Presentation on theme: " Transport can be passive or active. Passive requires no energy and moves down a concentration gradient from high to low concentration Active requires."— Presentation transcript:
Transport can be passive or active. Passive requires no energy and moves down a concentration gradient from high to low concentration Active requires energy and moves against a concentration gradient from low to high concentration Diffusion and osmosis are passive whereas active transport is as the name applies active.
Diffusion is the movement of molecules or particles from a region of high concentration to a region of low concentration OR We can say molecules or particles move from an area where there is more particles or molecules to an area where there is less
Molecules and particles are in constant random motion. This is due to the energy that they posses; this is known as KINETIC ENERGY Solids are closely packed so they vibrate and contain little kinetic energy Liquids move around to occupy the space of the container and contain more kinetic energy so they move more Gases move about freely in space and contains lots of kinetic energy so they can move faster
When molecules or particles are mixed the kinetic energy they posses allows them to move about until they are evenly distributed So the amount of kinetic energy a molecule posses will determine how fast it diffuses However there are other factors that will affect the rate of diffusion or how fast diffusion occurs
Diffusion can occur with: 1. liquids and solids (water and dye) 2. different liquids (water and ink) 3. different gases (gases in the air) When particles or molecules are evenly mixed no more changes occur We can compare the rate of diffusion of different substances
Diffusion occurs everywhere but can be demonstrated in the lab with different chemicals The rate of diffusion is affected by the size of the molecules and temperature The larger the molecules the slower it will move therefore smaller molecules will move faster and diffuse faster At higher temperatures particles or molecules posses more kinetic energy and therefore the higher the temperature the faster the rate of diffusion
When you smell a flower When someone sprays perfume on one side of the room and the person on the other side smells it When we add dye to water in celebrating Phagwa When making cool aid
Diffusion occurs in the cells of living organism This is how cells get substances across the membrane Remember 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 cells Facilitated 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 concentration
The 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.
The carbon dioxide is diffused across the cell membrane of plant cells from the atmosphere for photosynthesis
This 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 proteins This is also a passive type of transport process in the body.
Water molecules are smaller The selectively permeable membrane acts as a barrier for larger molecules Water molecules move across the selectively permeable membrane The volume in the second half increases but the concentration of the water molecules is even
Cells get water via osmosis Osmosis occurs in all living cells and helps to regulate the amount of water in the cells Water is very important for all chemical reactions occurring in the cell. If a cell is placed in too much water it can burst If 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.
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 membrane Both processes are important to the human body and living things Both can be applied to many processes in science and everyday life.
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.
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 acidsionsglucoseamino acids Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plantsroot hair
1. Simple diffusion is defined as the movement of A. Molecules from areas of higher concentration to areas of lower concentration. B. molecules from areas of lower concentration to areas of higher concentration. C. Water molecules across a membrane. D. Gas molecules across a membrane. E. Gas or water molecules across a membrane.
2. The rate of diffusion is affected by which of the following? A. Temperature B. Size of molecules C. A and B 3. Diffusion is one of the processes whereby materials are exchanged between a cell and its environment. A. True B. False 4. Which of the following best describes facilitated diffusion in cells A. A method of transporting molecules and particles across a membrane from a region of high concentration to a region of low concentration B. A method of transporting molecules and particles across a membrane from a region of low concentration to a region of high concentration C. Movement of molecules through the membrane from any direction