Year 1- Metabilism, Activation Energy, Inhibitors Flashcards Preview

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Flashcards in Year 1- Metabilism, Activation Energy, Inhibitors Deck (11)
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What is a metabolic pathway?

A cycle or chains of enzyme catalysts reactions


How is each step in a metabolic pathway controlled

It begins with a specific molecule, and that molecule is altered within a certain need of steps, resulting in a certain product


The chemical change in a metabolic pathway doesn't happen in one large leap, but...

A sequence of small steps


What is an example of a linear metabolic pathway?

Glycolysis: a part of respiration


What is an example of a metabolic pathway that is a cycle

Calvin cycle: it is a part of photosynthesis


What is activation energy

It is the amount of energy needed to get the reactants to the transition state (where bonds are broken and new ones are formed)

Aka the initial input of energy that is required to trigger a chemical reaction


How do enzymes lower activation energy (list the steps)

The substrate binds to the enzymes active site and the active site is altered to reach the transition state

Due to the binding, the bonds in the substrate molecule are stressed/ become less stable

The binding lowers the overall energy level of the transition state

The activation energy of the reaction is therefore reduced

Also, the net amount of energy released by the reaction is unchanged


Define an inhibitor

It is a molecule that binds to an enzyme and slows down or stops the enzymes function


What's the difference between and competitive inhibitor and a non-competitive inhibitor

Competitive: inhibitor fits in the active site and prevents the substrate from entering

Non-competitive: Inhibitor fits into an allosteric site, causing a conformational change in the active site. The substrate cannot attach to reach


One example of a competitive inhibitor?

Overcoming alcoholism:

Antabuse (disulfiram) competes with the aldehyde oxidase and prevents acetaldehyde from being converted into acetic acid

A build up of acetaldehyde follows, resulting in a strong feeling of nausea and other strong hangover symptoms - a good deterrent from drinking.

Antabuse is administered as a daily pill, so it's efficacy relies on the patients own motivations


Define metabolism

It is the sum of all chemical reactions that occur within an organism