Cellular Respiration

What is a decomposition reaction?

Decomposition reactions break larger molecules into smaller molecules, thus bonds are broken.

Is energy released or used up in a decomposition reaction?

Energy is released

What is produced at the end of the Krebs cycle? Write the FUNCTION of each of the products

Per glucose molecule, the Krebs cycle produces: 4 CO2, 6 NADH, 2 FADH2, and 2 ATP. The intermediate step produces 2 acetate, 2 CO2, and 2 NADH per glucose molecule. CO2 is a waste product that will leave the cell (remember you exhale it); NADH and FADH2 carry electrons to the Electron transport chain, and ATP is used for cellular processes that require energy.

Write out the reactants that go into Electron Transport Chain of Aerobic respiration

Per glucose molecule: 10 NADH, 2 FADH2, 6 O2, 32-34 (ADP + P)

Write out the reactants that go into Krebs cycle of Aerobic respiration

Per glucose molecule: 2 acetate, 6 NAD+, 2 ADP + 2 P, 2 FAD. This is for the Krebs cycle only. The reactants of the intermediate step between glycolysis and Krebs cycle are: 2 Pyruvates and 2 NAD+,

Compare and contrast lactic acid and alcohol fermentation.

Both types of fermentation follow glycolysis, regenerate NAD+, and take place in the cytoplasm. Lactic acid fermentation converts (reduces) pyruvate to lactate without any intermediate steps. It is used commercially in the production of yogurt, cheese and pickles. It also happens in human muscle cells if not enough energy is available for the aerobic respiration pathway. Alcohol fermentation converts pyruvate to CO2 and acetyladehyde in an intermediate step before acetylaldehyde is reduced to ethanol. It is commercially used in the production of breads, beer and wine.

Where does the ETC occur?

Inner membrane of the mitochondria.

What is the main purpose of the ETC?

To produce energy for cellular processes (growth, reproduction, maintaining homeostasis, etc.)

What is the main purpose of the Krebs Cycle?

To produce high energy electrons for the ETC. NADH and FADH2 are the electron carrying molecules used in cellular respiration.

What is the main purpose of fermentation?

To regenerate NAD+ so that glycolysis and hence some (a very little) energy production can continue.

Where does Glycolysis occur?

Where does Glycolysis occur?

Write out the OVERALL chemical equation for Aerobic RESPIRATION

C6H12O6 + 6 O2 à 6 CO2 + 6 H2O + energy

Give an example of a decomposition reaction.

Cellular respiration where glucose is broken down into CO2, and ATP is made. Hydrolysis of polymers (starch, glycogen, polypeptides, nucleic acids) into monomers (monosaccharides, amino acids, nucleotides, respectively)

Is energy released or used up in a synthesis reaction?

Energy is consumed (used up).

What is produced at the end of Glycolysis?

Net products: 2 pyruvates, 2 ATP, 2 NADH

Write out the reactants that go into Glycolysis

Net reactants: 1 glucose, 2 ADP + 2 P, 2 NAD+,

What is produced at the end of the ETC? Write the FUNCTION of each of the products

10 NAD+ -- recycled to the matrix and cytoplasm to be used as reactants in glycolysis, intermediate step and the Krebs cycle 2 FAD - recycled to the matrix to be used as reactants in the Krebs cycle 6 H2O - waste product, may be used to maintain water balance or it may leave the cell as a waste product. If you have ever exhaled on a mirror or window, you have observed the mirror/ window fogging up. This is because there is water as well as CO2 in your exhaled breath. This is because both are a product of cellular respiration. 32-34 ATP - used to perform work in the cell, such as maintaining homeostasis, or any of the traits of life which all require energy.

Give an example of a synthesis reaction.

Photosynthesis is an example of a synthesis reaction that rearranges CO2 and H2O (smaller molecules) into glucose (larger molecule) using energy from the sun. Another example is dehydration synthesis that links monomers together to form polymers (glucose + glucose + glucose + polysaccharide; amino acid + amino acid + amino acid = polypeptide)

Explain how photosynthesis and cellular respiration are related within a single plant cell.

Photosynthesis produces glucose and oxygen in the chloroplast. Fifty percent of the products of photosynthesis are used immediately in cellular respiration. When this happens, the products (glucose and oxygen) exit the chloroplast. Glucose is used in the cytoplasm for the process of glycolysis. Oxygen and the products of glycolysis are transferred to the mitochondria where they are used to make energy (ATP). Carbon dioxide and water are waste products of cellular respiration. They can exit the mitochondria and enter the chloroplast where they can again be used as reactants for photosynthesis. Thus the reactants and products of photosynthesis and cellular respiration form a cycle where the products of one reaction form the reactants of the other reaction.

What is a synthesis reaction?

Synthesis reactions build larger molecules from smaller molecules. Thus bonds are created.

Where does the Krebs cycle occur?

The Krebs cycle occurs in the matrix of the mitochondria.

Explain how photosynthesis and cellular respiration are connected within an ecosystem.

In the chloroplasts of plants, sunlight energy is used to convert CO2 and H2O into glucose and oxygen. Only 50% of the products are used immediately in cellular respiration. The rest of the products can be used to make plant tissue so the plant can grow, or it can be stored for later use. Often it is stored in fruits that are eaten by animals. The plants provide the animals with a food source, and hence a source of energy. As mentioned earlier only 50% of the products of photosynthesis are used immediately in cellular respiration. This includes the oxygen. 50% of the oxygen exits the chloroplast, then the cell, then the plant - entering the atmosphere. In fact, photosynthesis is responsible for producing the oxygen rich atmosphere that now exists on earth. Thus plants provide other organisms in the ecosystem with both of the reactants for cellular respiration. The animals then break down the glucose they received from the plants during cellular respiration using the oxygen that plants added to the atmosphere. By the end of cellular respiration, animals have produced CO2 and H2O as waste products of cellular respiration. In larger organisms these products will be exhaled back into the atmosphere for plants to use them during photosynthesis.