Lecture 4 (Membrane Structure & Function) Flashcards
What is RNA and DNA made of?
Nucleotides
What are made of Nucleic acids?
Nucleotides, RNA and DNA
What are proteins made from?
Peptides
What are Peptides made of?
Amino Acids
What are triglycerides made of?
Fatty acid and Glycerol
What are made of carbohydrates?
Polysaccharides, Disaccharides and Monosaccharides
what are Polysaccharides made of?
Disaccharides
What are Disaccharides made of?
2 Monosaccharides
What bonds are involved in the primary structure of Protein? What does the structure consist of?
Peptide bonds
Sequence of amino acids from amino -> carboxyl end
What bonds are involved in the secondary structure of Protein? What interactions does the structure consist of?
Hydrogen Bonds
Interactions between backbone portions of nearby amino acids
What bonds are involved in the tertiary structure of Protein? What interactions does the structure consist of?
Hydrogen, disulfide, van der Waal, Ionic, and hydrophobic bonds / interactions
Results from interactions between R groups
What bonds are involved in the quaternary structure of Protein? What interactions does the structure consist of?
H bonds,
disulfide bonds,
van der Waals
forces, ionic
bonds,
hydrophobic
interactions
Results from R
group interactions
between multiple
protein chains
(subunits)
What steps change amino acids into a protein?
Sequence
Folded / helix
3-d folding / wrapping
Presence of another amino acid chain
Myelin shealth
The electrical insulation for a nerve cell
what are amphipathic lipids?
Lipids that contain both hydrophilic and hydrophobic regions
What are phospholipids and phosphoglycerates?
lipids with a Phosphate group
Phospholipids built on a glycerol backbone
What is the composition of Sphingosine?
What about Ceramides and what are they the basic unit of?
An amino alcohol that contains a long hydrocarbon chain
Sphingosine linked to a fatty acid on the (R) of the Amino acid. Ceramide is the basic unit of all Sphingolipids
What is unique about cholesterol?
Smaller and less amphipathic lipid
makes up 50% of animal membranes
what are the 3 components of Plasma Membranes in Eukaryotic cells?
Carbohydrates, Glycoproteins and glycolipids
What are the functions of integral membrane proteins?
How are they anchored to the membrane?
function as receptors that bind ligands
channels / transporters to move ions & solutes across membrane
Anchored in membrane through Van Der Waals forces between amino acids and lipids
What are Peripheral membrane proteins and their function?
How are they bound to the membrane?
proteins on the surface of the membrane, act as enzymes, transmit membrane signals, can be recruited or released when needed.
Bound to membrane through weak electrostatic bonds
How are Lipid-anchored membrane proteins bound? what’s the difference in binding on the external face from the internal face?
They are covalently bonded to a lipid group in the membrane
The external face is bound through a GPI-protein while the internal is bound by a hydrocarbon chain.
What effects the fluidity / viscosity of cell membranes?
Temperature
How do cells maintain membrane fluidity when exposed to temperature changes?
By altering phospholipid composition
The cell changes the types of phospholipids being made in favor of more unsaturated fatty acids
Desaturation through desaturases
What are lipid rafts composed of? What is the purpose of Lipid rafts?
Tightly packed Cholesterol and sphingolipids
Lipid rafts provide a favorable position for cell receptors
What can move phospholipids in the membrane to flip between external and internal sides?
Enzymes called Flippases
What types of movements can proteins have?
Immobile
mobile in a directed manner
Randomized movement
Outline the general structure and functions of the
plasma membrane.
▪ Identify the basic structures and functions of the
carbohydrates and lipids within cellular membranes.
▪ Describe the three classes of membrane proteins and
their function within the lipid bilayer.
▪ Explain the importance of fluidity to plasma membrane
properties
