Integrated_Metabolism_Topic10_Indented_Anki Flashcards
(21 cards)
What is the overall pathway of energy conversion in photosynthesis?
Light reactions: Water (12 H₂O) split → 24 e⁻ + 6 O₂; Forms 12 NADPH and 18 ATP.
Calvin Cycle: 6 CO₂ fixed → 2 G3P → Glucose.
What is the overall pathway of energy conversion in cellular respiration?
Glycolysis: Glucose → 2 Pyruvate + 2 NADH + 2 ATP; Pyruvate → Acetyl-CoA: 2 NADH + 2 CO₂; Krebs Cycle (×2): 6 NADH + 2 ATP + 2 FADH₂ + 4 CO₂; ETC: NADH/FADH₂ donate e⁻ → 28 ATP, 12 H₂O formed.
How do chloroplasts and mitochondria compare in energy and proton transport?
Both use ETCs across membranes (thylakoid and inner mitochondrial); H⁺ pumped into lumen (chloroplast) or intermembrane space (mitochondria); ATP synthase uses proton gradient for ATP production; ATP:ADP exchange across membranes occurs in both.
What is PFK-1 and why is it important?
PFK-1 = Phosphofructokinase-1; Catalyzes F6P → F1,6BP (uses ATP); Key regulatory step in glycolysis (rate-limiting); Allosterically regulated by activators: AMP, ADP and inhibitors: ATP, citrate.
What is thermogenin (UCP-1), and where is it found?
Uncoupling protein that generates heat (instead of ATP); Found in brown fat of mammals and some plants (e.g., skunk cabbage); Important in hibernation and thermoregulation; Present in mitochondria → allows H⁺ leak, bypassing ATP synthase.
Why do reptiles need less energy than birds?
Reptiles need ~10% the energy birds require per gram of body weight because they are cold-blooded and don’t generate body heat internally.
How are carbohydrates, fats, and proteins used for energy?
Carbs: → Glucose → Glycolysis; Proteins: → Amino acids → NH₃ removed → enters at multiple points; Fats: → Glycerol (G3P) and Fatty acids → β-oxidation → Acetyl-CoA; All feed into glycolysis, transition step, or Krebs Cycle.
What is β-oxidation? What are its products?
Fatty acids are cleaved sequentially → Acetyl-CoA + FADH₂ + NADH; Each cycle removes 2-carbon units; Occurs in mitochondria or peroxisomes (for long chains).
How many ATP are generated per 16-carbon fatty acid?
Using formula: 8.5 × n - 7; For C16 FA: 8.5×16 - 7 = 129 ATP.
How is ethanol metabolized for energy?
Ethanol is converted directly to Acetyl-CoA; Then enters the Krebs Cycle; Can be used to generate ATP.
How do glucagon and insulin regulate metabolism?
Insulin (β cells): Anabolic → stimulates glycogenesis, glycolysis; Glucagon (α cells): Catabolic → stimulates glycogenolysis, gluconeogenesis.
Which organs uptake glucose without insulin?
Brain, liver, heart; Use GLUT1 and GLUT3 (insulin-independent).
Which tissues require insulin for glucose uptake?
Skeletal muscle (70%) and adipose tissue (10%); Use GLUT4, regulated by insulin.
What are the storage and mobile forms of carbohydrates in plants and animals?
Plants: Storage = Starch; Mobile = Sucrose; Animals: Storage = Glycogen; Mobile = Glucose.
What is the difference between Type 1 and Type 2 diabetes?
Type 1: No insulin production (autoimmune); Type 2: Cells insensitive to insulin; Both result in glucose buildup in blood.
What happens to glucose during exercise?
Muscle cells can take in glucose independently of insulin; GLUT4 is activated by exercise; Irisin hormone released → promotes fat burning (UCP-1 upregulated).
What are the three ways muscle cells produce ATP?
- Aerobic respiration (O₂ present); 2. Glycolysis with fermentation (no O₂); 3. Phosphocreatine system (fast, independent).
What is glycogenesis?
Formation of glycogen from glucose; Enzyme: Glycogenin initiates; Stimulated by insulin.
What is glycogenolysis?
Breakdown of glycogen into glucose; Produces G1P → G6P; Stimulated by glucagon.
What is gluconeogenesis?
Creation of glucose from non-carb sources: Lactate, some amino acids, glycerol; Occurs in liver; ‘Reverse’ glycolysis.
What is the Cori cycle and its role in metabolism?
Converts lactate from muscles → glucose in liver; Cycle: Muscle: Glucose → Lactate → Blood; Liver: Lactate → Glucose → Blood; Recycles during anaerobic activity (e.g. exercise).
