Cell Respiration Flashcards
3.7.1 - Define cell respiration
The controlled release of energy from organic compounds in cells in the form of ATP
3.7.2 – State that, in cell respiration, glucose in the cytoplasm is broken down by glycolysis
into pyruvate, with a small yield of ATP
Cells transfer energy by breaking down nutrients, mainly carbohydrates like glucose,
through the process of cell respiration. Plants synthesise these nutrients using sunlight in
photosynthesis, while heterotrophs will digest them from their food.
Cell respiration takes place in a number of steps, which helps to control the release of
energy. There are multiple enzymes which catalyse these reactions, and the energy is able
to be trapped in the molecule ATP (adenosine triphosphate). It is a nucleotide that carries
three phosphate groups. The nature of the molecule means that it is soluble and small
enough to pass through the cell membrane quite easily. It contains a lot of chemical energy
within its structure.
The first step is glycolysis, which takes place in the cytoplasm of the cell. Once broken
down, the glucose molecule (which has six carbon atoms) forms two pyruvate molecules
(each with three carbon atoms). A small yield of two molecules of ATP are produced.
Cell respiration formula
The first step is glycolysis, which takes place in the cytoplasm of the cell. Once broken
down, the glucose molecule (which has six carbon atoms) forms two pyruvate molecules
(each with three carbon atoms). A small yield of two molecules of ATP are produced.
Glucose( 6C)——-> 2 ATP + 2 Pyruvate( 3C + 3C)
3.7.3 - Explain that, during anaerobic cell respiration, pyruvate can be converted in the
cytoplasm into lactate, or ethanol and carbon dioxide, with no further yield of ATP
Anaerobic respiration is also called fermentation (a process which is important in making
wine, beer, bread, etc). It occurs when there is no oxygen available.
Some organisms will still respire anaerobically, even when there is oxygen available. The
most important one is yeast, which has applications mentioned above.
