AP Bio Enzymes

metabolism

the sum of all chemical processes

an individual, specific enzyme

what catalyzes each step of a metabolic pathway?

True

T or F: Metabolic pathways are sequential and connected

Catabolic

Type of metabolic pathway that involves breaking down biomolecules.

Catabolic Pathway

Amylase breaking down starch, small intestine digestion are examples of a ___ pathway

Anabolic

Type of metabolic pathway that involves building biomolecules

Anabolic Pathways

photosynthesis, DNA synthesis, protein synthesis are examples of ___ pathway

Pathway coupling

In order for anabolic pathways to function, catabolic pathways are needed to supply energy

1st law of Thermodynamics

any organism can transform, absorb, and release energy

entropy

measure of randomness of particle movement

2nd law of thermodynamics

each energy conversion increases entropy

more heat leads to more entropy

relationship between heat and entropy

heat

for every energy transfer/transformation, some energy becomes unavailable to do work because it has been converted to __

Raise body temp, homeostasis

How do organisms use heat?

Input of entropy/heat counteracts entropy output

Why is it difficult to observe entropy?

Burn reserves, store energy

what happens if energy flow stops?

Free Energy Change Delta G

accessibility of energy

free energy

molecules are able to be metabolized for fuel, all food has free energy

Exergonic

reactions that release energy: cell respiration

Endergonic

reactions that condense energy: active transport, cell movement

Energy coupling

Energy released from exergonic reactions powers endergonic reactions; e.g ATP powering any type of work

RIbose sugar, adenine base, 3 phosphate groups

Components of ATP: sugar, nitrogenous base, phosphate groups

7.3 kCal

How much free energy is released in hydrolysis of ATP?

Very little energy to form/release; like charges in phosphates repel, making them easy to break.

Significance of ATP bonding and hydrolysis.

H20 + ATP —> ADP +Pi + 7.3 kCal

ATP hydrolysis equation

ADP +Pi + 7.3 kCal —> H20 + ATP

ATP Synthesis Equation

Catalyze (speed up) chemical reactions

What do enzymes do

See picture (Name as many as possible)

Characteristics of Enzymes

They lower the activation energy or energy needed to start a reaction

How do enzymes speed up chemical reactions?

Heat will destroy molecules and maybe denature enzymes.

Why is heat bad to use as energy of activation for organism?

ATP

supplies activation energy for metabolism

substrate

the target molecule that the active site of an enzyme is binding to

active site

the part of the enzyme that changes shape and binds to the substrate to catalyze a chemical reaction

Enzyme substrate complex

Enzyme combined with substrate

Enzyme Specificity

Shape of enzyme’s 3D structure determines its function

Enzymes slightly change the shape of their active site to perfectly bind to the substrate

Induced Fit model

catalytic Cycle

How fast enzymes bind to a substrate, release product, and repeat

The change in shape of the active site puts stress on the bonds of a substrate, making it easier to break.

How do enzymes lower activation energy for hydrolysis reactions?

Active site sticks reactants together

how do enzymes help synthesis anabolic reactions?

Enzyme Saturation

active sites being frequently occupied/collided with substrate increase reaction rate

Assuming saturation, the more substrate, the more collisions between active site and enzyme may occur, increasing reaction rate and then plateauing at max.

Substrate concentration impact on enzyme productivity

Assuming saturation, the more enzymes, the more collisions between active site and enzyme may occur, increasing reaction rate and then plateauing at max.

Enzyme concentration impact on enzyme productivity

enzyme productivity goes down

temp above and below optimal enzyme temp impact

denaturing and enzyme productivity rate 0

temp extremely above optimal enzyme temp leads to

denaturing

when the 3D shape of an enzyme changes, changing its function and thus not allowing it to bind to a specific substrate and catalyze a specific reaction. Destroys hydrogen bonds (primary) then ionic and covalent (secondary) and then the 3D shape.

NO DENATURING but near 0 enzyme productivity as collisions rarely occur

temps extremely below optimal enzyme temp lead to

denaturing, enzyme productivity becomes 0

extremely acidic or basic pH compared to optimum enzyme pH effect

enzyme productivity decreases

slight pH changes from optimal enzyme pH

Competitive Inhibitors

Attach to active site of enzyme, stopping a substrate from attaching and thus stopping the catalysis of a reaction

Noncompetitive inhibitors

attach to allosteric site, which changes shape of enzyme’s active site, stopping the substrate from binding to it.

Permanent Allosteric Inhibitors

Poisons use what kind of inhibitors? E.g Carbon Monoxide

Allosteric Activator

Changing the shape of an allosteric site thus active site to speed up a chemical reaction

Allosteric Inhibitor

Changing the shape of an allosteric site thus active site to slow down a chemical reaction

Feedback Inhibition

The product of a metabolic pathway is an inhibitor that slows down the pathway. When all of the product is used up or needed, the inhibitors are taken off and the pathway resumes and cycles again.

The microenvironments from compartmentalization can have very different conditions for optimal enzyme activity.

How do enzymes benefit from compartmentalization?