sexual reproduction
Download
Skip this Video
Download Presentation
Sexual Reproduction

Loading in 2 Seconds...

play fullscreen
1 / 53

Sexual Reproduction - PowerPoint PPT Presentation


  • 108 Views
  • Uploaded on

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

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 ' Sexual Reproduction' - tavi


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
cellular reproduction
Cellular Reproduction

There are 2 types of reproduction:

  • Asexual Reproduction
  • Sexual Reproduction
cellular reproduction1
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 reproduction2
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”
gam e tes
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

homolog ous chromosomes
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.
vocabula ry

Homologous Chromosomes

chromatids

chromatids

Vocabulary

tetrad

vocabula ry1
Vocabulary

Sperm + egg = zygote

homolog ous chromosomes1

Eye color

Eye color

Hair color

Hair color

Paternal

Locus

Maternal

Homologous Chromosomes
remember
Remember… 

Interphase

Prophase

Metaphase

Anaphase

Telophase

Asexual

Reproduction

Mitosis

sexu al reproduction
Sexual Reproduction
  • There are 3 major steps:

~ Interphase

~ Meiosis I

~ Meiosis II

slide13
Interphase

Prophase I

Metaphase I

Anaphase I

Telophase I

Prophase II

Metaphase II

Anaphase II

Telophase II

Sexual

Reproduction

Meiosis

meiosis in humans

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
Video
  • Meiosis
interphase 4n 92
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 921
Interphase (4n = 92)
  • We can see the nucleolus and the nuclear membrane.

There are 92 chromosomes (46 pairs!!)

Nuclear membrane

Chromatine

Cell membrane

Nucleolus

m e ios is i 4 phases
Meiosis I (4 phases)

~ Prophase I

~ Metaphase I

~ Anaphase I

~ Telophase I

prophase i 4n 92
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
crossing over
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 over1
Crossing Over

The exchangeof sections ofhomologouschromosomes in aTETRAD.

Maternal

chromo

Paternal

chromo

m e taphase i 4n 92
Metaphase I (4n = 92)
  • Spindle fibers pull on the tetrads, and align them in the centre of the cell.
anaphase i 4n 92
Anaphase I (4n = 92)
  • Thetetrads separate and homologouschromosomes travel to the poles.
  • Homologues chromosomes are still attached by their centromeres.
t e lophase i cytokenisis 2n 46
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.
m e ios is ii 4 phases
Meiosis II (4 phases)

~ Prophase II

~ Metaphase II

~ Anaphase II

~ Telophase II

m e ios is 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
Prophase II (2n = 46)
  • Same as ProphaseinMitosis
m e taphase ii n 46
Metaphase II (n = 46)
  • Same as MetaphaseinMitosis
anaphase ii 2n 46
Anaphase II (2n = 46)
  • Same as AnaphaseinMitosis
  • DON’T FORGET! Chromosomes are separated into chromatids.
telophase ii cytokenisis n 23
Telophase II/Cytokenisis (n = 23)
  • Same as TelophaseinMitosisEXCEPT n = 23
  • The nucleolus and nuclear membrane reform
  • Cytokenisis

Important: 4 haploid gametes areformed.

slide40

Animation!!

Meiosis– McGraw-Hill animation

attention
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.
slide51

Video!!

United Streaming- Cell Division

visual representations

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

ad