Have web quest out.Quiz on Tuesday.

stem cell

What is a stem cell? A web research project

stem cell

SELF-RENEWAL(copying)

specialized celle.g. muscle cell, nerve cell

DIFFERENTIATION(specializing)

What can a stem cell do?

Identical stem cells

Stem cell

SELF-RENEWAL(copying)

Stem cell

Specialized cells

DIFFERENTIATION(specializing)

1) Describe the following stages of development:a) Zygote: right after an egg is fertilized. The zygote begins a two-week period of rapid cell division

2-16 cells

• After zygote but before the cell is a morula

• Morula- a ball of cells

FYI blastula: hollow ball right after morula but before inner mast cells form.

Blastocyst: A hollow ball that has a cluster of cells called the inner cell mass. These cells could become an embryo. These cells are used as embryonic stem cells. The outer layer of cells gives rise to the placenta.

http://www.medterms.com/script/main/art.asp?articlekey=18258

Location of the early embryo in a human

gastrula• the single-layered

blastula is reorganized into a trilaminar ("three-layered") structure known as the gastrula. These three germ layers are known as the ectoderm, mesoderm, and endoderm.

• Look back at your differentiation w.s.!

• http://www.hhmi.org/biointeractive/human-embryonic-development

#2) Explain type of SC, when & how harvestedPotency: A measure of how many types of specialized cell a stem cell can make

Totipotent: Can make any kind of cell. Unable/difficult to harvest due to small size.

Pluripotent: Can make all types of specialized cells in the body. Embryonic stem cells are pluripotent. Harvest from the bastocyst

Multipotent: Can make multiple types of specialized cells, but not all types (have some “programming”. Tissue (adult) stem cells are multipotent. Harvest from fetus or mature tissues (baby to elderly)

http://www.hhmi.org/biointeractive/cultured-human-embryonic-stem-cells

b) pluripotent: meaning they can divide into more stem cells or they can specialize and become any type of body cell. Because of this versatility, embryonic stem cells have the highest potential for use to regenerate or repair diseased tissue and organs in people.

http://www.mayoclinic.com/health/stem-cells/CA00081

Harvesting ES cells from human blastocysts is controversial because it destroys the embryo, which could have been implanted to produce another baby (but often was simply going to be discarded).

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Stem_Cells.html

multipotant: These are true stem cells but can only differentiate into a limited number of types.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Stem_Cells.html

adult stem cells are present in miniscule quantities and this can present difficulty for identifying and isolating them in numbers great enough to use therapeutically. Their self-renewal is also not as successful as embryonic stem cells and as such, they do not proliferate to the same degree

http://www.explorestemcells.co.uk/AdultStemCells.html

3) At what stage can embryonic stem cells be taken?

These stem cells come from bastocyst that are four to five days old. At this stage the cell consists of about 150 cells.

It is called an embryo once implanted into the uterus. Before that it can be called an early stage embryo.

• http://www.mayoclinic.com/health/stem-cells/CA00081

4) What are the two essential characteristics of stem cells?

First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity.

Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.

http://stemcells.nih.gov/info/basics/basics1.asp

#5S.C. Type Definitio

nDescribe/ diagram

Advantage

Disadvantage

Political/ ethical issues?

Embryonic Taken from early stage of development

Embryos created from invitro are donated. The membrane around them is dissolved and the mast cells are used as embryonic stem cells

They can be turned into almost any type of cell

They are controversial b/c the embryo is destroyed

Definition of life is a moral dilemma that becomes political

Embryonic stem (ES) cells:Where we find them

blastocyst

outer layer of cells= ‘trophectoderm’

cells inside = ‘inner cell mass’

embryonic stem cells taken fromthe inner cell mass

culture in the labto grow more cells

fluid with nutrients

Embryonic stem (ES) cells:What they can do

embryonic stem cells

PLURIPOTENT

all possible types of specialized cells

differentiation

neuronsgrow under conditions B

Embryonic stem (ES) cells:Challenges

embryonic stem cells

skin

grow under conditions A

blood

grow under conditions C

liver

grow under conditions D

?

Adult/ tissue

Taken from differentiated tissues

Isolated from the different tissues know to have stem cells.

Could match exact DNA, doesn’t destroy potential life

Difficult to harvest, don’t self renew as well

none

IPSC Reverted from any cell back to s.c.

