Smartbook Part 2 Flashcards
What are key functions carried out by membrane proteins?
cell surface identity markers
Transport ions across the membrane
Receive external chemical messages
chemical reactions on surface of membrane
Set a membrane proteins are attached to the surface of the membrane by special molecules, associate strongly with phospholipids, what describes anchoring molecules
They are modified lipid
They have chemical bonding domains that link them directly to the membrane proteins
What are the functions carried out by membrane proteins
Receive external chem messages
Attached membrane to cytoskeleton
Connect adjacent cells and hold them together
Transmembrane proteins must span the lipid bilayer at least ______ times to be anchored in the interior of the cell membrane
One
Membrane proteins can be anchored to the surface of the membrane by attached to the molecule associate strongly with phospholipids an insert into the lipid bilayer. These molecules are
Modified lipids
The hydrophobic region of a transmembrane proteins, which extends through the lipid bilayer contacting the nonpolar interior of the membrane, might be composed of what
B pleated sheets containing nonpolar amino acids
A helices containing nonpolar amino acids
Transmembrane domain has
Hydrophobic amino acids
Different proteins can cross the membrane in diff ways
What is the primary difference between transmembrane protein in terms of how they cross the membrane
Different proteins can cross the membrane a different number of times
Transmembrane B-sheets 1040 through a motif through the membrane that allow molecules pass through the membrane. This type of protein is called a
Pore protein
Each membrane-spanning region of a transmembrane protein is called a
Transmembrane domain
What is the function of transmembrane proteins called reticulons
They can cause a membrane to bend or even form a tube
Transport that occurs without a cell expanding any of its own energy is called
Passive transport
Describe pore proteins
They transmembrane proteins
They create openings or channels in the membrane that allow specific ions or molecule to pass through
They have extensive non-polar regions that are folded into a beta pleated sheets
when the concentration of a substance on one side of the membrane is different from its concentration on the other side of the membrane the substance is said to exhibit a concentration______
Gradient
due to the constant random motion of its atoms and molecules a substance will exhibit net movement from a region where it has higher concentration to a region where it has low concentration and net movement is called
Diffusion
which of the following transmembrane proteins are likely to be found in the membranes that form tubular structures
Reticulons
diffusion is caused by
Constant random motion of all atoms in molecules
When the concentration of a substance varies from one region to another, the substance is exhibit a
Concentration Gradient
A major barrier to crossing a biological membrane is it the hydrophobic interior of the membrane that repels what kind of molecules?
Polar molecules
what is the permeability of a typical cell membrane to a large polar molecule
Very limited permeability
Substance that cannot easily crossed by lipid bilayer, can still diffuse across the plasma membrane with the help of what
Specific channel, proteins or carrier proteins
oxygen diffuses across the plasma membrane due to what
All oxygen molecules are in constant random motion
In cell membranes the interior of the lipid bilayer repels what
Ions
Polar molecules
Hydrophilic molecules
Of the two types of transport proteins that mediate facilitated diffusion, ____ proteins actually bind with the sub being transported, while _____ proteins simply provide a hydrophilic space for the substance to move through
Carrier
Channel
transport proteins that actually find a specific substance being transported across the membrane are called
Carrier proteins
diffusion that is assisted by Chanel proteins or carrier proteins called
Facilitated diffusion
