B1: Cell Structure and Transport

What is the role of a nerve cell?

carry electrical pulses, specialised for Rapid Communication System

What are the adaptions of nerve cells?(x4)

• lots of drendrites - connect other nerve cells

• axon - carries nerve impulse

• synapses - pass impulses between cells

• lots of mitochondria - provide energy

What are the adaptions of a sperm cell? (x4)

• large nucleus - contains genetic material

• acrosome - stores digestive enzymes for breaking outer egg layer

• Middle section contains mitochondria - make tail move

• Long tail - move through water/ female reproductive system

Why are muscle cells specialised?

to relax and contract in pairs to move bones

What are the adaptions for a muscle cell? (x3)

• special proteins - fibre contact

• contains mitochondria - transfer energy chemical reactions → fibre to contract

• Stores Glycogen - cellular respiration by mitochondria

Why are red blood cells specialised?

to deliver oxygen to the tissues in body

What are some adaptions of red blood cells? (x4)

• no nucleus - allows more haemoglobin

• contains haemoglobin - combines with oxygen

• small and flexible - fit through narrow blood vessels

• biconcave shape - maximise surface area for oxygen

What are some adaptions for root hair cells? (x6)

• large surface area - available for water

• close to tips of growing roots

• large permeant vacuole - osmosis

• take water and minerals up more efficiently

• Close to xylem

• lots of mitochondria - transfer energy needed for transport of mineral ions

Why is the xylem tissue specialised?

carry water and minerals to leaves

What are some adaptions for xylem cells?

• hollow tunnel - carry more water,

• lignin - support cell walls and makes them stronger

• cells are dead

• contain pit of water - move laterally

What are the adaptions of a photosynthesis cell? (x5)

• chloroplast containing chlorophyll - trap light

• permeant vacuole - keep cell rigid

• Spread out - catch maximum sunlight

• in continuous layers, and outer layers - get maximum sunlight

• make out food

Why are phloem cells specialised?

carry food around plant

What are the adaptions for phloem cells?

• sieve plates - dissolved food can be carried up and down tubes

• companion cells - support structure

• mitochondria of companion cells - transfer energy to dissolve food

What is diffusion?

net movement/spreading of particles

What is the direction of movement for diffusion?

from high concentration to low concentration

Does diffusion go up or down the concentration gradient?

It occurs down

Does diffusion require energy?

It doesn’t require energy

What factors can speed up diffusion?

steeper concentration gradient

hotter temperature

small particles

What is Osmosis?

the net movement/spreading of water particles

Which way does the water move during osmosis?

from high water concentration to low water concentration

Which way does the water move along the concentration gradient?

down the water concentration gradient

Does osmosis require energy?

no energy required

What does osmosis have to occur across?

a partially permeable membrane (e.g. cell membranes and cell walls)

What is active transport?

the net movement or spreading of particles / ions / molecules

What is the direction of movement in active transport?

low concentration to high concentration

Does active transport occur up or down the concentration gradient?

up the concentration gradient

What does active transport require?

energy and carrier proteins

What are some adaptions for exchange surfaces?

large surface area -

thin membrane - shorter diffusion pathway

rich blood supply - maintain concentration gradient

well ventilated - maintains steep concentration gradient