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3.7.1 Define cell respiration

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Presentation on theme: "3.7.1 Define cell respiration"— Presentation transcript:

1 3.7.1 Define cell respiration
Syllabus definition: Cell respiration is the controlled release of energy from organic compounds in cells to form ATP.

2 ATP ATP or Adenosine triphosphate is the molecule which directly fuels the majority of biological reactions. Everyday each person will hydrolyse (reduce) 1025 ATP molecules to ADP. The ADP is reduced back to ATP using the free energy from the oxidation of organic molecules.


4 Boardworks A2 Biology Respiration What is respiration? Respiration is the process by which organisms extract the energy stored in complex molecules and use it to generate adenosine triphosphate (ATP). In this way they obtain energy to fuel their metabolic pathways. ATP provides the immediate source of energy for biological processes such as active transport, movement and metabolism. ATP

5 Boardworks A2 Biology Respiration Types of respiration During aerobic respiration, a respiratory substrate, e.g. glucose, is split in the presence of oxygen to release carbon dioxide and water. A large number of ATP molecules are produced, releasing the energy from the glucose. C6H12O O2  6 CO H2O ATP In anaerobic respiration, glucose is converted (in the absence of oxygen) to either lactate or ethanol. The ATP yield is low. C6H12O6  2 C2H5OH CO ATP ethanol C6H12O6  2 C3H6O ATP lactate 5

6 Glycolysis Glycolysis is the stage of respiration which takes place in the cytoplasm. It is the first stage of respiration. This stage is required in order for the second and third stages to occur.

7 Where does respiration occur?
Boardworks A2 Biology Respiration Where does respiration occur? Respiration occurs in all living cells. In eukaryotes the early stages of respiration occur in the cytoplasm. The later stages of respiration are restricted to the mitochondria. Mitochondria contain highly folded inner membranes that hold key respiratory proteins (including the enzyme that makes ATP) over a large surface area. Mitochondria provide an isolated environment to maintain optimum conditions for respiration. Mitochondria have their own DNA and ribosomes, so can manufacture their own respiratory enzymes.

8 GLYCOLYSIS If O2 is present then pyruvate enters the mitochondria and more ATP is produced.

9 No O2 then pyruvate is converted into lactic acid.
Multi-stage process here involving transfer of hydrogen and transfer of inorganic phosphate groups. No O2 then pyruvate is converted into lactic acid.

10 No O2 then ethanol and carbon dioxide are produced

11 Homework Where in the cell does glycolysis?
Explain the process of glycolysis. Where does aerobic respiration take place in eukaryotic cells? What are the products of anaerobic respiration?

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