Respiration, types of respiration

This is brief discussion on the Respiration and Types of respiration.
total process of glycolysis, citric acid cycle. This will help you to understand the respiration complete process of respiration

1. Respiration: Anaerobic Respiration Aerobic Respiration

2. Respiration: The action of breathing. A process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.

3. Aerobic Respiration: Aerobic respiration is the process of producing cellular energy involving oxygen. Cells break down food in the mitochondria in a long, multistep process that produces roughly 38 ATP . The first step is Glycolysis , the second is the Citric acid cycle, the third is the Electron transport chain.

4. Anaerobic respiration: is respiration using electron acceptors other than molecular oxygen.

5. Glycolysis:   is the process of breaking down glucose. Glycolysis produces two molecules of  pyruvate , two molecules of  ATP , two molecules of  NADH , and two molecules of  water . Glycolysis takes place in the  cytoplasm .

6. There are 10 enzymes involved in breaking down sugar. The 10 steps of glycolysis are organized by the order in which specific enzymes act upon the system.

7. Step 1: The enzyme  hexokinase  phosphorylates adds a phosphate group to glucose in a cell's  cytoplasm . In the process, a phosphate group from ATP is transferred to glucose producing  glucose 6-phosphate  or G6P. One molecule of ATP is consumed during this phase.

8. Step 2: Enzyme   phosphoglucomutase   isomerizes G6P into its  isomer  fructose 6-phosphate or F6P. Isomers have the same  molecular formula  as each other but different atomic arrangements.

9. Step 3: The enzyme  phosphofructokinase  uses another ATP molecule to transfer a phosphate group to F6P in order to form fructose 1,6-bisphosphate or FBP. Two ATP molecules have been used so far.

10. Step 4: The enzyme  aldolase  splits fructose 1,6-bisphosphate into a ketone and an aldehyde molecule. These sugars, dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GAP), are isomers of each other.

11. Step 5: The enzyme  triose-phosphate isomerase  rapidly converts DHAP into GAP (these isomers can inter-convert). GAP is the substrate needed for the next step of glycolysis .

12. Step 6: The enzyme  glyceraldehyde 3-phosphate dehydrogenase  (GAPDH) serves two functions in this reaction. First, it dehydrogenates GAP by transferring one of its hydrogen (H⁺) molecules to the  oxidizing agent   nicotinamide adenine dinucleotide (NAD⁺) to form NADH + H⁺. Next, GAPDH adds a phosphate from the cytosol to the oxidized GAP to form 1,3-bisphosphoglycerate (BPG). Both molecules of GAP produced in the previous step undergo this process of dehydrogenation and phosphorylation .

13. Step 7: Enzyme   phosphoglycerokinase   transfera phosphate from BPG to a molecule of ADP to form ATP. This happens to each molecule of BPG. This reaction yields two 3-phosphoglycerate (3 PGA) molecules and two ATP molecules.

14. Step 8: Enzyme   phosphoglyceromutase  relocates the P of the two 3 PGA molecules from the third to the second carbon to form two 2-phosphoglycerate (2 PGA) molecules.

15. Step 9: The enzyme  enolase  removes a molecule of  water  from 2-phosphoglycerate to form phosphoenolpyruvate (PEP). This happens for each molecule of 2 PGA from step eight.

16. Step 10: The enzyme  pyruvate kinase  transfers a P from PEP to ADP to form pyruvate and ATP. This happens for each molecule of PEP. This reaction yields two molecules of pyruvate and two ATP molecules.

17. Citric acid cycle : The citric acid cycle is also known as TCA ( tricarboxlyic acid cycle) or the Krebs cycle. Once acetyl CoA is formed,the krebs cycle begins.

18. Electron Transport Chain: The electron transport chain is the last component of aerobic respiration. An  electron transport chain  ( ETC ) is the a series of complexes that  transfer   electrons  from  electron donors  to  electron acceptors  via  redox  (both reduction and oxidation occurring simultaneously) reactions, and couples this electron transfer with the transfer of  protons  (H +  ions) across a  membrane .

19. Complex I This complex is composed of flavin mononucleotide (FMN) and an iron-sulfur (Fe-S)-containing protein. The enzyme in complex I is NADH dehydrogenase . Complex I can pump hydrogen ions across the membrane from the matrix into the intermembrane space, and it is in this way that the hydrogen ion gradient is established and maintained between the two compartments separated by the inner mitochondrial membrane.

20.   Complex II Complex II directly receives FADH 2. The compound connecting the first and second complexes to the third is  ubiquinone  (Q). Ubiquinone delivers its electrons to the next complex in the electron transport chain. Q receives the electrons derived from NADH from complex I and the electrons derived from FADH 2  from complex II

21. Complex III Also called cytochrome reductase. Cytochromes are groups of proteins which has heme as their complexes. The heme molecule is similar to the heme in hemoglobin, but it carries electrons, not oxygen Also has Iron core in which iron can exist in oxidised or reduced form depending on the electrons it has Contain three types of cytochromes b,c1,c.

22. Complex IV The fourth complex is also called cytochrome c oxidase. This complex contains two heme groups (one in each of the two cytochromes , a, and a 3 ) and three copper ions (a pair of Cu A  and one Cu B  in cytochrome a 3 ). The cytochromes hold an oxygen molecule very tightly between the iron and copper ions until the oxygen is completely reduced. The reduced oxygen then picks up two hydrogen ions from the surrounding medium to make water (H 2 O).