HARD vers. - biology - enzymes revision for exam

Enzymes are protein molecules that control all metabolic reactions in living cells.

Enzymes:

Catalysts are chemical substances that can accelerate/speed up chemical reactions and can be reused many times

Catalysts:

Atoms and molecules are in constant motion and colliding and they are the substances that bind to enzymes

Atoms and molecules:

Reactants are the starting materials that bind with the enzymes to form a chemical reaction

Reactants:

Products are the ending materials that the enzyme releases after the chemical reaction occurs

Products:

Metabolism is the sum of all chemical reactions occurring within a living organism

Metabolism:

Activation energy is the amount of energy required for the reaction to begin

Activation energy:

Chemical reaction is a chemical change that occurs when two or more substances combine to form a new substance

Chemical reaction:

Bond-breaking is when a chemical reaction takes place at the active site where the more complex molecule (substrate) is broken down into two simpler forms (products)

Bond-breaking:

Bond-forming is when the two less complex molecules are metabolised into a more complex molecule

Bond-forming:

Amino acids are molecules that combine to form proteins.

Amino acids:

The active site is the surface of the enzyme with a specific shape.

Active site:

Substrates are the molecules that enzymes react with to create a chemical reaction.

Substrates:

Lock-and-key model is that the active site is rigid and the small substrate molecule is reciprocally shaped and fits exactly into the active site, like a key in a lock.

Lock-and-key model:

Induced-fit model is the binding of a substrate to the active site of an enzyme, causing it to alter its shape slightly, to fit more tightly around the substrate.

Induced-fit model:

Complex molecule could be two or more molecules together and is a bigger molecule that may need to be broken down into smaller molecules which end up being the products after the chemical reaction takes place in the active site of an enzyme.

Complex molecule (substrate):

Simpler forms of molecules may need to be bonded into one bigger molecule after the chemical reaction takes place, where the amino acids in the active site bind the two small molecules together.

Simpler forms of molecules (products):

Intracellular is inside the cell

Intracellular:



Temperature increase:
Temperatures can rise up and may exceed the optimal temperatures for enzymes.

Rate of reaction increase:
The rate of reaction can increase as the temperature increases but once it hits its optimal temperature and starts to go over, then the enzyme will begin to denature.

Denature:
Denature happens to an enzyme when the temperature reaches above the optimal temperature, and becomes too hot for it. The excessive heat causes the enzyme to change shape and size, destroying it until it is no longer functional anymore. Therefore it is not able to bind to substrates because of its denatured form.

Extracellular is outside the cell

Extracellular:

Optimal temperature is the temperature that is most suitable for an enzyme to function properly.

Optimal temperature:

Temperatures can rise up and may exceed the optimal temperatures for enzymes.

Temperature increase:

The rate of reaction can increase as the temperature increases but once it hits its optimal temperature and starts to go over, then the enzyme will begin to denature.

Rate of reaction increase:

Denature happens to an enzyme when the temperature reaches above the optimal temperature, and becomes too hot for it.

Denature:

Excessive heat can make the enzyme structure bend and flex so much that it changes the shape of the active site. This in turn causes substrates to no longer be able to bind to the enzyme as the heat causes the enzyme to denature and the enzyme can’t function as it normally would.

Excessive heat - irreversible:

Excessive cold causes the enzyme to change shape and makes its function slow down or stop. However, it is often reversible, unlike excessive heat.

Excessive cold - reversible:

Optimal pH is the most suitable level of acidity or alkalinity an enzyme functions most effectively in.

Optimal pH:

Acidic solutions - low pH (below 7)

Acid:

Alkaline solutions - high pH (above 7)

Alkaline:

Neutral solutions - pH of 7

Neutral

Levels of acidity or alkalinity outside the optimum pH for an enzyme can affect it and alter the shape and slow down or stop it from functioning completely.

Levels of acidity or alkalinity:

Substrate concentration is the amount and rate of substrate molecules that collide with enzyme molecules.

Substrate concentration:

Saturation point:
Saturation point is the highest point where enzymes can no longer bind with substrates as all available enzymes are used.

Saturation point: