MCAT (Biological and Biochemical)

Question 1

Living cells must connect with the outside world regularly to obtain the elements they require for living and to eliminate waste. Which of the following processes relies solely on the material's gradient to regulate the direction in which it flows 
across the cell membrane?

Accepted Answer

Osmosis

Answer

Active Transport

Answer

Endocytosis

Answer

Passive Transport

Question 2

In order to divide and replicate themselves, somatic eukaryotic cells in the human body go through the cell cycle in a 
predictable pattern. The limitation point is the moment at which a cell decides to divide (R). How many chromosomes
 and chromatids does the cell have before this?

Accepted Answer

46 chromosomes, 46 chromatids

Answer

23 chromosomes, 46 chromatids

Answer

46 chromosomes, 92 chromatids

Answer

23 chromosomes, 23 chromatids

Question 3

For a cell to divide effectively, all five steps of mitosis must be completed correctly. Match the mitotic stage to
 the appropriate component:

Accepted Answer

Prophase — Dissolution of nucleoli

Answer

Metaphase — Formation of two distinct nuclear membranes

Answer

Anaphase — Separation of the cytoplasm and organelles

Answer

Cytokinesis — Separation of sister chromatids to their respective poles

Answer

Telophase — Formation of the equatorial plate

Question 4

Interactions between myosin and actin allow each sarcomere to shorten during muscle contraction. What other muscle 
contraction process, except the power stroke, necessitates the use of ATP?

Accepted Answer

Myosin-actin detachment

Answer

Tropomyosin-troponin interaction

Answer

Myosin-actin interaction

Answer

Calcium-troponin interaction

Question 5

During their adolescent years, Cystic Fibrosis (CF) patients frequently experience a loss of pancreatic activity. 
Which enzyme's absence, if isolated, would have the greatest impact on nutrient absorption?

Accepted Answer

Trypsinogen

Answer

Elastinogen

Answer

Carboxypeptidase

Answer

Lipase

Question 6

Neonatal Respiratory Distress Syndrome (NRDS) is a significant issue that occurs when a baby is born prematurely and 
their ability to assist oxygen passage through their alveolar membranes is disrupted. This is due to a lack of surfactant production.
 What role does surfactant play in the diffusion of oxygen?

Accepted Answer

Maintains alveoli in an open state

Answer

Dilates blood vessels

Answer

Increases surface permeability

Answer

Depresses cilia of the lung

Question 7

The electron transport chain, which is embedded in the mitochondrial membrane, is responsible for producing new ATP molecules
 for the cell to use. This is performed by a positive gradient of H+ ions forming outside the membrane and then passing back through 
ATP synthase, a specialized channel. The energy generated converts an ATP to an ATP, a process known as oxidative phosphorylation. 
What is the name of the mechanism that allows H+ to return to the mitochondrial interior?

Accepted Answer

Passive transport

Answer

Passive diffusion

Answer

Endocytosis

Answer

Active transport

Question 8

A ventricular septal defect is a hole in the septum between the right and left ventricles that is a common human heart abnormality. 
Which of the following statements is correct if a patient has this defect?

Accepted Answer

The percentage of oxygen in the right ventricle would be higher.

Answer

The percentage of CO2 in the right ventricle would be higher.

Answer

The percentage of oxygen in the left atrium would be lower.

Answer

The percentage of oxygen in the right atrium would be lower.

Question 9

Acute Myeloid Leukemia (AML) is a type of cancer in which myeloid progenitor cells divide rapidly while maintaining their semi-stem
 cell status. Which of the following cell types would develop from this stem cell under normal circumstances?

Accepted Answer

Platelet

Answer

NK cell

Answer

Lymphoid progenitor

Answer

T cell

Question 10

A patient arrives at the hospital after being bitten by a dog that was "behaving erratically," according to him. The incision is 
scabbed up and bleeding profusely. The dog was apprehended by animal control and described as foaming at the mouth and
 extremely hostile. When a rabies infection is suspected, the patient is given a serum containing rabies antibodies generated 
inside a horse. What kind of immunity is this an example of?

Accepted Answer

Passive

Answer

Artificial

Answer

Active

Answer

Natural

Living cells must connect with the outside world regularly to obtain the elements they require for living and to eliminate waste.Which of the following processes relies solely on the material's gradient to regulate the direction in which it flows across the cell membrane?

Living cells must connect with the outside world regularly to obtain the elements they require for living and to eliminate waste.
Which of the following processes relies solely on the material's gradient to regulate the direction in which it flows
across the cell membrane?