Deoxyribose Organelles

Deoxyribose nucleic acid (DNA) is present in the nucleus of all living organisms. It controls all the chemical changes within the cell and determines the kind of organism that is produced. Each cell is identical (unless specialised) and contains the genetic information of the living organism. DNA consists of a double strand of nucleotides, the sugar-phosphate chains are parallel to each other, and these chains are held together by bonds between the bases. Nucleotides are made up of three parts; a sugar base called ribose, a phosphate groups and an organic/nitrogenous base. The most common organic bases are adenine, thymine, guanine and cytosine. Adenine and guanine are purines meaning large molecule, cytosine and thymine are pyrimidines meaning

At the centre of the molecule lies a five-carbon sugar, ribose, which is attached to the nitrogenous base adenine and to the chain of three phosphates. There are four main stages of respiration, firstly glycolysis which is the breaking down of glucose. The glucose is phosphorylated into glucose-6-phosphate by taking a phosphate from ATP. The glucose-6-phosphate changes to fructose via isomerisation. This is then phosphorylated for a second time, splitting another molecule of ATP, forming fructose-1-6-bisphosphate. The fructose-1-6-bisphosphate then splits into two molecules called triose phosphate. They each have 3 carbon (C) and 1 phosphate. They are then converted into pyruvic acid. This involves the removal of hydrogen and its transfer to a hydrogen carrier molecule (NAD) to form reduced NAD. Each pyruvic acid yields 2 molecules of ATP in the process of its creation. The 2 reduced NAD made goes to the electron transport chain and the 2 molecules of pyruvate goes into the link reaction which is the next stage. The link reaction connects glycolysis to the Kreb’s cycle. The pyruvate undergoes decarboxylation and dehydrogenation to produce C02 and H+ which is used to reduce NAD. This forms acetate which taken by coenzyme A (coA) recycled from Kreb’s cycle to form acetyl coA. No ATP is produced or used in this stage so the net total of ATP is still 2. There is now 4 carbon. The third stage is the Kreb’s cycle, acetyl coA enters the Kreb’s cycle by combining with a 4C acid to form a 6C compound (citrate). Citrate undergoes decarboxylation and dehydrogenation to produce C02 and H+ which is used to reduce NAD which creates a 5C compound (Ketoglutaric Acid). Ketoglutaric Acid undergoes decarboxylation and dehydrogenation again producing a 4C compound. This time enough energy was created to synthesis a molecule of ATP. 4C compound is dehydrogenation to reduce NAD. The cycle runs twice so