BCHM 3050 Lecture 30 Outline of Last Lecture I Monosaccharides II Enantiomers and Diastereomers III Chemical Reactions of Monosaccharides IV Important Monosaccharides V Disaccharides Outline of Current Lecture I Polysaccharides II ATP Adenosine triphosphate III Glycolysis Overview IV Step 1 V Step 2 VI Step 3 VII Step 4 VIII Step 5 IX Step 6 X Step 7 Current Lecture I II Polysaccharides a Starch is the most common polysaccharide alpha glucose alpha glucose b Starch is our 1 food source c Starch is all alpha glucose units d Glycogen is identical to starch in terms of the chemical composition just with more branched chains i Takes more energy to break down glycogen ii Alpha glucose units connected by alpha 1 4 glycosidic linkages e Cellulose is beta glucose units i Creates a 3D mesh connected by hydrogen bonds ii Humans do not have the enzyme to digest cellulose f Chitin beta 1 4 linkages a modified form of glucose but not glucose g Peptidoglycen is present in the cell wall of bacteria beta 1 4 linkage connecting sugars ATP Adenosine triphosphate a Contains adenine ribose and 3 phosphate groups These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III IV V VI VII VIII b Energy currency c Obtain from food d Energy from ATP used to carry out other functions in your body Glycolysis Overview a Glycolysis The most ancient known reaction from times on earth when only anaerobic organisms were present before the amount of oxygen was sufficient b Present in virtually all organisms on earth c Harvest 2 molecules of ATP in the first step of glycolysis d NADH is made but not used until later on e NADH is an energy investment in the cell Step 1 a As soon are we consume glucose the body attacks it b Be able to write out this pathway from memory c Hexokinase adds a phosphate group to glucose glucose 6 phosphate d This is an energy investment phase because ATP is invested e When hexokinase meets glucose it is committing glucose to go through glycolysis f Exothermic reactions are spontaneous irreversible g Glucose 6 phosphate inhibits regulates hexokinase Step 2 a The enzyme is also called phosphohexoseisomerase the carbonyl oxygen in G6P is shifted from C1 to C2 an aldose to a ketose isomerization The next step 3 is Phophorylation at C1 and the hemiacetyl OH group of glucose would be harder to phosphorylate compared to the primary OH group in fructose b Not much is happening here Step 3 a Adds 2 phosphate groups onto fructose b Bis 2 phosphate groups on difference carbon atoms c Di 2 phosphate groups on the same carbon atom ex adenosine diphosphate d Irreversible e Enzyme activated by AMP and ADP f ATP is a universal inhibitor of glycolysis g ATP is a substrate for phosphofructokinase as well as an inhibitor Step 4 a This step is why the process is called glycolysis because of the lysis splitting of the F1 6bisphosphate b Splitting catalyzed by aldolase c This is the step where breaking down happens lyse reaction as it breaks down a 6 carbon compound into two 3 carbon compounds d Not exothermic Step 5 a In the presence of the enzyme TPI dihydroxyacetone phosphate gets converted into glyceraldehyde 3 phosphate IX X b Started with one glucose and ended up with 2 molecules of glyceraldehyde 3phosphate by the end of step 5 Step 6 a This is the start of the energy payback stage b Generation of the reducing agent NADH 2 molecules of NADH generated c The source of NADH is NAD d NAD is reduced to NADH e NADH is an electron carrier a reduced form of NAD f Always an oxidation reaction coupled with reduction reactions g Only enzyme in this process involved in oxidation phosphorylation reactions is glyceraldehyde 3 phosphate dehydrogenase h This is the only step where both oxidation and phosphorylation adding phosphate group from inorganic molecule are occurring i NADH can donate its electrons later on in the process Step 7 a 1 3 bisphosphoglycerate is a very high energy molecule b Substrate level phosphorylation c Here the ATP is made d 3 ways ATP can be formed in cells substrate level oxydative phosphorylation and photo phosphorylation in plants e Phosphoglycerate kinase f Broken even two ATP that was consumed has now being generated back g Standard free energies of hydrolysis of some phosphorylated compounds h This is the first step where we get energy back
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