Metabolism 1 & 2 Flashcards
What is anabolism (3)
- Synthesis of cell parts, storage and structural macromolecules from low molecular weight compounds
- Endergonic
- △G = +ve
What is Catabolism (5)
- Foodstuffs storage macromolecules → low molecular weight compounds (Stage 1)
- Foodstuffs storage macromolecules → CO₂, H₂O & nitrogen end-products (Stages 2+)
- △G = -ve and large
- Exergonic
- Stages 2 & 3 catabolism → energy transfer systems (stage 4 catabolism)
What is stage 1 catabolism (3)
- Carbohydrates → glucose + other monosaccharides
- Lipids → fatty acids + glycerol
- Proteins → amino acids
What is stage 2 catabolism (3)
- Glucose → glycolysis → pyruvate → acetyl coenzyme A (aerobic/anaerobic)
- Fatty acids → fatty acid cycle → acetyl coenzyme A (beta-oxidation)
- Amino acids → amino acid cycle → acetyl coenzyme A→ Krebs cycle intermediate
What is stage 3 catabolism (2)
- Acetyl coenzyme A → Krebs cycle
- Aerobic conditions only
What is stage 4 catabolism
Electron transport chain → ATP synthesis from ADP via oxidative phosphorylation
How are phosphates used as energy transfer systems (2)
- Phosphoenolpyruvate + H₂O → pyruvate + phosphoric acid (high energy phosphate)
- Glucose-6-phosphate + H₂O → glucose + phosphoric acid (low energy phosphate)
What is ATP (5)
- Adenosine triphosphate
- Stores energy from aerobic respiration
- In all living cells
- Universal energy currency
- Required for energy-required activities
How is ATP broken down
- ATP + H₂O → ADP + phosphoric acid
- ADP + H₂O → AMP + phosphoric acid
- AMP + H₂O → adenosine + phosphoric acid
What is the structure of ATP (3)
- Adenosine = N-containing heterocyclic base (adenine) - attached to C1 of ribose sugar
- Ribose sugar
- Connected to C5 (O⁻) of ribose sugar is the triphosphate
What is oxidation (3)
- Loss of electrons
- Gain oxygen
- Loss of hydrogen
What is reduction (3)
- Gain of electrons
- Loss of oxygen
- Gain of hydrogen
What is NAD (3)
- Nicotinamide adenine dinucleotide
- Adenosine N-containing heterocyclic base (adenine) + ribose + diphosphate + ribose + Nicotinamide ring (+ charge on N)
- Nitrogen in the nicotinamide ring contains + charge giving NAD⁺
How is NAD⁺ converted to NADH
+ charge on N accepts 1 electron and 1 hydrogen forming NADH (reduction)
What is FAD (3)
- Flavin adenine dinucleotide
- Adenosine N-containing heterocyclic base (adenine) + ribose + diphosphate + open ribose + flavin
- flavin is a fused tricyclic system
What is a dinucleotide
2 sugars + phosphate + base
How is FAD converted to FADH₂ (2)
- Middle Nitrogen + double bond + single bond double bond + nitrogen (zigzag shape) accepts electrons and hydrogens
- Can accept 2 electrons and 2 hydrogens (reduction)
What happens when NADH and FADH₂ are oxidised → NAD⁺ and FAD (4)
- Lose hydrogen(s) and electron(s)
- Forces electron transport chain to synthesise ATP from ADP
- 3 ATP formed from NADH
- 2 ATP formed from FADH₂
How is metabolism a series of interrelated reactions (3)
- When ATP is required the electron transport chain goes into action - stage 4
- The electron transport chain requires The Citric acid cycle/Krebs cycle - stage 2 & 3
- The Citric/Krebs cycle requires acetyl Co-A from Fatty acids (fatty acid cycle beta oxidation), carbohydrates (Glycolysis) and Proteins (amino acid cycle) - Stage 1
What enzymes control metabolism (5)
- Kinases
- Phosphatases
- Mutases
- Isomerases
- Dehydrogenases
