Why are proteins able to pass through the plasma membrane but
lipids cannot?
Why are proteins able to pass through the plasma membrane but
lipids cannot?
Solutions
Expert Solution
PLASMA MEMBRANE: It is the biological membrane that separates
interior of the cell to the external environment.
Structure of Plasma Membrane is Lipid bilayer with
phospholipids of hydrophobic and Hydrophilic heads with tails.The
Hydrophobic Heads deals with the external environment and
hydrophilic heads deals with the internal environment.
Permeability is the rate of exchange of substances with
diffusion.As the plasma membrane is hydrophobic it allows
electrically neutral substances,non polar solutes based on the size
of the substance,Solubility and molarity.
The Proteins pass through the plasma membrane because they do
not have direct interaction with hydrophobic ends. .Transporter
proteins are one of the proteins which help in transporting of non
permeable substances by binding to them.The channels present in the
plasma membrane are also proteins which easily permeable for
transporting substances through facilitated diffusion.
The lipids are polar solutes and large in size so they cannot
travel through plasma membrane and they need a transporter protein
for their permeability.
describe the structure of a generalized plasma
membrane . Include the major components
(lipids,proteins,glycolipids, polysaccharides).Describe transport
mechanisms by which materials move into and out cells.
1. What happens if one solute can pass through the membrane, but
another cannot?
2. How do semi-permeable membranes and the processes of
diffusion and osmosis contribute to homeostasis in cells?
Discuss the role of carbohydrates, lipids and proteins
in maintaining the structure of the cell membrane and explain the
effect of denaturation agents on the structure of
proteins.
1..The plasma (cell) membrane
is composed of a bilayer of proteins
is composed of a bilayer of phospholipids
is composed of chains of carbohydrate molecules
is a compl;ex of carbohydrates and proteins
H..Which of the following is not a function of
membrane proteins?
act as carrier molecules for various solutes
cell nutrient
act as anchors or stabilizers for the cell membrane
regulate the passage of ions
bind to ligands
I...The control center for cellular operations is the
mitochondria.
Golgi apparatus....
Describe the structure of the cell membrane. Identify 3
different types of components (proteins, lipids, or carbohydrates)
of your choice that are found within the membrane. What is the
function of the components and why is it located within the
membrane?
1. Explain the specific asymmetric phospholipid distribution in
the plasma membrane.
2. Explain where lipids are synthesized and the role of
flippases.
3. Explain the location of glycolipids in the plasma membrane
and why this location. What is functional importance of glycolipids
and glycoproteins?
4. Explain the ways that proteins can associate with the lipid
bilayer and define integral membrane protein vs. peripheral
membrane protein.
We
have learned that the plasma membrane that encloses eukaryotic
cells has a variety of proteins embedded in it (the transmembrane
proteins). Consider the functions of these proteins. Do you think
that there are any cells in your body that do not have these
proteins?
14). How, when, and where do the transmembrane proteins of the
plasma membrane get imbedded into the membrane, and how do they get
into the plasma membrane (their path).