Lecture 2 (Exam 2) Flashcards
Hydrolysis
the chemical breakdown of a compound due to reaction with water
Phosphorylation
the addition of a phosphate group (PO4) to a molecule
Phosphocreatine
an energy-rich compound that plays a critical role in providing energy for muscle action by maintaining ATP concentration
Oxidation
removing an electron
Reduction
addition of an electron
Redox potential
the ratio of NAD+ to NADH
-continues glycolysis
Oxidative Phosphorylation
mitochondrial process that uses oxygen and high-energy electrons to produce ATP and water
-ATP is generated from oxidation of NADH, FADH2, and subsequent transfer of electrons and pumping of protons (generates electrochemical gradient required to power ATP synthase)
Cori cycle
- Lactate is transferred back to the liver
2. In the liver, lactate is reconverted into pyruvate (pyruvic acid) then into glucose through glycogenesis
3 phases of Oxidative Phosphorylation
- Everything funnels to Acetyl-CoA
- Isocitrate Dehydrogenase: important enzyme in Krebs
- More NADH and FADH2 are produced BUT not used in Krebs used later in the ETC
Alanine Cycle
liver converts alanine into pyruvate
Beta-Oxidation
FFA’s travel through the blood to muscle fiber and are broken down by enzymes in the mitochondria into acetic acid, which is converted to acetyl CoA
3 ATP synthesis pathways and where they are performed within skeletal muscle
1) ATP-PCr system (anaerobic, cytoplasm)
2) Glycolytic system (anaerobic, cytoplasm)
3) Oxidative system (aerobic, mitochondria)
How does the Phosphagen System operate? (ATP-PCr system)
- short-term anaerobic energy system that maintains ATP levels
- can prevent energy depletion by quickly regenerating ATP from ADP
- Pi donation from PCr to ADP to form ATP
(energy system used during an all-out sprint for 10 seconds)
Phosphagen System’s Formula (products, substrates, and enzymes)
PCr + ADP ————Creatine Kinase———-> ATP + Cr
How does Creatine Kinase (CK) control rate of ATP production?
-Negative feedback system
When ATP levels decrease (ADP increase), CK activity increases
When ATP levels increase, CK activity decreases
Phosphofructokinase (PFK) and its effect on it’s energy pathway
rate-limiting enzyme in the glycolytic pathway
- as ATP decreases (ADP and Pi increase), PFK increases; which speeds up glycolysis
- as ATP increases, PFK decreases; which slows glycolysis
Creatine Kinase (CK) and its effect on it’s energy pathway
- enzyme that releases energy from PCr, which acts on PCr to separate Pi form creatine
- the energy released can then be used to add a Pi molecule to an ADP molecule, forming ATP
When ATP levels decreases (ADP increases), CK activity increases
When ATP levels increase, CK activity decrease
Hydrogen Carriers
NAD: Nicotinamide adenine dinucleotide
FAD: Flavin adenine dinucleotide
Hydrogen carriers purposes
Transfer of hydrogens and associated electrons to:
- the mitochondria to generate ATP (aerobic)
- convert pyruvic acid into lactate acid (anaerobic)
Purpose of Electron Transport Chain (ETC)
to convert the hydrogen ion generated by glycolysis and the Krebs cycle into water and produce energy for oxidative phosphorylation
2 sources of fat utilized for energy relase
Triacylglycerol in fat cells (adipocytes) Intramuscular triacylglycerol (triglyceride)
Pathway of fat metabolism
oxidative pathway
How is lactate utilized by the body? (3)
- Lactate produced in the cytoplasm can be taken up by the mitochondria of the same muscle fiber and oxidized
- Lactate can be transported via MCT transport proteins to another cell and oxidized there (lactate shuttle).
- Lactate can recirculate back to the liver, reconverted to pyruvate and then to glucose through gluconeogenesis. (Cori Cycle)
Relation between the 3 energy systems
they interact for all activities
- although one system might be dominant, the other two provide a small portion of the energy needed
- e.g. ATP-PCr system is dominant during a 10s sprint with a small amount of help from glycolytic and oxidative systems. Vis versa, oxidative is dominant during a 30min 10k, but both ATP-PCr and glycolysis contribute some energy
Energy Systems (3)
ATP-PCr
Glycolytic (Glycolysis)
Oxidative (from carbs or from fat)
Products, Substrate, and Major Regulators of Glycolysis Phase 1 & 2
Products: NADH, NAD+, pyruvic acid, lactic acid
Substrate: Carbs
Regulators: Phosphofructosekinase and Pyruvate Kinase
Products, Substrate, and Major Regulators of the Krebs Cycle
Products: 3 NADH, 1 FADH2
Substrate: Carbs and Fats
Regulators: ATP, NADH, ADP (???????)
Products, Substrate, and Major Regulators of Electron Transport Chain (ETC)
Products: 2.5 ATP’s per NADH, 1.5 ATP’s per FADH2
Substrate: Protein
Regulators: ADP, ATP
3 Steps of breaking down glucose
- Glycolysis
- Krebs Cycle
- Electron Transport Chain
