Download Cellular Reproduction

#1
1. To limit the size of cells. (Many small cells provides a
greater surface area to carry out diffusion/osmosis and
other cellular activities.)
2. To reproduce new cells (1 cell  2 cells)
3. To grow and heal certain injuries.
4. It is a continuous cycle. It takes approximately 12 – 24
hours to complete one cycle (for a normal animal cell).
#2
INTERPHASE

It is when the cell grows, carries out cellular
functions and prepares for cell division.
MITOSIS

The process of cell division that occurs in
somatic cells. The new cells are genetically
identical to the original cell.
CYTOKENESIS

The cytoplasm is divided into two new cells. A
nucleus re-forms in each new cell.
#2

G1:

S:
THERE ARE THREE STAGES OF INTERPHASE
The Synthesis stage is when the cell copies its DNA in preparation
for cell division.
DNA Replication

G2: The Gap 2 stage is when the cell prepares for the division of the
nucleus. The cell takes inventory and makes sure it is ready to
continue with mitosis.
https://www.youtube.com/watch?v=Q6ucKWIIFmg
“Cell Division and the Cell Cycle”
The Gap 1 stage occurs right after cell division. The cell is growing
and carrying out normal cell functions. Muscle and nerve cells exit the
cell cycle and do not divide again.
#3
 MITOSIS:
The process of cell
division that occurs in
somatic cells. The new cells
are genetically identical to
the original cell.
 SOMATIC
CELLS: body cells
(ex. skin cells, stomach
cells, muscle cells).
#5
•
•
Nucleus membrane disintegrates.
Chromosomes condense.
#5
Chromosomes attach to the spindle apparatus and align along the
equator of the cell.
#5
•
•
Chromosomes are pulled to opposite poles
Nuclear membrane begins to re-form.
#5
PHASE 4:
• Chromosomes reach poles of cell.
• Nuclear envelope re-forms
• Chromosomes decondense
CYTOKINESIS:
• In Animal Cells: cleavage furrow forms at equator of cell and pinches
inward until cell divides in two.
• In Plant Cells: cell plate forms, dividing daughter cells
#4
#4
#6
1. Damaged cells beyond repair go through
apoptosis (programmed cell death)
2. The cell cycle is also driven by a protein
called cyclin and an enzyme called cyclindependent kinases (CDKs).
3. The combination of these two substances
signal the start of the following activities in a
cell:



Start of the cell cycle
DNA replication
Nuclear division activities
#7
 CANCER:
uncontrolled growth and division of
cells – a failure in the regulation of the cell
cycle
#8
1.
Mutations of genes that regulate the cell cycle. These
mutations can be inherited or from environmental factors.
2.
Exposure to carcinogens:
- asbestos
- tobacco
- ultra violet radiation
- X and gamma rays
The production of offspring from ONE parent, without combining
genes from another individual.
Examples:
1. Regeneration in sea
stars
2.
3.
Binary fission in
bacteria
Budding in hydra

No sex cells (eggs and
sperm)

No sex organs (testes and
ovaries)

Uses mitosis

Offspring (future
generation) are clones,
they are genetically
identical to the parent
and to each other
#9
BENEFITS

An organism can stay in
one place and not use
energy to find a mate

Can rapidly expand a
population

Regeneration
DRAWBACKS

Lack of genetic variety
among offspring

An entire population can
be wiped out, they all
share the same weakness
The production of offspring by combining the genetic material
from TWO parents
Examples:
1. Animals
2. Insects
3. Fungi

Sex cells (eggs and sperm)

Sex organs (testes and
ovaries)

Uses meiosis

Results from mating in
which eggs are fertilized by
sperm

Offspring (future
generation) are genetically
different from the parents
and from each other
4. Plants
#9
BENEFITS


Offspring are a
genetic variety of two
parents, so more
likely to create a
“successful” offspring
Higher chance of
inheriting a beneficial
mutation
DRAWBACKS

Must find a mate to
make it happen!

More energy is
needed to find a mate
and “parent”

Special cells need to
be created for mating
to occur (sperm and
egg cells through via
meiosis)

MEIOSIS: The process of cell division that creates
gamete cells. These cells are genetically different
to the parent cells.

GAMETE CELL: are reproductive cells produced in
sex organs. Sperm are produced in the testes of
males. Eggs are produced in the ovaries of
females.
ZYGOTE: an egg that has been
fertilized by a sperm cell

#10
1. A parent cell’s DNA replicates
and divides into two cells.
2. Homologous chromosomes
pair up.
3. The homologous
chromosomes are separated and
the cells divide again. The
daughter cells have HALF the
normal number of chromosomes.
HOMOLOGOUS CHROMOSOMES:
Two chromosomes that code for the same traits (ex. eye color,
hair color). One of the homologous chromosomes is inherited
from your mother and the other one is inherited from your
father.
#11
GENETIC VARIABILITY: Meiosis creates unique sperm and eggs
that have individual characteristics.
#12
1. Fertilization - when a sperm and egg fuse together,
new combinations of genes are formed
2. Crossing Over – when two pairs of chromosomes link
together and segments of DNA are exchanged during
meiosis.
#13
A picture of
homologous
chromosome arranged
in size order.
What are chromosomes labeled #1 - #22?
They are somatic chromosomes and they determine the general characteristics for the
organism.
What is pair #23 called?
They are called sex chromosomes, which determines the sex characteristics of the
organism.
XX = female
XY = male
#13

NON-DISJUNCTION: when chromosomes do not separate
properly during meiosis. This results in gametes with
an abnormal number of chromosomes (more than 46 or
less than 46).
#13
MONOSOMY= Missing a copy
of a chromosome
Ex. Turner Syndrome
TRISOMY = Inheriting an
extra copy of a chromosome
Ex. Down Syndrome
1. Downs Syndrome
2. Turner Syndrome
3. Klinefelter Syndrome
4. Edwards Syndrome
5. Patau Syndrome
6. Triple X Syndrome
7. Angleman Syndrome
8. Williams Syndrome
9. Cat-eye Syndrome
10. Cri-du Chat Syndrome