Matric Notes Biology Class 10th Ch 10 Gaseous Exchange Short Questions
Q1: Why plants don’t need specialized respiratory system?
Ans: Need of specialized respiratory system for plants:-
1. Plants do not need any respiratory system such as lungs or gills which are found in animals.
2. Plants have large surface area and gaseous exchange occur in them by the process of diffusion.
3. Plants possess millions of leaves and each leave contains a lot of stomata.
4. Stomata are small pores which help in the exchange of gaseous.
5. The aquatic plants obtained the dissolved oxygen from water by diffusion.
6. The land plant obtains oxygen from the surrounding air through stomata on their leaves and young stems.
Q2: Differentiate between respiration and breathing?
Ans: Respiration
• Respiration is energy releasing process at cellular level whereby food is broken for release of energy.
• In this process complex organic substances like glucose, are broken down into simpler compounds like carbon dioxide and water with the release of energy.
Breathing
• Breathing is inhalation and exhalation of air for the intake of oxygen and giving out of carbon dioxide.
• In breathing fresh air is made available to the respiratory surface of lungs for gaseous exchange.
• In higher animals lungs are the organs of breathing,
Q3: How are the surface area of leaves and lungs important for gaseous exchange?
Ans: Importance of surface area for gaseous exchange:
I. Gaseous exchange is necessary for normal survival and metabolic activities of plants and animals. Gaseous exchange occurs through surface area which means that if there is more surface area then there would be more area available for the gases exchange and the exchange of gases would be effective.
II. In plants, more surface area of the stomata in leaves assist in the gases exchange.
III. Photosynthesis and respiration are the two main processes which need gaseous exchange. During day time both photosynthesis and respiration occur but at night only respiration occurs in plants. The gases i.e. oxygen and carbon dioxide exchanged through stomata of leaves in plants.
IV. During day time oxygen is produced in photosynthesis which is released through stomata. At night only respiration occurs in plants during which oxygen diffuses from environment
into the leaves and CO2 diffuses from leaves into the environment through stomata in leaves.
V. During day and night the carbon dioxide is produce in respiration which is released through lungs in animals.
VI. In animals, the more surface areas of the alveoli in lungs assist in the gases exchange.
VII. As the exchange of oxygen and CO2 is necessary for photosynthesis and respiration. So, the surface area is very important in gases exchange, more surface area more effective will be the gases exchange.
Q4: What is the function of the cartilage present in the wall of trachea and bronchi?
Ans: Cartilage: The soft bone in the body is called cartilage. It is a flexible connective tissue. It can bend a bit, but resist stretching.
Location: It is found in different parts of the body. e.g. in the joints, the ribcage, the ear, the nose, the throat and between the bones of the back
Cartilage in trachea: The trachea has the 16-20 C-shaped cartilaginous rings.
Cartilage in bronchi: The bronchi also possess cartilaginous ring but are smaller than those of the trachea.
Functions: It has following functions
Support: Cartilage provides support to the trachea and bronchi.
Prevent collapsing: Cartilages prevents trachea and bronchi from collapsing and keep the passage of air open.
Connection: It also connects two bones together.
Provide place for bones: It creates a place on which bones can form when they are first developed.
Protection: It also helps to protect the places where bones can work against each other.
Q5: What is diaphragm and its role in breathing?
Ans: Diaphragm: It is a muscular structure in the human body.
Structure: Diaphragm is a dome shaped sheet of skeleton muscles.
Position: Diaphragm is present below the lungs.
Functions: The muscles of diaphragm contract and relax during breathing which help in gaseous exchange.
Inspiration: During inspiration the muscles of diaphragm contract so it becomes flat instead of its dome shape.
Expiration: While during expiration the muscles of diaphragm relax and the diaphragm become dome shaped.
Working of diaphragm: When the diaphragm contracts and moves lower, the chest cavity enlarges, reducing the pressure inside the lungs. To equalize the pressure, air enters the lungs.
When the diaphragm relaxes and moves back up, the elasticity of the lungs and chest wall pushes air out of the lungs.
Q6: What are carcinogens? Name any two carcinogens present in tobacco.
Ans: Carcinogens: Carcinogens are the cancer causing chemicals.
There are more than 69 known carcinogens in the tobacco smoke.
Carcinogens in tobacco:
1. Nicotine:
Nicotine has many harmful effects such as increased heart rate and blood pressure, constriction in the blood vessel, damage to the muscles, and disturbance in the hormonal system and metabolisms.
Nicotine has also increased platelets stickiness in the blood which can cause blockage and cause coronary diseases.
2. Carbon monoxide:
It is formed when the cigarette is lit. It combines with the red blood cells and prevents oxygen transportation. When carbon monoxide enters the airways, it stays along with the toxic chemicals contained in the cigarette smoke. These toxin cause inflammation, impair lung functions, and increases the risk of lung cancer.
Q7: Compare the composition of inhale and exhale air?
Ans: Composition of inhaled and exhaled air:
Composition of inhaled and exhaled air:
| Air Components | Inspired |
| Expired | |||||
|---|---|---|---|---|---|---|---|---|
| 1. Oxygen | 21% | 16% | ||||||
| 2. CO2 | 0.04 | 4% | ||||||
| 3. Water vapors | Variable | Saturated 6.2 % | ||||||
| 4. Temperature | Variable | 38% |
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