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
