Afaq NSS Science 6 - Unit 4 Photosynthesis and Respiration in Plants

Afaq New Sun Series Science 6 - Unit 4 Photosynthesis and Respiration in Plants

Afaq NSS Science 6 - Unit 4 Photosynthesis and  Respiration in Plants

Point to Remember!

  • All organisms around us need the energy to perform al their activities.
  • there are two major biological processes that occur in plants, photosynthesis, and respiration.
  • Photosynthesis is the food-making process in plants that uses carbon dioxide and water.
  • Respiration is the process of breaking down food to provide energy to plants.
  • Both respiration and photosynthesis are very important for the survival of all organisms in our surroundings.

Definitions:

  • Photosynthesis: it is the process in which live plant cells make their own food in the presence of sunlight and chlorophyll.
  • Cuticle: It is the outermost protective layer on a leaf. It prevents the loss of water.
  • Xylem: It is present in the central region of a leaf and is involved in supplying water and minerals to all parts of the plant.
  • Phloem: It is also located at the center of a leaf near the xylem. It supplies prepared food to all parts of the plant.
  • Respiration: It is a biological process that all living organisms use to produce energy that they need to perform all their activities.

Exercise (Solved)

1. Answer the following questions briefly.

  1. Differentiate between the xylem and phloem?
    Ans: Xylem: it is present in the central region o fa leaf and is involved in supplying water and minerals to all parts of the plants.
    Phloem: It is also located at the center of a leaf near the xylem. it supplies prepared food to all parts of the plants.

  2. What is the importance of photosynthesis in our lives?
    Ans: Photosynthesis is very important for the survival of every organism living on earth. Photosynthesis the process in which live plant cells make their own food in the presence o sunlight and chlorophyll.

  3. What do mesophyll tissues do for plants?
    Mesophyll tissue has two different types of cells i.e. palisade and spongy cells that contain special membrane-bound organelles called chloroplasts. The chloroplasts contain a green pigment called chlorophyll. Chlorophyll gives the green color to leaves.

  4. What is the difference between photosynthesis and respiration?
    Photosynthesis is the process in which plant make their own food the presence of sunlight and chlorophyll.
    Respiration is a biological process that all living organisms use to produce energy that they need to perform all their activities.

  5. Explain how organisms will die if there is no respiration in plants.
    Ans: Respiration is very important for plants, plants can not get energy from food they need without respiration. All activities inside the plant will be stopped and eventually they will die.

2. Answer the following question in details.

Q.1 Explain the internal Structure of a Plant.
Ans: Leave are a very important part of plants. If we view a leaf under a light microscope, we observe the following internal structure.

  • Cuticle: It is the outermost protective layer on the leaf. it prevents the loss of water.
  • Epidermis: Epidermis is the outermost layers that make up the skin. Epidermis layer has special guard cells that control the opening of stomata. Water and other gases, such as carbon dioxide and oxygen, move in or out of cells.
  • Mesophyll: It is below the layer of the upper epidermis. It has tow different types of cells i.e. Palisade and spongy cell. These cells contain special membrane-bound organelles called the chloroplast.

3. Choose the correct option.

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4 Correct True/False statement

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