Metabolism / Enzymes / Biological specimens / Chromatography / Accuracy and Precision (W13) Flashcards
what is metabolism
all the enzyme catalysed chemical reactions in a cell (includes both anabolic and catabolic)
what are anabolic pathways, and what are 4 characteristics of them
the process of building up complex organic molecules
- it is biosynthesis
- it is reductive (requires electrons)
- it requires energy
- the pathway is usually divergent
is the process of making large molecules from a selection of small molecules oxidation or reduction
reduction (it requires electrons)
what are catabolic pathways and what are 4 characteristics of them
it is the degradation of larger complex substances into smaller molecules, while generating energy
- degradative
- oxidative
- yields energy
pathway is usually convergent
is the process of breaking larger molecules into smaller molecules oxidation or reduction
oxidation
how to the rates of anabolic and catabolic reactions compare
the rate of degradation = rate of synthesis
in a dynamic steady state
also the energy-yielding catabolic pathways are balanced by the anabolic pathways
what are 4 characteristics of enzymes
- they are mostly proteins (some are RNA molecules)
- they are reaction specific
- highly regulated
- essential for the proper function of cells
why are enzymes essential
without them the reactions needed in the body would progress too slowly for life
what are 3 reasons why we would study enzymes
- clinical pathologies (monitor and diagnose disease)
- design and development of new drugs
- gain understanding of how cells work
define chemical reaction and rate of reaction
a chemical reaction is any chemical change that produces at least one new substance
the rate of this is the rate that reactants are being used or products are being formed
what is the transition state during a reaction
it is the arrangement of atoms that requires the highest energy, and this must be overcome before converting into products
what is the free energy of activation
the minimum energy to get to the transition state from the reactants (activation energy)
how does the free activation of energy affect the speed of the reaction
high activation energy = low rate (slower reaction)
low activation energy = high rate (faster reaction)
how much can an enzyme increase rates of reaction
by up to 10ˆ20
define enzyme rate
the rate that an enzyme can catalyse a reaction
how are enzymes usually names
- according to function
- and ending in -ase, -me, -in
what are enzyme’s active sites complementary to
the transitional state of the reaction
what are 4 factors that can affect enzyme activity
- temperature
- pH
- concentration of enzyme
- concentration of substrate
what do the graphs look like for concentration of enzyme and substrate compared to enzyme activity
concentration of substrate: plateaux at Vmax
concentration of enzymes: increases linearly
Where is Km (michaelis constant) on a graph
on a substrate concentration graph it shows the strength of association between the enzyme and substrate.
it is where the reaction rate is half of the max
what are 6 examples of common biological specimens
- blood
- urine
- faeces
- solid tissue
- cerebrospinal fluid
- swabs
what are some of the components of whole blood (8)
cellular components:
- RBCs
- WBCs
- platelets
plasma components:
- Water
-Albumin
- immunoglobulins
- coagulation proteins
- electrolytes
etc.
what 4 things are needed for blood clotting to occur
- damage to blood vessels
- Ca2+
- platelets
- Clotting proteins
how is a sample of serum obtained
whole blood is taken and clot is formed (serum is the remaining liquid component)
how are serum and plasma different
given that plasma is the liquid component of blood, serum is basically plasma minus the clotting proteins
how is a sample of plasma obtained
whole blood is taken from the vein and mixed with anticoagulant (no no clot forms) then it is spun to separate the cell components from the plasma
what are the 5 types of anticoagulant and how do they each work
Heparin : inhibits clotting proteins
EDTA : complexes divalent cations ( removes Ca2+)
Sodium citrate : chelates calcium reversibly
Oxalate : chelates calcium irreversibly
Sodium fluoride : preserves glucose
state and describe 7 things to look out for when working with biological specimens
TACSIPP
-if plasma, correct anticoagulant? correct amount and thoroughly mixed?
- correct collection my phlebotomist (venous or arterial sample? or swabbing the right way)
- identification (labelling samples correctly etc.)
- Separation (correct centrifugation?)
- preservation and storage
- transport (quickly and safely)
- Patient (is the sample taken at the right time)
what is chromatography
a process to separate or isolate molecules based of a difference in size, charge, etc.
what are the 5 types of chromatography and what state are each of the phases
- adsorption - solid S and liquid M
- partition - liquid S and liquid or gas M
- ion exchange - solid S and liquid M
- size exclusion - liquid S and liquid M
- affinity - stationary ligand and liquid M
how does ion exchange chromatography work
resin is charged (pos or neg)
so molecules with different charges move through at different speeds
eg. with a negatively charged matix more negatively charged molecules will move through faster. pos charger molecules will spend more time drawn to the stationary phase and will move slower
how does size exclusion / gel filtration chromatography work
resin bead acts as a matrix (consists of strands of cross linked polymers)
- larger molecules move through faster and avoid beads whereas the smaller molecules get trapped for longer in the bead and taker longer to move through
describe affinity column chromatography
- column contains polymer bound ligands that are specific to the protein of interest.
- protein of interest binds to the ligand and and unwanted substances move through
- then ligand solution is put through to detach the proteins from the ligand
define accuracy and precision
accuracy - how close the value is to the true value
precision - how close values are to each other
