All Free Biology MCQs with Answers

• A. 50 times
• B. 20 times
• C. 70 times
• D. 100 times
• E. 200 times

Explanation: Oxygen is carried in the blood in two forms:(1)Plasma and (2) Hemoglobin. Hemoglobin carries 70 times more oxygen than plasma.

• A. Myoglobin
• B. Globin
• C. Haemoglobin
• D. Hemocyanin

Explanation: Myoglobin is a pigment that has the highest affinity to bind with oxygen.

• A. Trachea
• B. Bronchus
• C. Alveoli
• D. Nasal sac
• E. Larynx

Explanation: Pharynx leads to the air into the larynx through glottis, as shown in the diagram below:

• A. Osmosis
• B. Photosynthesis
• C. Translocation
• D. Transpiration
• E. Transcription

Explanation: Water is lost by the process of transpiration, the process of water movement through a plant, and its evaporation from aerial parts, such…

• A. X only
• B. X and Y only
• C. X and Z only
• D. Y and Z only
• E. X, Y and Z

Explanation: During breathing diaphragm contracts and external intercostal muscles contract, which are labeled as Z and Y respectively in the above…

• A. Option A
• B. Option B
• C. Option C
• D. Option D
• E. Option E

Explanation: During inspiration, contraction of the diaphragm causes its dome shape to flatten its dome shape whereas the contraction of the external…

• A. Clam warm
• B. Spider
• C. Silverfish
• D. Leech

Explanation: Book lungs are respiratory organs found in certain arthropods, specifically spiders and some related arachnids.

• A. More rate of respiration
• B. Less the rate of respiration
• C. Rate of respiration has nothing to do with the size of animal
• D. None of these

Explanation: Larger the organism, more is the distance covered for circulation of blood inside the body...so, more time is taken to circulate blood to…

• A. Decreases the heart rate
• B. Decreases the blood pressure
• C. Block the transport or oxygen
• D. Paralyzes cells

Explanation: Nicotine causes your blood vessels to constrict or narrow, which limits the amount of blood that flows to your organs.

• A. Larynx
• B. Trachea
• C. Bronchi
• D. Alveoli

Explanation: The gaseous exchange in the human respiratory system takes place between the alveoli and capillaries of the lungs.

• A. Nitrogen
• B. Iron
• C. Carbon
• D. Hydrogen

Explanation: Iron associated with the heme binds oxygen.

• A. Sodium bicarbonate
• B. Potassium bicarbonate
• C. Carbamino-haemoglobin
• D. Dissolved gas in plasma

Explanation: Nearly 20-25 percent of CO2 is transported by RBCs whereas 70 percent of it is carried as bicarbonate.

• A. Stomata
• B. Mesophyll
• C. Endoderm
• D. Xylem

Explanation: The exchange of oxygen and carbon dioxide in the leaf (as well as the loss of water vapor in transpiration) occurs through pores called…

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

Explanation: Smoking destroys the tiny air sacs, or alveoli, in the lungs that allow oxygen exchange.

• A. Pleura
• B. Rib cage
• C. Pericardium
• D. Diaphragm

Explanation: Option A: The pleura is a thin layer of tissue that lines the lungs and the chest cavity.

• A. In the form of bicarbonate ions.
• B. Bound to albumin compounds.
• C. Dissolved in the plasma.
• D. By the leukocytes.
• E. Bound to hemoglobin.

Explanation: Bicarbonate ions are involved in the transport of carbon dioxide in the blood.

• A. Globin
• B. Glycogen
• C. Myoglycogen
• D. Myoglobin

Explanation: Myoglobin is a low molecular weight oxygen-binding heme protein that is found exclusively in the heart and skeletal muscle cells.

• A. Tracheal cells
• B. Goblet cells
• C. Surfactant cells
• D. Pleural cells

Explanation: The primary function of goblet cells is to synthesize and secrete mucus.

• A. Less than 100
• B. 10,000
• C. One million
• D. None of the above

Explanation: Number of stomata depend on environmental factors like carbon dioxide concentration.

• A. 10
• B. 20
• C. 30
• D. 40

Explanation: In 100 ml of blood, there is about 15 g of Hb, so that 100 ml of blood has the capacity to bind 20.1 ml of oxygen.