unit: 2 - metabolic pathways Flashcards
What is metabolism?
The sum of all chemical reactions in an organism, including catabolism (breakdown) and anabolism (synthesis).
What are the two types of metabolic pathways?
Catabolic pathways, which break down molecules to release energy, and anabolic pathways, which build molecules and consume energy.
What is ATP and why is it important in metabolism?
ATP (adenosine triphosphate) is the energy currency of the cell, providing energy for metabolic reactions.
Why are membranes important in metabolic pathways?
Membranes compartmentalize processes, create concentration gradients, and house enzymes and transport proteins for metabolic reactions.
What role does the inner mitochondrial membrane play in metabolism?
It hosts the electron transport chain and ATP synthase for oxidative phosphorylation.
How do concentration gradients relate to metabolic pathways?
Gradients drive processes like ATP production (e.g., proton gradient in mitochondria).
What is a metabolic pathway?
A series of enzymatic reactions where the product of one reaction becomes the substrate for the next.
Give an example of a metabolic pathway.
Glycolysis: the breakdown of glucose into pyruvate, producing ATP and NADH.
How are metabolic pathways regulated?
Through feedback inhibition, enzyme activation, and gene expression
What is an enzyme?
A biological catalyst that speeds up chemical reactions by lowering activation energy
What is the active site of an enzyme?
The specific region where the substrate binds and the reaction occurs.
Explain the induced fit model of enzyme action
The enzyme changes shape slightly to fit the substrate more tightly, improving catalytic efficiency.
What factors affect enzyme activity?
Temperature, pH, substrate concentration, and inhibitors.
What are competitive inhibitors?
Molecules that compete with the substrate for the enzyme’s active site, reducing activity.
What are non-competitive inhibitors?
Molecules that bind to a different site (allosteric site) on the enzyme, altering its shape and reducing activity.
What is feedback inhibition?
When the end product of a metabolic pathway inhibits an earlier enzyme to prevent overproduction.
How is enzyme activity controlled by phosphorylation?
Enzymes can be activated or deactivated by the addition or removal of a phosphate group.
Do enzyme reactions take place in isolated areas or pathways?
Enzyme reactions do not take place in isolation but in pathways
are pathways able to be reversed?
Many of these pathways are reversible, but some are not
Is there an alternative pathway around pathways that cant be reversed?
Where pathways are irreversible, or energetically unfavorable, alternative pathways are usually available
What are anabolic reactions?
Anabolic reactions build up large molecules from small molecules and require energy
What are catabolic reactions?
Catabolic reactions break down large molecules into smaller molecules and release energy.
Are pathways linked, and how if they’re?
Most of these reactions are linked; the energy given off by one pathway is used to power another
What do proteins need to do several functions, and give examples?
Proteins within the membranes perform several functions, such as pores, embedded enzymes and channels
What is the rate of metabolism dictated by?
The rate of metabolism is dictated by the rate at which the enzymes work
