AMC MCQ PRACTICE TEST 1 — Questions and Answers

Question 1: Which of the following mammalian cells is unable to aerobically metabolize glucose to carbon dioxide?

Liver cells
RBC (Correct answer)
Untreated muscle cells
WBC

Correct answer: RBC

Red blood cells are not capable of metabolizing glucose to carbon dioxide aerobically. They contain hemoglobin pigment.

Question 2: True or False: Respiration is a physical process and depends on the principle of diffusion.

A) False (Correct answer)
B) True

Correct answer: A) False

Respiration is a complex biological process that involves both physical gas exchange and biochemical reactions. While the gas exchange aspect (external respiration) relies on the physical principle of diffusion, cellular respiration is a metabolic pathway involving a series of enzymatic reactions to produce ATP. Therefore, stating it is *solely* a physical process dependent *only* on diffusion is incorrect.

Question 3: True or False: A person can expel all the air from the lungs.

A) False (Correct answer)
B) True

Correct answer: A) False

It is physiologically impossible to expel all the air from the lungs. Even after the most forceful exhalation, a volume of air known as the residual volume always remains in the lungs. This residual air prevents the collapse of the alveoli and ensures continuous gas exchange between breaths.

Question 4: The larger part of carbon dioxide created by the body is transported to lungs _______

As bicarbonates
Dissolved in blood
Attached to hemoglobin
As carbonates (Correct answer)

Correct answer: As carbonates

The vast majority of carbon dioxide produced by the body is transported to the lungs in the form of bicarbonate ions (HCO3-). CO2 diffuses into red blood cells, where it is converted to carbonic acid and then dissociates into bicarbonate and hydrogen ions. This allows for efficient CO2 transport and helps regulate blood pH.

Question 5: The diaphragm _______ during inspiration.

Contracts (Correct answer)
Relaxes
Expands
No change

Correct answer: Contracts

During inspiration (inhalation), the diaphragm contracts and flattens, moving downwards. This action increases the volume of the thoracic cavity, which in turn decreases the pressure within the lungs. The resulting pressure gradient causes air to flow into the lungs.

Question 6: _________ is controlled respiration.

Cerebellum
Cerebrum
Hypothalamus
Medulla oblongata (Correct answer)

Correct answer: Medulla oblongata

The medulla oblongata, located in the brainstem, contains the primary respiratory control centers. These centers automatically regulate the rhythm and depth of breathing, responding to chemical changes in the blood such as CO2 and O2 levels, thereby controlling involuntary respiration.

Question 7: Which of the following Produces greatest ATP?

Glycolysis
Krebs cycle
Oxidative Phosphorylation (Correct answer)
Fermentation

Correct answer: Oxidative Phosphorylation

Oxidative phosphorylation is the stage of cellular respiration that produces the most ATP. It involves the electron transport chain and chemiosmosis, where the energy from electrons carried by NADH and FADH2 is used to generate a large amount of ATP through ATP synthase. Glycolysis and the Krebs cycle produce only a small amount of ATP directly.

Question 8: The Krebs cycle produces which of the following?

NADH
FADH
ATP
All of the mentioned (Correct answer)

Correct answer: All of the mentioned

The Krebs cycle (also known as the citric acid cycle) is a central metabolic pathway that produces several important molecules. It generates reduced coenzymes like NADH and FADH2, which carry electrons to the electron transport chain, and also produces a small amount of ATP (or GTP) directly through substrate-level phosphorylation.

Question 9: How much CO2 has expired?

32% (Correct answer)
25%
20%
7%

Correct answer: 32%

The percentage of carbon dioxide in expired air is significantly higher than in inspired air due to metabolic processes. While inspired air contains about 0.04% CO2, expired air typically contains around 3.6% to 5% CO2, reflecting the CO2 released from the body's tissues.

Question 10: ____________ are the carriers of oxygen.

Leucocytes
Monocytes
Platelets
Erythrocytes (Correct answer)

Correct answer: Erythrocytes

Erythrocytes, or red blood cells, are the primary carriers of oxygen in the blood. They contain hemoglobin, a protein that reversibly binds to oxygen in the lungs and releases it in tissues where oxygen levels are lower, facilitating oxygen transport throughout the body.

Question 11: The fat RQ is ____________

less than one (Correct answer)
infinity
one
more than one

Correct answer: less than one

The Respiratory Quotient (RQ) for fats is typically less than one (around 0.7). This is because fats have a lower oxygen content relative to their carbon and hydrogen atoms compared to carbohydrates, meaning more oxygen is required for their complete oxidation, resulting in a lower CO2 produced to O2 consumed ratio.

Question 12: RQ stands for

The ratio of CO2produced to O2 consumed (Correct answer)
The ratio of oxygen consumed to water produced
The ratio of CO2produced to substrate consumed
The ratio of oxygen consumed to CO2 produced

Correct answer: The ratio of CO2produced to O2 consumed

RQ stands for Respiratory Quotient, which is a dimensionless ratio used in physiology. It is defined as the volume of carbon dioxide produced divided by the volume of oxygen consumed during respiration, providing insight into the type of metabolic fuel being utilized by the body.

Question 13: Hemoglobin cannot transport carbon dioxide.

A) False (Correct answer)
B) True

Correct answer: A) False

Hemoglobin can indeed transport carbon dioxide, although it is not its primary function. About 10-20% of CO2 is transported bound to the amino groups of hemoglobin, forming carbaminohemoglobin. The majority of CO2 is transported as bicarbonate ions.

