Introduction to Biochemistry Flashcards
First law of thermodynamics
Energy is neither created nor destroyed
Second law of thermodynamics
When energy is converted to a new form, some becomes unavailable to do work
How is it possible for a +delta G reaction to occur
By pairing it with a -delta G reaction
What are standard conditions
pH 7, 298 K, 1 atmosphere, I mol/l
What delta value are readily reversible reactions near to.
Zero.
What type of reactions are spontaneous, endergonic or exergonic
Exergonic
What enzyme catalyses the conversion of glucose-6-phosphate to glucose-1-phosphate
Phosphoglucomutase
NET gain of ATP from glycolysis
2 ATP
What is the term given to the formation of new glucose from non-carbohydrate precursors
Gluconeogenesis. Remember, gluconeogenesis IS NOT simply the reverse of glycolysis
What shape is a water molecule
Tetrahedral
What type of substances do not dissolve in water - hydrophobic
Non-polar substances
What characteristic of micelles allows them to dissolve in water
Their hydrophobic tails face inside, whereas their hydrophilic heads face outside
What are stereoisomers
Non-superimposable mirror images of a molecule
Give an example of a non-polar hydrophobic group
CH3 (methyl) groups
What are the four ‘groups’ of amino acids
Polar, non-polar, acidic and basic
In what direction do peptide chains extend in
From the N-terminal to the C-terminal
What does the acid dissociation constant measure
The ability of an acid to donate a proton
What is Ka
Ka = the acid dissociation constant. This equilibrium constant is a quantitative measure of the strength of an acid in a solution.
What is the Henderson Hasselbalch equation used for
This equation links the Ka of an acid with the pH of a solution containing this acid. It can be used to calculate the properties of buffer solutions
Under what circumstance will pH = pKa
When the concentration of an acid is equal to the concentration of conjugate base
What are zwitterons
Electrically neutral molecules or ions
At which point does a molecule have no net charge
The isoelectric point = pI
Primary protein structure
The sequence of amino acids
Secondary structure
The localised conformation of the polypeptide backbone
Tertiary structure
3D structure of the polypeptide, including all of its sidechains
Quaternary structure
The special arrangement of polypeptide chains in a protein with multiple subunits
What are the 3 types of secondary protein structures
Alpha helix, beta sheets/stands and triple helix
Symptom of weakened collagen
Bleeding gums
What amino acid substitution causes sickle cell anaemia
Glutamic acid to valine
Give 3 examples of conditions which arise when protein folding is slow and errors subsequently occur
Alzheimer’s, Parkinson’s and CJD
Describe the structure of haemoglobin
4 subunits, two alpha and two beta chains, each with a haem group which can bind one oxygen each
What is allosteric regulation
When the binding of one molecule changes the affinity for the other subunits (e.g. haemoglobin)
