Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

Which of the following statements about the photoelectric effect is correct?

A. The kinetic energy of emitted electrons increases with increasing light intensity.. B. No electrons are emitted below a certain threshold frequency, regardless of light intensity.. C. Electrons are emitted even at zero frequency if the light intensity is high enough.. D. The number of emitted electrons decreases with increasing light frequency..

Like(0)

disLike (0)

Comment(0)

Explanation

According to the photoelectric effect, electrons are emitted from a material only if the incident light has a frequency above a certain threshold, regardless of the light's intensity.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

In the context of enzyme kinetics, what does a low Km value indicate about an enzyme's affinity for its substrate?

A. Low affinity. B. High affinity. C. No affinity. D. It depends on the enzyme's Vmax.

Like(0)

disLike (0)

Comment(0)

Explanation

A low Km value indicates high affinity of an enzyme for its substrate, meaning the enzyme can achieve its maximum catalytic efficiency at low substrate concentrations.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

What type of intermolecular force is primarily responsible for the high boiling point of water?

A. London dispersion forces. B. Dipole-dipole interactions. C. Hydrogen bonding. D. Ionic bonding.

Like(0)

disLike (0)

Comment(0)

Explanation

Hydrogen bonding, which occurs between the hydrogen atom of one water molecule and the oxygen atom of another, is the primary force responsible for water's high boiling point.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

In an electrolytic cell, which of the following occurs at the cathode?

A. Oxidation. B. Reduction. C. Electron flow into the anode. D. Positive ions migrate away from the cathode.

Like(0)

disLike (0)

Comment(0)

Explanation

In an electrolytic cell, reduction occurs at the cathode, where electrons are gained by the species being reduced.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

Which of the following is true regarding the relationship between Gibbs free energy (ΔG) and the spontaneity of a chemical reaction?

A. A reaction with ΔG > 0 is spontaneous.. B. A reaction with ΔG = 0 is at equilibrium.. C. A reaction with ΔG < 0 is non-spontaneous.. D. A reaction with ΔG = 0 has no change in entropy..

Like(0)

disLike (0)

Comment(0)

Explanation

When ΔG = 0, the system is at equilibrium, and there is no net change in the concentration of reactants and products.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

What is the main role of the enzyme carbonic anhydrase in red blood cells?

A. Transporting oxygen. B. Catalyzing the conversion of carbon dioxide to bicarbonate. C. Facilitating the absorption of glucose. D. Synthesizing hemoglobin.

Like(0)

disLike (0)

Comment(0)

Explanation

Carbonic anhydrase catalyzes the reversible conversion of carbon dioxide and water to bicarbonate and protons, which is crucial for CO2 transport in the blood.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

During oxidative phosphorylation, the energy for ATP synthesis is directly provided by:

A. The flow of electrons along the electron transport chain. B. The reduction of NAD+ to NADH. C. The establishment of a proton gradient across the inner mitochondrial membrane. D. The splitting of water molecules.

Like(0)

disLike (0)

Comment(0)

Explanation

The energy for ATP synthesis during oxidative phosphorylation comes from the proton gradient established across the inner mitochondrial membrane, which drives ATP synthase.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

Which principle explains the increase in pressure observed in a closed system when temperature is increased, assuming volume remains constant?

A. Boyle's Law. B. Charles's Law. C. Dalton's Law. D. Gay-Lussac's Law.

Like(0)

disLike (0)

Comment(0)

Explanation

Gay-Lussac's Law states that the pressure of a given mass of gas varies directly with the absolute temperature when the volume is constant.

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

Which of the following describes the type of bonding and interaction within a DNA double helix?

A. Ionic bonds between phosphate groups. B. Hydrogen bonds between complementary nitrogenous bases. C. Covalent bonds between ribose sugars. D. Van der Waals interactions between nitrogenous bases.

Like(0)

disLike (0)

Comment(0)

Explanation

The DNA double helix is stabilized by hydrogen bonds between complementary nitrogenous bases (adenine with thymine, and cytosine with guanine).

Mushkovic BIOLOGY - Chemical and Physical Foundations of Biological Systems

What is the primary function of myoglobin in muscle cells?

A. Transport oxygen from the lungs to tissues. B. Store oxygen for use during periods of high metabolic demand. C. Facilitate the breakdown of glucose. D. Catalyze the conversion of ADP to ATP.

Like(0)

disLike (0)

Comment(0)

Explanation

Myoglobin is an oxygen-binding protein in muscle cells that stores oxygen and releases it during periods of high metabolic demand, ensuring a continuous supply of oxygen for aerobic respiration.