Enzyme reaction velocity and pH

What is the main topic of the video described in the transcript?

The effect of pH on enzymes and how acidic or basic environments influence enzyme activity.

What are enzymes?

Molecules that help catalyze various reactions and are found throughout biological systems.

What are most enzymes made of?

They are usually large proteins made up of chains of amino acids.

What does the primary structure of an enzyme represent?

The sequence of amino acids in the protein chain.

What helps define the secondary structure of a protein?

Interactions within the amino acid backbone, especially hydrogen bonding.

What is a hydrogen bond according to the review?

An interaction between hydrogen and a more electronegative atom.

What example is used to explain hydrogen bonding?

Water molecules, where oxygen is more electronegative than hydrogen, creating partial charges.

Why does the oxygen end of a water molecule get a partial negative charge?

Because oxygen hogs electrons more due to its higher electronegativity, causing electrons to spend more time near it.

Why do hydrogen ends of water molecules get partial positive charges?

Because the shared electrons spend less time around the hydrogens.

What Greek symbol is used for “partial charge”?

The Greek lowercase delta (δ).

What attracts the partially negative end of one water molecule to the partially positive end of another?

Hydrogen bonding.

Besides oxygen, what other electronegative atom commonly forms hydrogen bonds in biological systems?

Nitrogen.

How can hydrogen bonds affect enzymes?

They help define the protein’s secondary structure, shape, and interaction with substrates.

How may substrates interact with enzymes at the molecular level?

Parts of the substrate may form hydrogen bonds with regions of the enzyme.

In the schematic described, what do the dotted lines represent?

Hydrogen bonds between the substrate and the enzyme.

In the diagram described, what is circled in yellow?

The substrate.

What does “pH” stand for in the context of the transcript?

Power of hydrogen.

How is pH defined in introductory chemistry?

As the negative log of the hydrogen ion concentration.

What is a hydrogen ion essentially?

A proton.

Why can pH affect an enzyme’s shape and ability to bind substrates?

Because hydrogen ions can disrupt or influence hydrogen bonds between amino acids or between enzymes and substrates.

How can hydronium ions affect enzyme hydrogen bonding?

They may usurp hydrogen bonds or repel positive ends of molecules, altering bonding interactions.

What does the reaction velocity vs. pH graph typically display?

Reaction velocity on the vertical axis and pH on the horizontal axis.

What does a high hydrogen ion concentration indicate on the pH scale?

A low pH, corresponding to an acidic environment.

What does a low hydrogen ion concentration indicate?

A high pH, corresponding to a basic environment.

What pH corresponds to a neutral environment?

A pH around seven.

Why do different enzymes show peak activity at different pH levels?

Because enzymes have distinct shapes and bonding interactions influenced by hydrogen ion concentration.

What is an example of an enzyme with peak activity at pH 4?

An enzyme typically found in the stomach, an acidic environment.

What pH might represent the peak activity of an enzyme that prefers neutral conditions?

A pH of seven.

What pH might represent the optimal activity of an enzyme suited to a basic environment?

A pH higher than seven.

How does stomach lipase behave with respect to pH?

Stomach lipase has optimum activity at a pH of about 4 or 5.

How does pancreatic lipase behave with respect to pH?

Pancreatic lipase, found in the small intestine, has optimal activity at a pH of about eight.

What is the big picture conclusion given near the end of the transcript?

An enzyme’s shape and substrate interaction depend heavily on hydrogen bonds, which are influenced by hydrogen ion concentration, causing enzymes to have different reaction velocities at different pH levels.

What environments can different enzymes be adapted to?

Acidic, neutral, or basic environments, depending on the enzyme and substrate