Download PowerPoint-Embryonic Development

Date: March 7th, 2017-period 5
Aim # 56: How does an embryo develop?
Do Now:
1) The joining of egg and sperm is called ___________.
2) What is another term for a fertilized egg?
a) Is this cell diploid or haploid cell?
3) What are the only haploid cells in a living organism?
How are the produced?
HW:
1)Daily Review of Class Notes
2)Sexual Reproduction Review due Tuesday
3)Castle Learning due Thursday
4)Test Friday(Textbook Homework for Extra Credit due)
Date: March 7th, 2017-period 1
Aim # 56: How does an embryo develop?
Do Now:
1) The joining of egg and sperm is called ___________.
2) What is another term for a fertilized egg?
a) Is this cell diploid or haploid cell?
3) What are the only haploid cells in a living organism?
How are the produced?
HW:
1)Daily Review of Class Notes
2)Sexual Reproduction Review due Wednesday
3)Castle Learning due Thursday
4)Test Thursday
Aim #56: How does an embryo
develop?
How does the zygote form?
Zygote – A fertilized egg
1) What happens to the zygote
after it is formed?
Mitosis – causes the zygote to
repeatedly divide producing the
developing embryo.
2) Embryonic Development:
Fertilization
Mitosis
+
Sperm
Egg
Zygote
Embryo- the stage in human development from the
first division of the zygote until about nine weeks
after fertilization.
4) Cleavage
•The term used to describe
the early cell division
associated with embryonic
development.
•During this time period, the
number of cells increase
tremendously.
5) The result of cleavage is an embryo that is …..
Morula
A solid ball of cells which moves
towards the uterus
6) Mitosis continues & the embryo becomes……
Blastocyst
A hollow ball of cells
Cell division continues & the embryo
starts to ….
Gastrula • Fold inwardly
7) Gastrulation
• Three layers
• Each layer will eventually
form the different organ
systems
8) CELLULAR DIFFERENTIATION
• Due to gene
expression, cells
undergo cellular
differentiation, in
which the cells
become
increasingly
specialized in
structure &
function.
9) Gene Expression
Genes that are being
expressed are “on”
Though all genes of the genome are present in every
type of cell, only a small, specific fraction of these
genes are actually expressed in each type of cell.
10) What makes some cells turn “on”
some genes while other genes are
“off”?
Environmental influences from within the cell, from
surrounding cells, or from outside the organism.
Why are they different?
Grown in light
These seeds carry
the same genes for
chlorophyll:
ENVIRONMENT AFFECTS
GENE EXPRESSION
Grown in dark
11) What is the end result of
differentiation?
An embryo with
many different
types of cells
12) What are Stem Cells
• Stem cells are
embryonic cells that
can turn into any
type of cell in the
body
13) How can stem cells help us?
• Can be used to make
any type of cell that
needs to be replaced in
our bodies
Why is the use of stem cells so
controversial?
• They are often taken
from fetuses.
• Opponents believe that
you are killing a life.
Are stem cells only embryonic?
No, there are some
adult stem cells, but
they don’t have the
potential to become
any kind of cell
A Cell Stem Story
Award-winning 15 minute video introduction to stem
cell research
http://www.eurostemcell.org/films