Transcript Ch. 4.2 Lecture

Asexual Reproduction
4.2
I. Asexual Reproduction
A. Asexual Reproduction- A new
organism is produced from
one parent
1. The new organism is
identical to the parent
I. Asexual Reproduction
B. Types of Asexual
Reproduction
1. Fission- Organism divides
to create an identical
organism
a) DNA must be copied
first
b) Occurs in bacteria
I. Asexual Reproduction
2. Budding-using cell division to
grow a new organism from the
body of the parent
b) When it is full grown
the new organism breaks off
3. Ex: Hydra, Yeast
I. Asexual Reproduction
3. Regeneration- Using cell
division to regrow damaged or
lost body parts
a) Pieces of an organism
can be used to grow an
entire organism.
b) Ex: Star fish, salamander
tails, Spongebob
I. Asexual Reproduction
4. Vegetative ReproductionA form of asexual
reproduction in which
offspring grow from part of a
parent plant
a) Ex: Stolons
(strawberries
and potatos)
I. Asexual Reproduction
Yeast budding under
microscope. See launch lab
in resource book
Use “Visualizing Cell Processes
DVD to illustrate.
--DNA Structure & Cell
reproduction
--Condensing chromosomes
--Stages of mitosis
--Cytokenesis
II. Why Divide
A. To replace dead cells
B. To grow
1.# of new cells exceed the # of
dying cells
C. Limit cell size
1. The smaller the cell, the more
efficient it gets nutrients and
gets rid of wastes
III. Chromosomes
A. Chromosomes- Cell structure
that carries genetic material
1. Composed of DNA wrapped
around proteins
2. Appear right before cell
division occurs (Condensed)
III. Chromosomes
3. 2 sister chromatids
are held together by a
centromere
a. Each chromatid
is identical
4. See video
IV. Cell Cycle
A. Overview
1. Interphase
2. Mitosis
3. Cytokenesis
B. Cell Cycle- Sequence of growth
and division of a cell.
III. Cell Cycle
C. Interphase
1. Rapid growth & metabolism
2. DNA replication
3. Centrioles replicate in
preparation for cell division
III. Cell Cycle
D. Mitosis (PMAT)
1. Prophase
a. Chromosomes
condense
b. Nuclear envelope and
nucleolus disintegrate
c. Spindle fibers form in
between centrioles at opposite
sides of the cell.
III. Cell Cycle
D. Mitosis (PMAT)
2. Metaphase
a. Spindle fibers attach to
centromeres of the
chromosomes
b. Chromosomes are
pulled to the center of the cell
III. Cell Cycle
D. Mitosis (PMAT)
3. Anaphase
a. The sister chromatids
are pulled apart to opposite
sides of the cell by the
spindle fibers
III. Cell Cycle
D. Mitosis (PMAT)
4. Telophase
a. Prophase in reverse!
b. The spindle fibers
disintegrate
c. The chromosomes
uncoil
III. Cell Cycle
D. Mitosis (PMAT)
4. Telophase
d. 2 new nuclear
envelopes appear around the
chromosomes
5. Only the nucleus has
divided, not the entire cell
III. Cell Cycle
E. Cytokenesis- The process in
which the cytoplasm (cell)
divides
1. Animal cells pinch off to
form 2 new cells
2. Plant cells form a cell plate
then 2 new cell walls form on
either side of the plate
III. Cell Cycle
F. The two new cells go back to
interphase to start the cycle
over again.
G. Result: 2 Cells identical to
each other
RECAP
-Why do cells need to divide?
-What are the stages of the cell
cycle? What happens in
each?
-What are the 4 phases of
miosis? What happens in
each?
RECAP
-What happens during
cytokenesis?
-What do you start and end with
at the beginning and end of
the cell cycle?
RECAP
-How many parents are involved
in asexual reproduction?
- Give an example of asexual
reproduction