Energy Reactions in Cells Flashcards
What is cell metabolism?
Sets of processes that derive energy and materials from food stuffs. These are then used in cells to support growth, repair, and activity of tissues
What are catabolic pathways?
Pathways where larger molecules are broken down into smaller intermediates. This breakdown releases free energy and is oxidative leading to a loss of hydrogen atoms
What are anabolic pathways?
Pathways that synthesise larger cellular components from the intermediates created by catabolic pathways. They use the free energy (ATP) released by catabolic reactions to do this. Reductive as uses the hydrogen atoms from catabolism
Why do cells need a continuous supply of energy?
Energy required for most important biochemical reactions
How is a continuous supply of energy provided to the cells?
There is a limited concentration of ATP and ADP in the cell and the concentration available will only last a few seconds so must be constantly recycle. ATP therefore acts as a carrier of energy rather than a store. NADH and FAD2H also a finite resource so must be constantly reduced and oxidised
What is creatine phosphate and where is it found in higher abundance?
An energy store
Important in skeletal muscle as metabolic activity can increase quickly
How is creatine phosphate used?
When ATP is readily available it is combined with creatine using the enzyme creatine kinase to form creatine phosphate and ADP. When the concentration of ATP suddenly falls, the reaction reverses providing a short term increase in the amount of ATP available
Give an example of a high-energy signal and how it is used to regulate metabolism
ATP is a high energy signal as it indicates the cell has enough ATP for its immediate needs so when concentration of ATP high (used as ratio to ADP and AMP rather than absolute concentration) anabolic pathways are activated
Give an example of a low-energy signal and how it is used in the regulation of metabolism
ADP and AMP are low energy signals as when concentrations of these are high it indicated the cell is lacking the ATP required so catabolic pathways are activated to produce more ATP
What are exergonic reactions?
Reactions that release energy - the enthalpy change is negative as the energy of the reactants is greater than that of the products so energy is released
What are endergonic reactions?
Reactions that require energy where the energy of the reactants is less than the energy of the products
