Biology Notes (Part 11) Cellular Respiration

Cellular Respiration

• The process of cellular respiration occurs so that energy from the food (carbohydrates) we eat gets converted to channel energy (ATP).

• This process occurs in all living organisms.

• Cells generally contain enough ATP to sustain from 30 minutes to a few minutes of activity.

• Cells use glucose to make ATP.

• Organisms store glucose as glycogen or starch.

• the formula for cellular respiration is CO6H12 + 6O2 + 6H2O + heat and energy.

• Cellular respiration breaks down glucose and produces ATP which usually involves the breakdown of glucose to CO2 and H2O.

• Aerobic is a term describing a process that occurs in the presence of oxygen.

• Anaerobic is a term that describes the process that occurs in the absence of oxygen.

• Redox coenzymes are coenzymes that transport electrons.

Redox reactions

• Redox reactions transfer energy via electrons.

• Reduction-oxidation reactions (redox reactions) are chemical reactions that involving the transfer of electrons.

• Oxidation and reduction always occur together and is a form of energetic coupling.

• Oxidation is exergonic and reduction is endergonic.

• Electrons can be transferred from an electron donor to an electron acceptor.

• Electrons are usually accompanied by a proton (H+).

• Reduction always adds hydrogen and oxidation removes hydrogens.

Redox Coenzymes

• NAD+ (nicotinamide adenine dinucleotides) in its reduced form is NADH.

• FAD (flavin adenine dinucleotide) in its reduced form is FADH.

Glucose Breakdown Summary Reaction

• Glucose is oxidized and is O2 is reduced and is the opposite of photosynthesis.

• What happens when glucose is oxidized? When glucose is oxidized to carbon dioxide by burning, some energy is released as heat and light.

• C6H12O6 (glucose) + 6O2 (oxygen) → 6CO2 (carbon dioxide) + 6H2O (water).

Catabolic Pathways Break Down a Variety of Molecules

• Cellular respiration interacts with other pathways (both catabolic and anabolic).

• For ATP production, cells first use carbohydrates, then fats, and finally proteins.

• Proteins, carbohydrates, and fats can all furnish substrates for cellular respiration.

Phases of Cellular Respiration

• Glycolysis is the first step of cellular respiration. In this process, the breakdown of glucose occurs and breaks down into two molecules of pyruvate. It is an anaerobic process and the major product formed is pyruvates.

• Oxidation of pyruvate is the second step of cellular respiration. Both pyruvates are broken down to Acetyl Coa. It is an aerobic process and the major product formed are Acetyl Coa.

• The citric acid cycle is the third step of cellular respiration and is also known as the Krebs Cycle. It is an aerobic process and the products formed are large amounts of redox coenzymes.

• The last step of cellular respiration is electron transport chain which is a series of carrier proteins. It is an aerobic process and the product formed is large amounts of ATP.