MCAT AAMC | Latest Update | 2024/2025
| Graded A+
What is the primary role of the liver in glucose metabolism?
✔✔ The liver regulates blood glucose levels by storing glucose as glycogen and releasing it as
needed. This helps maintain stable blood sugar levels throughout the day.
How does a competitive inhibitor affect enzyme activity?
✔✔ A competitive inhibitor binds to the active site of an enzyme, competing with the substrate.
This reduces the enzyme's ability to catalyze the reaction, but can be overcome by increasing
substrate concentration.
What is the function of the myelin sheath in neurons?
✔✔ The myelin sheath insulates nerve fibers, increasing the speed of electrical signal
transmission along the axon by allowing signals to jump between nodes of Ranvier.
1
, Describe the process of cellular respiration and where it occurs in the cell.
✔✔ Cellular respiration involves the breakdown of glucose to produce ATP. It occurs in several
stages: glycolysis in the cytoplasm, the Krebs cycle in the mitochondrial matrix, and oxidative
phosphorylation in the inner mitochondrial membrane.
How does the structure of hemoglobin contribute to its function in oxygen transport?
✔✔ Hemoglobin has a quaternary structure with four subunits, each containing a heme group
that binds oxygen. The cooperative binding effect allows hemoglobin to pick up oxygen in the
lungs and release it in tissues.
What is the role of ribosomal RNA (rRNA) in protein synthesis?
✔✔ rRNA is a key component of ribosomes, where it helps catalyze peptide bond formation
between amino acids during translation, facilitating protein synthesis.
Explain the difference between exergonic and endergonic reactions.
2
| Graded A+
What is the primary role of the liver in glucose metabolism?
✔✔ The liver regulates blood glucose levels by storing glucose as glycogen and releasing it as
needed. This helps maintain stable blood sugar levels throughout the day.
How does a competitive inhibitor affect enzyme activity?
✔✔ A competitive inhibitor binds to the active site of an enzyme, competing with the substrate.
This reduces the enzyme's ability to catalyze the reaction, but can be overcome by increasing
substrate concentration.
What is the function of the myelin sheath in neurons?
✔✔ The myelin sheath insulates nerve fibers, increasing the speed of electrical signal
transmission along the axon by allowing signals to jump between nodes of Ranvier.
1
, Describe the process of cellular respiration and where it occurs in the cell.
✔✔ Cellular respiration involves the breakdown of glucose to produce ATP. It occurs in several
stages: glycolysis in the cytoplasm, the Krebs cycle in the mitochondrial matrix, and oxidative
phosphorylation in the inner mitochondrial membrane.
How does the structure of hemoglobin contribute to its function in oxygen transport?
✔✔ Hemoglobin has a quaternary structure with four subunits, each containing a heme group
that binds oxygen. The cooperative binding effect allows hemoglobin to pick up oxygen in the
lungs and release it in tissues.
What is the role of ribosomal RNA (rRNA) in protein synthesis?
✔✔ rRNA is a key component of ribosomes, where it helps catalyze peptide bond formation
between amino acids during translation, facilitating protein synthesis.
Explain the difference between exergonic and endergonic reactions.
2
