Untitled

Slide 1

• protein molecules r v imptnt in ur body
• protein molecule made up of amino acids
• diff arrangements give diff proteins
• proteins carry out many diff functions in ur body - they act as: structural components such as muscles & tendons; hormones such as insulin; antibodies; catalysts in the form of enzymes
• we control rates of chemical reactions all the time
• sometimes we use special chems called catalysts to speed up reactions 4 us
• a catalysts speeds up reaction, but isn't used up in it - u can use catalyst over & over again
• in ur body, chem reactions rates r controlled by enzymes
• these r biological catalysts tht speed up reactions w/i ur body
• enzymes r large protein molecules
• long chains of amino acids r folded 2 produce a molecule w/ a spec shape
• this spec shape allows other molecules (substrates) 2 fit in2 the enzyme protein
• we call this the active site
• the shape of the enzyme is vital 4 how it works
• enzymes r involved in: building large molecules out of small ones; changing 1 molecule in2 another; breaking down large molecules in2 smaller 1s
• enzymes don't change reaction in any way - they just make it hppn faster
• diff enzymes catalyse spec types of reaction
• the substrate of the reaction fits in2 active site of enzyme like lock & key
• once in place enzyme & substrate bind together
• reaction takes place quickly & products released from surface of enzyme

Slide 2

• temp affects rate of chem reactions even when controlled by bio catalysts
• bio reactions r affected by same factors as any other chem reaction
• factors such as conc, temp, & SA will affect them
• howver, in living organisms an increase in temp only works up 2 a point
• reactions tht take place in cells hppn @ relatively low temps
• rate of enzyme-controlled reaction increases as temp increases
• but only tru up 2 temp abt 40C
• aftr this, protein structure affected by hi temp
• long amino acid chain strts 2 unravel, shape of active site changes, enzyme has been denatured, it cant act as catalyst so RoR drops
• most human enzymes work best @ 37C
• shape of active site of enzyme comes from forces btwn diff prts of protein molecule; these forces hold folded chain in place
• change in pH affects these forces, changes shape of molecule, active site lost, protein no longer catalyst
• diff enzymes work best @ diff pH levels
• change in pH can stop them working completely
• w/o enzymes, none of reactions in ur body wd hppn fast enough 4 u 2 survive
• that's why it's so dangerous 4 ur temp 2 rise above 40C

Slide 3