b2 revison cards

CELLS

ANIMAL CELLS CONTAIN CYTOPLASM, NUCLEUS, CELL MEMBRANE, RHIBOSOMES AND MITOCHONDRIA.

HOWEVER PLANT CELLS CONTAIN SOME XTRA FEATURES. PLANT CELLS CONTAIN A NUCLEUS, CYTOPLASM, CELL MEMBRANE, RHIBOSOMES, MITOCHONDRIA, CELL WALL, CHLOROPLASTS AND PERMANENT VACUOLE.

ORGANELLES

NUCLEUS-CONTAINS GENETIC MATERIAL THAT CONTROLS THE ACTIVITIES OF THE CELL

CYTOPLASM-A GEL LIKE SUBSTANCE WHERE ALL CHEMICAL REACTIONS HAPPEN. CONTAINS ENZYMES TO CONTROL THE CHEMICAL REACTIONS.

MITOCHONDRIA-MOST ENERGY IS RELEASED FOR RESPIRATION

CELL MEMBRANE-CONTROLS WHAT GOES IN AND OUT OF THE CELL

RHIBOSOMES-WHERE PROTEINS ARE MADE IN THE CELL (PROTEINSYNTHESIS)

CELL WALL-STRENGHENS THE CELL

CHLOROPLAST-CONTAINS CHLOROPHYL WHICH ABSORBS LIGHT FOR PHOTOSYNTHESIS

PERMANENT VACUOLE-FILLED WITH SAP TO KEEP THE CELL TURGID

SPECIALISED CELLS HAVE A SPECIFIC FUNCTION!

EXAMPLE:SPERM FERTILISES AN EGG CELL. SPERM IS PACKED WITH MITOCHONDRIA AS IT NEEDS PLENTY OF ENERGY FOR WHEN THE SPERM SWIMS TO THE EGG

DIFFUSION

IS THE PASSING OF PARTICLES FROM AN AREA OF HIH CONCENTRATION TO AN AREA OF LOW CONCENTRATION!

RATE OF DIFFUSION DEPENDS ON 3 MAIN THINGS

DISTANCE-SUBSTANCES DIFFUSE MORE QUICKLY WHEN THEY HAVN'T AS FAR TO MOVE!

CONCENTRATION GARDIENT-SUBSTANCES DIFFUSE FASTER IF THERE IS A BIG DIFFERENCE IN CONCENTRATION. IF THERE IS MORE PARTICLES ON ONE SIDE, THERE ARE MORE TO MOVE ACROSS.

SURAFACE AREA-THE MORE SURFACE AREA THERE IS AVAILABLE FOR MOLECULES TO MOVE ACROSS, THE FASTER THEY CAN GET FROM ONE SIDE TO ANOTHER!

OSMOSIS

OSMOSIS IS THE MOVEMENT OF WATER MOLECULES ACROSS A PARTIALLY PERMEABLE MMEBRANE FROM A REGION OF HIGH CONCENTRATION T0 A REGION OF LOW CONCENTRATION!

PHOTOSYNTHESIS

Carbon dioxide + Water + Light energy → Glucose + Oxygen

IN PHOTOSYNTHESIS, THE GREEN PLANT PIGMENT, CHLOROPHYL, TRAPS ENERGY FROM THE SUNLIGHT. THE ENERGY IS USED TO CONVERT CARBON DIOXIDE AND WATER INTO GLUCOSE. GLUCOSE IS A SUGAR, A KIND OF CARBOHYDRATE. PLANTS CAN USE GLUCOSE TO MAKE OTHER KINDS OF FOOD, SUCH AS STARCH, FATS AND PROTEINS. THE BY-PRODUCT OF PHOTOSYNTHESIS IS OXYGEN, WHICH PLANTS RELEASE. THE ENERGY FROM LIGHT BECOMES CHEMICAL ENERGY STORED AS GLUCOSE MOLECULES. THE ENERGY CAN BE UNLOCKED AGAIN WHEN ORGANISMS BREAK DOWN CLUCOSE IN RESPIRATION:

Improve Glucose + oxygen --> carbon dioxide + water + energy

HOMEOSTASIS

HOMEOSTASIS IS THE MAINTENANCE OF A CONSTANT INTERNAL ENVIRONMENT

THE SKIN AND TEMP CONTROL

THIS IS HOW THE SKIN CONTROLS THE RATE OF TEMP LOST

• YOUR HAIR STANDS UP
• ELEVATOR MUSCLES CONTRACT TO RAISE HAIRS
• BLOOD VESSELS IN THE SKIN NARROW
• SHIVERING OCCURS
• SWEAT GLANDS ARE NOT ACTIVE

HOW THE SKIN CONTROLS THE RATE OF TEMP GAIN

• YOUR SKIN HAIR LIES FLAT
• BLOOD VESSELS IN THE SKIN WIDEN
• YOU DONT SHIVER
• SWEAT GLANDS ACTIVE AND YOU SWEAT

MITOSIS

THERE ARE 46 CHROMOSOMES FOUND IN THE NUCLEUS

BEFORE DIVISION, THE CELL REPLICATES DNA

CELL SPLITS

CREATES TWO IDENTICAL COPIES

PRODUCES NEW CELLS TO REPLACE DAMAGED ONES

CELL DIVISION-MITOSIS

DNA SPREAD INTO LONG STRINGS

CELL THEN DUPLICATES DNA

CHROMOSOMES LINE UP IN THE CENTRE OF CELL AND THE CELL FIBRES PULL THEM APART

MEMBRANES THEN FORM

THE CYTOPLASM DIVIDES

THEY NOW HAVE IDENTICAL CELLS

MEIOSIS

GAMETES

HALF THE NUMBER OF CHROMOSOMES

TWO CHROMOSOMES JOIN DURING FERTILISATION

NOW HAVE FULL NUMBER OF CHROMOSOMES

NEW CELL IS UNIQUE

CELL DIVISION PROCESS-MEIOSIS

CELL DUPLICATES

CHROMOSOMES LINE UP IN THE CENTRE OF THE CELL

PAIRS OF CHROMOSOMES ARE PULLED APART

MIXING UP MOTHER AND FATHER CHROMOSOMES

CREATES GENETIC VARIATION

CHROMOSOMES LINE UP AND ARE PULLED APART

FOUR GAMETES MADE CONTAINING HALF ORIGINAL NUMBER OF CHROMOSOMES