Introduction to Carbohydrates and Glycolysis Nicole Catterlin P

Introduction to Carbohydrates and Glycolysis Nicole Catterlin, P 3 Howard University ACSEP 2015: Biochemistry

Basic Metabolism ● Anabolism: Build Up o Gluconeogenesis, DNA replication, Protein synth o “Anabolic Steroids” ● Catabolism: Break Down o dissolving lipids and sugar for energy, breaking down amino acids for nitrogen o “Cataclysm” Remember: Ana and her silly pet Cat IMAGE

Basic Metabolic Cofactors ● In order to transform substrates into products, certain molecules are needed to: o o accept/donate energy accept/donate functional groups ● ATP is the “currency” of the cell High energy stored in two tri-phosphate bonds ATP ➡ ADP ➡ AMP (a dud, with no more phosphate bonds to break) o ATP is spent to charge molecules about to undergo transformation o o

Basic Metabolic Cofactors ● NAD+/NADH high energy electron carrier: accepts/donates an H where needed o redox cofactor (both reduces and oxidises molecules) o ● Acetyl-Co. A o o o Acetyl Coenzyme A transports and attaches R (carbon) groups important in the citric acid cycle and lipid metabolism

NADH

Acetyl-Co. A

Finally… What are Carbohydrates? ● Carbohydrates are polymers of sugar molecules C 6 H 12 O 6 Carbo (carbon) - hydrates (water) o Great source of quick energy o Easily stored o Primary source of energy for the brain o

Monomers, Dimers and Trimers

Types of Carbohydrates ● Simple table sugar (sucrose), starch, grains, cereals, pasta § ANYTHING YOU LOVE AND CRAVE o broken down to glucose quickly, produces “sugar rush” o ● Complex o o Fruits, vegetables, legumes, chickpeas broken down more slowly, provides more prolonged energy

Glycolysis ● Glycolysis is the process of breaking glucose molecules (monomers) down for energy “glucose cutting” -- literally cuts the sugar in half Occurs in cell cytoplasm anaerobic § does not require oxygen o Products: 2 NADH+, 2 ATP, 2 Pyruvate o o o ● Considered the basic metabolic pathway to our survival (and biochemists)

Glycolysis

Steps of Glycolysis ● Glucose is phosphorylated o Glucose + ATP ➔ Glucose-P + ADP (via Hexokinase) ● Glucose (6 member ring) is isomerized into fructose (5 member ring) o Glucose-6 -P ➔ Fructose-6 -P (via phosphoglucoisomerase) ● Another P is added o Fructose-6 -P ➔ Fructose 1, 6 bisphosphate (via Phosphofructokinase)

Steps of Glycolysis ● Fructose 1, 6 bisphosphate is split into two molecules o Fructose 1, 6 bisphosphate ➔ Dihydroxyacetone-phosphate and glyceraldehyde phosphate (via aldolase) o These two molecules are isomers of each other o GA-P will be used; DHA-P will be converted to GA-P o Results: 2 GAP molecules, ready for next step

Steps of Glycolysis: Split Path (x 2) ● 1 Glyceraldehyde donates an H to NAD+ and receives another P, resulting in 1, 3 bisphoglycerate (via triose phosphate dehydrogenase) ● P is then cleaved off 1, 3 bisphoglycerate and transferred to an ADP, creating ATP and 3 phosphoglycerates (via phosphoglycerokinase) ● Phosphoglyceromutase swaps the P from the 3 rd position to the 2 nd position, creating 2 phosphoroglycerate

Steps of Glycolysis: Split Path (x 2) ● Water is removed from 2 -phosphoglycerate, forming phosphoenolpyruvic acid (via enolase) ● The last P is chopped off of PEP and transferred to an ADP, resulting in ATP and Pyruvic acid (via pyruvate kinase) ● END PRODUCTS: o Single Path: 2 ATP spent charging Glucose and fructose-6 -phosphate o Split Path: 1 NADH and 1 ATP from triose phosphate dehydrogenase (x 2) o 1 ATP from pyruvate kinase (x 2) o Total End Products: 4 ATP gained, 2 NADH gained, 2 ATP spent o 2 ATP, 2 NADH, 2 Pyruvate molecules § The two molecules of pyruvate are more important than they look. . .

Self-Synthesized Glucose ● Gluconeogenesis o generation of glucose from non-carbohydrate precursors o Why glucose? § easily accessible § easily stored, easily transportable § simplest sugar we can metabolize quickly, number one source of energy for the brain

Glycolysis vs Gluconeogenesis ● If glycolysis breaks down glucose, can’t you just reverse the pathway to make glucose? NO! there are irreversible steps in glycolysis § irreversible steps “commit” an molecule to a pathway and help with overcoming energybarriers § think of it like a Save-Point in a video game o therefore, you need different enzymes to perform the reverse reaction o o

● Glycolysis and Gluconeogenesis use different enzymes for all reactions dealing with phosphate ○ Transferring a P to a molecule, cutting a P off a molecule and grafting it onto ADP ● It also costs more ATP to make glucose than glucose produces in glycolysis

What Follows Glycolysis? ● End Products of Glycolysis 2 NADH, 2 ATP, 2 Pyruvate 2 ATP = pure energy 2 NADH = 6 ATP (via Oxidative Phosphorylation) 2 Pyruvate continue into the Citric Acid Cycle, which produces far more energy than the pathway that created it o We will cover TCA next week o o

Metabolism: Feedback Cycles ● Are all of these pathways turned on all the time? o No: our bodies need to distribute and control resources, so pathways are only “activated” when needed ● All pathways overlap o o o Remember the terrifying Biochemistry Pathway poster? multiple molecules are used multiple ways pathways borrow molecules from each other, OR vital-to-life molecules are made from pathway intermediates population of these double-use intermediates must be carefully controlled because they are needed in two locations

What I want you to know: ● ● ● What are the two components of metabolism? What are some cofactors that play a part in metabolic pathways? What is Glycolysis? What are the end-products of glycolysis? Why can’t glycolysis and gluconeogenesis be exactly the same, except reversed?

Sources ● ● ● ● ● Glycolysis: http: //study. com/cimages/multimages/16/Glycolysis. jpg Glycolysis vs Gluconeogenesis: http: //www. qualityinvention. com/library. Picture/gluconeogenesis. jpg Glycogen synth: https: //classconnection. s 3. amazonaws. com/955/flashcards/960955/jpg/picture 61324243272076. jpg NADH: https: //classconnection. s 3. amazonaws. com/838/flashcards/2220838/jpg/nad_nadh-13 F 207 A 9 D 05110 DD 70 E. jpg Acetyl COA: http: //bio 1151. nicerweb. com/Locked/media/ch 09/09_10 Pyruvate. To. Acetyl. Co. A_L. jpg Disaccharides: http: //courses. bio. indiana. edu/L 104 -Bonner/F 11/images. F 11/L 2/Sugars. jpg single sugar: http: //teacherweb. com/MS/Rosa. Scott/Biochemistry. Web. Quest/carbohydrate-sucros. gif aldolase: http: //upload. wikimedia. org/wikipedia/commons/0/0 a/Fructose-1, 6 -diphosphate_breaking_(by_aldolase). png Glycolysis energy map: http: //course 1. winona. edu/kbates/Bio 241/images/figure-07 -10. jpg