ch4 enzymes and metabolism

Question 1

metabolism

Answer 1

。sum of chemical reactions in an organism

Question 2

catabolism

Answer 2

。breaking down
。energy released

Question 3

anabolism

Answer 3

。building up
。energy absorbed

Question 4

activation energy

Answer 4

。energy supplied to reactant

Question 5

enzymes

Answer 5

。proteins in a specific 3D structure
。active site allows binding to substrate molecules and form an enzyme-substrate complex
。substrates are converted to products, no change in shape of enzyme
。lowers activation energy

Question 6

enzymes function as biological catalysts

Answer 6

。lower activation energy
。take place at body temperature at faster rate

Question 7

properties of enzymes

Answer 7

1) biological catalysts
。speed up metabolism and lower activation energy

2) actions are specific
。only act on substrates that fit into the active site

3) enzymes are proteins
。highly affected by temperature and pH
。denature and lose function at high temperature and extreme pH

4) reusable
。binding of active site and substrate is temporary
。shaoe of enzyme remains unchanged -> can bind with other substrates

5) needed in relatively small amounts
。reuseable

Question 8

factors affecting rate of reactions

Answer 8

1) temperature
。low temperature -> enzymes are inactive -> reaction rate is low
。temperature rises -> enzyme and substrate molecule move around rapidly -> collide frequently -> chance of forming enzyme-substrates increase -> reaction rate increases
。optimum temperature -> reaction reaches a maximum
。high temperature -> conformational change in active site -> denature -> substrate can no longer fit into active site -> reaction rate decreases

2) pH
。enzymes work in a narrow range of pH (work best at optimum pH)
。unsuitable pH will cause denaturation -> decrease rate of enzymatic reaction

Question 9

inhibitors

Answer 9

。chemicals that can decrease the rate of reactions

1) competitive inhibitor
。competes and occupies active site
。increasing substrate concentration -> increase rate of reaction

2) non-competitive inhibitor
。does not compete for active sit
。attach to enzyme and change the shape of active site
。prevents binding
。not reusable
。cannot be overcome by increasing substrate concentration