3.2 Carbohydrates, Lipids, Proteins
Terms in this set (7)
3.2.1 Distinguish between organic and inorganic compounds.
Compounds containing carbon that are found in living organisms
except hydrogen carbonates (HCO3-), carbonates (CO32-) and oxides of carbon (CO, CO2) are regarded as organic.
Inorganic compounds are by default are all the molecules other than those in the category above.
3.2.2 Identify amino acids, glucose, ribose and fatty acids from diagrams showing their structure.
3.2.3 List three examples each of monosaccharides, disaccharides and polysaccharides.
Monosaccharides: Glucose, Fructose, Galactose, Ribose
Disaccharides: Maltose, Lactore, Sucrose
Polysaccharides: Starch, Glycogen, Cellulose
3.2.4 State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants.
Glucose: Respiratory substrate
Fructose: Fruit sugar
Lactose: Milk sugar
Sucrose: Transported in phloem sap of plants
Glycogen: Storage of glucose in animal cells.
Cellulose: Structure fibres of plant cell wall
3.2.6 State three functions of lipids.
Energy storage in the form of fat in humans and oil in plants.
Heat insulation; A layer of fat under the skin reduces heat loss.
Buoyancy: Lipids are less dense than water so help animals to float.
3.2.7 Compare the use of carbohydrates and lipids in energy storage.
stored as glycogen (in liver);
short-term energy storage;
more easily digested than lipids so energy can be released more quickly;
more soluble in water for easier transport;
stored as fat in animals;
long-term energy storage;
more energy per gram than carbohydrates;
lipids are insoluble in water less osmotic effect;
3.2.5 Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; and between amino acids and polypeptides.
Large molecules such as polypeptides, polysaccharides and triglycerides can be broken down into smaller molecules by hydrolysis reactions.
Water molecules are used up in hydrolysis reactions.
Hydrolysis reactions are the reverse of condensation reactions.