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Primary structure -
Order of amino acids in a polypeptide chain . It's determined by the base sequence on one strand of DNA.
Secondary structure -
The shape that the polypeptide chains forms as a result of hydrogen bonds. This causes the long polypeptide chain to be twisted into a 3D shape.
Tertiary structure -
The secondary protein structure can be twisted & folded to form more complex, compact 3D structures.
Quaternary structure -
Some structures aren't functional without combination. In some cases they may combine with another polypeptide chain & may be associated with non-protein groups to form large, complex molecules such as haemoglobin.

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Proteins are a linear sequence of amino acid. The bond formed from the condensation reactions is a peptide bond and the resulting compound is a dipeptide.

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Proteins differ from lipids & carbohydrates because they also contain nitrogen. Many also contain sulphur & phosphorus. Proteins are made of monomers called amino acids(chains of these are called polypeptides). They're are around 20 different amino acids. All amino acids have the same basic structure:

An amino group - NH2 (N-terminal)

A carboxyl group - COOH (C-terminal)

A hydrogen atom

R group, differs in each atom

It can act as an acid or alkali - amphoteric.

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A few drops of biuret reagent(sodium hydroxide & copper(II) sulphate) are added. The 2 react with the protein to make blue copper hydroxide which interacts with peptide bonds present in the proton to make biuret which is purple. The more concentrated, the darker the purple, so the test is qualitative. To detect the concentration a biosensor is needed.

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Globular proteins are compact & folded into a spherical molecules, making them soluble in water and so they have different functions: enzymes, antibodies, plasma, proteins & hormones. Haemoglobin is an example, consisting of 4 folded polypeptide chains, at the centre of each is the iron-containing group - haem.

Fibrous proteins have long, thin molecules, their shape making them insoluble in water, so they have structural functions, as in bone. The polypeptides are in parallel sheets/chains with crosslinks forming long fibres, e.g keratin in hair. They are strong & tough. Collagen is a fibrous protein, providing the strength needed in tendons.

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The emulsion test -
A sample is mixed with absolute ethanol, which dissolves any lipids present. It is shaken with an equal volume water. The dissolved lipid comes out of the solution because they are insoluble water. They form an emulsion, making the sample cloudy white.
Implications -
Atherosclerosis is the fatty deposits in the coronary arteries. If the diet is high in saturated fats, fatty material called atheroma is deposited in the ratios and cause atherosclerosis. This restricts blood flow & oxygen delivered to the heart.
Heart attacks -
Anti-coagulants are used to thin the blood & reduce heart attacks
Angina -
Stable & unstable treatment dilate the blood vessels(glycerintrinitate)

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Phospholipids -

In biological membranes

Electrical insulation

Triglycerides -

Energy reserves in animals & plants

thermal insulation

Waxes -

waterproofing

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Unsaturated - double bonds between carbon
Saturated - no double bonds

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Lipids that melt above 45 degrees celsius. They have a waterproofing role in both animals, leaf's culture & insects exoskeleton.

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They are a special type of lipid, one end is soluble in water. The head is hydrophilic meaning it interacts with water and the hydrophobic tail is non-polar & doesn't interact with water.

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Organic, non-polar compounds and are insoluble in water but dissolve in organic solvents such as propane and alcohols.
Triglycerides are formed by a combination of one glycerol molecule and 3 fatty acid molecules. The glycerol is always the same, but the fatty acids vary. A condensation reaction joins the glycerol to the fatty acids & ester bonds are formed.

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It is a structural polysaccharide, found in the exoskeleton of insects & fungal cell walls. It resembles cellulose, with its long chains of β 1-4 linked monomers, but has groups derived from amino acids added to form a heterorpolysaccharide. It is strong, waterproof & lightweight. Like cellulose, monomers are rotated 180° in relation to their neighbour & the long, parallel chains are cross-linked to each other by hydrogen bonds, forming microfibrils.

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The main storage product in animals is glycogen, also called animal starch as it's similar to amylopectin. It has α 1-4 & α 1-6 glycosidic bonds. The difference is glycogen molecules have shorter α 1-4 linked chains & so is more branched than amylopectin.

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Glyceraldehyde - four in photosynthesis & respiraton

Ribose - RNA

Deoxyribose - DNA

All 3 have a double bandwidth carbon & oxygen. They're called aldehydes. One bon dis always with hydrogen.
Examples of ketones are fructose and ribulose. Both ketones & aldehydes give positive reactions wit Benedict's Reagent.

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Benedict's test detects reducing sugar. Equal volumes of Benedict's reagent & solution heated to at least 70°C. If a reducing sugar is present, the solution will turn from blue through free, yellow, orange, a brick-red precipitate.The sugar donates an electron to reduce Copper II ions in copper sulphate to red copper I oxide.
Non-reducing sugars-
Sucrose will give a negative result. It needs to be broken downing its two monosaccharides, e.g by heating with HCl. It needs alkaline conditions to work, so alkali is added. Benedict's is then added & heated like before. If solution now turns red then a non-reducing sugar was initially present.

