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BIOLOGY [3 marks Question Answer]

Respiratory System · ICSE STD 6 (ICSE - English Medium). 3 questions.

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[3 marks Question Answer]

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Question 13 Marks
What happens to Oxygen after it enters the lungs?
Answer
Each lung contains millions of alveoli. The walls of the alveoli are richly supplied with blood capillaries. The air which reaches the alveoli after passing through trachea, bronchi, bronchioles is rich in oxygen and contains very little $CO _2$. The blood capillaries of the alveoli contain blood that has more carbon dioxide and little oxygen. The oxygen diffuses from the thin walls of the capillaries into the blood and combines with hemoglobin in the red blood cells of blood thereby forming oxyhemoglobin. Hemoglobin is a type of protein which contains iron. The blood carries oxygen to all the cells of the body. In the cells, a series of chemical reactions, $CO _2$, water and energy are released. The carbon dioxide released combines with the hemoglobin to form carbomino hemoglobin. Then the blood rich in carbominohaemoglobin leaves the cells and reaches the alveoli where $CO _2$ gas is released and is exhaled out through the nose.
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Question 23 Marks
How is aerobic respiration different from anaerobic respiration?
Answer
Aerobic respiration
  1. It occurs in the presence of oxygen
  2. It occurs inside the mitochondria.
  3. Complete oxidation of food takes place.
  4. The end products are CO2 and water.
  5. 38 ATP molecules are produced by oxidation of one gram mole of glucose.

Anaerobic respiration

  1. It occurs in the absence of oxygen.
  2. It occurs outside the mitochondria.
  3. Incomplete oxidation of food takes place.
  4. Ethyl alcohol or lactic acid are the end products.
  5. 2 ATP molecules are produced by oxidation of one gram mole of glucose.
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Question 33 Marks
Explain the process of Cellular Respiration.
Answer
Cellular Respiration is a biochemical process which involves the oxidation of glucose to release energy, carbon dioxide, and water are released as by-products.
$\underset{\text { glucose }}{ C _6 H _{12} O _6{ }^{+}{ }^{+} 6 O _2} \xrightarrow{\text { exzgymen }} \underset{\text { Carbon dioxide }}{6 CO _2}+\underset{\text { water }}{6 H _2 O }+$ energy
It involves a series of chemical reactions controlled by different enzymes. The energy released in the process is stored in the form of an energy-rich substance called ATP (Adenosine triphosphate). The ATP molecules are stored in the cells and later on can be broken down to release energy for various metabolic activities. The entire process takes place partially in the cytoplasm and partially in the mitochondria of our body cells. The process of conversion of glucose molecules in food into energy-rich molecules, CO2 and water with the help of oxygen is known as respiration
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[3 marks Question Answer] - BIOLOGY STD 6 Questions - Vidyadip