Metabolic pathways Flashcards
What are metabolic pathways controlled by?
enzyme catalysed reactions within a cell
How can rates of enzyme reactions be controlled?
By intracellular and extracellular signal molecules
What do anabolic pathways require?
Energy and involve the biosynthetic processes
What do catabolic pathways require?
They release energy and involve the breakdown of molecules
What can most metabolic reactions do?
Be reversed
what does the presence or removal of substrate do?
Drive a sequence of reactions in a particular direction
What steps and routes do metabolic pathways have?
Reversible,irreversible steps and alternative routes
What does the activity of an enzyme depend on?
Their flexible and dynamic shape
Why do substarte molecules have a high affiny
for the active site
When does induced fit occur?
The active site changes shape to better fit the substrate after the substrate binds
What can the active site do to the substrate so they fit more closely
The active site can orientate
What is the role of the active site of an enzyme
is affecting activation energy
what lowers activation energy?
Enzymes
What do products of enzyme reactions do?
They have a low affinity for the active site of the enzyme and are released form the active site
what affects the direction and rate of an enzyme reaction?
The concentration of substrate and end product
What do enzymes often do?
The act in groups or as multi-enzyme complexes
What is non competitive inhibition?
Enzyme inhibition by a substance that permanently alters the active site of the enzyme
It cannot be reversed by increasing substrate concentration
What is competitive inhibition?
slowing of reaction rate due to the presence of a substance resembling the substrate
Can be reversed by increasing substrate concentration
How can competitive inhibition be reversed
Increasing substrate concentration
When does feedback inhibition occur?
When the end product reaches a critical concentration
The end product then inhibits an earlier enzyme,blocking the pathway, prevents further synthesis of the end product
Things that will affect the rate of reaction
Optimum pH
Temperature
Substrate concentration
Enzyme concentration
What are the two reactions of metabolic pathways
Anabolic- synthesis (requires energy)
Catabolic-degradation (gives out energy)
How are metabolic pathways controlled?
The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes
Describe the roles o genes in the control of metabolic pathways
Each step in a metabolic pathway is controlled by a specific enzyme, each enzyme is coded for by a gene
