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Chemical elements and biological compounds - Coggle Diagram
Chemical elements and biological compounds
Inorganic ions
Magnesium - Main part of chlorophyll which means it is essential for photosynthesis. Mammals need magnesium for their bones.
Iron - Part of haemoglobin which transports oxygen in red blood cells. Lack of iron in a human diet can lead to anemia.
Phosphate ions are used for making nucleotides they are also in part of phospholipids in biological membranes.
Calcium - important component of bone sand teeth in mammals.
Water
Dipole - positively charged end (hydrogen) and negatively charged end (oxygen) but has no overall charge. A molecule with separate charges is polar.
Hydrogen bonds form between the hydrogen atom of one molecule and the oxygen atom of another.
As a solvent - because water molecules are dipoles they attract charged particles like glucose. Non-polar molecules such as lipids do not dissolve in water.
Water is a metabolite - used in many biochemical reactions as a reactant - with carbon dioxide to produce in photosynthesis.
High specific heat capacity - a large amount of heat energy is needed to raise it temperature. This is because the hydrogen bonds between water molecules restrict their movements.
High latent heat of vapourisation - a lot of heat energy is needed to change it from liquid to a vapour.
Cohesion - water molecules attract each other forming hydrogen bonds as thee are so many of them they are together like a lattice. Allows water to be drawn up the xylem in plants.
Carbohydrates
Monosaccharides
Glucose is a hexose sugar, it has two isomers alpha and beta glucose which are based on the positions of the OH and H.
A source of energy in respiration. C-H and C-C bonds are broken to release energy which is transferred to make ATP.
Building block for larger molecules. Glucose is used to make the polysaccharides starch, glycogen and cellulose.
Intermediates in reactions - triodes are intermediates in the reactions of respiration and photosynthesis.
Constituents of nucleotides - deoxyribose in DNA, ribose in RNA and ATP.
Disaccharides
Composed of two monosaccharide units bonded together with the formation of glycosidic bond and elimination of water - condensation reaction.
Maltose
glucose + glucose
Biological role in germinating seeds.
Sucrose
glucose + fructose
Biological seeds in transport in phloem of flowering plants.
Lactose
glucose + galactose
Biological role in mammalian milk.
Testing for the presence of sugars
The Benedict's test date ts reducing sugars in a solution.
Equal volumes of the Benedict's reagent and the solution being tested are heated to at least 70c. If a reducing sugar is present the solution will turn from blue to red. If they are non-reducing sugars the solution stays blue.
Polysaccharides
Large complex polymers which are formed from a very large amount of monosaccharides which are linked by glycosidic bonds.Main source of energy in cells, it is soluble in water and it would increase the concentration of cell contents and will then draw water in by osmosis.
This is avoided by converting the glucose into a storage product (starch).
Is insoluble so it has no osmotic effect.
Cannot diffuse out of the cell.
Is a compact molecule and can be stored in a small space.
Carries a lot of energy in it C-H and C-C bonds.
Starch
Main source of glucose for plants. It is made up of alpha glucose molecules bonded together in two different ways - amylose and amylopectin.
Amylose - linear unbranched molecule with an alpha molecule with 1-4 glycosidic bonds forming between the first carbon atom and the adjacent one, this creates a helix.
Amylopectin - chains of glucose monomers joined together with 1-4 glycosidic bonds they are cross linked with 1-6 glycosidic bonds.
Testing for precedes of starch - iodine solution reacts with starch with a colour change from orange to blue/black.
Glycogen
Main storage product in animals is glycogen. it has 1-4 alpha and 1-6 alpha bonds.
Cellulose
Structural polysaccharide caride and is present in plant cell walls. chains of beta glucose at 1-4 bonds this allows hydrogen bonds to form between the OH groups.
Chitin
Structural polysaccharide, found in the exoskeleton of insects and in fungal cell walls. long chains of 1-4 beta monomers.
Lipids
Trigylcerides
They are formed of one glycerol molecule and three fatty acid molecules. the fatty acids join to glycerol by condensation reactions this is whereby three water molecules of water are removed and ester bonds are formed
Phospholipids
Each molecule has the unusual property of having one end that is soluble to water. This end has a lot of oxygen atoms and so this end of the molecule interacts with water and is hydrophilic. It is the polar head of the molecule. The other end is hydrophobic.
Properties of lipids
If the hydrocarbon chain only has one single C-C bonds the fatty acid is saturated. If any C-C bond is not a single bond the molecule is unsaturated.
Roles of lipids
Phospholipids
in biological membranes
Electrical insulation
Triglycerides
Energy reserves in both plants and animals as they contain more carbon-hydrogen bonds
Thermal insulation - when stored under the skin lipids insulate against the heat loss in the cold or the other way round.
Protection - fat is often stored around delicate internal organs protecting them against damage.
Metabolic water - this is water released during chemical reactions in the body.
Waxes
waterproofing - in terrestrial organisms waxes reduce water loss
Test for fats and oils - emulsion test
The sample is mixed with absolute ethanol which dissolves any lipids present. It is shaken with an equal volume of water. The dissolved lipids come out of solution because they are insoluble in water this makes the solution white.
Implications of saturated fats for human health
The main causes of heart disease are fatty deposits in the coronary arteries and high blood pressure.
When food has been absorbed at the small intestine, lipids and proteins combine to make lipoproteins.
If the diet is high in saturated fats, low-density lipoproteins build up and cause harm. Fatty material gets deposited in the coronary arteries restricting blood flow and oxygen delivery to the heart.
If the diet is high in unsaturated fats the body makes more high density lipoproteins which carries harmful fats away from the liver for disposal. The higher the amount the lower their risk of coronary heart disease is.
They are non polar compounds so they are insoluble in water but dissolve in organic solvents such as propane and alcohols
Protiens
Protein structure
Primary structure
This is the order of amino acids in a polypeptide chain. these can be joined in any number, order or combination. It is determined by the base sequence on one strand of the DNA.
Secondary structure
This is the shape that the polypeptide chain forms as a result of hydrogen bonding between the =O on -CO groups and the -H on -NH groups. This causes the shape to be twisted into a 3d shape. The spiral is an alpha helix or a beta pleated sheet.
Tertiary structure
The alpha helix of the secondary protein structure can be folded and twisted to give a more complex 3d structure.
This is maintained by:
Hydrogen bonds
Ionic bonds
Disulphide bonds
Hydrophobic interactions
Quaternary structure
Some polypeptide chains are not functional unless they are in combination. In some cases they may combine with another polysaccharide chain.
They also contain nitrogen - proteins are polymers made of monomers called amino acids. This chain is called polypeptides.
Proteins are linear sequences of amino acids this reacts with the carboxyl group of another with eh elimination of water. The result of this is a peptide bond and the resulting compound if a dipeptide.
amino acids are made up of -
an amino acid group
a carboxyl group
a hydrogen atom
the r group
Globular and fibrous protiens
Fibrous
long thin molecules and their shape makes the insoluble in waters they have structural functions like bone. polypeptides are in parallel chains or sheet. they are joined by hydrogen bonds making it very stable.
Globular
are compact and folded into spherical molecules. they are soluble in water and have different functions including enzymes antibodies plasma proteins and hormones.