Chapter 1

Question 1

light microscope
magnification
resolution

Answer 1

m = x2000
r = 200nm

Question 2

electron microscope
magnification
resolution

Answer 2

m = x 2000000
r = 0.2nm

Question 3

equation
magnification
size of real object
size of image

Answer 3

magnification = size of image / size of real object

Question 4

components in an animal cell (5)

Answer 4

nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

Question 5

Explain:

nucleus

Answer 5

controls all activities of a cell and contains genes

Question 6

Explain:

cytoplasm

Answer 6

where most chemical reactions take place

Question 7

Explain:

cell membrane

Answer 7

controls the passage of substances into the cell

Question 8

Explain:

mitochondria

Answer 8

where aerobic respiration takes place

Question 9

Explain:

ribosomes

Answer 9

where protein synthesis takes place

Question 10

components in a plant cell (8)

Answer 10

nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, cell wall, permanent vacuole

Question 11

Explain:

cell wall

Answer 11

Strengthens the cell and gives it support

Question 12

Explain:

chloroplasts

Answer 12

It contains chlorophyll which absorbs light and can make food by photosynthesis

Question 13

Explain:

permanent vacuole

Answer 13

Keeps the cell rigid to support the plant

Question 14

Give 3 examples of eukaryotic cells.

Answer 14

plants, fungi, protists

Question 15

Give an example of a prokaryotic cell.

Answer 15

bacteria

Question 16

Basic structure of a bacteria (6)

Answer 16

cell membrane, slime capsule, cell wall, plasmids, flagella, cytoplasm

Question 17

What do all eukaryotic cells contain (3)

Answer 17

cell membrane, cytoplasm, genetic material enclosed in a nucleus

Question 18

What do prokaryotic cells contain (4)

Answer 18

cytoplasm, cell membrane, cell wall, the genetic material is not in a distinct nucleus but in small loops called plasmids

Question 19

what is differentiation

Answer 19

As an organism develops, cells differentiate to form different types of specialised cells. It allows the cell to carry out a certain function.

Question 20

What is the purpose of a nerve cell

Answer 20

to carry electrical impulses around the body of an animal

Question 21

How is a nerve cell specialised (3)

Answer 21

1) Lots of dendrites to make connections to other nerve cells
2) An axon that carries the nerve impulse from one place to another. They can be very long
3) The nerve endings or synapses are adapted to pass the impulses to another cell or between a nerve cell using special transmitter chemicals. They contain lots of mitochondria to provide the energy needed to make the transmitter chemicals.

Question 22

What is the purpose of a muscle cell

Answer 22

to contract and relax

Question 23

How is a muscle cell specialised (3)

Answer 23

1) They contain special proteins that side over each other making the fibres contract
2) They contain many mitochondria to transfer the energy needed for the chemical reactions to take place
3) They can store glycogen, a chemical that can be broken down and used in cellular respiration

Question 24

What is the purpose of a sperm cell

Answer 24

They contain genetic material from the male parent and have to swim to and break the egg.

Question 25

How is a sperm cell specialised (4)

Answer 25

1) A long tail helps the cell swim 2) They are full of mitochondria which provides energy 3) The digestive enzymes can be used for breaking down the outer layers of the egg 4) a large nucleus for the genetic information to be passed on

Question 26

What is the purpose of a root hair cell

Answer 26

The root hair cells help them to take up water and mineral ions more efficiently .

Question 27

How is a root hair cell specialised (3)

Answer 27

1) They greatly increase the surface area available for water to move into the cell 2) They have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell. 3) They have many mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells.

Question 28

what is the purpose of photosynthetic cells

Answer 28

This is a cell where photosynthesis occurs

Question 29

How is a photosynthetic cell adapted (3)

Answer 29

1) They contain specialised green structures called chloroplasts that trap the light needed for photosynthesis 2) They are usually positioned in continuous layers in the leaves and outer layers of the stem of a plant to absorb as much light as possible 3) They have a large permanent vacuole that helps keep the cell rigid and helps support the plant. They also keep the leaf spread out to increase SA.

Question 30

what is the purpose of the xylem cell

Answer 30

This is the transport tissue in plants that carries water and mineral ions from the roots to the highest leaves and roots.

Question 31

How is the xylem cell adapted (2)

Answer 31

1) These cells are alive when they are first formed but a special chemical called lignin builds up in spirals in the cell walls. The cells die and form long hollow tubes that allow water and mineral ions to move easily through them, from one end of the plant to the other. 2) The spirals and rings of lignin in the xylem cells make them very strong and help them withstand the pressure of water moving up the plant. They also help support the plant stem.

Question 32

what is the purpose of the phloem cell

Answer 32

It is a specialised transport tissue that carries the food made by photosynthesis around the body of the plant. The dissolved food can move up and down the phloem tubes to where it is needed.

Question 33

How is the phloem cell adapted (2)

Answer 33

1) The cell walls between the cells break down to form special sieve plates. These allows water carrying dissolved food to move freely up and down the tubes to where it is needed. 2) Phloem cells lose a lot of their internal structures but they are supported by companion cells that help to keep them alive. The mitochondria of the companion cells transfer the energy needed to move dissolved food up and down the plant in phloem.

Question 34

explain: diffusion

Answer 34

the spreading out of the particles which results in the net movement from an area of high concentration to an area of low concentration.

Question 35

what affects the rate of diffusion

Answer 35

the rate of diffusion is affected by: 1) the difference in concentrations 2) the temperature 3) the available surface area

Question 36

explain: osmosis

Answer 36

the movement of water from a dilute to a more concentrated solute solution through a partially permeable membrane that allows water to pass through.

Question 37

explain: turgor

Answer 37

the pressure that builds up until no more water can enter the cell

Question 38

explain: active transport

Answer 38

moves substances from a dilute solution to a more concentrated solution (against a concentration gradient)

Question 39

What does active transport require

Answer 39

uses energy released from food in respiration

Question 40

What does active transport allow plants and animals to do (2)

Answer 40

1) allows plant root hairs to absorb mineral ions required for healthy growth from dilute solutions in the ground. 2) enables sugar molecules used for cell respiration to be absorbed from lower concentration in the gut into the blood where the concentration of sugar is high