the patient Flashcards
what are two uses of triaglycerols
they are efficient for energy storage
Fatty acids are stored as triaglycerols or fats
what are glycerophospholipids?
they are naturally occurring phospholipids, with very polar head groups. One hydroxyl is turned into a fatty acid Ester. There are variable R groups on the C2 carbon
what is the structure of glycerophospholipids
they don’t form micelles and they prefer to form bilayers
fatty acids form micelles
what is cholesterol
it is a member of the steroid group. They are weekly amphipathic. They are in a fused ring system. It is a relatively flat component of many animal membranes.
The influence membrane fluidity
polar end is the hydroxyl group in the A ring
it anchors itself into the bilayer by forming two H bonds with the phospholipids
what are nucleic acids
Polymeric molecules built from nucleotides
How are nucleotides connected?
By a phosphodiester linkage
What is the Watson and crick model?
where the sugar phosphate, backbone and DNA strands are anti-parallel. This provides stability to the DNA. Hydrogen bonds pair bases together and the DNA is super coiled leaving it compact.
Describe denaturing of proteins
The primary structure is left intact
Enzymes lose their catalytic activity
Most denaturing is irreversible, but renaturation is accompanied by the recovery of biological activity
What are lipids?
Small molecules that have a strong tendency to associate through noncovalent forces
They have a polar hydrophilic head
They have a hydrophobic tail [hydrocarbon.]
in water the tails associate via entropy driven hydrophobic affect
A second stabilizing effect arises from vanderwaals interactions between the hydrogen carbon regions
Why do straight chain hydrocarbons have a higher melting point
they can pack together easily, and they make a good solids
There are more points of interaction with adjacent molecules and more energy is needed to break these apart
what is a triaglycerol
A glycerol with three fatty acids esterified onto the glycerol
They are much less polar then fatty acids
They don’t fall micelles, efficiently
They are water insoluble
They form as oil droplets in the cytoplasm
What is an alpha carbon?
The central carbon atom in an amino acid
what’s an ogliopeptide
hundreds of amino acids
A protein basically
How do you draw an amino acid?
The amiee group is always on the left-hand side
eg val-cys
What is the primary structure?
carbon and nitrogen atoms along the backbone line in a zigzag arrangement. It is the amino acids all lined up.
What is the secondary structure?
The amide group -CO-NH- is both a hydrogen doughnut and a hydrogen bond acceptor
Alpha helix- the side chains point out, the hydrogen bonds are distant
beta pleated sheet – oh antiparallel, and the carboxyl ends and amino ends alternate.
What is the tertiary structure?
Folding results in maximum stability
What is a native protein?
A protein with the shape in which its functions in living systems
What is a simple protein
Composed of only amino acid residues
What is the quaternary structure?
where two proteins form a large ordered structure
What is negative regulation
A repressor/inhibitor binds to the promoter and competes with RNA polymerase
What is positive regulation
an activator protein binds to a weak promoter, and helps RNA polymerase to bind and transcribe
What is an operon?
A group of genes, or a segment of DNA that functions as a single transcription unit. It is comprised of an operator, a promoter, and two or more genes that are transcribed into one polycistronic mRNA.
what is a trp operator
is a repressible system. Five structural genes code for enzymes that make trytophan
what is a trp repressor
when trp is present in the growth, medium operon is switched off. The operator is recognized by trp repressor that’s blocks access of RNA polymerase.
what’s lac operon
uptake of lactose is mediated by lactose permease
Hydrolysis of lactose to galactose and glucose by 3-galactosidase
regulation of lac operon
by allolactose
no lactose: lac repressor is expressed and binds to lac operator sequence and inhibits transcription
allolactose present: lac repressor is displaced when it binds to allolactose. The promoter becomes active and transcribes the lac operon
Give two reasons why E. coli profiles glucose over lactose
1) that is sufficient glucose, and no expression of the lac operon
2) upon glucose depletion there is expression of the lac operon
Describe how cyclic AMP acts as a messenger to activate transcription
CAMP binds to cyclic AMP receptor proteins (CRP)
CRP binds to activator site and activates transcription
what is catabolite repression
as long as glucose is available, it is preferred as a carbon source for E. coli
If glucose runs out, intracellular, cyclic, AMP levels rise. It’s signals for metabolism of alternate carbon sources
Is lactose present? (e coli)
yes: lac repressor falls off and lac operator is transcribed
no: lac repressor inhibits lac operon transcription
what is a receptor
naturally occurring receptors are molecules that bind signaling molecules.
What are examples of natural receptors?
GPCRs, ion channels, gene transcription, enzymes
what’s an agonist
activate receptors
what are antagonists
block receptors and stop and natural ligand from binding
what is affinity
The tendency of strength of a ligand to bind to the receptor.
The greater the intermolecular force between the receptor and the ligand the higher the infinity. This is typically a reversible process.
What is the principle of the law of mass action?
The rate of a chemical reaction is directly proportional to the molecular concentrations of the reacting substances
what is k off
The dissociation rate constant (off rate)
what is k on
The association rate constant (on rate)
what’s k d
The equilibrium dissociation constant
The number tells us how well a receptor binds to a ligand
what is fractional occupancy?
It describes a fraction of receptors occupied at a particular ligand concentration
What is the fractional occupancy equation?
fractional occupancy= [L]/ k d + [L]
where [L] = the amount of drug bound
what’s efficacy
The degree to which different agonists produce bearing responses even went occupying, the same proportion of receptors
(how well an agonist activates a receptor)
what is potency
The amount of drug needed to produce a desired effect. Just depends on the receptor affinity and efficiency.
what’s ESCO
The concentration of an agonist that produces 50% of the maximum possible effect for that agonist
what are spare receptors
More than needed to get a maximum response, often found in the smooth muscle. It can be a defense mechanism. They are responsible to lower concentration of agonist
what is the schild plot
A higher antagonistic concentration, which binds strongly, means that a lot of agonist concentration will be needed for the same response
to work with a gene the gene must be:
Pure, homogenous, available in sufficient quantity
what is gene cloning?
Cloning is making many identical copies of the same gene
A vector must:
Be independent of the host, chromosome, be occupied by the cell, be maintained throughout the population of cells, allow for selection of cells containing the vector
what does gene cloning entail?
vector – restriction - linearized vector - ligation - transformation - vector replication - selection for cells containing the vector - cell multiplication
DNA can be cut at specific sequences by enzymes called
Restriction endonucleases
What does ligase do?
Reseals the phosphodiester backbone of DNA
what is meant by transformation
The plasmid is put inside the cell
What is a vector replication?
Copies of the same vector are made
what is selection/cell multiplication
only cells containing the plasmid can grow
What is secondary selection?
Antibiotic resistance, radioactive, glowing, specific color, the gene is deactivated
What are the three uses of gene cloning?
expression, investigation, manipulation
