BFDM - Week 1

The body is made up of

40% solids, 60% liquids

2/3 intracellular fluid, 1/3 extracellular fluid

80% interstitial fluid, 20% blood

polar molecule

-one end is slightly positive and the other is slightly negative

-distribution of elections between covalently bonded atoms is not equal

covalent bond

chemical bond that involves sharing of electrons between atoms

hydrogen bond

electrostatic attraction between hydrogen atom in one molecule and a small electronegative atom in another molecule

properties of water

1. surface tension: resist external force due to cohesive nature

2. cohesion: ability to adhere to one another due to H bond

3. adhesion: ability to adhere to another polar molecule

4. osmosis: movement of solvent from high to low concentration

osmotic pressure

pressure needed to stop solvent flow across membrane

• hydrostatic: liquid pushing outward to force

• oncotic/colloidal: liquid pulled inward by proteins/molecules

hydrophobic effect

nonpolar molecules spontaneously associate together without any energy input

• favors entropy because more interactions can occur

strength of bonds

covalent > ionic > hydrogen > van der waals

K_a

acid dissociation constant

• high K_a = stronger acid

• low K_a = weaker acid

pK_a

point where 50% of acid is dissociated from H⁺ ion

low pK_a = higher acidity

Are amino acids found in L-configuration or D-configuration?

L-configuration

they are made by enzymes that are also in L-configuration

zwitterion

dipolar ion containing positive (NH₃⁺) and negative (COO^-) charged groups that cancel out

first order reaction

rate directly proportional to reactant

A —> P

second order reaction

rate directly proportional to either reactant

A+B —> P

zero order reaction

rate independent of concentration of reactants, fastest that reaction can go

K_m

measure of affinity of enzyme for substrate at ½ V_max

higher K_m = more substrate needed to reach half capacity (lower affinity)

lower K_m = better and faster substrate binds to enzyme (higher affinity)

competitive inhibitor

resembles substrate and binds to enzyme active site

V_max unchanged, K_m increased

uncompetitive inhibitor

binds to enzyme-substrate complex to prevent product formation

V_max decreased, K_m decreased

noncompetitive inhibitor

binds allosteric site and prevents product formation

V_max decreased, K_m unchanged

peptide bond

• covalent bonds between amino acids via dehydration reaction

• displays resonance, making molecule anti-rotational

alpha helix

secondary structure of proteins, where carboxyl group is hydrogen bonded to amine group about four residues away

• proline causes a kink due to its inflexibility

• R groups with large masses or electrical charge can disrupt helix

beta pleated sheet

secondary structure of proteins, where amino acids are hydrogen bonded laterally in adjacent strands

• parallel: strands in same direction, H bonds longer and unstable

• anti-parallel: strands run in opposite directions, more stable H bonds

protein motif

group of secondary protein structures clustered together to carry out function

protein domain

modular protein that can carry out function if separated and can contain motifs within itself

chaperone protein

specialized protein that assists polypeptide chain to fold into correct native conformation

proteolytic enzyme

enzyme that catalyzes proteolysis, or the hydrolysis of peptide bonds

cofactor

molecule required to make enzyme functional, made of vitamin derivatives or metals

prosthetic group

cofactors that are tightly bound to enzyme

(e.g. heme in hemoglobin)

hemoglobin

protein in red blood cells that carries oxygen from lungs to tissues and transports carbon dioxide and H⁺ ions to lungs

• allosteric protein

• tetramer whose subunits have a heme group to bind four oxygen

myoglobin

located in cardiac and skeletal muscle as oxygen storage reserve

• made of alpha helices with prosthetic heme group

• globular protein with turns, one single polypeptide chain

• only binds one oxygen molecule

2,3-bisphosphoglycerate (2,3-BPG)

molecule that binds hemoglobin pocket to convert it into T state and reduce oxygen affinity

• allosteric inhibitor that causes release of oxygen into tissues

• released at lungs to turn hemoglobin to R state for oxygen uptake

Bohr effect in tissues

• more carbon dioxide present in tissues combine with water to make HCO₃ and H⁺ to force oxygen off hemoglobin

• carbon dioxide travels as HCO₃ to lungs to be released

Bohr effect in lungs

• high oxygen forces H⁺ off of hemoglobin to allow oxygen to bind

• H⁺ combines with HCO₃ and reverts to water and carbon dioxide

• carbon dioxide is released and oxygenated hemoglobin delivers oxygen to tissues

hypophosphatasia

inherited disorder that affects development of bones and teeth by disrupting mineralization where calcium and phosphorous are deposited in developing bones and teeth

• caused by defective or inactive ALP, where it can’t break down PP_i

• PP_i builds up and inhibits hydroxyapatite formation, which is needed to harden bone and teeth structures

alkaline phosphatase (ALP)

enzyme that hydrolyzes phosphates from molecule and is produced by osteoblasts

• important for freeing phosphate so hydroxyapatite can form and strengthen bones

• promotes hydroxyapatite formation

pyrophosphate (PP_i)

hydrolyzed by ALP to make two inorganic phosphates

• ALP promotes hydroxyapatite formation

• PP_i prevents hydroxyapatite formation

Paget’s disease

osteoclasts absorb bone at a faster rate, where osteoblasts cannot produce enough new bone to keep up with osteoclast bone breakdown

• cotton wool appearance

bisphosphonates

medications that inhibit osteoclast activity

• cannot recruit osteoblasts to build bone if there is not osteoclastic activity and remodeling

• bone necroses and can result in MRONJ