Biology 1002B Lecture Notes - Lecture 5: Active Transport, Photoreceptor Cell, Endergonic Reaction

4 views3 pages
Published on 15 Apr 2013
Department
Professor
Membrane Structure and Transport
January, 21, 2013
The membrane is a phospholipid bilayer
o It has a hydrophilic head and hydrophobic tail
Phospholipid bilayer can be formed spontaneous, no energy required
The membrane are more than 50% protein
Saturated vs. unsaturated
o Unsaturated have lots of kinks in them, lots of movement
Physiological importance of unsaturation
o Saturated ->(desaturase) -> Unsaturated
o When you regulate desaturase, you can regulate unsaturation
o Maintaining proper fluidity is very important, can’t be too lucid and can’t be too rigid
Membrane Permeability
o The tail of the fatty acid is very hydrophobic
o CO2, N2, O2 can move through the membrane, because they are very small
o As size and charge increases, will be denied
o So how to get other stuff across?
We use proteins to transport others across the membrane, the membrane
protein
Membrane proteins
o The protein interact with the membrane
o They can form some kind of channels
o For membrane protein, all one need is the primary sequence
Some sequences are rich in polar amino acids sequences and some sequences
are non-polar amino acid, it takes about 17 to 20 amino acids made of
predominantly of non-polar amino acid, then you’ll know it’s a membrane
protein
Alpha helical structures
o How can proteins interact with hydrophobic core?
Membrane transport
o Diffusion: if the molecules are small and non-charged
Driven by energy change (change in free energy), concentration gradient
o Facilitated: they leak from a high concentration to low concentration, there is a channel
just for one specific molecule/ion, without it they can’t move
o Active transport: (ABC transporter): moving molecules from low concentration to high
concentration, endergonic process
Trans-membrane domain is going to be different, not the same (need 1000s of
them)
They have a ATP binding site, ATP is the energy given to the transport
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Document Summary

It has a hydrophilic head and hydrophobic tail. Phospholipid bilayer can be formed spontaneous, no energy required. The membrane are more than 50% protein. Saturated vs. unsaturated: unsaturated have lots of kinks in them, lots of movement. Physiological importance of unsaturation: saturated ->(desaturase) -> unsaturated, when you regulate desaturase, you can regulate unsaturation, maintaining proper fluidity is very important, can"t be too lucid and can"t be too rigid. We use proteins to transport others across the membrane, the membrane protein. Membrane proteins: the protein interact with the membrane, they can form some kind of channels, for membrane protein, all one need is the primary sequence. Some sequences are rich in polar amino acids sequences and some sequences are non-polar amino acid, it takes about 17 to 20 amino acids made of predominantly of non-polar amino acid, then you"ll know it"s a membrane protein. Membrane transport: diffusion: if the molecules are small and non-charged.

Get OneClass Grade+

Unlimited access to all notes and study guides.

YearlyMost Popular
75% OFF
$9.98/m
Monthly
$39.98/m
Single doc
$39.98

or

You will be charged $119.76 upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.