B1 - Cell Structure and Transport

Question 1

benefits of using an electron microscope

Answer 1

• image can be seen in 3D
• gives a higher resolution
• 1000x more detailed than light microscopes
• can see organelles as small as ribosomes

Question 2

prokaryotic cell

Answer 2

• no nucleus
• always in single-cell organisms
• 100s of times smaller than eukaryotic cells
• have plasmids
• bacterial cells

Question 3

eukaryotic cell

Answer 3

• have a nucleus
• always in multi-cellular organisms
• 100s times larger than prokaryotic cells
• can have a vacuole
• can have mitochondria

Question 4

what does an electron microscope do

Answer 4

passes a beam of electrons through the specimen to be viewed on a screen at a very high resolution, but in black and white

Question 5

benefits of using a light microscope

Answer 5

• easy to use
• cheaper to run than electron microscopes

Question 6

nucleus

Answer 6

contains the genetic material that controls the activities of the cell

Question 7

cytoplasm

Answer 7

gel like substance composed of water and dissolved solutes
that supports internal cell structures
and is the site of many chemical reactions

Question 8

cell membrane

Answer 8

holds the cell together
controls which substances enter and leave the cell

Question 9

ribosomes

Answer 9

found in the cytoplasm, site of proteinsynthesis

Question 10

mitochondria

Answer 10

site of most of the reactions

Question 11

chloroplasts

Answer 11

contains green chlorophyll pigments to absorb light energy- for photosynthesis

Question 12

permanent vacuole

Answer 12

contains cell sap
used for storage of certain materials
supports the shape of the cell

Question 13

cell wall

Answer 13

made of cellulose
gives the cell extra support

Question 14

example of eukaryotic cell

Answer 14

plant cells
animal cells
fungi

Question 15

example of prokaryotic cell

Answer 15

bacterial cells

Question 16

plasmids

Answer 16

small circle of DNA that gives resistance to antibiotics

Question 17

capsule

Answer 17

protects the bacteria

Question 18

flagellum

Answer 18

allows movement

Question 19

pilus

Answer 19

tubes that inject into neighbouring bacteria to transfer plasmids

Question 20

DNA

Answer 20

contains genetic material

Question 21

special features of a nerve cell

Answer 21

very long cells (axon)
many branches at both ends to connect them
axon is covered in fat to prevent electrical impulses affecting the rest of the body
to carry nerve impulses around the body

Question 22

special features of a sperm cell

Answer 22

long thin tail to swim
acrosomes enzymes in sperm’s head to guide it
lots of mitochondria to release enough energy through respiration
to carry the father’s genetic information to the egg for fertilisation

Question 23

specialised features of ciliated epithelial cells (in trachea)

Answer 23

line all air passages down to the lungs
tiny hairs (cilia) to move microbes and debris out of the airways - smoking kills the cilia and mucus builds
to stop lung damage by removing mucus

Question 24

specialised features of muscle cells

Answer 24

contain contractile proteins that slide over each other causing muscle contraction
glycogen stores break down to release glucose during respiration
contain many mitochondria to release energy during muscle contraction
to provide force and motion

Question 25

specialisations of red blood cells

Answer 25

biconcave shape maximises surface area contains haemoglobin which picks up oxygen (oxyhaemoglobin) no nucleus makes room for more oxygen **carry oxygen from lungs to the body carry carbon dioxide from the body to the lungs**

Question 26

diffusion

Answer 26

the passive movement of particles from an area of high particle concentration to an area of low particle concentration

Question 27

how does temperature affect diffusion

Answer 27

**rate of diffusion increases at higher temperatures** because heat provides the particles with more kinetic energy

Question 28

how does concentration gradient affect diffusion

Answer 28

steeper concentration gradients lead to faster rate of diffusion

Question 29

concentration gradient

Answer 29

the difference between where the particles are coming from and where they are going to

Question 30

how does surface area affect the rate of diffusion

Answer 30

**larger surface area leads to faster diffusion** because it is easier for the oxygen to get diffuse in

Question 31

adaptations of the capillaries

Answer 31

thinner - shorter diffusion distance gaps between the cells - molecules can move freely

Question 32

osmosis

Answer 32

the passive movement of water from an area of higher water concentration to an area of lower water concentration through a semi-permeable membrane

Question 33

hypertonic solution

Answer 33

lower water concentration than the cell placed in it **cells shrivel**

Question 34

isotonic solution

Answer 34

equal water concentration as the cell placed in it

Question 35

hypotonic

Answer 35

higher water concentration than the cell placed in it **cells burst**

Question 36

active transport

Answer 36

the movement of a substance from an area of low concentration to an area of high concentration against a concentration gradient

Question 37

common adaptations in exchanging materials

Answer 37

increased surface area larger concentration gradients cell walls 1 cell thick good supply of nutrients

Question 38

diffusion in breathing

Answer 38

millions of alveoli give very large surface area constant supply of oxygen and rich blood supply: steep concentration gradient alveoli have 1 cell thick cell walls

Question 39

diffusion and digestion

Answer 39

villi and microvilli give very large surface area constant supply of food: steep concentration gradient Villi and microvilli have 1 cell thick cell walls

Question 40

diffusion in leaves

Answer 40

for photosynthesis

Question 41

magnification

Answer 41

size of image / size of object