Module 7 Flashcards

Flashcards based on lecture notes about enzymes, regulation, and genetics.

Why can our stomach digest proteins without digesting itself?

Because digestive enzymes are made as zymogens (inactive precursors).

What are zymogens?

Inactive enzyme precursors activated by cleavage.

Why are proteases synthesized as zymogens?

To protect the producing cell from being digested.

What type of protein is chymotrypsinogen?

A zymogen (inactive precursor of chymotrypsin).

What type of proteins are blood clotting factors?

Zymogen proteases.

What do kinases do?

Transfer a phosphate from ATP to an acceptor.

Why can our stomach digest proteins without digesting itself?

Because digestive enzymes are made as zymogens (inactive precursors).

What are zymogens?

Inactive enzyme precursors activated by cleavage.

Why are proteases synthesized as zymogens?

To protect the producing cell from being digested.

What type of protein is chymotrypsinogen?

A zymogen (inactive precursor of chymotrypsin).

What type of proteins are blood clotting factors?

Zymogen proteases.

What do kinases do?

Transfer a phosphate from ATP to an acceptor.

How is Protein Kinase A (PKA) activated?

By release of an endogenous pseudosubstrate inhibitor upon cAMP binding.

Which state of ATCase has higher activity?

The R-state has higher activity than the T-state.

Which state does aspartate binding promote in ATCase?

The R-state.

What is the liver-specific glucose phosphorylating enzyme an example of?

Isozymes (different forms of an enzyme for tissue-specific roles).

What is acetylation of histones an example of?

Covalent modification.

What is the blood clotting cascade composed of?

Zymogens.

What common substrate do all kinases use?

ATP.

What is an isozyme?

Different enzyme forms with similar function but varying kinetic/regulatory properties.

What does the form of LDH in the heart indicate?

High substrate affinity; it's an isozyme.

How does CTP regulate ATCase?

Through feedback inhibition.

What is PALA in the context of ATCase?

A bisubstrate analog that inhibits ATCase.

What kind of kinetics does ATCase exhibit?

Sigmoidal (cooperative) kinetics.

Is the lac operator a DNA or protein?

DNA sequence; False that it is.

What happens to lac operon in absence of lactose?

It is not transcribed.

Does the lac repressor change shape

True; it changes shape.