Glycolysis Javed Khan Department of Biotechnology PGCSTR, Jalgaon

Glycolysis Javed Khan Department of Biotechnology PGCSTR, Jalgaon

Metabolism Catabolic reactions: Complex molecules Simple molecules Energy Anabolic reactions: Biosynthetic reactions Simple molecules Energy (in cell) Complex molecules

(Glucose)n Pi Glycogen phosphorylase (Glucose)n-1 Glucose 1-phosphate Glycogen (one unit smaller)

Biosynthetic pathways 1. Biosynthesis of Carbohydrates Biosynthesis of Fatty acids 2. Biosynthesis of Lipids Biosynthesis of Membrane Lipids 3. Biosynthesis of Amino acids

Glycolysis Glucose is converted into two molecules of pyruvate. An anaerobic reaction in cytoplasm. 10 Reactions

Glycolysis Steps [1] – [5] energy investment phase: 2 ATP molecules are hydrolyzed. The 6-carbon glucose molecule is converted into two 3-carbon segments.

Glycolysis Steps [6] – [10] energy-generating phase: producing 1 NADH and 2 ATPs for each pyruvate formed.

Glycolysis Step [1] begins with the phosphorylation of glucose into glucose 6-phosphate, using an ATP and a kinase enzyme.

Glycolysis Step [2] isomerizes glucose 6-phosphate to fructose 6-phosphate with an isomerase enzyme.

Glycolysis Step [3] is the phosphorylation of fructose 6-phosphate into fructose 1,6-bisphosphate with a kinase enzyme.

Glycolysis Overall, the first three steps of glycolysis: 1.2 phosphate groups is added. 2.A 6-membered glucose ring is isomerized into a 5-membered fructose ring. 3. The energy stored in 2 ATP molecules is utilized to modify the structure of glucose

Glycolysis Step [4] cleaves the fructose ring into a dihydroxy-acetone phosphate and a glyceraldehyde 3-phosphate.

Glycolysis Step [5] isomerizes the dihydroxyacetone phosphate into another glyceraldehyde 3-phosphate. Thus, the first phase of glycolysis converts glucose into 2 glyceraldehyde 3-phosphate units and 2 ATP is used.

Glycolysis In step [6] the aldehyde end of the molecule is oxidized and phosphorylated by a dehydrogenase enzyme and NAD ; this produces 1,3-bisphospho-glycerate and NADH.

Glycolysis In step [7], the phosphate group is transferred onto an ADP with a kinase enzyme, forming 3-phosphoglycerate and ATP.

Glycolysis In step [8], the phosphate group is isomerized to a new position in 2-phosphoglycerate.

Glycolysis In step [9], water is lost to form phosphoenol-pyruvate.

Glycolysis In step [10], the phosphate is transferred to an ADP, yielding pyruvate and ATP with a kinase enzyme.

Glycolysis The 2 glyceraldehyde 3-phosphate units are converted into 2 pyruvate units in phase two of glycolysis. Overall, the energy-generating phase forms 2 NADHs and 4 ATPs.

Glycolysis 2 ATPs are used in phase one of glycolysis, and 4 ATPs are made in phase two of glycolysis. The net result is the synthesis of 2 ATPs from glycolysis. The 2 NADHs formed are made in the cytoplasm and must be transported to the mitochondria to join the electron transport chain and make ATP. Overall of glycolysis

The fate of pyruvate under aerobic conditions under anaerobic conditions in fermentation by microorganisms

Aerobic conditions Pyruvate must diffuse across the outer and inner membrane of mitochondria into the matrix. The NADH formed needs O2 to return to NAD , so without O2 no additional pyruvate can be oxidized.