Metabolism and homeostasis Flashcards
What is metabolism?
The sum of all of our bodies chemical reactions required for survival, growth and reproduction
Why do metabolic reactions require an enzyme?
They occur at higher temperature than body temperature, so they require enzymes to boost there energy hence catalysing the reaction
What are the 2 products of catabolic reactions?
Small building blocks and energy
What are anabolic reactions?
The use of the building blocks and energy from catabolic reactions to form the contents of the cell
What is the 1st law of thermodynamics and how does this relate to our food?
Energy cannot be created or destroyed only conserved and converted.
Chemical energy in our food is converted to chemical bond energy and heat
What is chemical bond energy?
Energy extracted from food through an overarching process of oxidation
What is oxidation?
Formation of CO2 and H2O from C and H in the presence of oxygen.
The loss of electrons
How do we convert energy
By the movement of electrons
What is reduction?
The gain of electrons
In terms of electron transfer how do we conserve energy?
During REDOX reactions - oxidation and reduction happen at the same time so electrons being moved at the same time
How is the conversion and conservation of energy controlled?
By enzymes
What is NAD+
An oxidising agent.
Carrier of electrons
What is FAD+ the active form of and what does this mean?
It is the active form of B2. So you need nutrients to break down other nutrients
How is ATP made?
Through substrate level phosphorylation or electron transport chain.
What is substrate level phosphorylation?
A process of forming ATP but he addition of a phosphate group to ADP
What is an electron transport chain?
Movement of electrons down a chain that provides the energy to pump H+ against the concentration gradient over a membrane. This then diffuses down the electrochemical gradient by chemiosmosis through ATPase and ATP is formed.
Electrons and protons react with oxygen to form water to maintain concentration gradient.
What is the function of ATP?
Gives energetically unfavourable reactions an energy boost by the addition of phosphate
What are coupled reactions?
When energetically favourable reactions re coupled with unfavourable reactions.
Catabolic reactions coupled with anabolic reaction.
Catabolic reactions release ATP to be used in anabolic reactions
What is the function of enzymes?
They lower activation energy of a reaction so spontaneous reactions can occur
How is enzyme activity affected by high substrate supply?
If all the enzymes active sites are taken up they can no longer increase the rate of reaction
What is the function of a rate limiting step and how is it controlled?
Controlled by enzymes
Ensures the reaction is occurring at the right speed for the body and catabolism and anabolism are not occurring at the same time
How is enzyme activity affected by allosteric control?
An allosteric effector (often a product of the pathway) binds to the allosteric site and causes a conformational change to the active site - activating or inhibiting the enzyme
What 2 ways can hormones affect enzyme activity?
Phosphorylation or enzyme induction
What is phosphorylation?
The addition of a phosphate group
