All Free Biology MCQs with Answers

• A. Tuberculosis
• B. Asthma
• C. Emphysema
• D. Bronchitis

Explanation: Option A, tuberculosis, is a bacterial infection of the lungs, characterized by persistent cough, fever, and weight loss.

• A. Help them float on water
• B. Limit water loss, by increasing the surface area
• C. Help them survive in salty environment
• D. Limit water loss, by reducing the surface area

Explanation: Xerophytes are plants that are adapted to survive in environments, with very little water.

• A. Bronchi
• B. Bronchioles
• C. Windpipe
• D. Alveolar duct

Explanation: Another name of the trachea is the 'windpipe'.

• A. Chemical process
• B. Biochemical process
• C. Mechanical process
• D. Both A and B

Explanation: Breathing is a mechanical process and it is a surface phenomenon.

• A. Emphysema
• B. Asthma
• C. Pneumonia
• D. Bronchitis

Explanation: Emphysema is one of the diseases that comprises COPD (chronic obstructive pulmonary disease).

• A. Alveoli
• B. Trachea
• C. Bronchiole
• D. Bronchus

Explanation: Option A: Lungs are the organs of ventilation in terrestrial animals. In humans, nostrils lead to the trachea or windpipe through the…

• A. Lungs
• B. Alveoli
• C. Windpipe
• D. Alveolar duct

Explanation: The respiratory surface is the actual surface where the exchange of gases actually takes place.

• A. Coronary heart disease
• B. Bronchitis
• C. Emphysema
• D. Asthma

Explanation: In emphysema, the inner walls of the lungs' air sacs (alveoli) are damaged, causing them to eventually rupture.

• A. Myoglobin and Haemoglobin has higher affinity for nitrogen
• B. Cyanide and Haemoglobin has a low affinity for oxygen
• C. Myoglobin has more affinity for oxygen as compared to haemoglobin
• D. Albumin, Globulin and Globin proteins are present in respiratory pigments

Explanation: Myoglobin's affinity for oxygen is higher than haemoglobin. And unlike haemoglobin which is found in the red blood cells, myoglobin is…

• A. Efficient gas exchange
• B. Both A and C
• C. Maintaining structural integrity of alveoli
• D. None of these

Explanation: Lung surfactant is a complex with a unique phospholipid and protein composition.

• A. Bronchi
• B. Bronchioles
• C. Pharynx duct
• D. Alveoli

Explanation: "The explanation for this question will be added soon!".

• A. Acute bronchitis
• B. Chronic bronchitis
• C. Coastal bronchitis
• D. Intercostal bronchitis

Explanation: 'Acute bronchitis' is a contagious viral infection that causes inflammation of the bronchial tubes - these are the airways that carry air…

• A. Lungs
• B. Gills
• C. Bladder
• D. Trachea

Explanation: The bladder is not directly associated with the process of respiration.

• A. The lungs get inflated
• B. The man dies as the lungs collapse
• C. The breathing rate decreases
• D. The breathing rate increases

Explanation: This would eventually lead to the damage of pleural membrane which in turn would disrupt the pressure balance of gases, which would lead…

• A. Voice box
• B. Epiglottis
• C. Bronchi
• D. Windpipe

Explanation: The trachea is also known as the windpipe as it carries air from the larynx to the bronchi so the correct answer is Option D.

• A. Melanin
• B. Myoglobin
• C. Rhodopsin
• D. Lutein

Explanation: Myoglobin is a protein primarily located in the striated muscle hence it is known as the muscle hemoglobin.

• A. Rise in pH of guard cells causes hydrolysis of starch.
• B. Cytokinins and cAMP are required.
• C. Absicisic acid promotes closure.
• D. All of the above.

Explanation: Correct option is D. Abscisic acid (ABA) stimulates closure of stomata in the epidermal tissue of the leaves.

• A. Both glottis and voice box
• B. Bronchi
• C. Glottis
• D. Voice box

Explanation: The glottis and voice box (larynx) are intermediates between the trachea and pharynx.

• A. Plasma membrane
• B. Epithelial membrane
• C. Meninges
• D. Mucous membrane

Explanation: Glottis is part of the upper respiratory tract and so, is lined by mucous membranes.

• A. Carbaminohemoglobin
• B. Protein
• C. Micelles
• D. Cholestrol

Explanation: When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed. Option B,C and D are incorrect