A level Biology: Post your doubts here!

[princeali97]

Can sum1 tell me the functions and structure of intrinsic , extrinsic and trans-membrane proteins?

 

[princeali97]

I dont understand the difference between transport protein,channel protein and carrier protein.Some1 pls try to explain this thing

 

[BeBeskii108]

I believe Its A2 :/

Yes they are from A2. Those tests are used for Paper 5. You're on AS ?

 

[BeBeskii108]

I dont understand the difference between transport protein,channel protein and carrier protein.Some1 pls try to explain this thing

I think they are all similar.

 

[VelaneDeBeaute]

I dont understand the difference between transport protein,channel protein and carrier protein.Some1 pls try to explain this thing

'Transport proteins' refer to the membranal proteins that help in the movement of substances across the membrane. They can be divided into two types:
1. Carrier proteins: The proteins that assist in facilitated diffusion or active transport processes, for moving substances like glucose etc.
2. Channel proteins: The proteins that provide a 'channel' for ions or other small molecules to be exchanged across a membrane. These are specific for specific substances. For instance, you may have heard of 'sodium channels' (allow movement of Na+ ions only) etc.

 

[princeali97]

'Transport proteins' refer to the membranal proteins that help in the movement of substances across the membrane. They can be divided into two types:
1. Carrier proteins: The proteins that assist in facilitated diffusion or active transport processes, for moving substances like glucose etc.
2. Channel proteins: The proteins that provide a 'channel' for ions or other small molecules to be exchanged across a membrane. These are specific for specific substances. For instance, you may have heard of 'sodium channels' (allow movement of Na+ ions only) etc.

But my friend, ions and other polar molecules move through the membrane by active transport only.So they move through the transport protein which is also called carrier protein.Then channel protein must be for facilitated diffusion ryt?

 

[Snowysangel]

Bro.. You are comparing two Diffrent things (Volume and Time).. For time measurement You also have to take account of your Human reaction time which is About 0.3-0.5s .. so We always round our values to nearest Second.

That's why I said similar and not the same.. Readings up till 2 decimal place are more precise

But my friend, ions and other polar molecules move through the membrane by active transport only.So they move through the transport protein which is also called carrier protein.Then channel protein must be for facilitated diffusion ryt?

yup. Active transport takes place through only carrier protei s but facilities diffusion can occur in both channel and carrier proteins

 

[Snowysangel]

'Transport proteins' refer to the membranal proteins that help in the movement of substances across the membrane. They can be divided into two types:
1. Carrier proteins: The proteins that assist in facilitated diffusion or active transport processes, for moving substances like glucose etc.
2. Channel proteins: The proteins that provide a 'channel' for ions or other small molecules to be exchanged across a membrane. These are specific for specific substances. For instance, you may have heard of 'sodium channels' (allow movement of Na+ ions only) etc.

Stents ions taken up by active transport?

 

[Mohammed salik]

That's why I said similar and not the same.. Readings up till 2 decimal place are more precise

yup. Active transport takes place through only carrier protei s but facilities diffusion can occur in both channel and carrier proteins

Okay..
But do You Understand why do we round?

 

[Snowysangel]

Okay..
But do You Understand why do we round?

Kinda ..

 

[princeali97]

That's why I said similar and not the same.. Readings up till 2 decimal place are more precise

yup. Active transport takes place through only carrier protei s but facilities diffusion can occur in both channel and carrier proteins

Yaar then whats the difference between carrier and channel proteins? Look, in carrier proteins the protein changes its shape to transfer the ions pass through it.In chanel proteins the protein does not change its shape.The molecules simply pass thru.This is very confusing or you r making it confusing

 

[Mohammed salik]

Kinda ..

Haha.. k!

 

[Snowysangel]

Yaar then whats the difference between carrier and channel proteins? Look, in carrier proteins the protein changes its shape to transfer the ions pass through it.In chanel proteins the protein does not change its shape.The molecules simply pass thru.This is very confusing or you r making it confusing

How is that confusing? Carrier proteins change into a conformational shape to allow ions, glucose, amino acids etc to pass through...just like you said. And channel proteins allow small ions to diffuse through their channel pores without changing their shape

 

[princeali97]

How is that confusing? Carrier proteins change into a conformational shape to allow ions, glucose, amino acids etc to pass through...just like you said. And channel proteins allow small ions to diffuse through their channel pores without changing their shape

Arent carrier proteins only for active transport of ions? annd channel protein only for facilitated diffusion of amino acids and glucose? :/

 

[thats_me]

Arent carrier proteins only for active transport of ions? annd channel protein only for facilitated diffusion of amino acids and glucose? :/

Solutes diffuse through the channel proteins, whereas carrier proteins bind solutes on one side of membrane and release it on the other side
Carrier proteins have very slow transport rates in comparison with channel proteins
Carrier proteins can have both active and passive transport (facilitated diffusion & active transport), while channel proteins can have only passive transport (facilitated diffusion)
Carrier proteins can transport molecules or ions against the concentration gradient, while channel protein cannot

 

[sunstar]

hey ppl
I was wondering if there were any predictions for Bio AS paper3 V32
Thnx in advance

 

[Moi]

PLEASE Explain for me genetic fingerprinting?
I DON'T UNDERSTAND how the DNA fragments are split into single stranded chains? what does that even mean? and where do the bands come from? what are they anyways....

plz explain and give me an example question and its answer from papers ! Thank you
i appreciate an answer as soon as possible

 

[VelaneDeBeaute]

But my friend, ions and other polar molecules move through the membrane by active transport only.So they move through the transport protein which is also called carrier protein.Then channel protein must be for facilitated diffusion ryt?

Carrier proteins simply 'carry' the molecules across the membrane and the process may be active or passive. It is important to note here that it is just not the 'type of molecule' that influences what membrane protein is used by a molecule for transport. Other factors such as temperature, electrochemical gradient etc. also influence what molecules go through which protein.
Channel proteins however are distinguished for actively transporting a specific type of 'ion' across them.

 

[VelaneDeBeaute]

PLEASE Explain for me genetic fingerprinting?
I DON'T UNDERSTAND how the DNA fragments are split into single stranded chains? what does that even mean? and where do the bands come from? what are they anyways....

plz explain and give me an example question and its answer from papers ! Thank you
i appreciate an answer as soon as possible

Check the application booklet, topic 'Gene Technology' or try googling electrophoresis.

 

[Gehad Mohamed]

Hello can someone please explain the following :
How to solve q 24 and 40 !
And why q38 ans should be A not B ?!
http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w10_qp_13.pdf