1. F214 Module 4 4.4.1 ATP and Glycolysis By Ms Cullen

2. Why do organisms need to respire? To produce ENERGY

3. What is this energy needed for? Active Transport to drive metabolic reactions in cells eg protein synthesis, DNA replication, moving chromosomes during mitosis and meiosis to contract muscle cells in animals to allow movement

4. Metabolic reactions If a metabolic reaction builds large molecules we call it anabolic If a metabolic reaction breaks down large molecules into smaller ones we call it catabolic

5. ATP Adenosine triphosphate A TP is a phosphorylated nucleotide A high energy intermediate compound found in cells Adenosine is composed of adenine and a ribose sugar In addition to this it has 3 phosphate (phosphoryl) groups

6. The structure of ATP

7. The energy released from hydrolysis of ATP

8. The ATP cycle

9. Glycolysis – ‘sugar splitting’ Occurs in the cytoplasm of cells. Does not need oxygen, therefore can take place in both aerobic and anaerobic conditions. A small proportion of the energy in each glucose is released, and used to make small amounts of ATP. Glucose is broken down in a series of steps, each catalysed by an enzyme. Essentially glucose (a 6C sugar) is broken down into pyruvate ( a 3C compound).

10. Summary of glycolysis

11. Stage 1 – Phosphorylation 1 ATP molecule is hydrolysed and the phosphate group becomes attached to glucose at carbon 6 to form glucose-6-phosphate. This is then converted into fructose- 6-phosphate. Another ATP molecule is hydrolysed attaches itself to fructose-6- phosphate at carbon 1 and becomes fructose 1,6-biphosphate. The energy from the hydrolysed ATP, activates the hexose sugar and prevents it leaving the cell. We now call the activated, phosphorylated sugar hexose 1,6- biphosphate. Glucose (6C) Glucose-6-phosphate ATP Fructose-6-phosphate ATP Hexose 1,6-biphosphate NB this stage has used 2 molecules of ATP for each glucose molecule.

12. Stage 2 – splitting of Hexose 1,6- biphosphate Each molecule of hexose 1,6-biphosphate is split into 2 molecules of triose phosphate. Triose phosphate is a 3C sugar molecule with a phosphate group attached. Hexose 1,6-biphosphate (6C) 2 x triose phosphate (3C)

13. Stage 3 – oxidation of triose phosphate This process is anaerobic, but involves oxidation. 2 hydrogen atoms and their electrons are removed from each triose phosphate molecule. This involves dehydrogenase enzymes and the coenzyme NAD. NAD is a hydrogen acceptor, it combines with the hydrogen to form reduced NAD. 2 molecules of NAD are reduced per molecule of glucose. Also 2 molecules of ATP are formed. This is called substrate- level phosphorylation. 2 x triose phosphate (3C) 2 x intermediate compound (3C) 2 ATP 2 reduced NAD

14. Stage 4 – conversion of triose phosphate to pyruvate 4 enzyme-catalysed reactions convert each triose phosphate molecule into a molecule of pyruvate. Pyruvate is also a 3C compound. During this process 2 molecules of ADP are phosphorylated (P i is added) to form 2 molecules of ATP. 2 x intermediate compound (3C) 2 x pyruvate (3C) 2 ATP

15. Products of glycolysis: There is a net gain of 2 ATP molecule (4 were produced, but 2 were used in the process). 2 molecules of reduced NAD 2 molecules of pyruvate

16. Coenzyme - NAD During glycolysis, hydrogen atoms are removed in oxidation reactions. These reactions are catalysed by dehydrogenase enzymes. However, these enzymes are not very good at catalysing oxidation and reduction reactions. Therefore coenzymes are needed to assist in the oxidation reactions of respiration. NAD is an example of a coenzyme.

17. Coenzyme - NAD Nicotinamide adenine dinucleotide - NAD NAD is made of 2 linked nucleotides. It is involved in glycolysis, link reaction and Kreb’s cycle of respiration.

18. Molecular structure of NAD