HSC Biology. Year 2014 Mark Pages 32 Published Jan 12, Biology: Maintaining A Balance. By Leah (97.7 ATAR)

Transcription

1 HSC Bilgy Year 2014 Mark Pages 32 Published Jan 12, 2017 Bilgy: Maintaining A Balance. By Leah (97.7 ATAR)

2 Pwered by TCPDF ( Yur ntes authr, Leah. Leah achieved an ATAR f 97.7 in 2014 while attending Tara Anglican Schl Fr Girls Currently studying Bachelr f Primary Educatin at The University f Sydney Achievements: 2nd in State HSC Gegraphy 2014 Caltex All Runder Award 2014 Gegraphy Teacher's Assciatin Arthur Phillip Award 2011 and 2012 Band 6 HSC Bilgy Band 6 HSC General Mathematics Band 6 HSC Gegraphy (mark f 97) Band 6 HSC Fd Technlgy Band 6 Studies f Religin I Leah says: Hi all, I achieved an ATAR f 97.7 in the 2014 HSC ranking 2nd in the State in Gegraphy. I'm currently studying a Bachelr f Primary Educatin at the University f Sydney and am super passinate abut educating yung peple t achieve incredible things. I have ver 2 years f tutring experience and my ntes cmprehensively cver all HSC syllabus dt pints. My advice is wrk hard and play hard- after all, this is yur last year f schl! Enjy yur last sprts carnivals, muck up days and all the extra curricular activities yu d whilst studying diligently and thrughly t enjy the all imprtant balance f year 12.

3 1.1 The rle f enzymes in metablism, chemical cmpsitin and a simple mdel t describe their specificity n substrates- Enzyme a chemical (prtein) that cntrls the rate f a specific cell reactin withut itself being altered by the reactin (bilgical catalyst Made f prteins (lng chains f amin acids) held tgether by their crsslinks Cntains active sites- where the substrate attaches at the active site Characteristics f enzymes Prtein Catalyst (speed up the reactin rate) Remain unchanged/unchanged Highly specific- fr each reactin Wrk best under ptimum cnditins Enzymes denature with temperature and extreme phs Human enzymes ptimum temperature 37 c, ph 6.5 Anablic Reactin- cmbining smaller units t make new substances in the bdy Catablic Reactin- breaks dwn chemical int smaller units e.g. digestin Lck and Key mdel- key represents enzyme (re-usable), lck represents substrate Enzymes are specific (certain key needs certain lck) Enzymes are re-usable Enzymes cause changes, but are nt changed themselves (lck changes) Explain specificity Keys are smaller than lcks (enzymes are larger than substrates) Keys are nt affected by temperature and ph induced fit thery - enzymes will mrph shape t fit 1.2 ph in describing the acidity f a substance- ph is a measure f the acidity f a substance ph is a lgarithmic value f the cncentratin f hydrgen ins (H + ) acidity f the stmach- ph 2 alkalinity f intestine- ph 8 1.a The 3 factrs that affect the rate f enzyme activity- Temperature at lw temperatures enzyme actin is slw because particle mvement is slw- takes lnger t cuple with substrate if temperature increases they wrk at a nrmal rate

4 at high temperatures enzymes denature at the active site ptimum temperature range- humans 36 c-37 c ph enzymes wrk in a medium f a specific ph-utside this range they denature enzymes wrk in the stmach at ph 2 Bdy cells have a ph 7.4 Change in substrate cncentratin Enzyme activity increases with increasing cncentratin f substrate t the maximum pint where it plateaus Lw cncentratin f substrates mean a higher number f enzymes= lw activity When all enzymes are lcked int the enzyme-substrate cmplex, increasing cncentratin des nt result in a further increase Effect f temperature n enzyme activity AIM- T test t see whether a variance in temperature will affect enzymatic activity EQUIPMENT Large beakers Test tubes Thermmeters Ice Kettle Liver Stpwatch Hydrgen perxide Detergent Ruler METHOD- 1. Set up water baths fr 2 c, 10 c, 20 c, 30, 40 c, 50 c, 60 c, 70 c and 80 c 2. Cut pieces f liver 0.2cm thick- place in test tubes 3. Place liver test tubes int water bath 4. Place 5mL hydrgen perxide int water bath 5. Measure temperature until the same 6. Put 3 drps f detergent int hydrgen perxide 7. Tip hydrgen perxide int liver and after 1 min measure the height f the bubbles VALIDITY- Measuring cylinders- exact amunt f hydrgen perxide

5 Enzyme and substrate kept at same temperature Inaccuracy with detergent Size f liver Stpwatch starting at different times RELIABILITY Nt reliable since each temperature is nly dne nce T increase reliability, repeat 5 times and average the results VARIABLES Independent- temperature f substrate and enzymes Dependent- height f fam (cm)- breakdwn f hydrgen perxide t prduce xygen bubbles Cntrlled- liver size, amunt f hydrgen perxide, time, amunt f detergent NOTES Use measuring cylinders Measure inside test tube NOT bath Dn t hld test tube during reactin (warm) Measure fam frm same place Enzyme- catalase (liver) substrate- hydrgen perxide Effect f ph n enzyme activity AIM- T test t see whether a variance in ph will affect enzyme activity EQUIPMENT Test tubes Hydrchlric acid Water Ptat Hydrgen perxide Ptat brer Sdium hydrxide Universal indicatr

6 Pwered by TCPDF (