CARBOHYDRATES

NAMES OF CARBOHYDRATES

Glucose- -monosaccharide -C6H12O6 Sucrose- -disaccharide -C6H22O11 Cellulose & Amylose- -polysaccharide -(C6H10O5)n

ANAEROBIC RESPIRATION

Anaerobic respiration is the oxidation of glucose in the absence of oxygen. This oxidation is exothermic but releases very little of the total potential energy of the glucose molecule. Anaerobic respiration is thus not as efficient as the aerobic pathway and only provides sufficient energy to maintain microorganisms such as bacteria and yeasts. Anaerobic respiration in plant cells such as yeasts is more commonly known as fermentation

PHOTOSYNTHESIS

Autotroph: "Self feeder" (a producer) - photosynthesis Heterotroph: "Feeder on others" (a consumer) Different organisms obtain their glucose in different ways. Autotrophs are self feeders, able to synthesis their own glucose. A heterotroph must consume other organisms as a source of glucose. Photosynthesis is the process by which autotrophs synthesize glucose from simple molecules in the presence of light. Light is absorbed by chlorophyl in the green parts of a plant. Photosynthesis is an endothermic reaction using the energy of light to build up the chemical potential energy of glucose from low energy reactants.

CONDENSATION OF MONOSACCHARIDES

Monosaccharides can join together to form larger molecules by losing a water molecule at each link. These are condensation reactions. 2C6H12O6 -------> C12H22O11 + H2O (monosaccharides) condensation reaction (disaccharide)

FORMS OF MONOSACCHARIDES

Monosaccharides exist in either of two forms; an open chain or cyclic. Monosaccharides condense to form larger molecules. Only their cyclic forms undergo condensation reactions.

HYDROLYSIS OF POLYSACCHARIDES

Polysaccharides can be broken down into their monosaccharide units by adding a water molecule at each link. This process is called hydrolosis which is the major type of reaction occuring in digestion. mono <--hydrolysis/condensation reaction --> poly+water

CARBOHYDRATES

While the molecular formula of a compound may suggest that of a carbohydrate (CxH2yOy) the structural formula will provide more evidence. Carbohydrates are more precisely defined as polyhydroxyl aldehydes or ketones in their open chain monomer form.

ANAREOBIC RESPIRATION ENERGY PROFILE DIAGRAM

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ENDOTERMIC ENERGY PROFILE DIAGRAM

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EXOTHERMIC ENERGY PROFILE DIAGRAM

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PHOTOSYNTHESIS ENERGY PROFILE DIAGRAM

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PHOTOSYNTHESIS EQUATION

6CO2 + 6H2O -------> C6H12O6 + 6O2 Conditions: Chlorophyl Light (In living cells)

ENERGY PROFILE DIAGRAMS

All chemical reactions are accompanied by an energy change as the chemical potential energy of reactants will differ from that of the products. A chemical change can be represented by a chemical equation which will show the rearrangement of matter. The energy change accompanying the chemical change is represented by an energy profile diagram. This diagram represents the change in chemical potential energy for a given reaction pathway. The difference in energy between products and reactants is the enthalpy of the reaction, ΔH

SACCHARIDES

Carbohydrates are commonly known as saccharides- mono, di or poly (saccharides). The simplest carbohydrates are the mono saccharides which can condense to form larger saccharides. The smaller saccharides are soluble in water and are known as 'sugars'. The most common monosaccharide is glucose which is the source of chemical potential energy for living systems.

GENERAL FORMULA

Carbohydrates contain carbon, hydrogen and oxygen with a general formula of Cx H2y Oy. If x=y, carbohydrate is a monosaccharide.

LAWS OF CONSERVATION OF ENERGY

Energy cannot be created nor destroyed. It can be changed from one form in to another. An energy transformation will accompany all chemical changes.

AEROBIC RESPIRATION

Glucose is oxidized in all cells of multi cellular organisms to provide energy for living. Aerobic respiration is the complete oxidation of glucose in living cells. This process is enzyme controlled and releases energy in a series of steps at moderate temperatures. C6H12O6 + 6O2 -> 6CO2 + 6H2O This reaction is exothermic in which the high chemical potential energy stored in the glucose molecule is changed in to other forms (heat, kinetic, sound, electrical....). Glucose is an example of a chemical fuel. A fuel is a substance with a high chemical potential energy able to be changed in to other forms as the result of a chemical change.