B1.1 Carbs & Lipids Flashcards
Why is carbon important in biology?
forms stable covalent bonds, enabling complex molecules
What structures can carbon form?
Chains, rings, and branched molecules (co
What is a hydrocarbon?
A molecule made of only carbon and hydrogen (often used as an energy source)
What are macromolecules?
Large biological molecules (carbs, lipids, proteins and nucleic acids).
What is a monomer?
A small molecular unit that forms polymers
What reactions forms polymers?
Condensation (removes water)
What reaction breaks polymers?
Hydrolysis (adds water)
What elements compose carbs
C,H,O (1:2:1 ratio)
What are monosaccharides?
Signle sugar moeculers that provide immediate energy (glucose, fructose, galactose)
What are disaccharides?
Two monosaccharides joined by a glycosidic bond via condensation (e.g sucrose = glucose + frucrtose, maltose = glucose + glucose)
What are polysaccharides?
Long chains of monosaccharides used for energy storage or structurall support (starch, glycogen and cellulose)
What is the function of starch?
Energy storage in plants, made of α-glucose
What is the function of glycogen?
Energy storage in animals and fungi, stored in liver and muscle cells; highly branched for rapid glucose release
What is the function of cellulose?
Structural support in plant cell walls, composed of β-glucose, forming strong fibres resistant to digestion
What are glycoproteins?
Proteins with carbohydrate chains attached, involved in cell communication and immune response
What are the functions of glycoproteins?
Cell recognition, immune defence, hormone receptors and. ell signalling in the plasma membrane
What are lipids?
Hydrophobic molecules made of C,H,O including fats, oils, steroids and phospholipids
What are the functions of lipids?
Long-term enrgy storage, insulation, protection, and cell membrane structure (phospholipids)
What is a triglyceride?
A glycerol molecule + 3 fatty acids, formed via ester bonds in a condensation reaction
What is the difference between saturated and unsaturated fats?
Saturated fats have no double bonds (solid at room temp, e.g butter)
Unsaturated fats have double bonds (liquid at room temp, e.g olive oil)
What are trans fats?
Artificially hydrogenated unsaturated fats that raise LDL (bad cholesterol) and increase heart disease risk
What is a fatty acid?
A long hydrocarbon chain with a carboxyl group (-COOH) at one end; major component of lipids
What are omega-3 and omega-6 fatty acids?
Essential fatty acids (cannot be synthesised by the body):
Omega-3 (double bond at carbon 3) = found in fish, reduces inflammation
Omega-6 (double bond at carbon 6) = found in veg oils, supports brain function
What are phospholipids?
A glycerol backbone, two fatty acids, and a phosphate group; key component of cell membranes
Why do phospholipids form bilayers?
Hydrophilic phosphate heads face water, while hydrophobic fatty acid tails avoid water, forming a bilayer
What is the role of cholesterol in membranes?
Regulates membrane fluidity, preventing it from becoming too rigid or too fluid
