Biothermodtynamics DAT Booster

_____ describes when a cofactor is covalently bound to an enzyme.

Prosthetic group

______ experiences cooperativity.

Hemoglobin

If Km value of an enzyme is elevated, then the _____.

substrate does not bind to the enzyme well

Km is the ______.

Substrate concentration at half of the maximum rate of a catalyzed reaction

A drug can inhibit a substrate by mimicking its structure & binding to its enzyme’s active site. What is occurring?

competitive inhibition

In order to counteract competitive inhibition, what can be done?

Increase substrate concentration

What occurs during competitive inhibition of an enzyme?

• Substance mimics a substrate and inhibits the enzyme by binding at the active site

• Vmax is unchanged

• Km increases

What occurs during non-competitive inhibition of an enzyme?

• inhibitor binds to enzyme’s allosteric site, reaction does not get catalyzed

• Vmax decreases

• Km is unchanged

Which biological molecule makes up enzymes?

Amino acids

If biding affinity is high, then Km is ____.

low

Vmax is the ___.

max rate of an enzyme catalyzed reaction

If Km value of an enzyme is low, what is occuring?

Enzyme requires a relatively low substrate concentration to reach ½ Vmax

If a reaction has a +^G value, then _____.

• the reaction is endergonic (require an input of energy to occur)

• the reaction in non spontaneous

The ability to drive a secondary active transport can be explained by _____.

Gibbs free energy

What is an example of how potential energy is stored in the biological systems?

The chemical bonds b/w phosphate groups in an ATP molecule

How are non-spontaneous reactions driven forward in biological systems?

Reaction coupling

True or false: ATP’s bonds b/w its phosphate groups are high energy

True

True or false: ATP can be used to power non-spontaneous chemical reactions

True

True or false: ATP is a nucleotide

True

True or false: ATP hydrolysis is a highly endergonic reaction

False

True or false: The formation of ATP from ADP requires energy to occur

True

True or false: Catalysts can lower the activation energy of the reaction

True

True or false: Catalysts can stabilize the transition state

True

True or false: Catalysts can make non-spontaneous reactions spontaneous

False

True or false: Catalysts can provide an alternative pathway

True

True or false: Catalysts can be reused, as they are not consumed in the reaction

True

Enzyme-substrate complexes are held together via_____.

Weak, temporary bonds

What best describes cofactors and how they are involved in enzyme catalysis?

Cofactors can bind covalently or non-covalently to the enzyme

True or false: Zymogens help with enzyme regulation

True

True or false: All zymogens are proenzymes

True

True or false: Zymogens can be activated through cleavage

True

True or false: Zymogens are active biological catalysts

False

Pepsinogen is a zymogen found in the human stomach

True

What effects enzyme function and regulation?

pH, chemical modification, temperature, gene expression

What does not effect enzyme function and regulation?

free energy

How can the Vmax of an enzyme can be increased?

Increasing the enzyme concentration

What may affect the Km of an enzyme?

Competitive inhibition

What decreases the Vmax of an enzyme?

Non-competitive inhibition

What is true regarding the Gibbs free energy of cellular respiration?

^H-T^S has ne negative value (makes a reaction favorable)

ATP is an unstable molecule because ____.

it has 3 negatively charged phosphate groups

What is Q10?

It measures how sensitive reaction rates are to temperature changes

Q10 temperature coefficient equation

Q10 = (K2/K1)^(10/t2-t1)

Examples of hydrolases

• Lipase

• Peptidase

• Nuclease

• Amylase

_____are enzymes that break down molecules using water (via hydrolysis).

Hydrolases

• Chymotrypsin

• Pepsin

• Trypsin

All of these enzymes are involved in protein digestion

____ is an enzyme that is responsible for breaking down starch into maltose.

Amylase

A researcher needs to cut a circular plasmid at a specific DNA sequence in the middle of the strand. What enzyme should be used to make this cut?

Endonuclease