C1.1 - Enzymes and Metabolism

a substance that can increases the rate of chemical reaction

Enzymes are biological catalysts, they speed up biochemicals reactions to occur quickly enough to sustain life processes.

Enzymes are not consumed in the reaction and can catalyze additional reactions.

The sum of all chemical reactions taking place in a cell at one time.

only 1 substrate will fit in the active site of an enzyme
This prevents unwanted side reactions and allows precise regulation of metabolic pathways.

If a cell produces an enzyme it can increase the speed of reaction that would otherwise happen slowly

Anabolic reactions synethise simple moleclues into complex molecules and catabolic reactions breakdown the complex molecules into simple molecules
Anabolic reactions require energy input, while catabolic reactions release energy.

photosynthesis protein synthesis and DNA replication

glycosis, digestion and cellular respiration

3d structure made out of amino acids. The amino acids that make up the activiation site may not be next to eachother in the polypeptide chain but are brought together by polypeptide folds(creates the 3d protein)

Enzyme specificity is determined by the shape of its active site, which only fits specific substrate molecules.
The active site binds to the substrate through interactions like hydrogen bonding or van der Waals forces, facilitating a chemical reaction and ensuring the enzyme catalyzes only specific reactions.

1) substrate goes into the active site of an enzyme through lock and key or induced fit(enzyme-substrate complex)
2)anabolic or catabolic reaction occur(This stresses substrate bonds, lowering activation energy)
3)products are released from active site

Substrate specific but not a fixed shape
1-Substrate binds to active site
2-Active site changes shape (conformational change)
3-Affects bonding in substrate(This stresses substrate bonds, lowering activation energy)
4-Product releases
5-Active site returns to original shape

Chemical reactions require molecules to collide.
They must have enough energy and the right orientation when they collide. Collisions can be increased by increasing temperature and concentration

In cytoplasmic reactions, both enzymes and substrates are free to move and randomly collide, facilitating interactions.

With large substrates, their slower movement may limit interaction rates, while immobilized enzymes remain fixed in place, requiring substrates to move towards them for the reaction to occur.

-Some enzymes can only bind with one substrate
-Other enzymes can bind with several closely related substrated

permanent change to the 3d structure of the active site of an enzyme causing the enzyme to be unable to catalyze the reaction

Causes:
Temp(When enzymes heated, bonds vibrate and are more likely to break)
pH(acditiy) If pH increases or decreases from the optimum, ionic bonds between amino acids in enzymes are altered and denatured

Effects to active site: prevent binding of substrates, prevent catalysis after binding

As concentration increases more frequent collisions occurr. Past a certain point the slope stagnates as all active sites are occupied

draw Slides 5 to 7

The factor being investigated ( manipulated )

temperature substrate concentration, enzyme concentration or pH

Amount of reaction / per unit time

1. Allow reaction to happen for a set amount of time and measure the amount of substrate used or product

2. ​Start with known amount of substrate and measure time taken for all substrates to convert to products

Energy needed to get a reaction started. It is used to break or weaken bonds in the substrate

an amount of energy is needed to Break bonds in substrate molecules to form products

Enzymes speed up reactions by lowering the activation energy by providing reactants an alternative pathway.