Moving Substances

Moving Substances

1. substances move in and out of cells in three different ways...

2. DIFFUSION

   • DIFFUSION is the PASSIVE OVERALL MOVEMENT of PARTICLES from a region of their HIGHER CONCENTRATION to a region of their LOWER CONCENTRATION
     • in easier words (for us silly peoples), diffusion is the gradual movement of particles from places where there are lots of them to places where there fewer of them - just the natural tendency for stuff to spread out
     • 'passive' just means that it takes place without needing any energy
   • an example of diffusion is this: when plants photosynthesise they use up carbon dioxide from the atmosphere and produce oxygen - these gases pass in and out of the plant leaves by diffusion
     • Photosynthesis

3. OSMOSIS

   • when I said that there were three different ways that substances move in and out of cells I was kind lying (sozlol) - osmosis is just a specific case of diffusion
   • OSMOSIS is the overall MOVEMENT OF WATER from a DILUTE to a MORE CONCENTRATED solution through a PARTIALLY (or semi) PERMEABLE MEMBRANE
     • got that?
     • a 'partially permeable membrane' is just un que only allows certain substances to diffuse through it, eg. it may only allow pico molecules comme water to pass through and not larger molecules comme sucrose
     • a DILUTE SOLUTION has a HIGHER CONCENTRATION of water molecules than a CONCENTRATED SOLUTION...weird, huh?
   • as shown in the lovingly lifted diagram, the solution on the right gets more dilute as more water moves in - die waßer acts as if it's trying to even up the concentration either side of the membrane - water, when will you learn?
   • plants (eg. doughnut trees) take in water by osmosis - there's usually a higher concentration of water in the soil than there is inside the plant, so the water is drawn ino the root by osmosis

4. ACTIVE TRANSPORT

   • ACTIVE TRANSPORT is the overall MOVEMENT OF CHEMICALS across a CELL MEMBRANE from a region of LOWER CONCENTRATION to a region of HIGHER CONCENTRATION using ENERGY released by respiration
     • it's basically diffusion backwards
   • active transport is the process that incurs when chemicals (eg. glucose) need to be moved from an area with a lower concentration of the chemical to an area with a higher concentration of the chemical across a cell membrane
   • EXAMPLE TIME!: plants take in minerals like nitrates through their roots by active transport...the concentration of minerals in root cells is usually plus haute que the soil around them...active transport uses energy from respiration to move minerals from the soil into the root cells

5. cells are super fusspots - the levels of certain substances need to be exactly spot on in order for them to function properly

Imagens e arquivos do mapa