Biochem Ex 1 - Lipids Flashcards
Name 3 Sphingolipids
Ganglioside GM1 Spingomyelin (neural cells) ABO antigens (red blood cells)
What are the three lipids that make up a membrane?
Phosphoglycerides Sphingolipids Cholesterol
How many fatty acids are there in a phosphoglycerides?
2
If it has nitrogen in the hydrophobic part of a fatty acid it is a
Sphingolipids
How can you tell if a fatty acid is a cholesterol?
It has a characteristic for ring structure with one looking like a house
4 things that cholesterol can do
1 - components of the cell membrane 2 - converted to vitamin D 3 - they are hormones (binding proteins moves them through the blood) 4 - they are bile salts are bio acids involved in digestion
What types of membranes are Sphingolipids found in?
Neural cells Red Blood Cells
Name the 3 twisted shape eicosanoids
Prostaglandins Prostacyclins Thromboxanes
Name the linear shape eicosanoid
Leukotriene
What type of eiconanoids look like a frog
Anything that looks like a frog is a prostaglandin or a prostacyclin, or thromboxane
What do eicosanoids signal for?
Pain Inflammation Fever Clotting
What is aspirins method of action
Aspirin’s method of action is to block cyclooxygenase. So it blocks it from signaling for pain, inflammation, fever, and clotting.
Eicosanoids are: A - Proteins B - Carbohydrates C - Lipids
Lipids
What are the 3 parts of a nucleotide?
- A sugar - A heterogeneous (more than one type of atom, i.e. C and N) base - A phosphate
What is a nucleoside?
A nucleotide without a phosphate
Why are drugs mostly nucleoside analogs rather than nucleotides?
Because they are more mobile since they don’t have the phosphate attached which makes it bigger and carries a negative charge
In a nucleotide, what do prime numbers denote?
The numbering system for the sugar
In a nucleotide, what do non-prime numbers denote?
The numbering system for the base
What is important about the 2’ position in a nucleotide
If it has an oxygen it is a ribose (RNA) sugar
if it does not have an oxygen it is a deoxyribose (DNA) sugar
What are the two types of nucleotide bases?
Purines (double ring)
and
Pyrimidines (single ring)
Name 2 Purine nucleobases
Adenine
Guanine
Name 2 Pyrimidine nucleobases
Cytosine
Thymine
How many bonds in a GC pairing?
3
How many bonds in an AT pairing
2
What are 2 things nucleotides do?
They have a role in energy metabolism
They are incorporated into making DNA and RNA
Why does ATP release so much energy?
Look at all the negative charges. When it becomes ADP or monophosphate(AMP) it loses the phosphates (making it more favorable) and thus releases energy. Also by releasing phosphate it has more resonance (associated with lower state of energy). Also, heat of solvation (dissolving of phosphate in water) allows hydrogen bonding to occur with phosphates off (this is also associated with a lower energy state).
ATP is also stable so it is a good source of energy storage
Name another nucleotide with energy as its role
Nicatinamide
What is another role of nucleotides, besides energy storage?
Regulation
The phosphate group that is attached causes something to turn on or off (regulation)
What is Adenylylation?
The covalent attachment of a nucleotide donated by another nucleotide causing an enzyme to be regulated (turned on or off)
Is ATP a regulatory molecule?
Yes
If a cell senses it has a lot of ATP it knows it is thriving and turns a lot of cell activity on or off
What is AMP and GMP regulation?
The phosphate here cuts out and forms a cyclic structure (Cyclic AMP or Cyclic GMP). cycle forms between 5’and 3’ causing the molecule to be recognized as cyclic amp or cyclic gmp instead of ATP and can then perform different functions
What does modification of a base in DNA do?
Silences a gene (Regulation at the level of gene expression)
Example: Methylation of Citosine in a CpG group (cytosine, phosphate, guanine). The continuous methylation causes the gene to be turned off (expression to be silenced).
An example: Red blood cells are about carrying oxygen. So genes that don’t call for carrying oxygen are methylated and thus turned off so they don’t waste energy.
What type of action does an Adenosine receptor have?
A depressant action
Nucleotides strung together are called
Nucleic acid
What is base stacking?
The attractive force that holds nucleotide antiparallel strands together with hydrogen bonds causing a helical shape
What is screening?
We also have these phosphates (pi) together carrying a lot of negative charge so stuff with positive charge (like Mg) is going to be around the Pi negative charges (called screening) to stabilize the DNA
What type of bond forms the strand in a nucleic acid?
Phosphodiester bonds
What type of bonds form the ladder in a nucleic acid?
Hydrogen bonds
What forms the helix in a nucleic acid?
Base stacking
How is the helix stabilized in a nucleic acid?
By cations (screening)
How do lipids interact with polar molecules?
Through their own polar groups (phosphoglycerides, bile acids and salts, sphingolipids)
or
by complexing with proteins (fatty acids, triglycerides, and steroids)
Why do lipids only have local effects?
Because they cannot be carried away by aqueous fluids (eicosanioids)
Define polar and non-polar
Polar = Has a separation of charge (dipole moment); nonpolar = Electronegativity difference of 0.5 - 1.9
Explain why lipids do not mix well with water
Lipids do not mix well with water because water is polar and lipids are nonpolar. Lipids are hydrophobic
Why are fatty acids fatty? What is fatty and what is acidic about them?
The acid is a carboxylic acid, the fatty is a nonpolar end consisting of carbon and hydrogen (hydrocarbon) which is lipid soluble (water insoluble).
Using the Delta and Omega nomenclatures, name this fatty acid:
Using the omega nomenclature (or n nomenclature): 20:5 omega-3 (20:5 n-3)
Using the delta nomenclature: 20:5 delta - 5,8,11,14,17
What is one reason why triacylglycerols make good energy storage?
Triacylglycerols make a good form of energy storage because they are highly reduced, so they can be oxidated. They also are hydrophobic and thus are not weighed down by water.
What is the importance of a phosphate group in a phospholipid?
The phosphate group is polar and thus is able to interact with the aqueous intercellular and extracellular regions.
What two cell types that we discussed in class have significant glycoshphingolipids in their cell membranes? What other lipid types are cell membranes typically composed of?
Two cell types containing glycosphingolipids: Neural cells and red blood cells.
Lipid types which cell membranes are composed of: glycerophospholipids, sphyngolipids, and cholesterol.
Name 4 roles of sterols in humans?
1 - part of the cell membrane
2 - converted to vitamin D
3 - they are hormones (which are transported through the blood stream by proteins)
4 - they are a component of bile salts or bile acids that have a role in digestion.
There are no binding proteins that chapperone eicosanoids through the circulation. How do they accomplish their function despite that?
Their actions are meant to be local so they are not circulated in the blood.
What is the mechanism of aspirin action?
Aspirin blocks the function of cyclooxygenase (an enzyme that causes Arachidonate to become an eicosanoid) so it blocks its ability to signal for pain, fever, inflammation, and clotting.
There is a difference of how many sugars between A B and O blood types
1 sugar
