B1 Cell Structure and Transport

Question 1

What are the two types of microscopes?

Answer 1

Light microscope and electron microscope

Question 2

How to calculate magnification?

Answer 2

Magnification = Size of image / size of real object

Question 3

What is the magnification of light microscopes?

Answer 3

Up to about x2000, and have a resolving power (detail) of about 200nm

Question 4

What is the magnification of electron microscopes?

Answer 4

Up to about x2,000,000 and have a resolving power (detail) of around 0.2nm

Question 5

What are the organelles in an animal cell?

Answer 5

• Cell membrane
• Ribosome
• Nucleus
• Cytoplasm
• Mitochondria

Question 6

What are the organelles in a plant cell?

Answer 6

• Cell membrane
• Ribosome
• Nucleus
• Cytoplasm
• Mitochondria
• Cell wall
• Vacuole
• Chloroplast

Question 7

What is the function of the nucleus?

Answer 7

• Control the activities of the cell
• Contains the genes and chromosomes needed to make new cells and organisms

Question 8

What is the function of the cytoplasm?

Answer 8

A liquid gel where most of the chemical reactions for the cell happen

Question 9

What is the function of the cell membrane?

Answer 9

Controls what enters and leaves the cell

Question 10

What is the function of the mitochondria?

Answer 10

Where respiration occurs. Oxygen and glucose react to release energy

Question 11

What is the function of the ribosomes?

Answer 11

Where protein synthesis takes place. All proteins needed in a cell are made here.

Question 12

Why do plant cells have more organelles than animal cells?

Answer 12

Plants need to make their own food

Question 13

What is the function of the cell wall?

Answer 13

Made of cellulose. Gives the cell structure and the plant strength and support

Question 14

What is the function of the chloroplast?

Answer 14

It is what makes the plant green. Also where photosynthesis takes place

Question 15

What is the function of the permanent vacuole?

Answer 15

Keeps the plant rigid and filled with sap (storage of material)

Question 16

The beginning of life on Earth

Answer 16

Began with a single-celled organism-like bacteria called prokaryotic cells. After millions of years, through evolution, eukaryotic cells came into being

Question 17

Prokaryotic cells

Answer 17

• Do not have “membrane-bound organelles”
• No distinct nucleus, mitochondria, chloroplasts or any other internal organelles in the same way plant and animal cells do

Question 18

What are the organelles in a prokaryotic cell?

Answer 18

• Cell wall
• Cell membrane
• Ribosomes
• Cytoplasm
• Genetic Material
• Flagella

Question 19

Order of magnitude

Answer 19

Number of zeros - 10x OM of 1
if the number doesn’t end with a zero, round it to the nearest order. E.g. 12x is close to 10x than 100x so OM of 1

Question 20

What are specialised cells?

Answer 20

In multicellular organisms, cells specialise so that they are very good at carrying out a particular function -> need adaptations. This is called differentiation

Question 21

Function of the nerve cell (Neurone)

Answer 21

Carry electrical signals around the body providing a rapid communication system between the different parts of the body

Question 22

Adaptations of the nerve cell (Neurone)

Answer 22

• Lots of connections to other nerve cells (Dendrites)
• Very long axon -> carry electrical signals
• Lots of mitochondria to provide the energy needed
• Synapse -> connect neurons to help transmit information from one neuron to the next

Question 23

Function of the muscle cell

Answer 23

Contract to bring about movement

Question 24

Adaptations of the muscle cell

Answer 24

• Special proteins that slide over each other making fibres contract
• Many mitochondria for respiration to produce energy
• Store glycogen -> chemical that can be broken down and used in respiration by the mitochondria if needed.

Question 25

Function of the sperm cell

Answer 25

Transfer genetic information from the male parent during reproduction

Question 26

Adaptations of the sperm cell

Answer 26

- Long tail to help the sperm move - Lots of mitochondria to transfer energy to the tail - Head stores enzymes to break down the outer layer of the egg cell - Nucleus to store genetic information

Question 27

Function of the root hair cell

Answer 27

Absorb water and mineral ions

Question 28

Adaptations of the root hair cell

Answer 28

- Large surface area -> increases rate of diffusion and active transport - Large permanent vacuole that speeds up the movement of water by osmosis - Lots of mitochondria that transfer energy needed for the active transport of mineral ions into the root hair cells

Question 29

Function of the photosynthetic cell

Answer 29

Make food using photosynthesis

Question 30

Adaptations of the photosynthetic cell

Answer 30

- Contain chloroplasts -> Where photosynthesis work - Large permanent vacuole to help keep the cell rigid as a result of osmosis. This helps support the stem and keeps the leaf spread out. - Regular shape -> Has a cell wall and vacuole to keep it rigid

Question 31

Function of the xylem cell

Answer 31

Carries water and mineral ions from roots to all leaves and shoots

Question 32

Adaptations of the xylem cell

Answer 32

- Lignin to strengthen - Cells die and form hollow tubes allowing water to move easily through them

Question 33

Function of the phloem cell

Answer 33

Carries food (sugar) made from photosynthesis around the plant

Question 34

Adaptations of the phloem cell

Answer 34

- Cell walls between cells break down to form special sieve plates (like a colander) - Lose a lot of the internal structure but are supported by companion cells that keep them alive - Mitochondria of the companion cells transfer the energy needed to move the food

Question 35

What is diffusion?

Answer 35

The movement of particles from a high to low concentration

Question 36

Factors to speed up diffusion

Answer 36

- Temperature - Bigger surface area - Higher concentration gradient

Question 37

How does an increase in temperature speed up the rate of diffusion?

Answer 37

The higher the temperature, the more energy the particles will have, increasing their random movement.

Question 38

What is osmosis?

Answer 38

The net movement of water from a high to low water concentration through a partially permeable membrane -> dilute to concentration solution

Question 39

What causes water to move in or out of a cell?

Answer 39

Differences in the concentrations of solutions inside and outside a cell cause movement via osmosis

Question 40

How can animal cells be damaged from osmosis?

Answer 40

When the concentration outside the cell changed dramatically. E.g. pouring salt on a slug causes it to die from osmosis