Free Powerpoint Presentations

Reduction-Division
Page
1

DOWNLOAD

PREVIEW

WATCH ALL SLIDES

Slide 1

MEIOSIS

MEIOSIS

Reduction-Division

Genetic Recombination

Slide 2

Meiosis

Meiosis

The form of cell division by which GAMETES, with HALF the number of CHROMOSOMES, are produced.

DIPLOID (2n)  HAPLOID (n)

Meiosis is SEXUAL reproduction.

TWO divisions (MEIOSIS I and MEIOSIS II).

Slide 3

Meiosis

Meiosis

Sex cells divide to produce GAMETES (sperm or egg).

Gametes have HALF the # of chromosomes.

Occurs only in GONADS (testes or ovaries).

Male: SPERMATOGENESIS -sperm

Female: OOGENESIS - egg or ova

Slide 4

Spermatogenesis

Spermatogenesis

Slide 5

Oogenesis

Oogenesis

Polar Bodies (die)

Slide 6

Interphase I

Interphase I

Similar to mitosis interphase.

CHROMOSOMES (DNA) replicate in the S phase

Each duplicated chromosome consist of two identical SISTER CHROMATIDS attached at their CENTROMERES.

CENTRIOLE pairs also replicate.

Slide 7

Interphase I

Interphase I

Nucleus and nucleolus visible.

Nucleus

nucleolus

cell membrane

chromatin

Slide 8

Meiosis I (four phases)

Meiosis I (four phases)

Cell division that reduces the chromosome number by one-half.

Four phases:

a. Prophase I

b. Metaphase I

c. Anaphase I

d. Telophase I

Prophase I

Slide 9

Prophase I

Prophase I

Longest and most complex phase (90%).

Chromosomes condense.

Synapsis occurs - Homologous chromosomes come together to form a tetrad.

Tetrad is two chromosomes or four chromatids (sister and non-sister chromatids).

Slide 10

Non-Sister Chromatids-HOMOLOGS

Non-Sister Chromatids-HOMOLOGS

Homologs contain DNA that codes for the same genes , but different versions of those genes

Genes occur at the same loci

Slide 11

Prophase I - Synapsis

Prophase I - Synapsis

Slide 12

Homologous Chromosomes

Homologous Chromosomes

Pair of chromosomes (maternal and paternal) that are similar in shape and size.

Homologous pairs (tetrads) carry GENES controlling the SAME inherited traits.

Go to page:
 1  2  3  4 

Contents

Last added presentations

© 2010-2024 powerpoint presentations