explain, with reference to suitable examples, what is meant by a), facilitated diffusion and b) active transpo

Question

need help answering this question

Answer 1

A biology question!

Right, is this about the phopholipid bilayer and that carrier proteins and stuff? Well, hopefully it is because I can explain it better and you'll understand what I mean at the same time too!

a) Faciliated Diffusion: diffusion is the net movement of particle down/ along a concentration gradient across a membrane. So, facilitated means 'helping out'. If a molecule is too big to pass through a phospholipid bilayer, but is essential to the cell, there will be a carrier protein in the bilayer to help with the diffusion of the molecule on the outside to enter the inside of the cell. Take a look on www.biologymad.com , it might explain it better as they have a diagram on it.

b) Active transport: the definition of this is..... the net movement of particles against a concentration gradient across a partially permeable membrane. Think of a ramp. Normal diffusion allows particles to flow from the top of the ramp down to the bottom. However, active transport is against the flow, so it will travel from the bottom of the ramp to the top. Active transport requires energy otherwise known as ATP which is a product from respiration- I'm not sure if you've learnt this yet.

Well, some of the stuff in there is A-level stuff and I'm not sure what you're studying at the moment. I hope it all helps and take a look at that site if you have time! Good luck!

Answer 2

Facilitated Diffusion - hundreds of protein channels have been found that allow particular substances to cross different membranes. Fast and specific. Does not require cells energy.

Avtive Transport- Requires energy. Transports proteins. Transp-ortation across cell membrane by process known as endocytosis and exocytosis.

Answer 3

Active transport is used when the diffusion gradient is not right ie when there is more of a substance inside than outside a cell, but you're still trying to get more of it in the cell.

If that makes sense?

Answer 4

Since your not Catholic than your not going to like any true answer. The Apostles Creed was created by the Catholic church before the Protestant Reformation. The Communion of Saints means those people in union with Jesus on earth, those in purgatory, and those in saints in heaven. A saint in its purest defintion is someone who is filled with grace. This means that at the time they are free from any sort of sin. All those in heaven are sinless and those in purgatory are on there way to heaven and only doing penances so they may be pure when they finally reach heaven in due time. Those people as Catholics believe who have just gone to Confession and made it a good one are free from sin. This also means theyt are saints. Also any person whose life has not been cut off from God by mortal sin is also a saint.

Answer 5

Can't remember all of it but active transport involves an expenditure of energy in order to get something across a cell membrane (e.g. glucose?).