Enzymes and Glycolysis

Talk about it Essentially, burning oil and cellular respiration are the same reaction. Why do you think there are so many reactions that need to take place in cellular respiration? Basically, why don’t we just burn all the gas at once, rather than use a little bit of gas at a time to run our cars? (If you didn’t know, our cars run because little explosions of the gas occur, forcing the pistons out which allows it to turn the wheels)

Controlled release of energy

Why does the combustion of sugar release energy? Electrons move to a more stable state, just like energy is released as someone sleds down a hill to a more stable state.

Glycolysis Chart Page 168

Glycolysis How could this break down into two identical units? Show how yeast undergo glycolysis. Talk about how glycolysis is the only thing that organisms could use to make energy when there was no oxygen in the atmosphere

What you should know about glycolysis Why there are 10 reactions rather than just 1 The specificity of enzymes How much ATP is used and given off What the initial molecule is and what you end with.

Look at pg 168 Find the Enzymes!

Enzymes Usually proteins Catalyze reactions Have an active site (where substrates bind)

Activation energy Amount of energy needed to start an exergonic reaction

Enzymes lower the activation energy barrier

How enzymes lower activation energy barrier Holds substrates together Stresses the bonds between substrates Serves as a pocket of a different chemical environment May temporally bind to the substrates and then go back to its original form

Conditions that affect the rate of reactions Enzyme and substrate concentration pH Temperature The presence of an inhibitor

Rates of reactions with enzymes Reaction speeds up until all enzymes active sites are full

Conditions that affect reaction rates

Regulation of Enzymes Inhibition Activation Fig 8.19 Competitive Allosteric (noncompetitive inhibition) Activation Fig 8.19

Enzymes fluctuate between inactive and active form

Feedback mechanisms Ex. ATP binds as an allosteric inhibitor while ADP functions as an activator So… When ATP is abundant, it slows down catabolism, when ADP is present then it speeds up catabolism Find 1 feedback mechanism on pg 168

What you should know about glycolysis Why there are 10 reactions rather than just 1 That each reaction has a specific enzyme That four ATP are produced but two are required… so net of 2 ATP produced Initial molecule is 6 carbon sugar and you end up with a 3 carbon sugar.

Online Tutorials http://bcs.whfreeman.com/thelifewire/conte nt/chp06/0602001.html and http://bcs.whfreeman.com/thelifewire/conte nt/chp06/0602002.html