MD2001 Week 3 Flashcards
5 roles of proteins
- provide structure (collagen)
- transport molecule (haemoglobin, LDL)
- defence (antibodies)
- biological catalysts (lysozyme)
- regulation of genes (lac repressor)
what is the prosthetic group in haemoglobin
haem is the prosthetic group in this molecule
what disease is caused by a mutation in the histidine residues of LDL receptors?
hypercholesterolemia
how does lac repressor work?
it binds to DNA and prevents expression of the genes in absence of lactose
draw histidine
draw histidine
draw aspartate
draw aspartate
draw proline
draw proline
3 basic amino acids
- histidine
- arginine
- lysine
2 acidic amino acids
- aspartate
2. glutamate
4 polar amino acids w/ uncharged R groups
- asparagine
- glutamine
- serine
- threonine
8 hydrophobic amino acids
- leucine
- isoleucine
- valine
- tyrosine
- alanine
- tryptophan
- methionine
- phenylalanine
pH - pKa = log[BH+]/[B]
Henderson Hasselbach Equation
What is the pKa of aspartate?
this amino acid’s pKa is 4.5
Biological significance of pKa?
dissociation largely occurs over 2 pH units centred around it so small changes in pH of environment can cause significant changes in charge carried
example of receptor-mediated endocytosis and how it works
uptake of low-density lipoprotein is an example of this type of endocytosis. pH in endosome reduces to 5, causing histidine residue to change confirmation of LDL (pK 6.5), releasing the LDL into lysosome
condensation reaction
this reaction occurs in peptide bond formation
which amino acid is frequently found in bends/loops?
proline is frequently found in this protein structure
3 layers of blood vessels
- tunica intima
- tunica media
- tunica adventitia
what and where is the fossa ovalis?
it is the remnant of the foramen ovale and is found in R atrium
what does the foramen ovale do?
it allows oxygenated blood form mother to by-pass non-functional foetal lungs
what benefit do muscular ridges give to the heart?
they give power of contraction w/out making heart walls too thick
what connect valve cusps of the heart to muscular ridges?
papillary muscles
what do the papillary muscles and tendinous cords prevent in the heart?
these structures prevent cusp eversion in the heart
main parts of coronary veins
- great cardiac vein
- middle cardiac vein
- small cardiac vein
- coronary sinus
what nerve supplies the SA node?
vagus nerve supplies this heart structure
internal cardiac conduction pathway
SA node -> AV node -> bundle of His -> interventricular septum -> either ventricle
which muscles are striated?
cardiac and skeletal muscle
which muscles have intercalated disks?
cardiac and smooth muscle
in which type of blood vessel is elastic tissue abundant?
this type of tissue is abundant in large blood vessels like the aorta
5 bonds found in tertiary structure
- H-bonds
- van der waals
- hydrophobic interactions
- ionic interactions
- disulphide bonds
4 examples of quaternary structure
- mechanosensitive conductance channel (7 identical subunits)
- stored insulin (6 identical subunits)
- heterotrimeric G protein (3 diff. subunits)
- 70S ribosome (30 diff. subunits)
proteins that make up haemoglobin
2 alpha global and 2 beta global chains make up this molecule
what holds haem and oxygen in place in haemoglobin?
H- bonds from histidine F8 holds Haem, and histidine E7 stabilizes oxygen
explain cooperative oxygen binding in haemoglobin
affinity of first O2 is low but binding of subsequent O2 is increased b/c histidine F8 changes position upon O2 binding
biological significance of cooperative oxygen binding
small changes in [O2] results in large changes in interaction of haemoglobin w O2. Means tight O2 binding in lungs and release in tissues where [O2] low
sickle cell anaemia
disease caused by hydrophilic glutamic acid replaced by hydrophobic valine
structure of tropocollagen helix and amino acids involved
3 polypeptide chains w/ a L-handed twist wound in a R-handed supercoil by glycine and (hydroxy)proline.
explain formation of the molecule that stabilizes the collagen fibre
lysine deaminated by lysol oxidase into its aldehyde derivative allysine. 2 Allysines combine to form Aldol condensation product
3 diseases involving collagen and their causes
- Osteogenesis imperfect (glycine replaced by cysteine)
- Scurvy (lack of proline hydroxylation)
- Ehlers-Danloss Syndrome (lack of pro collagen peptidase or lysol oxidase)
draw arterial and venous flow
draw arterial and venous flow
how does blood flow through veins? (3)
- muscle pump
- arterial pulsation
- intrathoracic pressure
what vein drains the thoracic wall?
azygos vein drains this
major lymph vessel of the L and R side respectively
thoracic duct (more major) and right lymphatic duct
3 palpable nodes
- cervical node
- axillary nodes
- inguinal nodes
cisterna chyli
lymph sac on thoracic duct
where do the thoracic duct and right lymphatic duct drain into?
they drain into the junction of the subclavian and internal jugular on either side
types of bones (5)
- long
- short
- flat
- irregular
- sesamoid
where are fibrous joints found? (3)
- suture joints
- syndesmosis
- sacroiliac joint
example of an ellipsoid joint
metacarpophalangeal or atlanto-occipital joint
fusiform muscle
spindle shaped muscle w/ belly and tapered ends
