Chapter B1 Cell Structure and transport

Question 1

what is the maximum magnification and resolving power of light microscopes?

Answer 1

x2000, 200 nm

Question 2

what is the maximum magnification and resolving power of electron microscopes?

Answer 2

x2000000, 0.2 nm

Question 3

magnification =

Answer 3

size of image / size of real object

Question 4

animal cell structures and functions

Answer 4

• nucleus: controls all activities of cell, surrounded by nucleus membrane.
• cytoplasm: liquid gel where organelles are suspended, chemical reactions take place.
• cell membrane: controls passage of substances in and out of cell.
• mitochondria: aerobic respiration takes place, releasing energy for cell.
• ribosomes: protein synthesis takes place

Question 5

average diameter of a nucleus

Answer 5

10um

Question 6

size of mitochondria

Answer 6

1-2um in length, 0.2-0.7um in diameter

Question 7

plant cell structures and functions

Answer 7

• nucleus
• cytoplasm
• ribosomes
• cell membrane
• mitochondria
• chloroplasts: chlorophyll absorbs light for photosynthesis.
• permanent vacuole: keeps cell rigid to support plant
• cell wall: strengthens cell, gives support

Question 8

chloroplasts size

Answer 8

3-5um long

Question 9

resolution meaning

Answer 9

clarity of the image

Question 10

Eukaryotic examples

Answer 10

animal and plant cells

Question 11

Eukaryotic structures

Answer 11

• cell membrane
• cytoplasm
• genetic material in nucleus

Question 12

Prokaryotes example

Answer 12

bacteria (single-celled living organisms)

Question 13

Prokaryotes structures and functions

Answer 13

• genetic material
• cytoplasm
• cell membrane
• slime capsule
• cell wall
• plasmids (small rings of DNA)
• flagella

Question 14

flagella function

Answer 14

long protein strand that lashes about, help move themselves about

Question 15

Prokaryotes size

Answer 15

0.2-2.0um in length, 1-2 orders smaller then Eukaryotes

Question 16

milli- symbol, 1000^m, 10^n, decimal

Answer 16

m, 1000^-1, 10^-3, 0.001

Question 17

micro- symbol, 1000^m, 10^n, decimal

Answer 17

u, 1000^-2, 10^-6, 0.000001

Question 18

nano- symbol, 1000^m, 10^n, decimal

Answer 18

n, 1000^-3, 10^-9, 0.000000001

Question 19

sperm cells structures and functions

Answer 19

• tail: helps move
• mitochondria: energy
• acrosome: stores digestive enzymes for, breaking down outer layer of the egg

Question 20

nerve cells structures and functions

Answer 20

• dendrites: to make connections with other nerve cells
• axon: carries the nerve impulse from one place to another
• synapse: pass impulses using special transmitter chemicals
• mitochondria: energy for transmitter chemicals

Question 21

muscle cells structures and functions

Answer 21

• special proteins: fibres contract
• mitochondria: energy for chemicals reactions as cells contract and relax
• glycogen: cellular respiration

Question 22

root hair cells structures and functions

Answer 22

• increased surface area: water to move into cell
• large permanent vacuole: speeds up movement of water by osmosis
• mitochondria: energy needed for active transport of mineral ions into the cell

Question 23

xylem cells structures and functions

Answer 23

-lignin spirals and hollow tube of xylem: makes them strong and help them withstand pressure of water moving in the plant. help support plant stem

Question 24

phloem cells structures and functions

Answer 24

• cell wall: break down to form special sieve plates, so water moves freely
• companion cells: helps keep them alive
• mitochondria: energy needed to move dissolved food up and down plant phloem

Question 25

diffusion

Answer 25

the spreading out of particles of any substance, in solution or gas, resulting in a net movement from an area of higher concentration to an area of lower concentration, down a concentration gradient.

Question 26

what is the rate of diffusion affected by?

Answer 26

- difference in concentrations - temperature - available surface area

Question 27

what dissolved substances move in and out of cells by diffusion?

Answer 27

glucose and urea

Question 28

what gases move in and out of cells by diffusion?

Answer 28

oxygen and carbon dioxide

Question 29

osmosis

Answer 29

movement of water from a dilute solution to a more concentrated solution

Question 30

maximising the rate of diffusion for short distances

Answer 30

- distance between high concentration and the low concentration - shorter the distance, quicker the rate of diffusion - net movement by diffusion will be quite slow. particles moving into an area of lower concentration by random movement will be slightly more than particles that are leaving the area

Question 31

maximising the rate of diffusion for large surface areas

Answer 31

- larger the surface area the more area it gives for particles to go through - area can increase by folding up the membrane of the cell, or the tissue lining an organ

Question 32

maximising the rate of diffusion for steep concentration gradients

Answer 32

- bigger difference in concentration, quicker diffusion will take place - small difference- net movement by diffusion will be slow. - bigger the difference, steeper concentration gradient - diffusion occurs down the concentration gradient

Question 33

net movement=

Answer 33

particles moving in - particles moving out

Question 34

active transport

Answer 34

- moves substances against the concentration gradient - uses energy from respiration - cells that carry out active transport have many mitochondria

Question 35

examples of active transport

Answer 35

- plant root hairs absorb minerals from dilute solutions in soil - glucose molecules are absorbed from low concentration in the gut

Question 36

for substances to exchange effectively they need:

Answer 36

- a big surface area - small diffusion distance - steep concentration gradient

Question 37

diffusion and osmosis (down the concentration gradient):

Answer 37

- passive | - no energy required

Question 38

active transport (against the concentration gradient):

Answer 38

- active - energy required from respiration - many mitochondria are found - steep concentration gradient isn't as important for active transport

Question 39

what happens when living organisms get bigger and more complex?

Answer 39

surface area to volume ratio gets smaller

Question 40

how to increase the effectiveness of an exchange surface?

Answer 40

-large surface area -thin membrane or being thin for short diffusion path In animals: -efficient blood supply, steeper concentration diffusion gradient -being ventilated, maintains steep concentration gradients

Question 41

how does organisms getting bigger negatively affect the speed of which materials exchange?

Answer 41

- gases and food molecules can no longer reach every cell inside the organism by simple diffusion - metabolic waste cannot be removed fast enough to avoid poisoning the cells

Question 42

details of microscopy practical

Answer 42

Use a light microscope to observe, draw & label cells.

Question 43

details of osmosis practical

Answer 43

Investigate the effect of a range of concentrations of solutions on the mass of plant tissue.

Question 44

microscope labels

Answer 44

- eye piece lens - stage clips - fine focusing knob - light - objective lens - stage - focusing knob - light switch

Question 45

what process takes place in mitochondria? word equation, 2 things needed, 2 waste products, purpose and use of product of this process.

Answer 45

- aerobic respiration - sugar + oxygen -> carbon dioxide + water +energy released - oxygen + sugar - carbon dioxide + water - releases energy for the cell - energy helps the cell perform work

Question 46

where do you find genes?

Answer 46

nucleus, chromosomes

Question 47

what do genes do?

Answer 47

carry the instructions for making the proteins needed to build new cells or new organisms

Question 48

what are proteins made of?

Answer 48

chain of amino acids

Question 49

examples of proteins

Answer 49

keratin, collagen, elastin, insulin