Animal and Plant Cells
animal: nucleus- controls activities of cell, cytoplasm- most of the chemical reactions needed for life, cell membrane- controls passage of substances in cell, mitochondria- site of respiration, ribosomes- protein synthesis
plant: nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, cell wall- strengthens cell and gives its shape, chloroplasts- absorb light for phs and gives colour, vacuole- keeps cell rigid
ENZYMES CONTROL ALL CHEMICAL REACTIONS IN CELLS
Fat Cell: Very little cytoplasm. Very few mitochondria. Expands up to 100 times its size
Cone Cell: Outer segment- visual pigment, changes chemically in coloured light. Middle segment- many mitochondria, the changes produce energy.
Root Hair Cell: Increase surface area for water, Vacuole- affects water movement from soil to cell.
Sperm Cell: Long tails. Many mitochondria. Acrosome stores digestive enzymes. Large nucleus containing half genetic info.
CELLS MAY BE SPECIALISED TO CARRY OUT A PARTICULAR FUNCTION
Rates of Diffusion: The bigger the difference in concentration, the faster the rate of diffusion
Diffusion in Living Organisms: -RESPIRATION- oxygen passes from air to lungs to cells by diffusion -SIMPLE SUGARS- glucose amino acids etc also pass through cell membranes to your gut by diffusion.
DIFFUSION IS THE NET MOVEMENT OF PARTICLES FROM AN AREA OF HIGH CONCENTRATION TO AN AREA OF LOW CONCENTRATION ALONG A CONCENTRATION GRADIENT
Animals: RED BLOOD CELLS- shrivel- if the concentration of the solution around the cell is higher than inside the cell, water will leave the cell by osmosis, making it shrivel, disabling the transportation of oxygen around the body. burst- if the concentration around the cell is lower than inside the cell, water will move into the cell, causing it to eventually burst.
Plants: Water moves into the plant by osmosis, making the cytoplasm swell and press against the cell walls. This causes pressure to build up so that no more water can ghet into the plant, making the cell hard and rigid.
OSMOSIS IS THE NET MOVEMENT OR WATER PARTICLES FROM AN AREA OF HIGH CONCENTRATION TO AN AREA OF LOW CONCENTRATION ALONG A CONCENTRATION GRADIENT
Plants AND Animal: when these cells need to move substances (such as glucose) against a concentration gradient, active transport is used.
THE MOVEMENT OF SUBSTANCES AGAINST A CONCENTRATION GRADIENT AND/OR ACROSS A CELL MEMBRANE, USING UP ENERGY.