1. Adenosine triphosphate (ATP) :
1.1. ATP is the molecule produced during respiration.
1.2. ATP is made from ADP, adenosine triphosphate.
1.2.1. ADP is a molecule with two phosphate groups and inorganic phosphate.
1.3. The process of ATP being made is called phosphorylation.
1.3.1. Phosphorylation : addition of phosphate.
1.3.1.1. This makes the molecule more energy rich.
1.3.1.2. When the third phosphate is removed, energy is released that can then drive metabolic reactions within the cell.
2. Comparing aerobic and anaerobic respiration :
2.1. Respiration is vital to the activities of every living cell.
2.1.1. Respiration is the release of energy from food and happens in the cells.
2.1.1.1. Aerobic respiration : respiration in the presence of oxygen.
2.1.1.1.1. Glucose + Oxygen = Carbon dioxide + Water
2.1.1.2. Anaerobic respiration : respiration without the presence of oxygen.
2.1.1.2.1. Glucose = Carbon dioxide + Ethanol
2.1.1.2.2. Glucose = Lactic acid
3. The structure and function of ATP :
3.1. The structure of ATP :
3.1.1. Three phosphate groups
3.1.2. One nucleotide base adenine
3.1.3. One ribose sugar.
3.2. ATP is the immediate energy source in the cell and is often referred to as currency.
3.2.1. ATP provides energy for metabolism and any body processes that require energy.
3.3. The advantages of ATP:
3.3.1. It releases small, manageable amounts of energy.
3.3.2. A single reaction is involved so energy can be released quickly.
3.3.3. It is a small soluble molecule that can be easily transported around the body.
4. Breathing :
4.1. The lungs and respiratory system allows humans to breathe.
4.1.1. Respiration : the exchange of oxygen and carbon dioxide.
4.1.1.1. This brings oxygen into our bodies and send carbon dioxide out.
4.2. Diffusion : every few seconds, each inhalation, air full a large portion of the millions of alveoli.
4.2.1. The process of diffusion :
4.2.1.1. 1. Oxygen moves from the alveoli to the blood through the capilleries lining the alveolar walls.
4.2.1.1.1. 2. Once in the bloodstream, oxygen get picked up by the haemoglobin in red blood cells.
4.2.1.2. 4. In the capillaries of the tissues, oxygen is freed from the haemoglobin and moves into the cells.
4.2.1.2.1. 5. Carbon dioxide moves out of the cells into the capillaries, where most of it dissolves in the plasma of the blood.
4.2.1.3. 6. Blood rich in carbon dioxide then returns to the heart through the veins.
4.2.1.3.1. 7. From the heart, this blood is pumped to the lungs, when carbon dioxide passed into the alveoli to be exhaled.
5. Basal metabolic rate :
5.1. Basal metabolic rate : the minimum amount of energy our body needs to 'tick over' when we are completely at rest.
5.1.1. Humans rarely have this baseline as we would have to sitting for a really long time motionless.
5.1.1.1. It can be measured by using the heat produced pre unit of surface area of a period of time.
5.2. Metabolic rate : the sum total if activity in our body in terms of processes.
5.2.1. Examples of process that are included are : digestion, breathing and tissue repair.
6. The biochemistry of anaerobic respiration :
6.1. Glycolysis starts off anaerboic respiration.
6.1.1. Glucose is converted into pyruvate with the net release of :
6.1.1.1. 2 ATP molecules
6.1.1.2. 2 molecules of reduced NAD
6.2. Then reduced NAD donates hydrogen and electrons to pyruvates, producing lactate and NAD.
6.2.1. This regenerates more oxidized NAD for glycolysis.
6.2.1.1. This enables anaerobic respiration to continue and ensures that small amounts of energy can still be made in the absence of oxygen, allowing biological reactions to keep ticking over.
6.2.2. Continued anaerobic respiration results in the build-up lactate which needs to be broken down.
6.2.2.1. Cells can convert lactate back into pyruvate, which is then able to enter aerobic respiration at the Krebs cycle.
7. The biochemistry of aerobic respiration :
7.1. Aerobic respiration happens in four main stages :
7.1.1. 1. Glycolysis :
7.1.1.1. The process of Glycolysis :
7.1.1.1.1. 1. Glucose is phosphorylated using the phosphate groups from two molecules of ATP.
7.1.1.1.2. 3. Hydrogen is removed from triose phosphate to convert it into pyruvate.
7.1.1.2. The splitting of 6-carbon glucose into two 3-carbon pyruvate molecules.
7.1.1.2.1. This process does not require oxygen and is involved in both aerobic and anaerobic respiration pathways.
7.1.2. 2. Link reaction :
7.1.2.1. The conversion of pyruvate into 2-carbon Acetyl-CoA.
7.1.2.1.1. This process takes places in the mitochondrial matrix.
7.1.2.2. The process of Link Reaction :
7.1.2.2.1. 1. A carbon atom is removed from pyruvate forming carbon dioxide, coverting the pyruvate into a two-carbon molecule called acetate.
7.1.3. 3. Krebs cycle :
7.1.3.1. The feeding of Actyl-CoA into a series of reactions that ptoduces hydrogen atoms which are used in the next step.
7.1.3.1.1. This cycle is a series of reactions which generates reduced NAD and a similar molecule reduced FAD which is needed for oxidative phosphorylation.
7.1.3.2. The process of Krebs cycle :
7.1.3.2.1. 1. Carbon and hydrogen are removed form citrate, forming carbon dioxide and reduced NAD.
7.1.4. 4. Oxidative phosphorylation :
7.1.4.1. When hydrogen is passed a set of carried molecules, it is process during which most of the ATP is produced.
7.1.4.1.1. Oxidative phosphorylation takes place across the inner mitochondrial membrane.
7.1.4.2. It uses the electrons that are being carried by reduced NAD and reduced FAD that have been generated in the first three stages.
7.1.4.2.1. There are two parts of oxidative phosphorylation : The electron transport chain and Chemiosmosis.
7.1.4.3. The process of Oxidative Phosphorylation :
7.1.4.3.1. 1. Reduced NAD and reduced FAD releases hydrogen atoms which splits into hydrogen ions and electrons.
7.1.4.3.2. 3. As they travel between the electron carriers, they lose energy, This energy is used by the carriers to pump hydrogen ions from the mitochondrial matrix across the inner membrane.
7.1.4.3.3. 5. Hydrogen ions flows back into the matrix through the ATP synthase which uses the movement of hydrogen ions to add a phosphate group onto ADP to form ATP.
7.2. The total ATP production : 38 ATP
7.2.1. Glycolysis : 2 + 2 x 3 = 8 ATP
7.2.1.1. 2 - direct production
7.2.1.2. 2 x 3 - 2 reduced NAD are converted into ATP through oxidative phosphorylation
7.2.2. Link reaction : 2 x 3 = 6 ATP
7.2.2.1. 2 x 3 - 2 reduced NAD are converted into ATP through oxidative phosphorylation
7.2.3. Krebs cycle : 2 + (3 x 6) + (2 x 2) = 24 ATP
7.2.3.1. 2 - direct production
7.2.3.2. 3 x 6 - 6 reduced NAD are converted into ATP through oxidative phosphorylation
7.2.3.3. 2 x 2 - 2 reduced FAD are converted into ATP through oxidative phosphorylation