DAV Class 7 Science Chapter 7 Respiration in organisms Question Answer Notes
DAV Class 7 Science Chapter 7 Respiration in organisms Question Answer Notes Solution by Expert Science Teacher. DAV Class 7 Science 7th Chapter Respiration in organisms for Students of DAV Schools.
Lesson No 7
Respiration in organisms
A.) Fill in the blanks.
Answer: (1) anaerobic (2) tracheae (3) inhalation (4) 14, 20 (5) diaphragm, ribcage (6) Haemoglobin
B.) Match the following:
1. Lactic acid | (a) Transpiration |
2. Stomata | (b) Pores on branches |
3. Respiratory carrier | (c) Muscle cramps |
4. Lenticels | (d) Fermentation of yeast |
5. Alcohol | (e) Haemoglobin |
Answer: 1. (c), 2. (a), 3. (e), 4. (b), 5. (d)
C.) Tick the correct option.
Answer:
1.) obtaining energy
2.) exchange of gases
3.) is aerobic respiration
4.) oxygen
5.) skin
D.) Answer the following questions in brief.
Q.)1.) Define respiration. Name the two types of respiration.
Q.) 2.) Name the respiratory organ of the following:
(a) crab (b) man (c) leech (d) an insect
Answer:
(a) Gills
(b) Lungs
(c) Skin
(d) Tracheae
Q.) 3.) Define transpiration.
Transpiration is the process by which water is evaporated from the leaves of plants. It is a natural process that helps plants move water and nutrients from the roots to the leaves. It is also an important part of the water cycle, in which water evaporates from leaves, rises into the atmosphere, and eventually falls as precipitation. Transpiration occurs mainly during the day when the stomata, or tiny pores on the leaves, are open. During this time, water from the roots of the plant is drawn up the xylem vessels and out of the stomata. As the water evaporates, it cools the leaf and also helps to create air movement around the leaf, which is essential for photosynthesis.
Q.) 4.) Define the term ‘breathing rate’.
Answer:
Breathing rate is the rate at which a person inhales and exhales air during respiration. The normal breathing rate for adults is usually between 12 to 20 breaths per minute. This rate can vary depending on a person’s age, activity level, and environment. For example, a person who is exercising or under stress may have a higher breathing rate than a person who is sitting quietly. Respiratory rate is measured by counting the number of breaths a person takes over a period of one minute. The rate is usually measured by counting the number of times a person’s chest rises and falls as they inhale and exhale.
Q.) 5.) Name the body organs which help lungs during the process of breathing.
Answer: Ribcage and the diaphragm.
Q.) 6.) Why do we need to breathe out carbon dioxide?
Carbon dioxide is a result of cellular respiration and must be exhaled. Oxygen is absorbed up during cellular respiration and transformed into fuel for the cells. In order for the body to keep a balanced equilibrium of oxygen as well as removal of carbon dioxide, as carbon dioxide is generated as a waste material and requires to be exhaled.
E.) Answer the following questions.
Q.) 1.) Why do we get muscle cramps after heavy exercise?
The exact cause of muscle cramps after exercise is not known, but there are several theories as to why they occur. One theory suggests that it is caused by lactic acid, a by-product of the body’s metabolism, which builds up in the muscles and causes them to contract involuntarily. Another theory suggests that it is caused by dehydration and electrolyte imbalances. When the body is dehydrated, muscles can become deprived of electrolytes, such as sodium, potassium, and magnesium, which can lead to cramping. Additionally, dehydration and electrolyte imbalances can cause electrolyte levels to drop, which can further contribute to cramping.
Q.) 2.) Why does a potted plant die when over watered?
Answer: A potted plant will die when it is over watered because when a plant is over watered, its roots are deprived of oxygen. This is because the water floods the root system, cutting off the air supply. As a result, the root system suffocates, which prevents the plant from being able to take up the essential nutrients, minerals, and water that it needs to survive. Over watered plants will typically show signs of wilting, yellowing, and even rotting of the roots. Oxygen is essential for the functioning of plant roots, as they rely on it to access and process essential elements such as nitrogen and phosphorus. Without oxygen, the roots are unable to absorb these elements, which are essential for healthy growth. Without access to these elements, the plant will eventually die due to lack of nutrients.
Q.) 3.) Where are stomata found in a plant? State their function.
Stomata are small pores found on the epidermis of leaves and stems. They are also found on the surface of other plant organs such as fruits, flowers and roots. Their function is to regulate the exchange of gases such as oxygen, carbon dioxide and water vapor between the plant and the atmosphere. They are also involved in the process of transpiration, which helps to cool the plant and reduce water loss.
Q.) 4.) How is oxygen transported from lungs to the other parts of the body?
Answer: Oxygen is transported from the lungs to the other parts of the body via the circulatory system. The circulatory system consists of the heart, blood vessels, and blood. When a person inhales, oxygen enters the lungs and is absorbed into the bloodstream. The oxygen-rich blood is then pumped by the heart to the rest of the body. The oxygen-rich blood is then transported through the arteries which carry the oxygenated blood away from the heart and to the tissues and cells of the body. Once the oxygen-rich blood reaches the cells of the body, the oxygen is released from the red blood cells and enters the cells of the body. The cells of the body then use the oxygen to produce energy and to carry out their bodily functions.
Q.) 5.) Draw a neat, well-labelled diagram of the human respiratory system.
Q.) 6.) Describe an activity to show that exhaled air contains carbon dioxide.
