Stem cells + cell differentiation

HW task 2015

Animal cell differentiation

After cell division most animal cells differentiate and become specialised cells.

Newfacts

Red blood cell

Neurone (nerve cell)

• In animals most cell differentiation happens during embryo development.

• In mature animals cell division is mainly restricted to making cells for repair and replacement (new cells are not made for growth, so mature animals do not grow!).

Newfacts

Plant cell differentiation

• Plant cells also differentiate to become specialised cells.

Mesophyll cell

(many chloroplasts for photosynthesis)

Root hair cell

(big surface area to absorb water + ions)

Xylem vessel (hollow to transport water + ions)

Newfacts

• However, many plant cells can differentiate throughout their life so plants are able to keep growing.

• Which parts of a typical plant are the main growing regions?

Newfacts

• Which parts of a typical plant are the main growing regions?

Shoot and root tips (and buds)

• Some differentiated plant cells can re-differentiate and become different cells.

• This is used in plant tissue culture to clone identical plants.

Newfacts

To do

• Answer the questions in box 1 on the HW sheet.

red blood cells

Stem cells are unspecialized cells that can develop into any type of cell. Unlike most cells, stem cells can divide unlimited times.

muscle cells

liver cells

stem cells

Newfacts Stem cells

Stem cells and their uses

Watch the 3 videos from the website or via these links

What are stem cellshttp://youtu.be/evH0I7Coc54 What are stem cells (Bang goes the theory) http://youtu.be/cEB8656TCIE Watch the video clip “Building body parts saving

lives salamander style”.http://youtu.be/eMHVRkwJ_R0

Newfacts

Stem cells may be used in the future to:

a) grow replacement organs for transplant (no rejection problems if a patients own stem cells are used).

b) Treat people who are paralysed. By injecting stem cells into damaged areas of the spinal cord, new nerve and muscle cells may form.

To do

Answer the questions in box 2 on the homework sheet

Newfacts

Stem cell ethics

• Many people object to the use of stem cells for medical purposes.

• This is partly because embryos are the best source of stem cells.

• You need to be able to argue the pros and cons of using stem cells….

Using stem cells

Reasons for•Best chance of cures for spinal paralysis, diabetes, Alzheimer's.•Spare embryos used would be destroyed anyway.•Embryonic stem cells from cord blood do not harm anyone. •Embryonic stem cells could help grow new tissues and organs for transplants.

Reasons against•Embryonic stem cell research is experimental and side effects may include cancer. •All embryos have the potential to be a baby. Destroying them is wrong.•Embryo’s have a right to life and cannot give permission to be used, so its unethical.•Money spent on stem cell research would be better spent on other medical approaches.

construct + apply

To do

• Answer the question in box 3 on the homework sheet