Chapter 6 - Energy Transfer in the Body Flashcards
What is the Energy Currency of the Body?
- ATP
What provides major sources of potential energy?
- Macronutrients
How does ADP form?
- When ATP joins with water
What enzyme catalyzes the reaction of ATP and Water to form ADP?
- Adenosine Triphosphatase (ATPase)
What are the Cells’ two major energy-transforming activities?
- Extract potential energy from food/conserve it within ATP bonds
- Extract/transfer chemical energy in ATP to power biological work
How much ATP does the body store at resting condition?
- 80-100g ATP
How long can resting stores of ATP in the body provide energy?
2-3 seconds of Maximal Exercise
What ways can the mitochondria produce ATP?
- Citric Acid Cycle
- Respiratory Chain (Aerobic)
- Pyruvate from glucose
- Some deaminated amino acids
What ways for ATP production occur in the Cytosol?
- Glycolysis (Anaerobic)
- Phosphocreatine
- Glucose/Glycogen
- Glycerol
- Some Deamniated Amino Acids
Where does Aerobic ATP production occur?
- Mitochondria
Where does Anaerobic ATP production occur?
- Cytosol
Where does ATP production from phosphocreatine occur?
- Cytosol
What happens with the anaerobic splitting of a phosphate from Phosphocreatine?
- ATP resynthesis
How much Phosphocreatine do cells store compared to ATP?
- 4-6 times
How long can Phosphocreatine provide energy for?
- around 10s
What does Adenylate Kinase Reaction represent?
- single-enzyme mediated reaction for ATP
Where does most energy for phosphorylation derive from?
- Carbohydrates
- Lipids
- Protein
What do oxidation reactions do?
- Donate electrons
What do Reduction reactions do?
- Accept Electrons
What constitutes the biochemical mechanism that underlies energy metabolism?
- RedOx Reactions (oxidation - reduction)
What do redox reactions provide from catabolism of stored macronutrients?
- Hydrogen Atoms
What are the energy factories in the mitochondria? What do they do?
What
- Carrier Molecules
Do
- Remove electrons from hydrogen (oxidation)
- Pass them to oxygen (reduction)
- Synthesis ATP
Are hydrogen atoms turned loose in intracellular fluids during cellular oxidation?
- NO
What catalyze’s hydrogen’s release from the nutrient substrate?
- substrate-specific dehydrogenase enzymes
What accepts pairs of electrons from hydrogen?
- coenzyme component of the dehydrogenase
What happens when Nicotinamide Adenine Dinucleotide (NAD+) gains hydrogen and two electrons?
-Reduces to NADH
What happens to the other Hydrogen when one pairs with NAD+?
- Appears in the cell fluid as H+
How many electrons does Flavin Adenine Dinucleotide accept?
- Two
What are NAD+ and FAD?
- Electron Acceptors
What are Cytochromes?
- A series of Iron-protein electron carriers dispersed on the inner membranes of the mitochondrion
What is a bucket brigade?
- Passing of electrons carried by NADH and FADH2 down the Cytochromes
What represents the final common pathway where electrons extracted from hydrogen pass to oxygen?
- Electron Transport
What drives the respiratory chain? How?
Oxygen
- serving as final electron acceptor to combine with hydrogen to form water
What happens for each pair of hydrogen atoms that reach the cytochrome?
- Two Electrons flow down the chain and reduce to one atom of oxygen
What is released during the passage of electrons down the chain?
- Enough energy to re-phosphorylate ADP to ATP`
How does oxidative phosphorylation synthesize ATP?
- Transfer of electrons from NADH and FADH2 to oxygen
How much ATP synthesis occurs in the respiratory chain by oxidative reactions coupled with phosphorylation?
- 90%
How many coupling sites during the electron transport does energy transfer from NADH to ADP to reform ATP?
- three distinct places
Why do only 2 ATP molecules form for each hydrogen pair oxidized from FADH2?
- FADH2 enters respiratory chain at lower energy level
- Beyond point of first ATP synthesis
What is the result of shuttling hydrogen in the electron transport chain requiring energy?
On Average
- NADH produces 2.5 ATP
- FADH2 produces 1.5 ATP
How much energy does 1 mole of ATP formed from ADP + P conserve?
- 7kcal energy
What is the relative efficiency level for harnessing chemical energy via the electron transport oxidative phosphorylation?
- 34%
What is created by electron transport energy-releasing reactions in the mitochondria?
- Proton (H+) gradient across the inner mitochondrial membrane
What provides the electrochemical basis for coupling electron transport to oxidative phosphorylation to form ATP?
- Stored energy in the inner mitochondrial membrane
What three prerequisites exist for continual re-synthesis of ATP during coupled oxidative phosphorylation?
- Tissue availability of NADH and FADH2
- Presence of oxygen in tissue (oxidizing agent)
- Sufficient concentration of enzyme and mitochondria to ensure energy transfer reactions proceed at appropriate rate