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Respiration in Organisms - Class 7 Science

By  May 27, 2021  

Respiration in Organisms - Class 7 Science

  • Respiration-The biological process in which food is utilized to produce energy is called respiration. Respiration is necessary for the survival of all living beings.
    Carbohydrate + Oxygen → Carbon dioxide + Water + Energy

    • Types of Repiration

  • Aerobic respiration-Aerobic respiration takes place in the presence of oxygen. Carbon dioxide and water are the end products.
    Glucose + Oxygen → Carbon dioxide + Water + Energy
  • Anaerobic respiration-Anaerobic respiration takes place in the absence of oxygen.It usually happens in microbes. Alcohol and carbon dioxide are the end products.
    Glucose(in absence of oxygen) → Alcohol + Carbon dioxide + Energy
  • Lactic acid-Anaerobic respiration also happens in our muscle cells. When someone runs or walks too fast, one may feel a throbbing pain in the calf muscles. This happens because of deposition of a chemical compound called lactic acid.If we take rest for sometime the pain goes away as the supply of oxygen increases which breaks down the lactic acid into carbon dioxide and water
    Glucose(in absence of oxygen)→Lactic Acid + Energy

    • Breathing- The process of taking in and giving out air for respiration is known as breathing

    Human Respiratory System

  • Nasal passage
  • Oral cavity
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Lung
  • Heart
  • Ribs

    • Inhalation-Inhalation is the process where we breathe in air rich in oxygen

    Exhalation-Exhalation is the process where we breathe out air rich in carbon dioxide

    Breathing rate-The number of time a person breathes in a minute is known as breathing rate

    How do we breathe?

  • The process of breathing takes place in our lungs
  • The process of breathing is controlled by the movement of diaphragm
    Diaphragm is a membrane present between the chest and abdomen.
    The movement of diaphragm is controlled by a group of muscles known as intercostal muscle.
  • When the diaphragm moves down the ribcage expands. This leads to the expansion inside the lungs. As a result, the air moves into the lungs. This process is known as inspiration or inhalation
  • When the diaphragm moves up the ribcage contracts. This leads to the contraction of the lungs. As a result, the air moves out of the lungs. This process is known as expiration or exhalation

    • Repiration in plants

    In plants the external layer of cells can breathe, roots breathe through root hairs, stems breathe through epidermis, leaves have numerous small pores called stomata for breathing.

    Breathing in other animals

  • Flatworms- Flatworms use their outer surfaces as gas exchange surfaces
  • Earthworms- In earthworms gas exchange occurs at capillaries(a series of thin-walled blood vessels)
  • Unicellular organisms(amoeba, paramecium)-Unicellular organisms exchange gases through their cell membrane
  • Amphibians - Ambphibians use their skin and lungs
  • Terrestrial animals - Many terrestrial animals have their respiratory surfaces inside the body and connected to the outside by a series of tubes. These tubes are known as tracheae. Spiracles are openings at the body surface that lead to tracheae. Tracheae branch into smaller tubes known as trachcoles.
  • Fish - Fist breathe oxygen dissolved in water through gills

    • Respiratory system principle

    Process of respiration is completed by the following steps:

    1. Movement of an oxygen-containing medium so it contacts a moist membrane overlying blood vessels
    2. Diffusion of oxygen from the medium into the blood
    3. Transport of oxygen to the tissues and cells of the body through blood
    4. Diffusion of oxygen from the blood into cells
    5. Carbon dioxide follows a reverse path and moves out of the body

    Objective Type Questions

    A.Fill in the blanks.

    1. Aerobic respiration takes place in the presence of oxygen.
    2. Alcohol and carbon dioxide are the end products of anaerobic respiration.
    3. A person feels a throbbing pain in the calf muscles due to the production of lactic acid
    4. The number of times a person breathes in a minute is known as the breathing rate
    5. The movement of diaphragm is controlled by a group of muscles known as the intercostal muscles
    6. Earthworms have a series of thin-walled blood vessels known as capillaries
    7. Tracheae branch into smaller tubes known as tracheoles
    8. Each plant breathes through its external layer of cells

    B.True and False.

    1. Taking in air is exhalation - F
    2. Amphibians breathe through skin as well as lungs - T
    3. Anaerobic respiration needs oxygen - F
    4. Respiration is a process in which engery is released - T
    5. Our nose filters oxygen from air - F

    C.Correct answer.

    1. Aquatic animals get the oxygen from - air and water
    2. Organism that does not need oxygen to survive - yeast
    3. Anaerobic respiration produces - Carbon dioxide and energy
    4. When we run there is a deposition in muscle cells known as - Lactic acid
    5. When we blow air into a test tube containing limewater, the limewater turns milky.This happens because of reaction of limewater with - carbon dioxide

    Very Short Answer Questions

    D.Answer the following in brief.

    1. Name the respiratory organs in humans.
      2. Ans. Nose, Mouth, Larynx, Pharynx, Lungs and Diaphragm.
    2. Which membrane controls the movement of lungs?
      3. Ans. Diaphragm
    3. Which is the respiratory organ in fish?
      4. Ans. Gills
    4. What is the respiratory organ in cockroach?
      5. Ans. Spiracles
    5. Which organ is used by a frog for breathing under water?
      6. Ans. Skin
    6. What is the end product of respiration in most of the organisms?
      7. Ans. Carbon dioxide, water and energy
    7. What is the end product of anaerobic respiration in muscle cells?
      8. Ans. Alcohol, carbon dioxide and energy

    Short Answer Questions

    E.Define the following

    1. Breathing
      2. Ans. Breathing is the process by which air rich in oxygen is taken inside the body of an organism and air rich in carbon dioxide is expelled out from the body with the help of lungs.
    2. Respiration
      3. Ans. The biological process in which food is utilized to produce energy. It is also the process of releasing energy from food. The process of respiration involves taking in oxyge from air into the cells and then eliminating the waste products(carbon dioxide and water) from the body.
    3. Inhalation
      4. Ans. When the diaphragm moves down the ribcage expands. This leads to the expansion inside the lungs. As a resut, the air moves into the lungs. This process is known as inhalation.
    4. Exhalation
      5. Ans. When the diaphragm moves up the ribcage contracts. This leads to the contraction of the lungs. As a resut, the air moves out of the lungs. This process is known as exhalation.

    F. Differentiate between the following

    1. Respiration and breathing
    2. Aerobic and Anaerobic respiration
    3. Gills and Tracheae
    4. Inhalation and Exhalation

    G.Answer the following in brief

    1. What is cellular respiration?
    2. When we run or walk fast, we feel throbbing pain in calf muscles. Why? How it can be relieved?
    3. How do frog respires in water and land?
    4. Why is it suggested not to overwater plants?