Chapter 5: Cellular Respiration and Metabolism Flashcards
Define metabolism.
All rxns in body that involve energy transformations
- requires oxidation-reduction rxns (transfer of e-)
- cellular respiration is the metabolic pathway in which ATP is produced
Define catabolism.
Breaks down molecules and releases energy
- Primary source of energy for making ATP
Define anabolism.
Makes larger molecules and requires energy
- Source of body’s large energy-storage compounds
Discuss glycolysis.
- metabolic pathway by which glucose is converted into 2 pyruvates (pyruvic acid)
- Does not require O2
- Glucose is stored as glycogen in the liver; liver releases it into the blood stream where it’s glucose which enters the cells and is phosphorylated
- From here glycolysis occurs in cytoplasm of the cell
- 4 ATP are generated but 2 are used to drive the equation therefore NET production of glycolysis is:
2 ATP
2 NADH’s
2 Pyruvates
Be able to draw this
Discuss phosphorylation.
- the addition of a phosphate group which traps glucose inside the cell
Discuss the lactic acid pathway.
- Occurs in anaerobic conditions
- NADH’s produced in glycolysis need to give away their H’s
- If O2 is not present to take the H’s (and convert to H2O) NADH gives its H’s to pyruvate which creates lactic acid
- Only yields a net gain of 2 ATP per glucose
- Occurs in skeletal and cardiac muscle for short time periods
- angina pectoris - chest pain because cardiac muscle needs more O2 than what is being supplied
Differentiate between glycogenesis and glycogenolysis.
Glycogenesis: formation of glycogen
- i.e. glucose made into glycogen to be stored in the liver and muscles
Glycogenolsis: break down of glycogen
- i.e. clips glucose out of glycogen making glucose 6 phosphate for glycolysis or free glucose that be secreted into the blood stream
Define gluconeogenesis.
production of glucose from non-carbohydrate molecules (non-glucose sources) like lactic acid, amino acids
- occurs when amino acids or other non-cargo’s are converted to leto acids, then pyruvates, then glucose
- Cori Cycle
Define lipogenesis
Formation of triglycerides (fat).
- Acetyl CoA can be linked together to form fatty acids
- fatty acids + glycerol = fat
Define lipolysis.
- Breakdown of triglycerides (fat) into fatty acid and glycerol
- Acetyl CoA from free fatty acids serves as major energy source for many tissues
Define ketogenesis.
Formation of ketone bodies which are 4-carbon-long organic acids, from fatty acids
Discuss the Cori Cycle.
- Opposite rxn of the Lactic Acid Pathway.
- Lactic acid is converted to pyretic acid which can be put into Krebs cycle
- An example of gluconeogenesis
Discuss Krebs Cycle. (aka Citric Acid Cycle)
- Be able to draw it!
- Occurs in the mitochondria
- pyruvic acid enters mitochondria, Acetyl CoA combines with Oxaloacetic acid to form citric acid
- series of rxns occur converting critic acid back to oxaloacetic acid and in the process it releases CO2 and forms:
3NADH
1 FADH2
1 ATP - Krebs cycle can be turned twice per glucose molecule (because 2 pyruvates come out of 1 glucose so double the numbers above for “per glucose”)
- NADH and FADH2 carry electrons to electron transport chain (ETC)
Discuss the electron transport chain (ETC).
- a linked series of proteins on the folds of the mitochondria
- NADH and FADH2 are oxidized (give away their H’s)
- the H+ gets passed along the chain in a series of oxidation and reduction rxns
- energy is used to phosphorylate ADP to make ATP (this is called oxidative phosphorylation)
- at the end of the ETC, O2 will pick up the H+ and make H2O
- Can pump 10 H+ for every NADH and 6 H+ for every FADH
= 2.5 ATP for NADH and 1.5 for FADH - Gross ATP production 36-38 but NET 30-32
Discuss ATP formation. (2 ways)
- Direct (substrate-level) phosphorylation
- ATP generated when bonds break (2 from krebs + 2 from glycolysis = 4 ATP) - Oxidative Phosphorylation
- ATP generated by ETC = 26 ATP’s
Net production of ATP = 30 for each glucose
