Someone explain co-transport, active transport??

Watch
daytrippper
Badges: 10
Rep:
?
#1
Report Thread starter 3 years ago
#1
I'm doing AQA a level biology and I've been revising transport across membranes and I've never been so confused?? I know it's a simple topic but can someone explain the difference between carrier and channel proteins? Also can someone explain in detail how active transport, co-transport and facilitated diffusion works? PLEASE!
*do channel proteins only allow water soluble substances through?
0
reply
TSR Jessica
Badges: 19
Rep:
?
#2
Report 3 years ago
#2
Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.
0
reply
6573282
Badges: 8
Rep:
?
#3
Report 3 years ago
#3
Channel proteins can only move substances by passive transport (diffustion, osmosis etc.) while carrier proteins can move substances by passive and active transport.

facilitated diffusion is the movement of solutes down a concentraion gradient using transport proteins

Active transport is the movement of solutes against a concentration gradient using carrier proteins ONLY and ATP

Co-transport is the movement of 1 solute against its concetration gradient by transporting another solute down its own concentration gradient. We only need to know the co-transport of Na+ and glucose, but here's a brief summary:

  1. NA+ is actively transported from epithelial cells into the blood
  2. there's a lower concentration gradient in the cells than the lumen, so Na+ moves from the lumen into the epithelial cells by facilitated diffusion
  3. As Na+ is being transported down its concentration gradient, glucose is moved against its own concentration gradient
  4. There's a higher concentration of glucose in epithelial cells than the blood, so glucose moves by facilitated diffusion.


If there's anything in prarticular you don't understand, feel free to ask.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Feeling behind at school/college? What is the best thing your teachers could to help you catch up?

Extra compulsory independent learning activities (eg, homework tasks) (13)
7.14%
Run extra compulsory lessons or workshops (30)
16.48%
Focus on making the normal lesson time with them as high quality as possible (30)
16.48%
Focus on making the normal learning resources as high quality/accessible as possible (27)
14.84%
Provide extra optional activities, lessons and/or workshops (49)
26.92%
Assess students, decide who needs extra support and focus on these students (33)
18.13%

Watched Threads

View All