Carbohydrates and lipids Flashcards
What defines a lipid?
Lipids are generally water-insoluble, hydrophobic molecules. They can also be amphipathic, containing both polar and non-polar regions.
What are the main types of fatty acids?
Saturated: No C=C bonds. Unsaturated: At least one C=C bond; includes monounsaturated (1 C=C) and polyunsaturated (>1 C=C).
What are essential fatty acids?
Linoleate (18:2 ∆9,12) and Linolenate (18:3 ∆9,12,15) cannot be synthesized by the body.
What are triacylglycerols?
Molecules with three fatty acyl residues joined to glycerol. Serve as energy storage and form fat droplets in cells.
What are fatty acid derivatives used for?
Prostaglandins, thromboxanes, and leukotrienes act as chemical mediators in inflammation and clotting.
What is ATP and its primary function?
ATP (adenosine triphosphate) is the universal energy currency in cells. Drives metabolism by shifting equilibrium in unfavorable reactions.
What makes ATP energy-rich?
The presence of two phosphoanhydride bonds, which release significant energy upon hydrolysis.
What is the ATP-ADP cycle?
ATP is hydrolyzed to ADP and AMP, releasing energy. Regeneration of ATP from ADP ensures a continuous energy supply.
What enzymes interact with ATP?
Kinases: Add phosphate groups. Phosphatases: Remove phosphate groups.
How much ATP is turned over daily?
Approximately 40 kg per day, with higher rates during exercise.
What are carbohydrates?
Biological molecules with the general formula Cn(H2O)n. Serve structural (e.g., cellulose) and energy roles (e.g., glycolysis).
What are monosaccharides?
Simple sugars like glucose, galactose, and fructose. Classified by the number of carbons: triose (3), pentose (5), hexose (6).
What is a condensation reaction?
The process where two monosaccharides combine, losing a water molecule, to form disaccharides.
What is stereochemistry in carbohydrates?
Chirality of sugars influences enzyme recognition. D-sugars are naturally occurring; L-sugars are rare.
What is the significance of anomeric carbons?
The orientation (alpha or beta) of the hydroxyl group at the anomeric carbon determines sugar properties.
What are diastereoisomers and enantiomers?
Enantiomers: Mirror images, not superimposable (e.g., D-glucose and L-glucose). Diastereoisomers: Differ at multiple chiral centers but are not mirror images.
What are the roles of aldohexoses and ketohexoses?
Aldohexoses (e.g., glucose) contain an aldehyde group. Ketohexoses (e.g., fructose) contain a ketone group.
