Metabolism

would not work since more ATP would be utilized within the cycle than that which is

In contrast, there are four metabolic stages happened in cellular respiration, which are the glycolysis, the citric acid cycle, and the oxidative phosphorylation. Glycolysis occurs in the cytoplasm, in which catabolism is begun by breaking down glucose into two molecules of pyruvate. Two molecules of ATP are produced too. Some of they either enter the citric acid cycle (Krebs cycle) or the electron transport chain, or go into lactic acid cycle if there is not enough oxygen, which produces lactic acid. The citric acid cycle occurs in the mitochondrial matrix, which completes the breakdown of glucose by oxidizing a derivative of pyruvate into carbon dioxide. The citric acid cycle produced some more ATPs and other molecules called NADPH and FADPH. After this, electrons are passed to the electron transport chain through

In order to understand how enzymes work, it is important to know what a catalyst is. A catalyst is a substance that enhances the rate of a chemical reaction without undergoing any irreversible chemical change at the end of the reaction (Chemicool). An enzyme is a protein that functions as a catalyst during chemical reactions. In order for chemical reactions to occur, a certain amount of energy in what is known as the activation

The reaction for this process is: C6H12 O6 → 2C2H5 OH + 2CO2 + ATP This process also uses the glycolysis stage of respiration, however it can not use the Krebs cycle or electron transport as oxygen is required. Therefore without oxygen it allows cells to make small amounts of ATP.

Enzymes are very efficient catalysts for biochemical reactions. They speed up reactions by providing an alternative reaction pathway of lower activation energy. Like all catalysts, enzymes take part in the reaction - that is how they provide an alternative reaction pathway. But they do not undergo permanent changes and so remain unchanged at the end of the reaction. They can only alter the rate of reaction, not the position of the equilibrium. Enzymes are usually highly selective, catalyzing specific reactions only. This specificity is due to the shapes of the enzyme molecules.

Enzymes lower the activation energy of the chemical reaction, thus it can be considered as a catalyst, as it drastically speeds up the reaction. As enzymes are proteins, they have their individual optimum temperature and pH level, in which it performs at its best, and going beyond that point leads to the breaking of hydrogen bonds with heat, and disulphide/ionic bonds with pH, thus the 3D shape is changed, leading to a different shaped active site which is now longer complementary to its previous substrate. This is called enzyme denaturation, which means that the enzyme is no longer able to carry out its allocated function. Obviously, the optimum temperature and pH varies from enzyme to

Enzymes are catalysts. This means that they make biochemical reactions happen faster than they would otherwise. Sometimes the essential reactions would not happen at all without the help of enzymes. After each time the enzymes are ready to catalyze.

Whereas the large molecule food (Sucrose) will take longer to break down because of its large molecules, this will waste the energy of the yeast as it has to break down the large molecules into smaller molecules before it can use them. This means that the sucrose is not as efficient as the glucose at providing the yeast with a better medium by which it will produce a faster rate of respiration. Theory:

Enzymes are biological catalysts, which speed up the rate of reaction without being used up during the reaction, which take place in living organisms. They do this by lowering the activation energy. The activation energy is the energy needed to start the reaction.

Furthermore, ions pass through the membrane and they use energy to assist with the making of ATP. Therefore, this generates ATP in the mitochondria and in the chloroplasts. Hydrogen ions are pumped through the thylakoid membranes, and this creates energy that allows the hydrogen ions to pass through.

Of the many functions of proteins, catalysis is by far the most vital. When catalysis is not present, most reactions in the biological systems take place very slowly to produce at an adequate pace for metabolising organism. The catalysts that take this role are called enzymes. Enzymes are the most efficient catalysts; they can enhance rate of reaction by up to 1020 over uncatalysed reactions. (Campbell et al, 2012).

There are two types of cellular respiration, aerobic and anaerobic. Aerobic respiration occurs when there is oxygen present and in the mitochondria (in eukaryotic cells) and the cytoplasm (in prokaryotic cells). Aerobic respiration requires oxygen; it proceeds through the Krebs cycle. The Krebs cycle is a cycle of producing carbon dioxide and water as waste products, and converting ADP to thirty-four ATPs. Anaerobic respiration is known as a process called fermentation. It occurs in the cytoplasm and molecules do not enter the mitochondria for further breakdown. This process helps to produce alcohol in yeast and plants, and lactate in animals. Only two ATPs are produced through this process. In yeast fermentation is used to make beer, wine, and whiskey.

The two carbon molecule bonds four carbon molecule called oxaloacete forming a carbon molecule knew as citrate. The second step reaction is classified as oxidation/reductions reactions. This process is formed by two molecule of CO2 and one molecule of ATP. The cycle electrons reduce NAD and FAD, which join the H+ ions to form NADH and FADH2, this result to an extra NADH being formed during the transition. In the mitochondrion, four molecules of NADH and one molecule of FADH2 are produced for each molecule of pyruvate, two molecules of pyruyate enter the matrix for each molecule of oxidized glucose, as a result of these eight molecules of NADH+ two molecules are produced. Six molecules of NADH+, molecules of FADH2 and two molecules of ATP synthesize itself in Krebs cycle. As a result, no oxygen is used in the described reactions. During chimiosmosis, oxygen only plays a role in oxidative phosphorylation. The next step is the electron transport; the electrons are stored on NADH and FADH2 and are used to produce ATP. Electron transport chain is essential to make most ATP produced in cellular respiration. The NADH and FAD2 from the Krebs cycle drop their electrons at the beginning of the transport chain. When the electrons move along the electron transport chain, it gives power to pump the hydrogen along the membrane from the matrix into the intermediate space. This process forms a gradient concentration forcing the hydrogen through ATP syntheses attaching

This lab investigates the effects of Sucrose concentration on cell respiration in yeast. Yeast produces ethyl alcohol and CO2 as a byproduct of anaerobic cellular respiration, so we measured the rate of cellular respiration by the amount of CO2

Glycolysis is followed by the Krebs cycle, however, this stage does require oxygen and takes place in the mitochondria. During the Krebs cycle, pyuvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. This begins when pyruvic acid produced by glycolysis enters the mitochondria. As the cycle continues, citric acid is broken down into a 4-carbon molecule and more carbon dioxide is released. Then, high-energy electrons are passed to electron carriers and taken to the electron transport chain. All this produces 2 ATP, 6 NADH, 2 FADH, and 4 CO2 molecules.