Life at the cellular level 4 Flashcards Preview

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Flashcards in Life at the cellular level 4 Deck (10):

what are the general properties of water? (6)

- bathes cells (interstitial fluid)
- dissipates heat
- acts as a solvent
- participates in chemical reactions
- can hydrogen bond
- can stabilse enzyme substarte reactions (though H-bonding)


what is the hydrophobic effect?

hydrophobic molecules aim to minimise disruption to hydrogen bonding by allowing cages of water to form around hydrophobic molecules


what is a chylomicron?

a complex that transports hydrophobic lipids in the bloodstream


what is Kw?

a constant that represnts the extent to which water dissociates
(= 1x10^ -14)


what is Ka?

the tendency for an acid to lose its proton


what is the equation for Ka?

Ka = [H+][A-] / [HA]


how do buffers work?

- if extra acid is added it reacts with the A- to remove the extra hydrogen ions helping to maintain the pH
- if a base is added the OH- reacts witht he H+ ions and so more HA dissociates to replace the H+ ions lost maintaining the pH
- this can only occur until all of the A- or HA has reacted


what is the henderson-hasselbach equation?

pH = pKa + log ([A-]/[HA])


name some common buffers present in the body

- phosphate buffers: H2PO4 --> H+ + HPO4(^2-)
- bicarbonate buffers: H2CO3 --> H+ + HCO3(^1-)


how do buffers help with drug absorption?

in the stomach a weak acid will be largely unprotanted (uncharged) which makes it easier for it pass through cell membranes