B2.1- Cells and simple transport

Question 1

What parts do plant cells have which animal cells don’t?

Answer 1

• cell wall
• vacuole
• chloroplasts

Question 2

What does the nucleus contain?

Answer 2

Genetic material which controls the activities of the cell

Question 3

What is the cytoplasm and what does it contain?

Answer 3

• A gel-like substance where most of the chemical reactions happen
• Contains enzymes which control the chemical reactions

Question 4

What does the cell membrane do?

Answer 4

Holds the cell together and controls what goes in and out

Question 5

What happens in the ribosomes?

Answer 5

Where proteins are made

Question 6

What is the cell wall made of and what does it do?

Answer 6

• Made of cellulose

- Supports the cell and strengthens it

Question 7

What does the vacuole contain?

Answer 7

Cell sap (a weak solution of sugar and salts)

Question 8

What happens in the chloroplasts and what do they contain?

Answer 8

• Photosynthesis occurs (and makes food for the plant)

- Contain chlorophyll

Question 9

What is a type of single-celled organism?

Answer 9

Yeast

Question 10

What type of cell has no nucleus? Where is the genetic material stored?

Answer 10

• Bacteria

- Floats in the cytoplasm

Question 11

What is the definition of diffusion?

Answer 11

The spreading out of particles from an area of high concentration to an area of low concentration

Question 12

What will affect the rate of diffusion?

Answer 12

The difference in concentration

Question 13

How do dissolved substances move in and out of cells?

Answer 13

Through the cell membrane by diffusion

Question 14

What type of molecules can diffuse through the cell membrane?

Answer 14

Very small molecules- oxygen, glucose, amino acids, water

Question 15

What type of cells are adapted for photosynthesis?

Answer 15

Palisade leaf cells

Question 16

How are palisade leaf cells adapted for photosynthesis?

Answer 16

• packed with chloroplasts -for photosynthesis (at the top of the cell so nearer the light)
• tall shape- more surface area exposed down for absorbing CO2
• thin shape- many can be packed in at the top of a leaf

Question 17

What type of cells are adapted to open and close stomata (pores)?

Answer 17

Guard cells

Question 18

How do guard cells work?

Answer 18

• open and close the stomata in a leaf
• when the plant has lots of water the guard cells fill with it and become turgid- stomata open so gases can be exchanged (for photosynthesis)
• when plant is short of water the guard cells lose it and become faccid- stomata close and stop water vapour escaping

Question 19

How are guard cells adapted?

Answer 19

For gas exchange and controlling water loss:

• thin outer walls + thicker inner walls make opening and closing work
• sensitive to light + close at night to save water without losing photosynthesis

Question 20

What are red blood cells designed to do?

Answer 20

Carry oxygen

Question 21

How are red blood cells designed to carry oxygen?

Answer 21

• concave shape with a big surface area to absorb oxygen
• packed with haemoglobin
• no nucleus to leave more room for haemoglobin

Question 22

How is the sperm cell adapted for reproduction?

Answer 22

• long tail and stream lined head to help it swim to the egg
• a lot of mitochondria to provide it with the energy needed
• enzymes in the head to digest through the egg membrane