Mitosis and Meiosis/ Genetics

1
Mitosis and Meiosis/ Genetics
2
Announcements
next week is the Embryology lab. There is a
quiz next week and as usual cover materials
from this lab and the upcoming one. home
assignment for today will be posted on my
web-page late today
3
Today
Mitosis difference between animal and plant
cells Meiosis
4
Mitosis
it serves as a means of growths and repair in
multicellular eukaryotes it a common feature of
a lot of tissues in the human body e.g.
skin wounds heals by mitosis e.g. bone
fractures heals by mitosis e.g. Liver tissue
can regenerate ? Brain cells ? Heart muscle
cells(fibers) uncontrolled cell divisionbenign
or malignant
tumors
5
Mitosis
Cell cycle
G1, S, and G2 are termed Interphase
6
Chromosomes
Karyotype is numbers, forms and types of
chromosomes in a cell
7
Mitotic phase
1-Prophase Chromatin in the nucleus condense.
The nucleolus disappears. Centrioles begin
moving to opposite ends of the cell and fibers
extend from the centromeres.
2-Metaphase Spindle fibers align the chromosomes
along the middle of the cell nucleus. This line
is referred to as the metaphase plateor equator
8
Mitotic phase
3-Anaphase The paired chromosomes separate at
the kinetochores and move to opposite sides of
the cell.
4-Telophase Chromatids arrive at opposite poles
of cell, and new membranes form around the
daughter nuclei. The chromosomes disperse and
are no longer visible under the light
microscope.
9
Animal vs Plant cells
karyokinesis is the same cytokinesis (cytoplasm
division) -in animal cells, it is a function of
the actin filaments of the spindle fiber. -in
plant cells, it is a function of the cell wall
10
Mitosis
In brief, -one round of cell division per
round of DNA synthesis. -one cell end with
two cells of the same genetic content(2N)
11
Meiosis
it serves as a means of reproduction two rounds
of cell division per one round of DNA
synthesis. one cell with 2N content end with 4
cells of 1N content. 2 stages, Meiosis 1 and
2 homologous recombination (synapse) occur
between homologous pair of chromosomes. in
anaphase of meiosis one, the two sister
chromatids remain attached and the whole
chromosome is pulled toward one end
12
I got the picture
examine demo -Onion root tip mitosis
-chiasmata(recombination or crossing-over) in
meiotic cells of grasshopper simulating mitosis
and meiosis
13
The genetic disease project
group project I will demonstrate how to use
library resources two weeks from today you will
present for the class -PowerPoint presentation
(15-20m) -all the group members must share in
the oral presenatation and written report