Question 14: The maximum expiration of the lungs after deep inspiration is referred to as ________

Total lung capacity
Inspiratory capacity
Functional residual capacity
Vital capacity (Correct answer)

Correct answer: Vital capacity

Vital capacity is defined as the maximum amount of air a person can exhale from the lungs after a maximum inhalation. It represents the total volume of air that can be moved in and out of the lungs with a forceful breath, indicating overall lung function.

Question 15: The toxicity of oxygen is related to _________

Failure of ventilation of lungs (Correct answer)
Collapsing of the alveolar wall
Improper functioning of alveoli
Blood poisoning

Correct answer: Failure of ventilation of lungs

Oxygen toxicity, particularly pulmonary oxygen toxicity, occurs when high concentrations of oxygen are breathed for extended periods. This can damage the delicate alveolar-capillary membranes, leading to inflammation, fluid accumulation, and reduced lung compliance, which impairs gas exchange and can result in a failure of lung ventilation.

Question 16: When CO2 levels in the blood increase, breathing becomes ____________

no effect on breathing
shallower and deeper
slow and deep
faster and deeper (Correct answer)

Correct answer: faster and deeper

When carbon dioxide levels in the blood increase, the blood becomes more acidic, which is detected by chemoreceptors. These receptors signal the respiratory centers in the brain to increase both the rate and depth of breathing. This response helps to expel excess CO2 from the body and restore normal blood pH.

Question 17: In the lungs, the partial pressure of oxygen is ______________.

110 mm Hg
60 mm Hg
100 mm Hg (Correct answer)
40 mm Hg

Correct answer: 100 mm Hg

In the alveoli of the lungs, the partial pressure of oxygen (PO2) is approximately 100 mm Hg. This high partial pressure creates a steep gradient, driving oxygen from the alveoli across the respiratory membrane into the pulmonary capillaries, where the PO2 of deoxygenated blood is much lower.

Question 18: In respiratory metabolism, RQ equals 0.6, which means _________

Reaction is anaerobic
Carbohydrate is used as a respiratory substrate
Organic acids are used as a respiratory substrate
Oxidation of respiratory substrate consumed more O2than CO2produced (Correct answer)

Correct answer: Oxidation of respiratory substrate consumed more O2than CO2produced

An RQ of 0.6, which is less than 1, indicates that the respiratory substrate being oxidized requires more oxygen for its complete breakdown than the amount of carbon dioxide it produces. This is characteristic of substrates like fats or certain organic acids, which have a lower oxygen content relative to their carbon and hydrogen.

Question 19: On the inner surface of bronchioles and fallopian tubules, epithelial tissues are ________.

Ciliated (Correct answer)
Cuboidal
Squamous
Glandular

Correct answer: Ciliated

Both the inner surface of bronchioles in the respiratory system and the fallopian tubules in the reproductive system are lined with ciliated epithelial tissue. The cilia are hair-like projections that rhythmically beat to move mucus and trapped particles out of the respiratory tract, and to propel the ovum in the fallopian tubes.

Question 20: CO2 amount in expired air is _________.

0.03%
3.6% (Correct answer)
21%
0.04%

Correct answer: 3.6%

The amount of carbon dioxide in expired air is significantly higher than in inspired air, reflecting the CO2 produced by cellular metabolism. While inspired air contains about 0.04% CO2, expired air typically contains around 3.6% to 5% CO2.

Question 21: Bronchioles are the finest branches of the bronchial intercom.

A) False (Correct answer)
B) True

Correct answer: A) False

Bronchioles are indeed fine branches of the bronchial tree, but they are not the finest. The bronchioles further divide into terminal bronchioles, which then lead to respiratory bronchioles, alveolar ducts, and finally the alveolar sacs, where gas exchange occurs. The alveoli are the ultimate fine structures of the respiratory system.

Question 22: Which of the following is a condition in which cell division occurs uncontrollably and results in a tumor?

Lung cancer (Correct answer)
Emphysema
Bronchi cancer
Bronchioles cancer

Correct answer: Lung cancer

Lung cancer is a condition characterized by the uncontrolled division and growth of cells within the lung tissues, leading to the formation of malignant tumors. This abnormal cell proliferation is the hallmark of cancer, distinguishing it from other lung conditions.

Question 23: In heavy smokers, the alveoli become enlarged and damaged due to a reduction in surface area. This is referred to as ___________.

Silicosis
Asthma
Bronchitis
Emphysema (Correct answer)

Correct answer: Emphysema

Emphysema is a chronic obstructive pulmonary disease (COPD) primarily caused by smoking, where the walls of the alveoli are progressively destroyed. This destruction leads to enlarged, inefficient air spaces and a significant reduction in the surface area available for gas exchange, permanently impairing lung function.

Question 24: Which of the following does not belong to the respiratory system's conducting portion?

Bronchioles
Nose
Pharynx
Alveoli (Correct answer)

Correct answer: Alveoli

The conducting portion of the respiratory system includes structures like the nose, pharynx, and bronchioles, which function to transport, warm, humidify, and filter air. The alveoli, however, are part of the *respiratory portion*, where the actual exchange of gases (oxygen and carbon dioxide) between air and blood takes place.

Question 25: The humburger shift is also known as ___________

Chloride shift (Correct answer)
Bicarbonate shift
Sodium shift
Potassium shift

Correct answer: Chloride shift

The Hamburger shift is also known as the chloride shift. This process occurs in red blood cells, where bicarbonate ions (HCO3-), formed from CO2, are exchanged for chloride ions (Cl-) across the cell membrane. This mechanism facilitates the transport of CO2 from tissues to the lungs while maintaining electrical neutrality within the red blood cell.

AMC MCQ PRACTICE TEST 1

Which of the following mammalian cells is unable to aerobically metabolize glucose to carbon dioxide?