Everything from the 5 lessons of this topic on a few pages: the key idea of each lesson, the diagram to remember, the points to learn and the traps examiners set. Read it, cover it, test yourself.
Each test pairs a reagent with a colour change. Benedict's (heat) goes from blue to a brick-red precipitate with reducing sugars, through green, yellow and orange as the sugar concentration rises. A non-reducing sugar such as sucrose gives a negative Benedict's until it is hydrolysed by boiling with dilute acid and then neutralised. Iodine in potassium iodide turns blue-black with starch, the emulsion test gives a milky-white emulsion with lipids, and biuret turns lilac with proteins. Standardise the Benedict's test and compare with colour standards, and it becomes a way to estimate concentration.
Benedict's must be in excess for the semi-quantitative test. If all the Cu2+ is used up, every concentration above a certain value gives the same brick red, and the test can no longer tell them apart.
If the first Benedict's test is already positive, a colour after hydrolysis proves nothing on its own: you would need a deeper colour (more precipitate) after hydrolysis than before to show a non-reducing sugar was there as well.
Carbohydrates are built from monosaccharides such as glucose (a hexose) and ribose (a pentose). Glucose exists as α-glucose (OH on carbon 1 below the ring) and β-glucose (OH on carbon 1 above). Two monosaccharides join by condensation, losing water and forming a covalent glycosidic bond; hydrolysis adds water to break it. Chains of α-glucose coil into starch and glycogen, compact insoluble energy stores; chains of β-glucose, with alternate units inverted, lie straight and hydrogen-bond into the microfibrils of cellulose.
Each hydrogen bond in cellulose is weak; the strength comes from the very large number of them between many parallel chains. And cellulose is not coiled: only α-glucose chains form helices.
A triglyceride is one glycerol joined to three fatty acids by three ester bonds, each formed by condensation between an OH of glycerol and the COOH of a fatty acid. Triglycerides are non-polar and hydrophobic. Saturated fatty acids have no C=C double bonds and straight tails; unsaturated ones have at least one C=C, which kinks the tail. Their many C-H bonds make triglycerides an energy-dense, insoluble store. In a phospholipid one fatty acid is replaced by a phosphate group, giving a hydrophilic (polar) head and two hydrophobic (non-polar) tails.
A triglyceride is not a polymer: glycerol and fatty acids are different molecules, not a chain of repeating monomers. And do not call the phospholipid head "hydrophobic because it contains phosphorus": it is hydrophilic because the phosphate group is charged.
Every amino acid has a central carbon carrying an amine group (NH2), a carboxyl group (COOH), a hydrogen atom and a variable R group. Amino acids join by condensation to form peptide bonds. The primary structure is the sequence of amino acids; secondary structure is the α-helix or β-pleated sheet held by hydrogen bonds in the backbone; tertiary structure is the overall 3D folding held by hydrophobic interactions, hydrogen bonds, ionic bonds and disulfide bonds between R groups; quaternary structure is two or more polypeptides together. Globular proteins such as haemoglobin are soluble with physiological roles; fibrous proteins such as collagen are insoluble with structural roles.
The hydrogen bonds of secondary structure are between atoms of the polypeptide backbone (C=O and N-H), not between R groups. The hydrogen bonds that help hold tertiary structure are between R groups.
Oxygen attracts the shared electrons in each O-H bond more strongly than hydrogen, so a water molecule is polar: the O is slightly negative (δ−) and each H slightly positive (δ+). A hydrogen bond is the attraction between a δ+ hydrogen of one molecule and a lone pair on the δ− oxygen of another. Because water is polar it is an excellent solvent for ions and polar molecules. Because hydrogen bonds must be broken first, water has a high specific heat capacity (its temperature changes slowly) and a high latent heat of vaporisation (evaporation removes a lot of heat).
Do not mix up the two thermal properties. Specific heat capacity is about how much energy it takes to raise the temperature, so it explains stable temperatures. Latent heat of vaporisation is about the energy needed to evaporate water, so it explains cooling by sweating and transpiration.