Regular body cells reverted to stem cells

Could match exact dna. The capacity to develop into almost all kinds of cells, like embryonic stem cells do

Cancer formation, inefficient process

none

Tissue stem cells:Where we find them

muscles

skin

surface of the eye brain

breast

intestines (gut)

bone marrow

testicles

Tissue stem cells:What they can do

MULTIPOTENT

blood stem cell

found in bone marrow

differentiation

only specialized types of blood cell:red blood cells, white blood cells,

platelets

Induced pluripotent stem cells (iPS cells)

cell from the body

‘genetic reprogramming’= add certain genes to the cell

induced pluripotent stem (iPS) cellbehaves like an embryonic stem cell

Advantage: no need for embryos! all possible types ofspecialized cells

culture iPS cells in the lab

differentiation

Induced pluripotent stem cells (iPS cells)

cell from the body (skin)

genetic reprogramming

pluripotent stem cell(iPS)

differentiation

Review with scishow

• http://www.youtube.com/watch?v=jF2iXpoG5j8

IPSC

• http://www.youtube.com/watch?v=D2u6ix_eOQw 2012 ips cells 25:59

6) How are adult stem cells different from embryonic stem cells?

They are multipotent, hard to harvest, might have mutations BUT they do have some potential and are not likely to be rejected

• Where are stem cells found in the adult body?Skin, Bone marrow, Brain, blood vessels, Liver, Skeletal

muscle http://www.explorestemcells.co.uk/AdultStemCells.html

• 7) What advantages do embryonic stem cells have over adult stem cells for medical research?

• No mutation, blank slate (pluripotent), easy to harvest

• Reieneke’s brain

• 8. what is a stem cell line?Embryonic stem cells that have been cultured in

a artificial environment that allows for multiple divisions (mitosis) without differentiation form months to years.

http://www.hhmi.org/biointeractive/creating-embryonic-stem-cell-lines

9) Make a diagram of cloning

CloningThere are two VERY different types of cloning:

Reproductive cloning

Use to make two identical individuals

Very difficult to do

Illegal to do on humans

Molecular cloning

Use to study what a gene does

Routine in the biology labs

gene 1

gene 2

Reproductive cloning

remove nucleus and take the

rest of the cell

egg

take the nucleus (containing DNA)

cell from the body

Cloneidentical to the individual

that gave the nucleus

Dolly the sheep

Molecular cloning: Principles

gene 1

gene 2

2) Make a new piece of DNA

gene 1

gene 2

1) Take DNA out of the nucleus

cell 1 cell 2

gene 1 gene 2

3) Put new DNA into a test cell and grow copies

gene 1

cell divides

Daughter cells contain same DNA:

Genes 1 and 2 have

been cloned

gene 2

insert new DNA

10) Watch the following: http://www.hhmi.org/biointeractive/stemcells/animations.html

(Somatic Cell Nuclear Transfer Animation )a) Somatic cell nuclear transfer would allow researchers to create a large supply of diseased cells if they used nuclei from patients with disease. Why would that be advantageous for medical researchers?

Then you could test the diseased cells instead of the whole patient!

Stemcells.nih.gov

Molecular cloning: Applications

Normal mouseembryo

gene A missing

remove a gene to see if anything works differently

Loss of function

gene is involved ingiving the eye its colour

eye

Reporter geneadd a gene that shows

us when another gene is working

gene is active in blue areas only

Lineage tracingmark a group of cells to

see where their daughter cells end up

gene is passed on to cells all over the body

• http://media.hhmi.org/biointeractive/click/Stem_Cell_Therapies/13.html

• http://youtu.be/szxLvG4Vy-Q using stem cells to treat disease

• More review and more applications http://www.youtube.com/watch?v=evH0I7Coc54

• Making body parts http://www.teachersdomain.org/resource/nsn11.sci.life.stru.bodyparts/

11) Why is researching how animals are able to regenerate important to stem cell research?

If we can understand how regeneration (with stem cells ) allows animals to rte create limbs etc then we may be able to do the same for humans.

• Hhmi.com

12) watch the following video...it's about 15 minutes long & about 5 years old. http://www.pbs.org/wgbh/nova/body/stem-cells-research.html

• Summarize the argument that embryonic stem cell research should not be done.Basically comes down to the idea that you have to destroy embryos. Pro-life people believe that life begins at conception thus if you are destroying an embryo you are destroying a human life. Basically murder in the name of science. Other people believe it is just a ball of cells, thus have no issue. Others believe that it’s not a life until it is viable outside the mothers body (which is about 25/40 weeks of pregnancy).

• Why is using adult stem cells much less controversial?Because an adult can consent to having their stem cells

harvested.