Key Area 4: Cellular Differentiation

Question 1

What is cellular differentiation?

Answer 1

The process by which a cell expresses certain genes to produce proteins characteristic to the cell type.

Question 2

What do cells undergo to become specialised?

Answer 2

Differentiation

Question 3

What does differentiation adapt cells to do?

Answer 3

To carry out a particular function.

Question 4

What are characteristics of cells that carry out specific functions?

Answer 4

They have specific shapes and biochemical pathways.

Question 5

What can happen to genes depending on the function of a specialised cell?

Answer 5

They can be switched on or off.

Question 6

What happens during differentiation?

Answer 6

Many genes remain switchen on; other genes necessary for the cell’s functions are switched on; and unnecessary genes are switched off.

Question 7

What is a meristem?

Answer 7

Regions of unspecialised cells in plants that can self-renew and/or differentiate

Question 8

What are the two main types of meristem?

Answer 8

Apical meristem, and lateral meristem.

Question 9

Where can the apical meristem be found?

Answer 9

At the root and shoot tips.

Question 10

Where can the lateral meristem be found?

Answer 10

Throughout the plant.

Question 11

What do apical meristems give rise to?

Answer 11

Increase in plant length/height.

Question 12

How do apical meristems increase plant length/height

Answer 12

Cells at root and shoot tips undergo repid mitosis and cell division, producing new cells. New cells then take in water by vacuolation and expand by elongation. New cells produced can then differentiate to form specialised tissue.

Question 13

What is the other name given to lateral meristems?

Answer 13

Cambium.

Question 14

Where can lateral meristems be found?

Answer 14

In vascular bundles between the xylem and phloem.

Question 15

What do lateral meristems cause?

Answer 15

Thickening of the plant.

Question 16

What do all sexually reproducing animals start out as?

Answer 16

A zygote.

Question 17

What happens to the zygote?

Answer 17

It divides by mitosis and cell division to form an embryo.

Question 18

How much of the genetic code does the zygote hold?

Answer 18

The entire genetic code.

Question 19

What is the status of the genes in an embryo?

Answer 19

They are all switched on, or have the potential to be switched on.

Question 20

How is an embryonic stem cell naturally altered genetically?

Answer 20

Genes are switched on and off at specific points in time and at particular points within the organism.

Question 21

Which genes does a cell express once it has been differentiated?

Answer 21

The genes that code for the proteins specific to the workings of that particular cell.

Question 22

What is a stem cell?

Answer 22

An unspecialised cell in animals that can self-renew and/or differentiate.

Question 23

What are the different types of stem cell?

Answer 23

Embryonic and tissue.

Question 24

How many cell types can embryonic stem cells differentiate into?

Answer 24

Due to them being pluripotent, they can divide into all cell types.

Question 25

How many genes in an embryonic stem cell can be switched on?

Answer 25

All of them.

Question 26

What are tissue stem cells involved in?

Answer 26

Growth, repair and renewal of cells.

Question 27

What is the word given to tissue stem cells due to the fact that they can differentiate into all types of cell found in a tissue type?

Answer 27

Multipotent.

Question 28

What are some therapeutic uses of stem cells?

Answer 28

Repair of damaged or diseased organs or tissues.

Question 29

What are some research uses of stem cells?

Answer 29

They can be used as model cells to study how diseases develop or they can be used for drug testing.

Question 30

What is the controversy around the use of embryonic stem cells?

Answer 30

They can offer effective treatments for disease and injury, however, it involves the destruction of emryos and the destruction of a potential life.