B1 Cell Biology

Question 1

What is diffusion?

Answer 1

The spreading out of particles with a net movement from a high concentration to a low concentration

Question 2

Why is oxygen needed in the body?

Answer 2

It is needed for respiration in cells

Question 3

Why does oxygen move into a cell?

Answer 3

There is a high concentration outside the cell as it is surrounded by blood from the lungs.

Question 4

Why does carbon dioxide move out of the cell?

Answer 4

There is a high concentration of carbon dioxide in the cell

Question 5

What is carbon dioxide in the body?

Answer 5

A waste product of respiration

Question 6

What is urea?

Answer 6

A waste product produced in cells

Question 7

Why does urea move out of the cell?

Answer 7

There’s a high concentration in the cell so if users through the membrane into blood plasma

Question 8

What factors increase the rate of diffusion?

Answer 8

A higher surface area
A greater concentration gradient
High temperature

Question 9

What is surface area to volume ratio?

Answer 9

A measure of how large an organism surface area is compared to its volume.

Question 10

Why can single celled organisms use diffusion to get all the gases?

Answer 10

They have a large surface area to volume ratio

Question 11

What happens when an organisms gets larger?

Answer 11

Surface area to volume ratio falls

Question 12

Why can multicellular organisms not use diffusion to get gases?

Answer 12

The surface area to volume ratio is not large enough so oxygen cannot diffuse to the centre of the organism

Question 13

What adaptation do gills have?

Answer 13

Large surface area
Thin membrane
High blood flow

Question 14

What is osmosis?

Answer 14

The movement of water molecules over a partially permeable membrane from an area of high concentration to an area of low concentration

Question 15

What is active transport?

Answer 15

The movement of particles against concentration gradient using energy transferred during respiration

Question 16

How do plants use active transport?

Answer 16

It allows minerals in areas of low concentration in the soil to move into the root hair cells against a concentration gradient

Question 17

How is active transport used in digestion?

Answer 17

When there is a low concentration of nutrients in the gut but higher concentration of nutrients in the blood.

Question 18

What is the difference between active transport and diffusion?

Answer 18

Active transport uses energy while diffusion is passive.

Question 19

How are alveoli adapted for gas exchange?

Answer 19

Large surface area
Moist lining for dissolving gases
Very thin walls
Good blood supply

Question 20

What are villi?

Answer 20

Tiny projections in the small intestine to help absorb digested food as quickly as possible

Question 21

What are the adaptations of villi?

Answer 21

Single layer of surface cells

Very good blood supply to assist quick absorption

Question 22

What adaptations do leaves have?

Answer 22

Stomata
Oxygen and water diffuse out of the stomata
Flatten shape to increase area of exchange surface
Air spaces inside the leaf

Question 23

What is a prokaryotic cell?

Answer 23

A smaller and simpler cell compared to a eukaryotic cell

Question 24

What is a eukaryotic cell?

Answer 24

A complex cell including all animal and plant cells.

Question 25

What structures do bacterial cells have?

Answer 25

Strands of DNA Plasmids No chloroplast or mitochondria Cell wall

Question 26

What are the parts of a microscope?

Answer 26

``` Eyepiece Coarse adjustment knob Fine adjustment knob Light Stage High and low power objective lenses ```

Question 27

what is 1 order of magnitude mean?

Answer 27

It means 10x | every order of magnitude is 10 times greater than the one before.

Question 28

what are mitochondria?

Answer 28

where aerobic respiration takes place

Question 29

what are ribosomes?

Answer 29

the site of protein synthesis

Question 30

what other structures do plants cells contain?

Answer 30

chloroplasts cell wall vacuole

Question 31

what are chloroplasts?

Answer 31

they contain chlorophyll and are the site of photosynthesis

Question 32

what is the cell wall?

Answer 32

it is made of cellulose and strengthens the cell

Question 33

what is the vacuole?

Answer 33

a sac filled with cell sap which helps give the cell shape

Question 34

what is specialisation?

Answer 34

when a cell has adaptations which help them to carry out their particular function

Question 35

what adaptations do sperm cells have?

Answer 35

a long tail - allows it to swim, makes it streamlined packed with mitochondria - provide the energy to swim contain enzymes - allows the sperm to digest the outer layer of the ovum

Question 36

what are the adaptations of a muscle cell?

Answer 36

protein fibres - can change length to allow cells to contract mitochondria - provides energy for muscle contraction

Question 37

what are the adaptations of a nerve cell?

Answer 37

an axon - carries the electrical impulses myelin sheath - insulates axon to speed up transmission synapses - allow impulses to pass between cells dendrites - increase surface area so other nerve cells can connect more easily

Question 38

why do plant roots have root hairs?

Answer 38

to increase the surface area of the root so it can absorb water and dissolved minerals more easily

Question 39

what adaptations do root hair cells have?

Answer 39

root hair - increases surface area | no chloroplasts - cells are underground

Question 40

what adaptations do xylem cells have?

Answer 40

lignified walls - provide support broken down end walls - water can flow easily no internal structures - makes it easy for water to flow

Question 41

what adaptations do phloem cells have?

Answer 41

sieve plates - allow dissolved sugars to move through the plant companion cells - provide energy for the vessel cell

Question 42

what are some limitations of light microscopes?

Answer 42

limited magnification | limited resolution

Question 43

what are some advantages of an electron microscope?

Answer 43

greater magnification and resolution

Question 44

what is the formula for calculating magnification?

Answer 44

magnification = size of image/real size of object

Question 45

what is meant by turgid?

Answer 45

when water moves into the cell by osmosis and becomes swollen. it does not burst as the cell wall supports the cell

Question 46

what does flaccid mean?

Answer 46

when water moves out of a plant cell by osmosis and causes it to shrink

Question 47

what is a concentration gradient?

Answer 47

the difference between the areas of high concentration and low concentration