Biochemistry Overview AB

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What does thermodynamics primarily describe?

Exchange of energy between a system and its environment. (correct)
The behavior of ideal gases.
The relationships between different forms of matter.
The conversion of chemical energy into thermal energy.

Which of the following is an example of an extensive state variable?

Volume (correct)
Concentration
Pressure
Temperature

What does the first law of thermodynamics state?

Energy is conserved and can only change forms. (correct)
Energy can be created and destroyed.
Energy cannot do work.
Energy can be lost during a phase change.

Which of the following pairs of variables includes one intensive and one extensive variable?

Temperature and Volume (D) Signup and view all the answers

In thermodynamics, what does the symbol ∆U represent?

The internal energy change of the system. (B) Signup and view all the answers

What is the relationship between Gibbs free energy change and redox potential in the context of electron transfer?

Gibbs free energy decreases as redox potential increases. (C) Signup and view all the answers

In which state are nutrients primarily stored as glycogen, protein, and fat?

Postprandial state (B) Signup and view all the answers

What drives the synthesis of ATP in the electron transport chain?

Protons are driven back into the mitochondrial matrix. (C) Signup and view all the answers

What is the role of electronegativity in chemical bonding?

It indicates the ability of an atom to attract shared electrons. (C) Signup and view all the answers

Which of the following accurately describes the process of respiration?

It involves the transfer of electrons to an external electron acceptor. (D) Signup and view all the answers

What occurs during the basal (overnight fast) state?

Glycogen is mobilized to maintain blood glucose levels. (D) Signup and view all the answers

What is the effect of uncoupling in brown fat cells?

It dissipates the proton motor force, generating heat instead of ATP. (C) Signup and view all the answers

In the context of electron transport, what does the equation ∆μ = - n F ∆E represent?

The relationship between chemical potential and redox potential. (B) Signup and view all the answers

What role do chaperones play in protein folding?

They prevent protein aggregation during the folding process. (A) Signup and view all the answers

What happens to proteins when they are subjected to denaturing conditions?

They become irreversibly aggregated. (C) Signup and view all the answers

Which structure forms first during protein folding?

Helix (A) Signup and view all the answers

What is the function of Hsp70 in a cell?

It prevents protein folding on the ribosome and assists in stabilizing partially folded proteins. (B) Signup and view all the answers

How does the behavior of ATP synthase relate to conformational changes in proteins?

It undergoes a rotational motion influenced by proton flux, which is critical for ATP generation. (D) Signup and view all the answers

What typically triggers the proteasome to degrade a protein?

The protein fails to fold correctly after multiple attempts. (C) Signup and view all the answers

What is the primary function of allosteric inhibitors in proteins?

They decrease the activity of the protein by binding away from the active site. (D) Signup and view all the answers

What is the impact of acid on protein structure?

It leads to unfolding due to the disappearance of negative charges. (B) Signup and view all the answers

What is the significance of hydrophobic effects in protein folding?

They assist in the rapid formation of a helix and stabilization of the folded state. (B) Signup and view all the answers

What effect does a low pH (high H+ concentration) have on hemoglobin?

It promotes the T state, leading to increased O2 release. (B) Signup and view all the answers

Which type of fatty acid contains only single bonds between carbon atoms?

Saturated fatty acids (C) Signup and view all the answers

What is a primary characteristic of unsaturated fatty acids?

They can contain one or more double bonds. (D) Signup and view all the answers

What forms the basic structure of triacylglycerols?

A glycerol molecule linked to three fatty acids. (C) Signup and view all the answers

Which lipid is primarily responsible for cell membrane fluidity?

Cholesterol (A) Signup and view all the answers

What distinguishes phospholipids from other lipids?

They have a hydrophilic head and hydrophobic tail. (D) Signup and view all the answers

What is the main component generated by normal metabolism that contributes to acidity in the body?

Carbon dioxide (A) Signup and view all the answers

How are glycolipids different from phospholipids?

Glycolipids contain a sugar in their polar head. (C) Signup and view all the answers

What characteristic of a buffer determines its effectiveness in resist changes in pH?

Its concentration (C), Its pKa relative to pH of the solution (D) Signup and view all the answers

What type of bond involves the sharing of an electron pair between two atoms with similar electronegativity?

Covalent bond (A) Signup and view all the answers

What type of bonds do saturated fatty acids form, contributing to their solid state at room temperature?

Single bonds (D) Signup and view all the answers

What defines a hydrogen bond in water?

A partially positive hydrogen is attracted to a partially negative oxygen (C) Signup and view all the answers

What is the consequence of the presence of trans double bonds in fatty acids?

They are rare in nature and usually created industrially. (C) Signup and view all the answers

Which statement best describes ionic bonds?

They are formed by atoms with large differences in electronegativity. (D) Signup and view all the answers

What typically occurs during non-hydrogen dipole interactions?

Attractive and repulsive forces depend on dipole orientation. (C) Signup and view all the answers

What is a common feature of induced dipoles?

They are generated by the presence of an ion or dipole. (A) Signup and view all the answers

What type of bonding occurs when there is a significant difference in electronegativity between two atoms?

Ionic bonding (D) Signup and view all the answers

Which statement is true regarding London dispersion forces?

They arise from fluctuations in electron density within non-polar groups. (D) Signup and view all the answers

What is the relationship between electronegativity and the tendency of an atom to gain electrons?

High electronegativity leads to a strong tendency to gain electrons. (B) Signup and view all the answers

What is the relationship between entropy and spontaneous reactions?

Increasing entropy in a system indicates a spontaneous reaction. (D) Signup and view all the answers

For a process to occur spontaneously in an isolated system, which statement is true?

The system will reach maximal entropy and equilibrium. (B) Signup and view all the answers

In an open system, under what condition will processes occur spontaneously?

If the total change in entropy of the system and environment is greater than zero. (B) Signup and view all the answers

What does the Gibbs free energy (G) indicate about a system?

It predicts if a process can occur spontaneously based on entropy changes. (C) Signup and view all the answers

How is the entropy of the environment related to heat exchange in a system?

It increases as the system exchanges heat with its surroundings. (A) Signup and view all the answers

What does the equation ∆G = ∆Hsys - T∆Ssys indicate?

It relates changes in enthalpy and entropy to predict spontaneity. (D) Signup and view all the answers

What is the significance of a negative change in Gibbs free energy (∆G < 0)?

The process has a larger total increase in entropy. (C) Signup and view all the answers

Which relationship does the Henderson-Hasselbalch equation express?

The relationship between pH, dissociation constant, and concentration of acid. (A) Signup and view all the answers

What does the term 'equilibrium' refer to in a thermodynamic context?

The point at which net changes cease to occur in the system. (A) Signup and view all the answers

Which of the following describes a characteristic of weak acids?

Only a small percentage of molecules dissociate. (C) Signup and view all the answers

Thermodynamics

The study of how energy is exchanged between a system and its surroundings. This encompasses various energy forms and their transformations for doing work.

State Variables

Properties that describe the state of a system at a specific moment. They don't depend on how the system reached that state.

Extensive State Variable

State variables that add up when combining two systems. For example, the total volume of two combined containers is the sum of their individual volumes.

Intensive State Variable

State variables that don't add up when combining two systems. For example, the temperature doesn't change if two systems at the same temperature are combined.