Unit 2 - KA 1: Metabolic Pathways Flashcards
What s a metabolic pathway?
Metabolic pathways are integrated and controlled pathways of enzyme-catalysed reactions within a cell.
Describe the two types of metabolic pathways.
Catabolic- The breakdown of molecules, producing energy.
Anabolic- Biosynthesis pf a molecule, requires energy.
What are the three types of steps a metabolic pathway can have?
Reversible
Irreversible
Alternative
What are the components of a cell membrane?
Proteins and phospholipids.
Describe the proteins present in the cell mebrane.
Channel Proteins/Protein Pores- allow diffusion of larger molecules across the membrane (passive transport)
Carrier Protein/Protein Pump- Transports molecules across the membrane (active transport)
Enzyme- catalyses metabolic reactions
Describe activation energy and an enzyme’s affect.
Activation energy is the minimum energy input required to start a chemical reaction to either build or break bonds.
Enzymes lower a reactions activation energy.
Describe induced fit.
Once a substrate has binded with the active site of an enzyme, the shape of the active site may change to better fit the substrate, increasing the rate of reaction.
Describe affinity in a catalysed reaction.
The substrate(s) has a high affinity with the enzyme, the product(s) have a low affinity with the enzyme’s active site, allowing them to vacate the active site.
Describe the reversibility of a metabolic reaction.
Most metabollic reactions are reversible. An enzyme can often catalyse a reaction forwards and backwards.
The presensce of a substrate or the removal of a product will drive a sequence of reactions in a particular direction.
Describe competitive inhibition.
A competitive inhibitor competes withsubstrate molecules for the active site of an enzyme, blocking the active site.
Describe non-competitive inhibition.
A non-competitive inhibitor attaches to a non active site, and alters the shape of the active site. Stopping substrates from bonding.
Describe the reversal of inhibition.
Competitive inhibition’s effects can be reversed by increasing the concentration of the substrate, whereas this has no effect on non-competitive inhibition.
Describe feedback inhibition.
This type op inhibition occurs when an end product of a metabolic pathway builds up andreacts with earlier enzymes, preventing the required substrate from binding. This prevents further synthesis of an end product.
