UNIT 1 - KA6 Flashcards
What are metabolic pathways
Metabolic pathways are interrogated and controlled pathways of enzyme - catalysed reactions within a cell
What are anabolic reactions
Anabolic reactions build up large molecules from small molecules and require energy
What are catabolic reactions
Catabolic reactions break down large molecules into smaller molecules and release energy
What types of steps and routes can metabolic pathways have
Metabolic pathways can have reversible steps, irreversible steps and alternative routes
What are metabolic pathways controlled by
Metabolic pathways are controlled by the presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes
What is the activation energy
The activation energy is the energy required to break chemical bonds during a chemical reaction.
How much activation energy is needed with no enzymes
Higher activation energy needed with no enzymes :(
How much activation energy is needed with enzymes
Lower activation energy is needed with enzymes :)
Produce a graph of high and low activation energy
Check jotter
What are the three key functions of enzymes
1) lower the activation energy (required for a reaction)
2) SPEED UP the rate of reaction
3) DO NOT change and can be reused
What would not be able to proceed without enzymes
Enzymes are the body’s catalysts and without them the biochemical reactions essential for life would be unable to proceed at a fast enough rate to sustain life
How many enzymes work for how many substrates
Enzymes are said to be specific which means that each enzyme only works on one substrate
What is the substance and enzyme works on called
The substance and enzyme works on is called it’s substrate
List three enzyme substrate and products
Amylase - starch - (Maltose/glusoce) simple sugars
Lipase - LIPDS (fats) - fatty acids and glycerol
Protease (eg pepsin) - protein - amino acids
What is a model that explains how enzymes and substrates react
A model that explains how enzymes and substrates react when mixed is the INDUCED FIT model
When does induced fit occur
Induced fit occurs when the active site changes shape to better fit the substrate after the substrate binds
What are the steps of induced fit during an enzyme catalysed reaction
1- substrate with High affinity for active site binds to active site. Substrate becomes bound to active site
2- once the substrate binds induced fit occurs as the enzymes active site has changed shape to better fit the substrate (enzyme substrate complex formed).
3- substrate is broken down to end products
4- end products released
5- enzyme has returned to original shape. End products have low affinity allowing them to leave the active site
Factors affecting the rate and direction of enzyme reactions
1 - temperature
2 - pH
3 - substrate concentration
4 - inhibitors
What is the effect of substrate concentration on enzyme activity at W
- the reaction rate is lower at w because the substrate concentration is lower. So there are less substrate molecules to react with the available active sites. The reaction rate is quicker at x
The effect of substrate concentration on enzyme activity at x-y and Z
- as substrate concentration increases from x-y more substrate is available to bind to free enzyme active sites so reaction rate increases. At z there are no free enzyme active sites available so even if substrate concentration is increased the reaction cannot go any faster
Draw a graph of substrate concentration and reaction rate
Check jotter
High substrate concentration
Substrate — ——> product
Enzyme
Low substrate concentration
Substrate <——— product
Enzyme
High product concentration
Substrate <——— product
