Cell Biology

Question 1

What are cells?

Answer 1

Cells are basic units of life.

Question 2

What are the four types of cell?

Answer 2

Animal, plant, fungal and bacterial

Question 3

Name all the organelles in an animal cell.

Answer 3

• ribosomes
• cell membrane
• mitochondria
• cytoplasm
• nucleus

Question 4

Name all the organelles in a plant cell.

Answer 4

• chloroplasts
• cell membrane
• cell wall (cellulose)
• cytoplasm
• mitochondria
• vacuole
• ribosomes
• nucleus

Question 5

Name all the organelles in a fungal cell.

Answer 5

• cytoplasm
• cell wall (no cellulose)
• cell membrane
• vacuole
• mitochondria
• ribosomes
• nucleus

Question 6

Name all the organelles in a bacterial cell.

Answer 6

• plasmid
• bacterial chromosome
• cell wall
• cell membrane
• cytoplasm
• ribosomes
• flagellum

Question 7

What is the function of the nucleus?

Answer 7

Controls cell activities.

Question 8

What is the function of the cell membrane?

Answer 8

Controls movement of substances in and out of the cell.

Question 9

What is the function of the cell wall?

Answer 9

Supports the cell, gives it a rigid structure.

Question 10

What is the function of the cytoplasm?

Answer 10

Contains organelles and is the site of chemical reactions.

Question 11

What is the function of the ribosome?

Answer 11

Site of protein synthesis.

Question 12

What is the function of the mitochondria?

Answer 12

Site of aerobic respiration.

Question 13

What is the function of the chloroplast?

Answer 13

Site of photosynthesis.

Question 14

What is the function of the vacuole?

Answer 14

Stores water, sugar and salt as cell sap.

Question 15

What is the function of the plasmid?

Answer 15

Circular rings of DNA that contain additional genes which are beneficial to the cell.

Question 16

Is the cell membrane selectively permeable?

Answer 16

Yes, it only allows small and soluble molecules to cross.

Question 17

What is the cell membrane made up of?

Answer 17

Proteins and phospholipids.

Question 18

What is diffusion?

Answer 18

The movement of molecules down a concentration gradient from a higher to a lower concentration.

Question 19

Is diffusion a passive or active process?

Answer 19

Passive, which means it does not require energy.

Question 20

What is a concentration gradient?

Answer 20

It is the difference between a high and low concentration.

Question 21

Why is diffusion important?

Answer 21

• To gain the raw materials for respiration
  —> oxygen and food (e.g glucose)
• To remove waste products
  —> carbon dioxide, urea

Question 22

What is the diffusion of water called?

Answer 22

Osmosis.

Question 23

What is osmosis?

Answer 23

Osmosis is the movement of water molecules from a higher water concentration to a lower water concentration through a selectively permeable membrane.

Question 24

Is osmosis a passive or active process?

Answer 24

A passive process, this means it does not require energy.

Question 25

What happens to an animal cell placed in pure water?

Answer 25

Water enters the cell by osmosis down a water concentration gradient, the animal cell bursts.

Question 26

What happens to an animal cell when it’s placed in a dilute sugar/salt solution?

Answer 26

As there is no difference in the water concentration inside and outside the cell, no change occurs.

Question 27

What happens to an animal cell placed in a concentrated sugar/salt solution?

Answer 27

Water leaves by osmosis down a water concentration gradient, the animal cell shrinks.

Question 28

What happens to a plant cell that is placed in pure water?

Answer 28

Water enters by osmosis causing the cell to swell, the cell wall prevents it from bursting. The cell is now described as turgid.

Question 29

What happens to a plant cell placed in a dilute sugar/salt solution?

Answer 29

As there is no difference in the water concentration, no change occurs.

Question 30

What happens to a plant cell placed in a concentrated sugar/salt solution?

Answer 30

Water leaves by osmosis. This causes the vacuole to shrink away from the cell wall. The cell is now described as plasmolysed, the tissue is described as flaccid.

Question 31

What is active transport?

Answer 31

Active transport is the movement of molecules across a cell membrane from a low to a high concentration i.e against the concentration gradient

Question 32

Does active transport require energy?

Answer 32

Yes, as energy is needed to move molecules against the concentration gradient.

Question 33

What is DNA?

Answer 33

DNA is a molecules which carries genetic information.