Published on March 19, 2014
MOVEMENT OF MOLECULES Do they ever stop moving?!!
DIFFUSION All molecules move about. In gaseous state, they are widespread and with weak bonds holding them together. In liquid state, they are closer with stronger bonds holding them together. In solids they are very close and could only vibrate in their place.
NOW PUT UP YOUR HAND AS SOON AS YOU CAN DETECT THE SMELL OF THE AIR FRESHENER.
WHAT DO YOU NOTICE? Who were the first to detect the smell? Who were last to detect the smell? Why isn’t there anyone who did not detect the smell? Explain how you could smell the scent although you are far away from the air freshener. What if we opened the door or window? Would others outside be able to smell the scent?
WHAT WOULD HAPPEN TO A LUMP OF SUGAR PLACED IN A CUP OF WATER?
WHAT WOULD MAKE MOLECULES MOVE/SPREAD OUT FASTER OR SLOWER? Temperature Stirring/ air currents Number of molecules Surface area Distance/ thickness of membrane Difference between molecule concentration in both areas
DIFFUSION Is the movement of molecules from a region of high concentration to a region of low concentration down a concentration gradient.
OSMOSIS A special type of diffusion involving the movement of water molecules only, through a partially permeable membrane. Partially permeable membrane is a membrane with small holes that can allow only small molecules to pass through.
NOW I NEED FOUR VOLUNTEERS!
OSMOSIS Is the movement of water molecules from a dilute solution (high water potential) to a concentrated solution (low water potential) through a partially permeable membrane. A cell membrane is a partially permeable membrane.
WHAT HAPPENS TO ANIMAL CELLS IF THEY WERE PLACED IN A SOLUTION OF A DIFFERENT CONCENTRATION THAN OF THEIR CYTOPLASM?
WHAT ABOUT PLANT CELLS?
OSMOSIS IN PLANT CELLS. Water enters a plant cell, the water molecules put pressure on the walls. The rigid cell wall will prevent the cell from bursting. This plant cell is said to be turgid. This keeps the plant firm.
OSMOSIS IN PLANT CELLS When water leaves the plant cell the elastic cell membrane shrinks, while the rigid cell wall keeps the shape of the cell fixed. This plant cell is said to be plasmolysed.
ACTIVE TRANSPORT In some situations, there is a need to move molecules from a region of low concentration to a region of high concentration. A root hair cell needs to take in minerals from the soil, even if the concentration in the soil is lower than that in the cells. 10
Diffusion, Osmosis, Active Transport There are two ways in which substances can enter or leave a cell: 1) Passive a) Simple Diffusion b) Facilitated Diffusion
Active transport uses energy to move substances against (up) a concentration gradient or across a partially permeable membrane. In active transport a ...
Diffusion, Osmosis and Active Transport. Explore how water and ions can diffuse both passively and actively through cell membranes. Download & Launch
Passive transport is a movement of biochemicals and other atomic or molecular substances across cell membranes without need of energy input. Unlike active ...
Diffusion and osmosis activity. Dissolved substances pass into and out of cells by diffusion. Water passes into and out of cells by osmosis.
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Osmosis is a selective diffusion process driven by the internal energy of the solvent molecules. ... Other types of transport, called active transport, ...
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Is osmosis an example of facilitated diffusion or active transport? - 1593516 ... Hi there! Have questions about your homework? At Brainly, there are 60 ...
In this video clip I will be looking at the processes of osmosis and active transport in living cells, and what factors affect these transport ...