Unit 2.b: Cell Structure

Question 1

Function of a nucleus.

Answer 1

• Contains the genetic information of the cell,
• This is in the form of chromosomes (which are made of DNA). Parts called genes determine what substances the cell make.
• The nucleus dictates the activities of the cell.

Question 2

Function of the cell membrane

Answer 2

• Forms a boundary between cytoplasm and outside.
• can control what passes in and out of cell,
• it’s selectively permeable.

Question 3

Function of cytoplasm

Answer 3

• Watery fluid wich contains all organelles and enzymes,
• Many chemical reactions take place here. These are called metabolic reactions.

Question 4

Function of the mitochondria

Answer 4

• Carry out aerobic respiration,
• release energy for the cell,
• cells that have high energy needs have many mitochondria.

Question 5

Function of ribosomes.

Answer 5

• Very small particles found in cytoplasm.
• Make protein through protein synthesis.

Question 6

Function of chloroplast

Answer 6

Contain a green pigment (chlorophyll). This absolve light energy to make food by photosynthesis.

Question 7

Function of cell wall.

Answer 7

• Made of cellulose,
• helps protect the cell and keep it’s shape,
• freely permeable.

Question 8

Function of the vacuole

Answer 8

• Filled with cell sap. This is a store of dissolved sugars, mineral ions and water.
• Help keep cell’s shape.

Question 9

Specialised cells

Answer 9

• Palisade cell -> green pigment -> absorbs sunlight,
• root hair cell → large surface area → absorbs lots,
• red blood cells → no nucleus → large surface area to carry oxygen,
• nerve cells → branches → can connect to many cells,
• sperm cells → tail → needs to swim
• guard cells → create openings → enables oxygen to diffuse

Question 10

What are stem cells

Answer 10

They are an undifferentiated cell that have the ability to become specialised. You can get them from embryos or bone marrow.

Question 11

Pros and Cons of embryonic

Answer 11

Pro:
- large numbers can be easily grown,
- can turn into many possible cells,

Con:
- ethical issues,
- can be contaminated in labs

Question 12

Pro and cons of adult

Answer 12

Pros:
- have same antigens as original cells,
- no ethical issues,

Cons:
- only found in small numbers,
- limited range and difficult to grow,
- cells may have DNA damage