Human Cells Unit 1 KA 6 Flashcards
Metabolic Pathways
What is Metabolism?
Metabolism is all the chemical reactions that occur within the human body
What is involved in Metabolic pathways? (2)
Metabolic pathways involve the…
1) BUILDING UP of molecules
2) BREAKING DOWN of molecules
What do Anabolic pathways involve, what does it require?
Anabolic pathways involve biosynthetic (building up) processes
It requires energy
What do Catabolic pathways involve, what does it release?
Catabolic pathways involve the breakdown of molecules, it releases energy
How is the Rate of a chemical reaction indicated?
The rate of a chemical reaction is indicated by the quantity of chemical change that occurs per unit time
What is the Activation energy?
The activation energy is the energy required to break chemical bonds in the reactant chemicals
What is the Transition state?
The transition state is when bonds break because the molecules of the reactant have absorbed enough energy to make them unstable
In what form does the energy input of a reaction often occur in?
The energy input of a reaction often occurs in the form of heat energy
A reaction will only proceed at a high rate if the chemicals are raised to a ____ ____
(Fill in the blank)
A reaction will only proceed at a high rate if the chemicals are raised to a high temperature
What is a Catalyst? (3)
A catalyst is a substance that -
1) Lowers the activation energy
2) Speeds up reaction rate
3) Remains unchanged
What is an Enzyme?
An enzyme is a Biological catalyst
(Made of protein)
An Enzyme contains an ____ ____
which is a ____ ____
(Fill in the blanks)
An enzyme contains an active site which is a specific shape
Why does an Enzyme only act on one substrate?
An enzyme only acts on one substrate because the enzyme is specific to its substrate
The substrate is complementary to the enzymes active site
Substrate molecules have a ____ affinity for the active site
(Fill in the blank)
Substrate molecules have a high affinity for the active site
Products have a ____ affinity for the active site
(Fill in the blank)
Products have a low affinity for the active site
What happens after the Product leaves the active site?
After the product leaves the active site, the enzyme is left free to repeat the process with new molecules of substrate
What is the structure of the Active site like?
The structure of the active site is flexible and dynamic
What is Induced fit?
Induced fit is when the active site changes shape to better fit the substrate after the substrate binds
What does Induced fit increase the chance of?
Induced fit increases the chance of the reaction taking place
(Ensures active site comes in close contact with substrate)
When a reaction involves 2+ substrates, why is the shape of the Active site important?
When a reaction involves 2+ substrates, the shape of the active site is important as it determines the orientation of the reactants
What does the Enzyme do to the activation energy?
The enzyme weakens chemical bonds in the reactants, lowering the activation energy
What does an Enzyme require to function efficiently? (4)
A suitable…
1) Temperature
2) pH
3) Substrate concentration
4) Enzyme concentration
What are Inhibitors?
Inhibitors are a substance that decreases the rate of an enzyme controlled reaction
As Substrate concentration increases, rate of reation ____
(Fill in the blank)
As substrate concentration increases, rate of reaction increases
Why does the rate of reaction remains constant if all active sites are occupied?
If all active sites are occupied then the rate of reaction remains constant because enzyme concentration is the limiting factor
How can Metabolic pathways be controlled? (3)
1) Presence of an enzyme
2) Absence of an enzyme
3) Key enzymes regulating the rate of the reaction
What does the direction of a reaction depend on?
The direction of a reaction depends on the concentrations of the reactants and products
Describe a Competitive inhibitor - (3)
1) Similiar molecular structure to substrate
2) Competes with substrate for enzyme active site
3) Binds to active site, prevents substrate from binding
How can Competitive inhibition be reversed?
Competitive inhibition can be reversed by increasing substrate concentration
Describe a Non-competitive inhibitor - (3)
1) Does not have a similiar molecular structure to substrate
2) Binds to allosteric/regulator site, changing active site shape to prevent substrate from binding
3) Can NOT be reversed
What happens to reaction rate if the regulatory molecule is an Activator?
If the regulatory molecule is an activator, reaction rate increases
What happens to the reaction rate if the regulatory molecule is an Inhibitor?
If the regulatory molecule is an inhibitor, reaction rate decreases
What is Feedback inhibition?
Feedback inhibition is when the end product reaches a critical concentration and binds to an enzyme that catalyses a reaction earler in the pathway, inhibiting it and blocking the pathway
What does Feedback inhibition prevent?
Feedback inhibition prevents further synthesis of the end product