For this experiment we would require a drinking straw a test tube or a container and lime water. We need to take the lime water solution within the test tube or container and then put a drinking straw into it such that the straw is submerged within the lime water. when we slowly exhale air from our body into the straw we see an interesting observation. We see that the lime water turns Milky. we know that lime water turns Milky when carbon dioxide passes through it, thus this experiment proves that exhaled air contains carbon dioxide.
Q.) 7.) Describe the changes that take place (i) around the rib cage (ii) diaphragm (iii) chest cavity, during inspiration. State the effect of these changes.
(i) Around the rib cage: During inspiration, the muscles around the rib cage contract and cause the rib cage to expand outward and upward. This increases the size of the thoracic cavity and creates a vacuum, which causes air to rush into the lungs. The effect of this change is to increase the amount of air entering the lungs, allowing the body to take in more oxygen.
(ii) Diaphragm: During inspiration, the diaphragm contracts and flattens, which increases the size of the thoracic cavity and creates a vacuum, which causes air to rush into the lungs. The effect of this change is to increase the amount of air entering the lungs, allowing the body to take in more oxygen.
(iii) Chest cavity: During inspiration, the chest cavity expands outward, creating a larger space for air to enter the lungs. The effect of this change is to increase the amount of air entering the lungs, allowing the body to take in more oxygen.
With each contraction of the lungs the air inside it expelled out resulting in exhalation of gases like Co2.
More Extra Questions for Preparation
Q.1.) True or false.
1.) During respiration energy is produced.
Answer – True
2.) During day, Oxygen is taken in and carbon dioxide is released by plants.
Answer – True
3.) Anaerobic respiration is also called fermentation.
Answer – True
Q.2.) Fill in the blanks.
1.) We breathe about 5000 times every day.
2.) Lactic acid is produced during the physical exercise.
3.) Plants are made up of cells.
Q.3.) Define the following.
1.) Respiration.
Answer – Respiration is the name of general process in which organism convert sugar into biochemical energy using oxygen.
2.) Inhalation.
Answer – Taking in of air, rich in oxygen is called inhalation.
3.) External respiration.
Answer – The taking in and giving out of air is called external respiration.
4.) Haemoglobin.
Answer – The blood while passing through the lungs pick up oxygen with the help of a pigment called haemoglobin.
Q.4.) Choose the correct answer.
1.) Blood is red due to presence of .
a.) Fluid
b.) Coloured water
c.) Haemoglobin
d.) Cells
Answer – c. Haemoglobin
2.) The no of times a person breathes is
a.) 30 to 40 times per min
b.) 14 to 20 times per min
c.) 5 – 10 times per min
d.) 2 – 3 times per min
Answer – b.14 to 20 times per min
3.) Fishes breathe by .
a.) Air
b.) Nose
c.) Drinking water
d.) None of these
Answer – c. Drinking water
4.) Type of respiration without use of oxygen
a.) Aerobic
b.) Anaerobic
c.) Both a and b
d.) None of these
Answer –b. Anaerobic
5.) Respiration involves changes of
a.) Gases
b.) Hormones
c.) Water
d.) Both b and c
Answer – a. Gases
Q.5.) Explain smoking affects lungs.
Answer –
a.) When one smokes cigarettes, many chemicals enters one’s body through the lungs.
b.) Burning of tobacco produces more than 4000 chemicals.
c.) Nicotine, carbon monoxide and tar are some of these substances.
d.) Smoking damages the lungs and airways to a great extent.
e.) Smokes generally suffer problems related to breathing.
Q.6.) Why blood is red and haemoglobin acts as respiratory carrier?
Answer –
a.) Blood is red due to presence of haemoglobin in it.
b.) Haemoglobin transports oxygen to different parts of the body.
c.) It also picks up some of carbon dioxide, produced by the cells, during cellular respiration and transports to the lungs for respiration.
d.) Hence, haemoglobin acts as respiratory carrier.
Q.7.) How can CO2 affects the body?
Answer –
a.) High levels of CO2 in the body can be toxic and hence CO2 needs to be removed.
b.) It is brought to the lungs by blood and then removed when we exhale.
Q.8.) Explain respiration process in animals.
Answer –
A.) In small organisms like amoeba and Hydra:- Respiration is done through process of diffusion.
B.) In earthworm and leech:- Skin is the organ for respiration.
C.) In fish, prawns and crabs:- The respiratory organs are gills.
Q.9.) Explain the opening and closing of stomata in plants?
Answer –
a.) Stomata are present on surface of leaves.
b.) The stomata generally open up during the day time and remain closed at night.
c.) They help in exchange of CO2 and O2.
Q.10.) Explain the process useful in making alcoholic beverage and bakery items?
Answer –
a.) Aerobic respiration is useful in making alcoholic beverage and bakery items like bread and cakes.
b.) In plants, yeasts and bacteria, anaerobic respiration results in production of alcohol and carbon dioxide.
c.) This process is used in the brewing and baking industries.
d.) This process is known as fermentation.
Q.11.) Explain cellular respiration.
Answer – Cellular respiration is the process in which cells produce the energy they need to stay alive. During cellular respiration, cells use oxygen to break down the sugar to produce energy.
Q.12.) Difference between Aerobic and Anaerobic respiration.
Aerobic respiration |
Anaerobic respiration |
1. Release of energy from glucose in presence of oxygen. | 1. Oxygen is not used for the release of energy. |
2. Aerobic means” in air”. | 2. Anaerobic means” absence of air”. |