Question

Metabolism is essential to life and is the process by which cells make energy to carry out all of the processes required for them to survive. Metabolism requires that the organism transport substances from the environment into the cell to utilize in their metabolic pathways. Bacteria have a diverse array of potential metabolic processes to make energy. Given the information below (A. and B.), describe how the organisms would make ATP in the environment they are found. Make sure to discuss in detail each of the pathways, including the starting products, end products, components of the ETC (if applicable), how the cell makes ATP during this process, where in the cell each of these pathways occur and the transport mechanism(s) utilized to move the starting products from the environment into the cell.

I am just very confused, all I really need to know are the pathways that each of these organisms would use to make ATP under their circumstance.

          A. An anaerobic organism that is only able to ferment lactose.

          B. A facultative aerobic organism that is in an environment that lacks oxygen but is rich in

          nitrate which can serve as a terminal electron acceptor

Answer 1

If we first talk about a background information which is related to the question then it will be better for you to understand on the Pathways. Cellular respiration is a process of breakdown of glucose for the generation of ATP. The sole purpose of cellular respiration is the generation of ATP because ATP is the energy currency of the cell and cell required ATP for performing all the metabolic activities. It is of three types aerobic respiration and anaerobic respiration and fermentation.

Aerobic respiration is the complete breakdown of glucose into carbon dioxide and water and it generates around 32 to 34 molecules of ATP. This is the most efficient type of respiration because it produces the maximum number of ATP. But this type of respiration occurs only when there is an abundance of oxygen in the immediate environment. It is most commonly seen in all the animals and plants who live in normal climatic conditions where oxygen is abundant in the air. In this case glucose is broken down into six molecules of carbon dioxide and oxygen is the final electron acceptor which gets reduced to form water.

Another type of respiration is anaerobic respiration which take place in the complete absence of oxygen. It is similar to aerobic respiration but the final electron acceptor is not oxygen. It can be sulphur which leads to the formation of hydrogen sulphide gas or it can be nitrate or nitrite which leads to the formation of Nitrogen gas. It takes place mainly in anaerobic bacteria. It is energetically less efficient as compared to aerobic respiration because it produces less than 32 molecules of ATP. This is the answer to your second option. In the absence of oxygen, the organism will show anaerobic respiration.

Third type of respiration is fermentation which occurs in the deficiency of oxygen. It is the poorest type of fermentation because it produces only two molecules of ATP. The first step is breakdown of glucose into pyruvic acid by glycolysis which produces two molecules of ATP and the second step is reduction of pyruvic acid. In this case, pyruvic acid is the final electron acceptor. If it is taking place in the presence of lactate dehydrogenase enzyme, then it leads to the formation of lactic acid and this occurs in some bacteria and human muscle cell. But if the enzyme is alcohol dehydrogenase, then it leads to the formation of alcohol and release of carbon dioxide and and it takes place in some bacteria and saccharomyces. In the second step when pyruvic acid is converted into lactic acid or alcohol, NADH is oxidised to NAD+. This is the main purpose of fermentation, that is to regenerate NAD+ so that it can enter aerobic respiration. This is because fermentation does not produce much ATP so that the cell can survive so it regenerates this molecules so that aerobic respiration can take place. This is the answer to the first part.

Please give a good racing.