Thermodynamics Review

Front

What do enzymes do to the free energy (ΔG) of a reaction?

Back

No change

Answer explanation

Enzymes do NOT change the ΔG of a reaction; they only lower the activation energy

Front

What is the process of the enol form of pyruvate converting to the keto form called?

Back

Tautomerization

Answer explanation

Front

What does Mg2+ do to the ΔG°' of ATP hydrolysis?

Back

Increase (less negative)

Answer explanation

Mg2+ stabilizes the negatively charged oxygen atoms in the phosphate groups by reducing electrostatic repulsion, which makes the ΔG°' less negative and releases less energy.

Front

What are the room and biological temperatures in K, respectively?

Back

298, 310

Front

A(n) _______ system allows NO exchange of matter or energy.

Back

isolated

Front

A(n) _______ system ONLY allows energy exchange.

Back

closed

Front

True or false: Thermodynamics tells us whether a reaction will occur and how fast that reaction will occur.

Back

False

Answer explanation

Thermodynamics only tells us the spontaneity of a reaction, NOT the rate of a reaction (kinetics).

Front

Rotation of the phi (Φ) and psi (Ѱ) angles directly leads to the formation of which level of protein structure?

Back

Secondary

Answer explanation

Front

Which of the following amino acids does NOT typically appear in an ⍺-helix? Proline, Methionine, Serine, Tryptophan

Back

Proline

Answer explanation

Proline is a helix breaker due to its rigid cyclic backbone.

Front

True or False: 3-10 helices are generally more stabilized compared to canonical ⍺-helices.

Back

False

Answer explanation

In ⍺-helices:

• - more side chain groups are exposed, leading to more interactions

• - they have fewer structural restrictions

• - more stable, especially in longer ⍺-helices

In 3-10 helices

• - use Van der Waals forces (less favorable)

• - they have several short and close contacts

• - are more restricted due to steric hinderance