Cell Structure - Set 1

Question 1

What is the structure of the plasma (cell surface) membrane? What is it mainly made up of? What does it contain?

Answer 1

The phospholipid bilayer found on the surface of animal cells, and just inside the cell wall of plant and prokaryotic cells.

It is made mainly of lipids and proteins.

It is a phospholipids bilayers that contains intrinsic and extrinsic proteins.

Question 2

What is the function of the plasma (cell surface) membrane?

Answer 2

1. regulates the movement of substance into and out of the cell.
2. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.

Question 2

What is the structure of the cell wall? What is it mainly made up of?

Answer 2

A rigid structure that surrounds plant cells.

It is mainly made of the carbohydrate cellulose.

Question 3

What is the function of the cell wall?

Answer 3

Supports plant cells

Question 4

What is the nucleus?

Answer 4

An organelle found in eukaryotic cells that stores the genetic information of the cell as chromosomes, and is surrounded by a membrane called the nuclear envelope.

Question 5

What does the nucleus contain? What is this made up of?

Answer 5

The nucleus contains chromatin (the material from which chromosomes are made).

Chromosomes are made up of sections of linear DNA tightly wound around proteins called histones.

Question 6

Describe the structure of the nucleus.

Answer 6

1. Surrounded by a nuclear envelope (a semi-permeable double membrane).
2. Nuclear pores allow substances to enter/exit.
3. Dense nucleolus made of RNA and proteins assembles ribosomes.

Question 7

Why are nuclear pores important?

Answer 7

Nuclear pores are important channels allowing mRNA and ribosomes to travel out of the nucleus, as well as allowing enzymes and signalling molecules to travel in.

Question 8

Describe the function of the nucleus. (5)

Answer 8

1. Contain DNA coiled around chromatin into chromosomes.
2. Site of transcription and primary mRNA splicing.
3. Site of DNA replication.
4. Nucleolus makes ribosomes.
5. Nuclear pores allow the movement fo substances into and out of the cytoplasm.

Question 9

What is the nuclear envelope?

Answer 9

A double membrane, separated by fluids, that surrounds the nucleus. It contains nuclear pores that control the movement of substances into and out of the cytoplasm.

Question 10

What is the function of the nucleolus?

Answer 10

Makes ribosomes.