B1 - Cell Structure and transport

Question 1

How does a light microscope work?

Answer 1

Light microscopes use a beam of light to form an image

Question 2

How does an electron microscope work?

Answer 2

Electron microscopes use a beam of electrons to form an image

Question 3

Give a pro and con of light microscopes:

Answer 3

Pro
Relatively cheap
Can be used almost anywhere
Can produce colour images
Small - takes up less room

Con
Low resolving power

Question 4

Give a pro and con of electron microscopes:

Answer 4

Pro
Higher resolution
Higher magnification
Can see tiny sub-cellular structures

Con
Very expensive
Must be kept in certain conditions
Large - take up a lot of space
Only produces black and white images

Question 5

What are the two types of eukaryotic cell?

Answer 5

Animal and plant

Question 6

What type of cell are bacteria?

Answer 6

Prokaryotic

Question 7

Where is DNA found in animal and plant cells?

Answer 7

Nucleus

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 mitochondria?

Answer 9

Site of aerobic cellular respiration to transfer energy for the cell

Question 10

What is the function of chloroplasts?

Answer 10

The organelles in which photosynthesis takes place. Contains chlorophyll to absorb light energy for photosynthesis

Question 11

What is the function of ribosomes?

Answer 11

Where protein synthesis takes place, making all the proteins needed in the cell

Question 12

What is the function of the cell wall?

Answer 12

Made of cellulose
Strengthens and supports the cell

Question 13

What is the structure of the main genetic material in a prokaryotic cell?

Answer 13

Single loop of DNA

Question 14

What is the function of a red blood cell?

Answer 14

Carries oxygen around the body

Question 15

Give 2 adaptations of a red blood cell:

Answer 15

No nucleus
Contains a red pigment called haemoglobin
Has a bi-concave disc shape

Question 16

What is the function of a nerve cell?

Answer 16

Carries electrical impulses around the body

Question 17

Give 2 adaptations of a nerve cell:

Answer 17

Branched endings
Myelin sheath insulates the axon

Question 18

What is the function of a sperm cell?

Answer 18

Fertilises an ovum (egg)

Question 19

Give 2 adaptations of a sperm cell:

Answer 19

Long tail whips from side to side to help move sperm to egg
Middle section has mitochondria to transfer energy needed for tail to work
Acrosome stores digestive enzymes for breaking down outer layers of egg
Large nucleus contains genetic information to be passed on

Question 20

What is the function of a muscle cell?

Answer 20

Specialised cell that contracts and relaxes in pairs to move the skeleton/ move food through gut

Question 21

Give 2 adaptations of muscle cells:

Answer 21

Contains special proteins that slide over each other making the fibres contract
Contains mitochondria to transfer energy needed for the chemical reactions that take place as the cells contract and relax
Can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria to transfer the energy needed for the fibres to contract

Question 22

What is the function of a palisade cell?

Answer 22

Carries out photosynthesis in a leaf

Question 23

Give 2 adaptations of a palisade cell:

Answer 23

Lots of chloroplasts
Located at the top surface of the leaf

Question 24

What is the function of a root hair cell?

Answer 24

Absorbs minerals and water from the soil

Question 25

Give 2 adaptations of a root hair cell?

Answer 25

Long projection - surface area Lots of mitochondria to transfer energy needed for active transport

Question 26

What is osmosis?

Answer 26

A special case of diffusion. The movement of water from a dilute to a more concentrated solution through a partially permeable membrane.

Question 27

What is active transport?

Answer 27

The movement of substances from an area of low concentration to an area of high concentration. It goes against a concentration gradient, requiring energy from respiration.

Question 28

What is a partially permeable membrane?

Answer 28

A membrane that only allows certain substances to pass through

Question 29

What is passive transport?

Answer 29

The movement of substances from an area of high concentration to an area of low concentration, requiring no energy. Moves down concentration gradient.

Question 30

What is diffusion?

Answer 30

The spreading out of particles of any substance in a solution, or particles in a gas, resulting in a net movement of particles from an area of high to low concentration down a concentration gradient. The net movement of particles from an area of high concentration to an area of low concentration.

Question 31

What is the difference between an animal and plant cell?

Answer 31

Animal cells **don’t** have a cell wall. Animal cells **don’t** have chloroplasts

Question 32

What is the difference between the genetic material in a prokaryotic cell and the genetic material in a eukaryotic cell?

Answer 32

In prokaryotic cells, the genetic material is not enclosed in a nucleus. The bacterial chromosome is a single loop of DNA found free in the cytoplasm. Prokaryotic cells may also contain extra small rings of DNA called plasmids.

Question 33

What do plasmids do?

Answer 33

Plasmids code for very specific features such as antibiotic resistance.

Question 34

Some types of bacterium have flagella. What is this?

Answer 34

A long protein strand that lashes about. These bacteria use their flagella to move themselves around.

Question 35

What is the nucleus?

Answer 35

An organelle containing genetic information and controls all the activities of the cell.

Question 36

What is cytoplasm?

Answer 36

The water-based gel in which the organelles in all living cells are suspended and most of the chemical reactions of life take place.

Question 37

What is a vacuole?

Answer 37

Contains cell sap (fluid) surrounded by a single membrane.

Question 38

Why should you start with the lowest magnification?

Answer 38

Makes it easier to find what you’re looking for.

Question 39

What is the equation for magnification?

Answer 39

Magnification = size of image/ size of real object

Question 40

What is xylem?

Answer 40

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

Question 41

How has xylem adapted?

Answer 41

Lignin - strength Dead - long hollow tubes

Question 42

What is phloem?

Answer 42

The transport tissue that carries the food made by photosynthesis around the body of the plant.

Question 43

What is transpiration?

Answer 43

The loss of water vapour from the leaves of plants through the stomata when they’re opened to allow gas exchange for photosynthesis.

Question 44

What is translocation?

Answer 44

The movement of sugars from the leaves to the rest of the plant through the phloem.

Question 45

What is the rate of diffusion affected by?

Answer 45

Concentration difference Temperature Surface area

Question 46

Isotonic = ? Hypertonic = ? Hypotonic = ?

Answer 46

Isotonic = equal Hypertonic = higher outside Hypotonic = lower outside