Cellular Respiration

• what is cellular respiration?

  it is a biochemical process that takes place in the cytosol and the mitochondria, it converts glucose into energy the form of ATP
• state the main stages of cellular respiration

  1.Glycolysis

  2.Citric Acid Cycle (Krebs Cycle)

  3.Electron Transport Chain
• Explain glycolysis

  Glycolysis breaks down one molecule of glucose into two molecules of pyruvate in the cytosol of the cell. It produces 2 ATP and 2 NADH, this energy is not sufficient enough for multicellular organisms. If oxygen is present, pyruvate is actively transported to the mitochondrial matrix for further energy production.
• anaerobic process

  Glucose molecule is split into two molecules of pyruvate in glycolysis in the cytoplasm, when oxygen is absent the cells need to regenerate NAD+, which is crucial for glycolysis to continue, to keep producing energy, this is where fermentation comes in, it produces 2 ATP per glucose molecule and it makes it faster than aerobic its waste product includes: lactic acid in animals and carbon dioxide and alcohol in plants
• Two forms of fermentation

  alcohol fermentation

  lactic acid fermentation
• alcohol fermentation

  Occurs in plants, it produces carbon dioxide and ethanol, plants can't use ethanol because it cant revert back into carbohydrates or broken down into oxygen, ethanol is also toxic to cells which is why plants and yeast cant let it build up, plants respire anaerobically for a short time before switching back to aerobic before ethanol levels get too high -- otherwise they will be poisoned
• lactic acid fermentation

  occurs in animals, lactic acid is produced when oxygen isn't available for energy production e.g. during exercise, the body prefers using oxygen for energy but when it can't get oxygen quickly it uses anaerobic respiration which leads to a build up of lactic acid, once exercise slows oxygen is available and the body converts lactic acid back into pyruvate to continue aerobic respiration for recovery
• anaerobic produces less energy than aerobic and anaerobic leaves more energy locked in ethanol or lactic acid molecules
• anaerobic is less efficient than aerobic as it only partially breaks down glucose
• Aerobic respiration

  This takes place in the presence of oxygen in the mitochondria, where glycolysis, citric acid cycle, and electron transport chain take place, it produces up to 30-38 ATP per glucose molecule which is more than anaerobic and its waste products include: carbon dioxide and water
• Factors that affect the rate of respiration

  Temperature - if this increases do does the rate until it begin to drop again as temperature gets too high, above a certain temperature enzymes denature

  Oxygen - if this increases so does the rate until maximum level is reached

  Glucose - if this increases so does the rate until maximum level is reached
• Photosynthesis and aerobic cellular respiration are interdependent, the products of photosynthesis which is glucose and oxygen are the input for aerobic respiration and vice versa
• Compensation point

  the point at which uptake of carbon dioxide for photosynthesis equals the amount produced by respiration
• Aerobic respiration and photosynthesis: a comparison

  aerobic happens in the mitochondria and photosynthesis happens in chloroplast, aerobic happens all the time while photosynthesis occurs in the presence of light, aerobic inputs are glucose and oxygen while photosynthesis inputs are carbon dioxide and water, aerobic outputs are carbon dioxide and water and photosynthesis outputs are glucose and oxygen as a result energy is released as ATP in aerobic and energy is stored in photosynthesis
• Cellular respiration occurs in cytoplasm and mitochondria and metabolises organic compounds, aerobically or anaerobically to release usable energy int he from of ATP
• what are the byproducts of cellular respiration and how are they managed or utilised by the cell?

  the byproducts include carbon dioxide and water, carbon dioxide is exhaled though the respiratory system, while water is used in various cellular processes or excreted, in anaerobic respiration byproducts like lactic acid or ethanol are either metabolised or removed by the cell
• What are the differences between aerobic and anaerobic respiration, and how do they impact energy production?

  Aerobic respiration requires oxygen and produces a large amount of ATP (about 36-38 ATP per glucose molecule). Anaerobic respiration occurs in the absence of oxygen, resulting in much less ATP (about 2 ATP per glucose molecule) and produces lactic acid (in animals) or ethanol (in yeast) as byproducts.
• How does cellular respiration contribute to overall energy balance in an organism?

  Cellular respiration is the primary process for producing ATP, the energy currency of the cell. It provides the energy needed for all cellular activities, contributing to the organism's overall energy balance by ensuring that energy intake from food is converted into usable energy.
• Why is cellular respiration essential

  Producers and consumers perform respiration in their cells by releasing energy stored in glucose molecules to produce energy as ATP. Cellular respiration is essential as it provides cells with the energy it needs to function.
• Explain citric acid cycle


  In the citric acid cycle the production of energy-carrying molecules is carried out. Pyruvate molecules enter the mitochondrial matrix with the presence of oxygen. In the matrix, pyruvate undergoes a series of reactions, producing 3NADH, 1FADH2 and releasing 2 CO2 per cycle. The cycle generates about 2 ATP per glucose molecule
• Explain the electron transport chain

  Electrons are transported by energy-carrying molecules NADH and FADH2 from the citric acid cycle. The energy produces a chemical gradient across the inner mitochondrial membrane. Oxidative phosphorylation occurs as ATP is generated from ADP+P. Oxygen and hydrogen ions combine to form water. Approximately 28 ATP are released.
• Total ATP produced in aerobic respiration is 30-38
• Differences between aerobic and anaerobic

  Aerobic - takes place with oxygen in mitochondria, citric acid cycle results to CO2 and H20 and electron transport chain take place, combined with glycolysis aerobic respiration can produce 38 ATP per glucose molecule.

  Anaerobic - occurs without oxygen in the cytosol, resulting in much less ATP, producing 2 ATP per molecule, however it is a faster process, it is less efficient; it only partially breaks down glucose, it produces lactic acid in animals and CO2 and alcohol for plants and yeast
• How does the presence or absence of oxygen influence the cellular respiration pathway

  In the presence of oxygen, cells undergo aerobic respiration, leading to complete breakdown of glucose into CO2 and H2O, producing maximum ATP. In oxygen absence, cells switch to anaerobic respiration, leading to partial breakdown of glucose, resulting in less ATP and byproducts like lactic acid and ethanol.
• How is cellular respiration regulated?

  It is regulated by the availability of substrates which would be glucose and oxygen, enzymes involved in glycolysis and citric acid cycle are key control points.
• How does cellular respiration contribute to energy balance?

  Cellular respiration is the primary process for processing ATP. It provides the energy needed for all cellular activities , contributing to the organism's overall energy balance by ensuring that energy intake from food is converted into usable energy.
• alcohol fermentation equation

  glucose -> ethanol + carbon dioxide + 2 ATP
• lactic acid equation

  glucose -> lactic acid + 2 ATP