2.1 Metabolic Pathways and their control Flashcards
Define ‘metabolism of a cell’
Sum total of all biochemical reactions that occur within a cell
What are the three types of steps in a metabolic pathway/
Reversible
Irreversible
Alternative
What is an advantage of having reversible steps in a metabolic pathway?
Allows processes to be kept under precise control
What is an advantage to having alternative steps in a metabolic pathway?
Allows an end product still to be reached if a specific enzyme/ substrate is unavailable
Describe an ‘Anabolic’ pathway
Anabolic
- Synthesis/Build up of a larger molecule from smaller molecules
- Requires Energy
Give an example of an anabolic process
Photosynthesis
Describe a ‘Catabolic’ pathway
- Break down of larger molecules into smaller molecules
- Releases Energy
Give an example of a catabolic process
Aerobic Respiration
What is it called when an anabolic pathway becomes interdependent on a catabolic pathway?
Integrated Metabolic Pathway
Describe the function of a membrane?
Controls the entry and exit of materials in a cell
What are the inner folds of a membrane called?
Cristae
What are the types of proteins found in a cell membrane?
- Protein Pump
- Channel forming protein
- Enzyme
Describe the phospholipid bilayer
- Double layer of phospholipids which are in CONSTANT MOTION
- Keeps the structure fluid but stable
- Contains proteins, which are attached by weak chemical bonds
Describe the structure of a phospholipid
Hydrophilic head (water loving) Hydrophobic tail(water hating)
What is the function of a protein pump?
- Move molecules AGAINST A CONCENTRATION GRADIENT
- Requires Energy
Give an example of a protein pump?
Sodium Potassium Pump(Potassium In, Sodium Out)
What is the function of a channel forming protein?
- Form channels for large molecules to diffuse through
- No ATP required
- Passive Process
What is the function of a membrane in compartmentalisation
Divide up cells into regions which have specialised functions and are required for specific metabolic steps
Give an example of a double membraned organelle
Nucleus
Give an example of a single membraned organelle
Endoplasmic Reticulum
How are metabolic pathways controlled at gene expression level?
- When a gene is expressed a protein is produced
- Proteins make up enzymes
- Enzymes are responsible for controlling steps in metabolic pathways
What will result in a block to a metabolic pathway?
Mutations
What is the ‘activation energy’
The minimum energy required to initiate a chemical reaction
How do enzymes speed up the rate of a chemical reaction?
Speed up the reaction but are not used up because they lower the activation energy
What does ‘Affinity’ stand for?
Affinity is the strength of attraction between two molecules
Do substrates have high or low affinity for the active site of an enzyme?
High
Do products have high or low affinity for the active site of an enzyme?
Low
How does substrate concentration effect reversible reactions?
Reversible reactions can go either way depending on the relative concentrations of substrate/products
Describe how ‘orientation’ affects enzymes and substrates
The substrate has to be at the right orientation in order to fit into the active site
Explain the process of ‘Induced Fit’
Induced fit is the process by which an enzyme molds its active site to fit more tightly around a substrate. It ensures the substrate is pulled in close and increases the chance of a reaction occurring.
Describe a multi enzyme complex
A multi enzyme complex is a collection of enzymes found together on a membrane
