Mitosis and Asexual Reproduction

Getting from one cell to many
Going from egg to baby….
the original fertilized egg has to divide…
and divide…
and divide…
and divide…
Biology is the only subject in
which multiplication is the
same thing as division…
division…
ALL CELLS COME FROM
PRE-EXISTING CELLS
ALL CELLS COME FROM
PRE-EXISTING CELLS
__________________________________
___________________________________
___________ (single source of DNA) it
is called asexual reproduction
__________________________________
_______________
____________ (two sources of DNA) it is
called sexual reproduction
___________________________________
___________________________________
By cell division, one cell
divides to become two. This
process is used by some
organisms to reproduce. In
other multicellular organisms,
this process is used to grow or
to replace tissues.
amoeba
lizard
amoeba
starfish
amoeba
Remember Cytology…
the nucleus…
Copying DNA
A dividing cell _____________________
…_________________________…
…_________________________…
…________________________________
creates 2 copies of all DNA
separates the 2 copies to opposite ends
of the cell
splits into 2 daughter cells
DNA
cell
plant cell
nucleus
animal cell
CHROMOSOMES = LOTS OF DNA
Making new DNA
The DNA in a cell is
usually loosely
wound in the nucleus.
If you tried to divide it
like that, mistakes can
happen!
This is a single copy…
Notice the PATTERN!
DNA
cell
DNA has been
“wound up”
nucleus
DNA as chromatin in an
everyday “working” cell
cell
nucleus
DNA packaged up in chromosomes
in cell getting ready to divide
DNA exists as a single copy of
the ‘DOUBLE HELIX’ until it
copies itself. After this
copying, it actually has two
copies of it self!
Making new DNA
Making new DNA
Another enzyme, DNA
polymerase, adds the
bases to the opened
chain, according to the
pattern!
helicase
An enzyme, helicase, opens up
the double helix, so one side
can act as a the template for the
other side.
Making new DNA
DNA bases
in nucleus
DNA
polymerase
One the entire side of
DNA is matched up, we
now have two identical
double helices.
We made our copy!
DNA
polymerase
DNA
polymerase
Copied & Paired Up Chromosomes
Copying & packaging DNA
When cell is ready to divide…
copy DNA first, then…
coil up doubled chromosomes
like thread on a spool…
now can move DNA around cell without having it
tangle & break
Copying DNA
Coil DNA into
compact chromosomes
THE CELL CYCLE
THE CELL CYCLE
the process by which the cell and its
nucleus _________________ to produce two
cells with nuclei having _________________
______________________________________
eukaryotic cells often have a diploid
number of chromosomes
when the cell cycle is uncontrolled, cells
keep on dividing… which is called _______
this basic process happens in all human
cells EXCEPT _____________________
Cell division involves the dividing of the genetic material
(________________) and the division of the cytoplasm and
organelles (_________________)
DNA must be copied…
DNA in chromosomes
chromosomes in cell
Cell Cycle: Copying DNA
Stage 1: INTERPHASE
___________________________________
___________________________________
________________________ and is copied
other organelles are copied too!
cell
4 single-stranded chromosomes
duplicated chromosomes
nucleus
DNA
duplicated
chromosomes
cell
cell
nucleus
4 double-stranded chromosomes
Cell Cycle : Dividing DNA
Stage 2: PROPHASE
____________________________________
____________________________________
____________________________________
____________________________________
nucleus
Cell Cycle : Dividing DNA
Stage 3: METAPHASE
___________________________________
___________________________________
duplicated chromosomes
line up in middle of cell
duplicated chromosomes
cell
nucleus
1st stage of
MITOSIS
2nd stage of
MITOSIS
Cell Cycle : Dividing DNA
Stage 4: ANAPHASE
___________________________________
___________________________________
Cell Cycle : Dividing DNA
Stage 5: TELOPHASE
___________________________________
___________________________________
chromosomes start to unwind
and cell starts to split
chromosomes split and
move toward poles
3rd stage of
MITOSIS
Cell Cycle : Dividing cells
Stage 6: CYTOKINESIS
after new nuclei form, _________________
____________________________________
both of which are
genetically
identical to the
parent cell
4th stage of
MITOSIS
New “daughter” cells
Get 2 exact copies of original cells
same DNA
“clones”
Mitosis in whitefish embryo
Cell division in animal cells
________________
________________
________________
Mitosis in plant cell
Cell division in plant cells
does NOT have
centrioles
______________
______________
______________
______________
______________
onion root tip
Is cloning a cell the same as cloning a person?
cloning cells is basically the same as
mitosis… but by artificial means
cloning organisms starts with cloning
cells, by a process called ______________
Overview of mitosis
1) binary fission:
Types of asexual reproduction
carried out by unicellular organisms,
some animals, and many plants
asexual reproduction is ___________
___________________________________
___________________________________
___________________________________
2) budding:
A) unicellular organisms
___________________________________
___________________________________
carried out by yeast
_____________________________________
_____________________________________
basically, is simple animal cell mitosis
carried out by paramecia, ameba, bacteria,
and many algae
2) budding:
B) multicellular organisms
a patch of cells from the parent grow on
the original if conditions are favorable
___________________________________
__________________________ hydra
3) sporulation:
___________________________
________ that are released from
the parent and can develop into
new individuals if conditions are
right
occurs in fungi and some plants
4) regeneration:
5) vegetative propagation:
lizard
A) of body parts
___________________________________
___________________________________
occurs in such animals as lobsters,
crabs, and gecko lizards
starfish
B) new organisms
when an entire organism is
produced from part of the
original
occurs in seastars and
planarians
5) vegetative propagation:
C) tubers
stem-like structures that grow
____________ from the parent
can grow into new individuals if conditions
are right
• potatoes
D) runners
stem-like structures that grow
______________________ from the parent
can grow into new individuals if conditions
are right
• strawberries
when new plants develop from parts of the
parent plant
A) cuttings
____________________________________
__________________
• geranium, coleus
B) bulbs
____________________________________
• tulips, onions
5) vegetative propagation:
E) grafting
special embryonic plant tissues called
cambium can be cut and reattached to
similar woody plants
can get plants with interesting
characteristics!