What are the range of functions proteins perform? Give examples alongside. (HINT: there’s 5)
- STRUCTURE: Collagen = the protein of bone, skin & tendon. The main component of connective tissue & makes up 25-35% of our total protein
- TRANSPORT: Hb, found in erythrocytes, carries & delivers oxygen to metabolic tissues. Composed of 4 protein subunits, each of which contains a Haem group
LDL & LDL receptors transport cholesterol molecules & coordinates uptake into cells - DEFENCE: Ab = defence against INFECTION. Made from light & heavy polypeptide chains covalently linked by disulphide bonds
- REGULATION: Lac repressor helps to control gene expression
- CATALYSTS: Enzymes = regulation of ALL biological systems. E.g. Lysozyme catalyses cutting of polysaccharide chains
If the shape of a protein is changed, what is also affected?
Its function/activity
What is the primary structure of a protein?
The sequence of amino acids it is made up from
Give an example of each of the following; (i) non-polar aliphatic (ii) non polar aromatic (iii) polar uncharged (iv) polar -vely charged (v) polar +vely charged (vi) sulphur containing (vii) Imino.
(i) Glycine
(ii) Phenylalanine
(iii) Serine
(iv) Aspartic acid
(v) Histidine
(vi) Cysteine
(vii) Proline
What are polypeptides?
polymers of AA monomers linked by peptide bonds (covalent bond formed between carboxyl & amino group)
Define (i) Amino acid residue (ii) Prosthetic group (iii) N-terminal end (iv) C-terminal end.
(i) what is left of an AA when 2 or more are combined & water is removed
(ii) a non-AA substance that’s strongly bound to a protein & necessary for the protein part of an enzyme to function
(iii) has a free amine group, is the start of the polypeptide sequence
(iv) has a free carboxyl group
What is an acid? What is a base?
An acid is a molecule that tends to release a hydrogen ion
A base is any molecule that readily combines with a hydrogen ion
What is the equations for the equilibrium constant & the henderson-hasselbach equation?
Ka = [H+][A-] / [HA] pH = pKa + log[A-] / [HA]
What is the pKa?
The pH at which HALF the molecules are disassociated
What is the secondary structure of a protein? What are they stabilised by?
The initial folding pattern of a linear polypeptide
Stabilised by hydrogen bonds
What are the 3 main types of secondary structure? Describe them.
- ALPHA HELIX - formed when polypeptide chain is twisted into a rod, with the carbonyl group H bonded to the H of the amide, which is 4 residues down the chain. Is right handed, each turn has 3.6 AA residues
- BETA SHEETS - H bonds form between peptide chains that lie alongside each other. If adjacent strands are oriented in the SAME direction, it’s a parallel beta sheet. If the strands run in the OPPOSITE direction (i.e. C-N then N-C) direction, it’s a anti-parallel beta sheet.
- BEND/LOOP - usually 4 AA’s required to form the turn. Chains can fold upon themselves forming a bend/loop. Proline residues are frequently found in bends/loops.
Describe the difference between a doctor-centred & a patient-centred style of doctor.
DOCTOR-CENTRED (i.e. disease centred) - blocking behaviour - no acknowledgement of pt perspective - closed q's - inappropriate interruptions - little empaty - no emphasis on rapport building - restriction of content to somatic PATIENT-CENTRED (i.e. person centred) - ability to elicit pt beliefs - ability to activate the pt to take control of their illness management - active listening - absence of inhibiting behaviour (open q's) - reflection - agree on problem/question - negotiate reasonable goals - empathy
Why is good communication important? (HINT: there’s 5 reasons)
Pt understanding Pt satisfaction Adherence Health outcomes Pt safety
Describe the circulatory principles, with reference to a central heating system.
It requires a pump (THE HEART); a series of conducting pipes (ELASTIC PIPES); smaller distributing pipes to radiators w.thermostatic controls (MUSCULAR ARTERIES & ARTERIOLES); radiators for heat exchange (CAPILLARY BEDS) & a system of return pipes that increase in diameter from the radiators back to the pump (VENULES & VEINS)
What are the 3 layers within blood vessels? (From deep to superficial)
Tunica intima
Tunica media
Tunica adventitia
Where does the heart lie in the body?
Lies centrally in the chest between the lungs & pleura, in the middle mediastinum is surrounded by the pericardial sac of fibrous tissue that’s lined by serous slippery membrane that secretes a minuscule amount of lubricating fluid.
Describe the route of blood through the heart, starting with deoxygenated blood returning in the veins from the systemic circulation.
Enters the RA via the superior & inferior vena cava. Blood also enters from the coronary sinus.
- Deoxygenated blood passes from the RA, through the tricuspid valve, to the RV during atrial systole
- the RV pumps blood, during ventricle systole, past the pulmonary valve & into the pulmonary trunk, which divides into the L & R pulmonary arteries that go to the LUNGS allowing blood to be oxygenated
- Oxygenated blood returns from the lungs in the L&R, inf&sup, pulmonary veins to the LA
- From the LA, oxygenated blood passes through the mitral (bicuspid) valve to the LV. The atrioventricular valves are prevented from being turned inside out by papillary muscles & tendinous cords.
- the LV pumps the blood past the aortic valve & into the aorta, from where it is conducting to the entire body
Describe the coronary arteries.
Only fill during diastole because of their position behind the aortic valve
During systole, when the valve is open, the arteries are effectively switched off. Arise from aortic sinuses
Describe the coronary veins.
Apart from the anterior cardiac veins that drain directly into the RA, the veins of the heart converge on the coronary sinus, which enters the RA
What is the cardiac conduction system?
The wave of conduction (&contraction) passes from the sino atrial (SA) node, through the atria to the atrio ventricular (AV) node
- the bundle of his is the only route by which conduction may pass from the AV node & onward to the interventricular septum, where it continues into the L&R bundle branches that spread the conductino through each ventricle
What can myocardial infarction affect?
May affect the bundle of his OR the bundle branches & cause cardiac arrhythmias
What is the tertiary structure of proteins? (HINT: include what bonds are involved)
Results from a variety of interactions between the AA side chains
These interactions may include all types of bonding:
- hydrogen bonds
- van der waals interactions
- hydrophobic interactions
- ionic interactions
- disulphide bonds
Proteins are organised into multiple ‘domains’. What does each domain contribute to?
A specific function to the overall protein
What is the quaternary structure of proteins? With reference to a subunit & oligomeric.
The association of more than one polypeptide
Each unit of this protein is called a subunit & the protein is referred to as a oligomeric protein. Disulphide bonds often stabilise the oligomeric structure
E.g. IgG the Ab molecule.
