B2.1 - Cells&transport

BOTH HAVE:

• a nucleus -- controls activites of cell+contains instructions for making new cells
• cytoplasm -- where most of the chemical reactions take place
• a cell membrane -- controls what subtances leave&enter the cell
• mitochondria -- where oxygen is used to release energy by respiration
• ribosomes -- where protein synthesis occurs, proteins made from amino acids

PLANTS CELLS ONLY HAVE:

• A cell wall -- made of cellulose, strengthens the cell
• chloroplasts -- contains chlorophyll -->absorbs light energy to make food
• A permanent vacuole -- filled w/ cell sap, contains sugars/salt & keeps cell rigid

BACTERIA CELLS:

• do not have a nucleus
• have a pasmid (ring of DNA) that can independently replicate
• have a flagella
• have ribosomes

YEAST CELLS:

• have fat gobules
• have a vacuole

BOTH CELLS:

• have a cell wall
• have a cell membrane
• have cytoplasm

ROOT HAIR CELLS - tiny hair like structures- increase surface area of cell

EGG CELL - large, has food reserves for developing embryo

XYLEM - long, thin, hollow to transport water through stem&root

WHITE BLOOD CELLS - change shape to engulf pathogen

SPERM CELLS - tail, nucleus packed with mitochondria and energy

PALISADE CELLS - packed with chloroplasts for photosynthesis

REB BLOOD CELLS - no nucleus, maximum space for haemoglobin to transport oxygen

NERVE CELLS - long, thin axons which carry nerve impulses

Diffusion happens in dissolved substances and gases.

To get into or out of cells, dissolved substances have to cross the cell membranes.

Diffusion is the net movement of gas/solute particles from an area of higher concentration to an area of lower concentration.

Net movement is the overall movement of particles.

Oxygen required for respiration passes through cell membranes by diffusion.

The greater the difference in concentration, the faster the rate of diffusion.