Class Notes (836,148)
Canada (509,657)
Biology (6,817)
Biology 1002B (1,346)
Tom Haffie (863)
Lecture 5

lecture 5.docx

3 Pages
Unlock Document

Biology 1002B
Tom Haffie

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  Modeling a Neuron o Ions diffuse along electrochemical (charged) gradients o In a neuron, there is a selective permeable membrane only permeable to potassium (K)  One side will have more K, so it will diffuse across from high to low concentration, but it the other side has a more
More Less

Related notes for Biology 1002B

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.