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Large, complex polymers. Monomers are linked together by glycoside bonds.
Starch
It's the main store of glucose for plants, starch grains are found in high concentrations in seeds & storage organs such as potato tubers. Starch is made of Alpha-glucose molecules bonded together in 2 ways, forming 2 polymers - amylose & amylopectin.

Amylose is a linear, unbranched molecule with α 1-4 glycosidic bonds forming between the first carbon atom on one glucose monomer & the fourth carbon on the adjacent one. This is repeated to got a chain which coils into a helix. 80% total composition in starch. Has hydrogen bonds.

Amylopectin also has chains of glucose monomers joined with α 1-4 glycosidic bonds. They are cross-linked with α 1-6 glycosidic bonds & fit inside the amylose. When glycosidic bond forms on C6 an α 1-4 glycosidic bond continues from the start of the branch. 20% total composition in starch & doesn't have hydrogen bonds.

Testing for starch - iodine-potassium iodide test. Iodine(dissolved in aqueous potassium-iodide) reacts with starch resulting the colour to change from orange-brown to black-blue. It's a qualitative test & an accurate concentration cannot be determined.

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Composed of 2 monosaccharide units bonded together with the formation of a glycosidic bond & the elimination of water. A condensation reaction.

Disaccharide Monosaccharides biologica role
Maltose - glucose + glucose germinating seeds
Sucrose - glucose + fructose  transport in phloem
Lactose - glucose + galactose.  mammalian milk

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Cellulose is a structural polysaccharide & its presence in plant cell walls makes it the most abundant organic molecule on earth. Consists of many long, parallel chains of β-glucose units. Monomers are joined by β 1-4 glycosidic bonds & the β link rotates adjacent glucose molecules 180°. Allowing H bonds to form between OH groups of adjacent parallel chains & adds to the stability. Between 60 & 70 cellulose molecules become tightly cross-linked to form bundles of microfibrils. Bundles of these are called fibres. A cell wall has several layers of fibres, running parallel within a layer but at an angle to the adjacent layer. This laminated structure contributes to the strength of the cell wall. The fibres are freely permeable because there are spaces between fibres. Water & its solutes can penetrate through these spaces in the cell walls to the cell membrane.

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Water is a dipole, meaning it has a positively charged end(hydrogen) & a negatively charged end(oxygen), but no overall charge. It is a polar molecule. Hydrogen bonds can form between molecules, they're weak but in large numbers they make water molecules difficult to separate, giving water a wide range of physical properties.

A solvent - organisms can obtain key elements from solvents. Because they're dipoles they attract ions(glucose) which dissolve in them. This means chemical reactions take place solution. Water is a good transport medium.

High specific heat capacity - large amounts go heat energy are required to raise the temperature because of the hydrogen bonds. This means temperature doesn't fluctuate, stable habitats & enzymes can work efficiently.

High latent heat of vaporisation - a lot of heat energy is needed to change it from a liquid to a vapour. As late evaporates, the body cools.

Cohesion - molecules attract each other forming hydrogen bonds. The molecules stick together in a lattice, called cohesion. Allowing columns of water to be drawn up xylem vessels in plants.

High surface tension - cohesion between molecules causes surface tension so that the body of an insect is supported(e.g a pond skater)

High density - Ice is less dense than water, meaning ice floats. This is because hydrogen bonds hold molecules further apart than those in water. It's a good insulator & prevents water losing heat & allowing animals to survive.

Transparency - allowing light to pass through, letting aquatic plants photosythesise

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Mg 2+ is part of chlorophyll & essential for photosynthesis. Plants without Mg have yellow leaves, a condition called chlorosis. Mammals need Mg for their bones.

Fe ²⁺ is a constituent of haemoglobin, which transports oxygen in red blood cells. Lack of ironing the diet ca lead to anaemia.

PO ₄ ³⁻are used for making nucleotides, including ATP & a part of phospholipids, found in membranes.

Ca ²⁺ component of bones & teeth in mammals along with cell walls, providing strength.

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The small organic building blocks for larger carbohydrates. A triose sugar has 3 carbon atoms; a pentose sugar has 5 carbon atoms & a hexose has 6. Glucose is a hexose sugar.
The carbon atoms in monosaccharides for a ring when the sugar is dissolved in water, they can also be straight chains when in equilibrium. Glucose has 2 isomers - α & β glucose based on the position of the (OH) and (H). The different forms result in biological differences when they form polymers, such as starch & cellulose. The functions are a source of energy in respiration, building blocks, intermediates in reactions & constituents of nucleotides.

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Organic compounds containing hydrogen, oxygen & carbon. Basic unit is a monosaccharide & two of these form a disaccharide. Many monosaccharide units combine to form a polysaccharide.

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Living organisms need inorganic ions(electrolytes/minerals) to survive. They're important in many cellular processes - muscle contractions, maintaining osmotic pressure in cells.
There are two groups - macronutrients: needed in small concentrations, and micronutrients: needed in minute concentrations e.g zinc, copper