b1 - cell structure

same as anki imported here for eoy cram

how much can light microscopes magnify up to

2000x

what is the resolving power of a light microscope

20nm

how much can electron microscopes magnify up to

2000000

what is the resolving power of an electron microscope

0.2nm

magnification formula

size of image / size of real object

micro in standard form

10^-6

nano in standard form

1x10^-9

what do all animal cells have in common

a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes

what do plants and algal cells have in common

a cellulose cell wall and all the features in all animal cells

what are permanent vacuoles filled with

sap

what are defining features of eukaryotic cells

• cell membrane
  - cytoplasm
  - genetic material enclosed in a nucleus

what are defining features of a prokaryotic cell

• cytoplasm
  - cell membrane
  - dna is in plasmids

are bacteria eukaryotic or prokaryotic

prokaryotic

are eukaryotes or prokaryotes bigger

eukaryotes

why do cells specialise

to become better adapted to their surroundings

examples of specialised cells in plants

• root hair cells
  - xylem cells
  - phloem cells

examples of specialised cells in animals

• sperm cells
  - nerve cells
  - muscle cells

nerve cell adaptations

• lots of dendrites
  - long axon

3 adaptations of a muscle cell

• special proteins that can slide
  - many mitchondria to transfer necessary energy
  - glycogen

sperm cell adaptations

• long flagella
  - lots of mitochondria
  - acrosome stores digestive enzymes
  - nucleus contains the genetic information to be passed on

root hair cell adaptations

• large surface area
  - large permanent vacuole
  - many mitochondria

xylem cell adaptations

• long and hollow tubes
  - very strong

what is diffusion

the net movement of particles from an area of high concentration to low concentration, down a concentration gradient

what is the rate of diffusion affected by

• difference in concentrations
  - temperature
  - available surface area

single cell organisms SA:V ratio

large

what does a large SA:V ratio mean

sufficient transport of molecules into and out of the cell to meet the needs of the organism

characteristics of a good exchange surface

- large surface area
- thin membrane
- good ventilation

small intestine adaptations

• villi and microvilli increase surface area

• thin walls give short diffusion distance

• rich blood supply maintains concentration gradient

• active transport helps absorb nutrients

lungs adaptations

• alveoli give large surface area

• thin walls allow fast diffusion

• moist lining helps gases dissolve

• rich blood supply maintains steep concentration gradients

fish gills adaptations

• gill filaments

• lamellae

• these increase:

  • surface area

  • thin walls

• allow diffusion and counter-current flow maximises oxygen uptake

leaves adaptations

• large surface area

• thin leaves

• stomata allow gas exchange

• air spaces speed up diffusion

• guard cells control opening of stomata

what is osmosis

the net movement of water from an area of high to low concentration across a partially permeable membrane

to be deleted

okay

to be deleted

ok

what is active transport

the movement of substances from a dilute to concentrated solution

what does active transport allow

plants to uptake nutrients from very dilute soil solutions

exchange surface adaptations

• large surface area
  - thin walls
  - efficient blood supply
  - well ventilated

are specialised exchange surfaces needed in large or small organisms

large as they have a smaller SA:V ratio meaning diffusion through surfaces like skin is difficult

what is the top term

hypotonic

what is the second term

flaccid

what is the bottom term

plasmolysed

what is the top term

hypotonic solution

what is the second term

isotonic

what is the third term

hypertonic solution