2.2 And 2.3 Growth And Differentiation And Stem Cells

Question 1

What are stem cells

Answer 1

A cell that has not yet become specialized

Question 2

Differneation in animal cells

Answer 2

By the time a human baby is born most of its cells are sepcialzed to carry particular functions,such as nerv cells, skins cells etc. so they have differentiated.
-some genes have been switched on and off so a result different types of sepcialized cells have different sub-cellular structures to carry out sepcific functions

-most specialized cells can divide by mitosis but can only form same sort of cell
-some differentiatedbcells,such as red blood cells and skin cells,cannot divide at all so adum stem cells replace dead or damaged cells

Question 3

Differentaiation in plants

Answer 3

-undifferentiated cells are formed at active regions of the stems and roots known as mertisms. In these areas mitosis takes olace almost continously. The cells then elongate and grow before they differentiate

-plant cells produced do not differentiate until their final position in plant and its not permanent. You can move a plant cell from one partnof a plant to another. There it can redifferentiate and become a completely different type of cell

Question 4

Embryonic stem cells

Answer 4

-form when an egg and sperm fuse to form a zygote
-they can differentiate into any type of cell
-scientists can clone these cells and direct them ti differentiate into almost any cell in body
-could potentially be used to replace insulin-producing cells in those suffering fiabetess, new newral cells and nerve cells

Question 5

Adult stem cells

Answer 5

Found in bone marrow they fqn from many types of cells including blood cells

Question 6

Meristems in plants

Answer 6

-found in root and shoot tips
-they can differentiate into any type of plant, and have the ability througout the life of the plant
-they can be used ti make clones of the plant. Necessary if the parent plant has certain desirable features for research or to save rare plant from extinction

Question 7

Stages of therapeutic cloning

Answer 7

-nucleus from human skin cell is removed and kept
-nucleus from a human egg cells is removed and discarded
-skin cell nucleus is inserted into empty egg cell
-egg cell is guven an electric shock to stimulate it into dividing
-develops into an embryo
-the cells from this embryo are stem cells and are used to treat diseases

Question 8

What is meant by differentiation

Answer 8

Is the process by which a cell changes to become specialized for its job

Question 9

What is a specilaized cell

Answer 9

Has specific structure and performs a specific function

Question 10

When di animal cells los the ability to differentiate

Answer 10

After they become sepcialized

Question 11

What type of cells can adult cstem cells differentiate into

Answer 11

They can differentiate into cells from the type of tissue where they are found. E.g lifer stem cells can only form liver cells

Question 12

What type of cells can embryonic stem cells differentiate into

Answer 12

Can differentiate into almost every type of cell under right conditions of lab

Question 13

Name types of diseas stem cells have been ysed to trest diseases

Answer 13

Paralysis
Diabetes
Blidness

Question 14

What is thereupatic cloning

Answer 14

Involves an embryo being produced with the same gene as patient
-embryo produced couldd then be harvested to obtain ebryonic stem cells
-these could be grown into any cells if patient needed,such as new tissues or organs