Biochemistry 1 Flashcards
Describe stored ATP
-stored in small amounts in the body (80-100g)
-immediate energy source
What is creatine phosphate used for?
-converts ADP back to ATP by direct phosphorylation
-immediate muscle energy store
-CP stores are limited -not effective in providing enough ATP
Define creatine kinase
an enzyme that catalyses direct phosphorylation
Where is CK found?
-found inside healthy muscle
-muscle damage causes CK to be lost into the blood stream
What is CK a marker for?
Myocardial infarction
define glycogenolysis
breakdown of glycogen stored in muscle or liver
Define gluconeogenesis
formation of glucose from other nutrients in the liver
what is the equation for the complete catabolisim of glucose?
C6H12O6 + 6O2
→ 6H2O + 6CO2 + 38 ATP + heat
Name the 3 linked metabolic pathways involved in the complete catabolism of glucose
-glycolysis
-krebs cycle
-Electron transport chain
describe the overall process of glycolysis
1) glucose is broken down into 2 pyruvic acid molecules in the cytoplasm
2)uses 2 ATP to activate the glucose, forms 4 ATP through pathway- Net gain of 2 ATP
3) intermediate metabolites are oxidised
H+ and e- are removed and picked up by a carrier NAD+ which is converted to 2NADH + H+
Describe the anaerobic outcome of glycolysis
in a lack of O2- pyruvic acid is converted to lactic acid-leads to muscle fatigue and acidosis
NADH+ H+ converted back to NAD+ anaerobic pathway- overall production of 2 ATP per glucose molecule
Describe the aerobic outcome of glycolysis
-in enough O2
-Pyruvic acid enters mitochondria for the krebs cycle
-potential production of 38ATP molecules per glucose molecule
Describe the transition process from pyruvate dehydrogenase to acetyl-co enzyme A
-pyruvate dehydrogenase converts each pyruvate into acetyl-coenzyme A
-redox reaction-hydrogens are removed, oxidation of pyruvate, picked up by NAD+ which is reduced to NADH + H+
1c removed as cO2 waste
Where does krebs cycle occur?
mitochondria
Describe the products when each acetyl-CoA enters the krebs cycle
-carbon atoms removed as CO2 waste
-3NAD+ are reduced to 3 NADH+H+
-another carrier FAD is reduced to FADH2
What is phase 1 of glycolysis?
-sugar activation
-glucose is activated by phosphorylation and converted to fructose-1-6-bisphosphate
What is phase 2 of glycolysis?
-sugar cleavage
-fructose-1-6-bisphosphate is cleaved into two 3-carbon fragments
What is phase 3 of glycolysis?
-sugar oxidation and formation of ATP
-the 3 carbon fragments are oxidised by removal of hydrogen and 4 ATP molecules are formed
Where does glycolysis occur?
cytosol
Define oxidation
addition of oxygen,removal of hydrogens and electrons
Where is NAD and FAD derived from?
NAD- derived from the B vitamin niacin
FAD-derived from the B vitamin riboflavin
What are the equations for NAD and FAD in there oxidized and reduced from?
NAD+ + 2H –> NADH + H+
FAD + 2H —> FADH2
lhs-oxidized form
rhs-reduced form
where does oxidative phosphorylation occur?
Via the elctron transport chain
Describe the events that occur in oxidative phosphorylation
1) NADH + H+ and FADH2 pass on their hydrogens and high energy e- to O2 as the final acceptor producing H2O
2) linked to high ATP production
3) Each NADH + H+ carriers leads to 3 ATP production
4) each FADH2 carrier leads to 2 ATP formed
NAD+ and FAD are regenerated at the same time so can accept another lot of e-/H+
what is the ETC?
e- are transferred from complex to complex and some of their energy is used to pump protons into the intermembrane space, creating a proton gradient
What is chemiosmosis?
ATP synthesis is powered by the flow of H+ back across the inner mitochondrial membreane through ATP synthase
How is CO2 produced in the catabolism of glucose?
-produced in the conversion of pyruvate to acetyl-COA and oxidation of acetyl-COA via the kreb cycle
Describe the catabolism of lipids
-glycerol can enter glycolysis, and if enough O2 is available, itll carry on into krebs and ETC
describe how the 3 fatty acids that have 16c-18c are split up
2c split through a series of enzymatic reactions called beta-oxidation in the mitochondria
each 2c is coverted to acetyl-CoA
if enough O2 full catabolism of fat will occur through Kreb’s cycle and ETC
When does ketoacididosis happen?
-high fat use, acetyl CoA converted to ketones, blood becomes acidic, due to reduced availability of carbohydrates
-low CHO
-starvation
-uncontrolled diabetes mellitus
What are the effects of ketoacidiidosis?
-kussmauls respiration
-ketone breath
-ketones in urine
-eventually coma
Describe the catabolism of protein
-used when other sources are unavailable, or during prolonged excersise
1) in the liver, NH2 is removed from AA= deamination. NH2 converted to NH3 then to urea
2)Remaining part of molecules may be converted to pyruvic acid or acetyl CoA
-carry on krebs and ETC
Define Respiratory exchange ratio
used to determine the predominant energy source being used
oxygen consumed: CO2 produced
