Free Digestion MCQs with Answers
680 Digestion MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The human digestive system covers the organs from mouth to anus, the movement of food, and the mechanical and chemical breakdown of carbohydrates, proteins and fats. It also includes the roles of digestive enzymes, bile, absorption through intestinal villi, and the assimilation of nutrients by body cells.
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Read the Digestion notesFree MDCAT chapter notes with key terms680 questions · page 19 of 34
- A. Increases rate of breathing
- B. Increases respiratory volume
- C. Makes blood more acidic
- D. Decreases the oxygen carrying capacity of Hb
Explanation: Hypercapnia is a build-up of carbon dioxide (CO2) in the blood. It occurs when tiny air sacs in the lungs called alveoli are unable to…
Correct answer: Increases respiratory volume- A. 54ml/100ml of blood
- B. 50ml/100ml of blood
- C. 60ml/100ml of blood
- D. 4ml/100ml of blood
Explanation: Venus blood contains 4% more CO2 per 100ml (54ml/100ml) of blood as compared to arterial blood (50ml/100ml).
Correct answer: 54ml/100ml of blood- A. Oxygen
- B. Carbon dioxide
- C. Nitrogen
- D. Carbon monooxide
Explanation: Factual Recall. Carbon dioxide is more soluble in blood than oxygen, about 5 to 7 percent of all carbon dioxide is dissolved in the plasma.
Correct answer: Carbon monooxide- A. 20ml
- B. 16ml
- C. 13.4ml
- D. 19.6ml
Explanation: Factual Recall. When oxygen tension is 115 mmHg mercury haemoglobin is 98% saturated and therefore contains 19.6ml of oxygen per 100ml of…
Correct answer: 19.6ml- A. HCO3
- B. O2
- C. H+
- D. CO2
Explanation: Factual Recall. Note that: 70% of carhon dioxide is transported in the form of NaHCO3 as CO2 combines with amine group of haemoglobin.
Correct answer: HCO3- A. 158 mmHg
- B. Less than 100 mmHg
- C. 115 mmHg
- D. Less than 60 mmHg
Explanation: During cellular respiration, oxygen is used and carbon dioxide is produced, due to the consumpuon of oxygen there is least partial…
Correct answer: Less than 60 mmHg- A. 200 ml/liter
- B. 400 ml/liter
- C. 300 ml/liter
- D. 500 ml/liter
Explanation: Approximetaly there is 20% oxygen in the air (20ml/I 00ml or 200ml/l000ml).The air in Earth's atmosphere is made up of approximately 78…
Correct answer: 200 ml/liter- A. High CO2 concentration
- B. High pH
- C. High temprature
- D. High acitidy
Explanation: The hemoglobin molecule has four binding sites for oxygen molecules: the iron atoms in the four heme groups.
Correct answer: High pH- A. CO2
- B. O2
- C. Hydrogen ion
- D. CO
Explanation: Reduced hemoglobin (deoxyhemoglobin) contains four heme groups, each with a ferrous (Fe2+) ion capable of binding and transporting oxygen.
Correct answer: Hydrogen ion- A. Haemoglobin in erythrocytes
- B. Globulin in blood plasma
- C. Myoglobin in sarcoplasm
- D. Bicarbonate ions in RBCs
Explanation: Factual Recall. 90% of cytoplasm of erythrocytes is occupied by haemoglobin. Each molecule of haemoglobin carries four oxygen molecules.
Correct answer: Haemoglobin in erythrocytes- A. Amino group of haemoglobin
- B. Haem portion of haemoglobin
- C. Iron part of haemoglobin
- D. Plasma proteins
Explanation: Factual Recall. About 70% CO2is transported in the form of bicarbonate ions and about 20% is transported carboxyhaemoglobin.
Correct answer: Amino group of haemoglobin- A. Dissociation
- B. Stability
- C. Formation
- D. Transformation
Explanation: More CO2, less O2, high temperature and less pH facilitate oxygen dissociation from oxyhaemoglobin.
Correct answer: Dissociation- A. Active transport
- B. Cyclosis
- C. Phagocytosis
- D. Diffusion
Explanation: Gaseous exchange in humans takes place primarily through the process of diffusion.
Correct answer: Diffusion- A. 5 liter
- B. 0.5 liter
- C. 1.5 litre
- D. 3500 ml
Explanation: Tidal volume is the amount of air that moves in or out of the lungs with each respiratory cycle.
Correct answer: 0.5 liter- A. 5 liter
- B. 1.5 liter
- C. 500 ml
- D. 3500 ml
Explanation: Factual Recall. Residual volume is the volume of air remaining in the lungs after maximum forceful expiration.
Correct answer: 1.5 liter- A. 3000 ml
- B. 6000 ml
- C. 5000 ml
- D. 3500 ml
Explanation: Inspiratory reserve volume (IRV) is the additional volume of air that can be forcibly inhaled after a normal inhalation.
Correct answer: 3000 ml- A. It is a globular protein
- B. It contains organic haem group and inorganic Fe +
- C. Abundantly found in RBCs
- D. Each haem in haemoglobin can bind to four O2 molecules
Explanation: Option D is false. Each haem group in haemoglobin can bind to only one oxygen molecule (O2).
Correct answer: Each haem in haemoglobin can bind to four O2 molecules- A. 80 times
- B. 75 times
- C. 90 times
- D. 100 times
Explanation: Hemoglobin in humans increases the oxygen-carrying capacity of the blood by about 75 times.
Correct answer: 75 times- A. Haem
- B. B-globin chains
- C. A-globin chains
- D. Central iron atom
Explanation: The characteristic red color of hemoglobin is primarily due to the presence of the haem group, which contains an iron atom that can bind…
Correct answer: Haem- A. It is dipeptide and present in RBC
- B. It is dipeptide in mammals and localized in RBC
- C. It is present in dissolved state in blood plasma
- D. It is having haem group .
Explanation: Hemoglobin is a protein found in red blood cells (RBCs) that contains a haem group.
Correct answer: It is having haem group .