Cells- Biology

• cell wall- made of cellulose, supports the cell, strengthens the cell
• permanent vacuole- contains cell sap, weak solution of sugars and salts
• chloroplasts- for photosythesis, contain chlorophyll which aborb light energy
• nucleus- contains genetic material- DNA, controlls activities of the cell
• cytoplasm- contains enzymes which controll chemical reactions
• cell membrane- holds the cell together, controlls what goes in and out of the cell
• mitochondria- where reactions for respiration take place- releases energy the cell needs to work
• ribosomes- where protiens are made  

• nucleus- contains genetic material- DNA, controlls activities of the cell
• cytoplasm- contains enzymes which controll chemical reactions
• cell membrane- holds the cell together, controlls what goes in and out of the cell
• mitochondria- where reactions for respiration take place- releases energy the cell needs to work
• ribosomes- where protiens are made

• single celled organism
• microorganism
• nucleus- contains genetic material- DNA, controlls activities of the cell
• cytoplasm- contains enzymes which controll chemical reactions
• cell membrane- holds the cell together, controlls what goes in and out of the cell
• cell wall - supports the cell and strengthens it  

• single celled microorganism
• they dont have a nucleus- the genetic material floats in the cytoplam
• cytoplasm- contains enzymes which controll chemical reactions
• cell membrane- holds the cell together, controlls what goes in and out of the cell
• cell wall- supports and strengthens the cell

The egg cell:

function- carry female DNA, look after the embryo in its early stages

• contains lots of food reserves to feed the embryo
• the membrane changes its structure when it fuses with a sperm, to stop more sperm from getting in- so the offspring had the correct amount of DNA

The sprem cell:

function- carry male DNA to the female DNA

• long tail and streamlined head to help it swim
• contains lots of mitochondria- provide energy that is needed
• carry enzymes in their head- to digest the cell membrane of the egg so it can get inside

function- to open and close pores in a leaf to allow gas exchange and control water loss

• kidney shape which opens and closes the stomata (pores) in a leaf
• when the plant has lots of water- guard cells fill up, becoming plump and turgid, this causes the stomata to open so gases can be exchanged for photosythensis
• when plant is short of water- guard cell loses water, becomes flaccid, causing the stomata to close which stops too much water from escaping
• thin outer walls with thicker inner walls to help with opening and closing
• sensitive to light to help with photosythesis 
• close at night to save water

function- carry oxygen around the body

• concave shape- gives a big surface area for absorbing oxygen and helps them to pass smoothly through capilaries to reach body cells
• packed with haemoglobin- pigment which absorbs oxygen
• no nucleus to allow for more room for haemoglobin

function- photosythensis

• packed with chloroplasts for photosythensis
• most of the chloroplasts are at the top of the cell so they are can get as much light as possible
• tall shape- lots of surface area on the side for absorbing CO2
• thin shape- pack loads of them tightly at the top of the leaf where most of the photosythensis occurs