexual Reproduction (5 phases) 1 mother cell divides into 2 daughter cells Daughter cell is identi cal to its mother

Download Presentation

Sexual Reproduction

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


Sexual Reproduction


Cellular Reproduction

There are 2 types of reproduction:

  • Asexual Reproduction

  • Sexual Reproduction


Cellular Reproduction

  • Asexual Reproduction (5 phases)

  • 1 mother cell divides into 2 daughter cells

  • Daughter cell is identical to its mother

  • Interphase + Mitosis

  • All human cells have46 chromosomes called “DIPLOID cells”

  • Produce SOMATIC cells(not sexual cells)


Cellular Reproduction

2. Sexual Reproduction (9 phases)

  • 1mother cell divides into4daughter cells

  • Daughter cells have ½ the chromosomes of their mother (23) “HAPLOID cells”

  • Interphase + Meiosis I + Meiosis II

  • Crossing over of genetic material often occurs.

  • SEXUAL cells (egg and sperm) known as “gametes”


Vocabulary


Gametes

~ Another name for eggsand sperm

~ They are haploid (In humans, that is 23 chromosomes)

~ They are sexual cells

~ They are produced by sexual reproduction


Homologous Chromosomes

  • A pair of chromosomes (maternal and paternal)that have similar/identical shapes andsizes.

  • Have genesfor the same characteristics (ie: eye color).

  • Eachlocus(geneposition) controls the same traitand is inthe same place on homologous chromosomes.


Homologous Chromosomes

chromatids

chromatids

Vocabulary

tetrad


Vocabulary

Sperm + egg = zygote


Eye color

Eye color

Hair color

Hair color

Paternal

Locus

Maternal

Homologous Chromosomes


Remember… 

Interphase

Prophase

Metaphase

Anaphase

Telophase

Asexual

Reproduction

Mitosis


Sexual Reproduction

  • There are 3 major steps:

    ~ Interphase

    ~ Meiosis I

    ~ Meiosis II


Interphase

Prophase I

Metaphase I

Anaphase I

Telophase I

Prophase II

Metaphase II

Anaphase II

Telophase II

Sexual

Reproduction

Meiosis


2n=46

4n=92

2n=46

meiosis I

Meiosis in Humans

n=23

AfterInterphase

n=23

4 haploid

gametes (n)

n=23

n=23

diploid (2n)

meiosis II


Video

  • Meiosis


Interphase (4n = 92)

  • Same as Interphase in Mitosis

  • Chromosome replication, growth and preparation (chromatin rolls etc)

  • Each of the replicated chromosomes possesses2chromatideswhich are attachedat theircentromere.


Interphase (4n = 92)

  • We can see the nucleolus and the nuclear membrane.

There are 92 chromosomes (46 pairs!!)

Nuclear membrane

Chromatine

Cell membrane

Nucleolus


Meiosis I (4 phases)

~ Prophase I

~ Metaphase I

~ Anaphase I

~ Telophase I


Prophase I (4n = 92)

  • 2 homologous chromosomes combine. This combination is called a TETRADXX

  • Spindle fibers grow, and attach to each side of the tetrad

  • Thenuclearmembraneand thenucleolusboth disappear


Spindle fibers

centrioles

Prophase I (4n = 92)


Crossing Over

  • DuringProphase I

  • One chromatid of each chromosome crosses over with the chromatid of the other chromosome.

  • The result is anexchangeof their genetic material


Crossing Over

The exchangeof sections ofhomologouschromosomes in aTETRAD.

Maternal

chromo

Paternal

chromo


Metaphase I (4n = 92)

  • Spindle fibers pull on the tetrads, and align them in the centre of the cell.


Metaphase I (4n = 92)


Anaphase I (4n = 92)

  • Thetetrads separate and homologouschromosomes travel to the poles.

  • Homologues chromosomes are still attached by their centromeres.


Anaphase I (4n = 92)


Telophase I/Cytokenisis(2n = 46)

  • Each pole has a diploidnumber of chromosomes.

  • Cytokenisis - 2 diploids cells are formed.

  • Spindle fibers and centriolesdisappear.

  • The nuclear membrane sometimes reforms, and the nucleolus does not reform at this point.


Telophase I (2n = 46)

Cell division


And the division continues!!!!


Meiosis II (4 phases)

~ Prophase II

~ Metaphase II

~ Anaphase II

~ Telophase II


Meiosis II

Interphase II – does not exist

** Don’t forget!! This process is now occurring in both daughter cells created during Meiosis I **


Prophase II (2n = 46)

  • Same as ProphaseinMitosis


Metaphase II (n = 46)

  • Same as MetaphaseinMitosis


Anaphase II (2n = 46)

  • Same as AnaphaseinMitosis

  • DON’T FORGET! Chromosomes are separated into chromatids.


Telophase II/Cytokenisis (n = 23)

  • Same as TelophaseinMitosisEXCEPT n = 23

  • The nucleolus and nuclear membrane reform

  • Cytokenisis

    Important: 4 haploid gametes areformed.


Telophase II/Cytokenisis (n = 23)


Animation!!

Meiosis– McGraw-Hill animation


Let’s review!!!


Comparison of mitosis and meiosis


Mitosis vs Meiosis


Mitosis vs Meiosis


Meiosis


La mitose vs la méiose


Attention!!!!!!!!!!!!!

  • Female meiosis is somewhat different. 4 gametes are initially created, but Cytokenisis is UNEQUAL. In this case, ONE GAMETE survives, and the other 3 are not viable.


Video!!

United Streaming- Cell Division


Let’s see just how smart you are…


Mitosis vs. Meiosis

Visual Representations

http://www.cellsalive.com/meiosis.htm

http://www.csuchico.edu/~jbell/Biol207/animations/meiosis.html

http://www.sumanasinc.com/webcontent/animations/content/meiosis.html


  • Login