Key Area 1: Metabolic Pathways And Their Control Flashcards
What is metabolism?
Metabolism encompasses the integrated and controlled pathways of enzyme-catalysed reactions within a cell
What type of reaction is a catabolic reaction?
A degredation reaction (breaks down molecules)
What type of reaction is an anabolic reaction?
Synthesis reaction (builds up molecules)
Which type of reaction produces energy?
Catabolic reaction
What are the three ways a metabolic pathway can go?
Reversible, irreversible and alternative route
What are the two main components of the plasma membrane?
Phospholipids and proteins
What are the three main functions of proteins?
- protein pump (active transport)
- protein pore (diffusion)
- enzymes
What are the two functions of membranes for metabolic reactions?
They provide a surface for the reaction to take place
They keep what’s needed for different reactions in their own compartments
Why is it important for organelles to have a large surface area to volume ratio?
To allow substances to diffuse quickly in and out of cells
What controls metabolic processes?
Signal molecules including hormones and enzymes
What factors regulate a metabolic pathway?
Intra- and extra- cellular factors
Induced fit: what are the roles of the active site?
To bind with the substrate
Orientating the substrate to get the substrate in the correct position
Induced fit: what is the shape of the active site compared to the substrate?
They are similar but not exact so as the enzyme can bind with more than one substrate
Induced fit: what is the activation energy of a reaction?
The energy needed to break chemical bonds
Enzymes lower the activation energy needed in a reaction
Describe affinity to active sites in terms of the substrate and the product
The substrate has a high affinity to the active site
The product has a low affinity to the active site
What happens to the rate of reaction as the substrate concentration increases?
As the substrate concentration increased the rate f reaction increases until it levels off
What does reversibility mean when applied to metabolic reactions? And what does it depend on?
Reversibility means enzymes can catalyse reactions in both ways
It depends on the concentration of the substrate and the product
What is a multi-enzyme complex?
Enzymes that have more than one active site ( eg DNA polymerase )
What is enzyme induction?
The process of switching on a gene when it is needed by a cell
Why is enzyme regulation needed in cells?
If more than the required amount of enzymes are made then it would be a waste
What is non-competitive inhibition?
When the inhibitor joins to the allosteric site on the enzyme and changes the shape of the active site
What is a competitive inhibitor?
When the inhibitor binds with the active site on the enzyme to block interaction with the substrate
What is feedback inhibition?
When there is too much of the end product it acts as inhibitors to the enzyme back at the start of the metabolic pathway
