osmosis active transport in cells Movement of molecules into and out of cells T ransport can be passive or active P assive requires no energy and moves down a concentration gradient from high to low concentration ID: 474464
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SIMPLE DIFFUSIONosmosis active transportin cells Slide2
Movement of molecules into and out of cellsTransport can be passive or active.Passive requires no energy and moves down a concentration gradient from high to low concentrationActive requires energy and moves against a concentration gradient from low to high concentrationDiffusion and osmosis are passive whereas active transport is as the name applies active.Slide3
WHAT IS DIFFUSIONDiffusion is the movement of molecules or particles from a region of high concentration to a region of low concentration ORWe can say molecules or particles move from an area where there is more particles or molecules to an area where there is lessSlide4Slide5
HOW DIFFUSION OCCCURSMolecules and particles are in constant random motion.This is due to the energy that they posses; this is known as KINETIC ENERGYSolids are closely packed so they vibrate and contain little kinetic energyLiquids move around to occupy the space of the container and contain more kinetic energy so they move moreGases move about freely in space and contains lots of kinetic energy so they can move faster Slide6Slide7
HOW DIFFUSION OCCURSWhen molecules or particles are mixed the kinetic energy they posses allows them to move about until they are evenly distributedSo the amount of kinetic energy a molecule posses will determine how fast it diffusesHowever there are other factors that will affect the rate of diffusion or how fast diffusion occursSlide8
MORE ON DIFFUSIONDiffusion can occur with: liquids and solids (water and dye) different liquids (water and ink) different gases (gases in the air)When particles or molecules are evenly mixed no more changes occurWe can compare the rate of diffusion of different substancesSlide9
MORE ON DIFFUSIONDiffusion occurs everywhere but can be demonstrated in the lab with different chemicalsThe rate of diffusion is affected by the size of the molecules and temperatureThe larger the molecules the slower it will move therefore smaller molecules will move faster and diffuse fasterAt higher temperatures particles or molecules posses more kinetic energy and therefore the higher the temperature the faster the rate of diffusionSlide10
EXAMPLES OF DIFFUSIONWhen you smell a flowerWhen someone sprays perfume on one side of the room and the person on the other side smells itWhen we add dye to water in celebrating PhagwaWhen making cool aidSlide11
FACILITATED DIFFUSION IN CELLSDiffusion occurs in the cells of living organism This is how cells get substances across the membraneRemember the cell membrane is partially permeable so not every particle will pass through it. There are molecules in the cell membrane that facilitates or makes it easier for the movement of these particles. This is know as facilitated diffusion and occurs in cellsFacilitated diffusion is a method of transporting substances across the membrane, however diffusion is the movement of particles from a region of high concentration to a region of low concentrationSlide12
Facilitated diffusion occurs when the molecules pass through a carrier molecules, from a region of high concentration to a region of low concentration down a concentration gradient. This is a passive type of transport process in the body as it doesn’t use energy . Slide13
DIFFUSION OF OXYGEN IN THE LUNGSThe oxygen you breathe in diffuses across the cell membrane in your lungs to get to your blood so that it can be transported to other cells. There is a high concentration of oxygen molecules in the lungs and a low concentration in the blood vessel around the lung, therefore the oxygen will diffuse across the membrane from the lung into the blood.Slide14Slide15
DIFFUSION OF CARBON DIOXIDEThe carbon dioxide is diffused across the cell membrane of plant cells from the atmosphere for photosynthesisSlide16
OSMOSISThis is the movement of water particles from a region of high water concentration to a region of low water concentration through a selectively permeable membrane. Water particles are small enough to pass through the membrane and does not require carrier proteinsThis is also a passive type of transport process in the body.Slide17
WHAT DO YOU OBSERVE IN THE PICTURE BELOWPINK = WATER PURPLE = SUGAR Slide18
Water molecules are smaller The selectively permeable membrane acts as a barrier for larger molecules Water molecules move across the selectively permeable membraneThe volume in the second half increases but the concentration of the water molecules is evenSlide19Slide20
IMPORTANCE OF OSMOSISCells get water via osmosisOsmosis occurs in all living cells and helps to regulate the amount of water in the cellsWater is very important for all chemical reactions occurring in the cell.If a cell is placed in too much water it can burstIf a cell is placed in a concentrated solution it can shrink and become dehydrated.Plant cells have a cell wall that prevents the cells from bursting.Slide21Slide22
COMPARING BOTH DIFFUSION AND OSMOSIS Diffusion and Osmosis is the process of moving particles from a region of high concentration to a region of low concentration down a concentration gradient as they are both going from a high concentration to a low.Diffusion occurs with any particle Osmosis occurs ONLY with water molecules across a selectively permeable membraneBoth processes are important to the human body and living thingsBoth can be applied to many processes in science and everyday life.Slide23
Active Transport Another method of movement of molecules in the human body is active transport.This is when molecules move from a region of low concentration to a region of high concentration. It moves against a concentration gradient because it moves from a lower concentration to a higher one.Slide24
How does Active Transport occur.Active transport occurs with special proteins in the membrane of the cell which uses energy to help the molecules to pass though the membrane into and out of the cells.Active transport is usually associated with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acidsExamples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plantsSlide25Slide26
Useful websites http://www.biology4kids.com/files/cell2_activetran.html https://www.youtube.com/watch?v=kfy92hdaAH0 Slide27
QUESTION 1. Simple diffusion is defined as the movement of Molecules from areas of higher concentration to areas of lower concentration.molecules from areas of lower concentration to areas of higher concentration.Water molecules across a membrane.Gas molecules across a membrane. Gas or water molecules across a membrane.Slide28
2. The rate of diffusion is affected by which of the following?TemperatureSize of moleculesA and B 3. Diffusion is one of the processes whereby materials are exchanged between a cell and its environment. True False 4. Which of the following best describes facilitated diffusion in cellsA method of transporting molecules and particles across a membrane from a region of high concentration to a region of low concentrationA method of transporting molecules and particles across a membrane from a region of low concentration to a region of high concentrationMovement of molecules through the membrane from any direction