CBSE Class 7 Science Chapter 11: Transportation in Animals and Plants NCERT Solutions

Solution: The correct matching between the structures in Column I and their functions in Column II is as follows:

• (i) Stomata - (b) Transpiration: Stomata are pores on the leaf surface that regulate gas exchange and release water vapor during transpiration.
• (ii) Xylem - (d) Transport of water: Xylem is the vascular tissue responsible for transporting water and dissolved minerals from the roots upwards to the rest of the plant.
• (iii) Root hairs - (a) Absorption of water: Root hairs are tiny extensions of epidermal cells in plant roots that significantly increase the surface area for absorbing water and minerals from the soil.
• (iv) Phloem - (c) Transport of food: Phloem is the vascular tissue that transports sugars (food) produced during photosynthesis from the leaves to other parts of the plant where they are needed for growth or storage.

Solution: Here are the completed sentences:

• (i) The blood from the heart is transported to all parts of the body by the arteries. Arteries carry blood away from the heart.
• (ii) Haemoglobin is present in red blood cells. Haemoglobin is the protein that carries oxygen.
• (iii) Arteries and veins are joined by a network of capillaries. These are tiny vessels where exchange of substances occurs.
• (iv) The rhythmic expansion and contraction of the heart is called heartbeat. This pumping action circulates blood throughout the body.
• (v) The main excretory product in human beings is urea. Urea is a waste product from protein metabolism.
• (vi) Sweat contains water and salt. Sweat helps in regulating body temperature by cooling the skin as it evaporates.
• (vii) Kidneys eliminate the waste materials in the liquid form called urine. Urine is primarily composed of water, urea, and salts.
• (viii) Water reaches great heights in the trees because of suction pull caused by transpiration. Transpiration is the evaporation of water from plant leaves, which creates a pulling force that draws water up from the roots.

Solution:

(a) In plants, water is transported through (i) xylem. Xylem is specialized tissue for water conduction from roots to leaves.

(b) Water absorption through roots can be increased by keeping the plants (iii) under the fan. Placing a plant under a fan increases air movement, which enhances transpiration. Higher transpiration rates create a stronger suction pull, drawing more water from the soil into the roots.

Solution: The transport of materials is essential in both plants and animals because their cells require a continuous supply of necessary substances and need to eliminate waste products. Cells perform metabolic activities, which consume nutrients and oxygen and produce waste materials like carbon dioxide and urea. The transport system ensures that nutrients and oxygen reach all cells, and waste products are efficiently removed from the cells and the body. In plants, this includes transporting water and minerals from roots to leaves and food from leaves to other parts. In animals, the circulatory system transports oxygen, nutrients, hormones, and removes metabolic wastes.

Solution: If there are no platelets in the blood, the body would lose its ability to clot blood effectively. Platelets are crucial components of blood that initiate the clotting process when a blood vessel is injured. In the absence of platelets, even minor injuries could lead to prolonged bleeding, resulting in significant blood loss. This excessive blood loss can be life-threatening, potentially leading to shock or death.

Solution: Stomata (singular: stoma) are tiny pores or openings, typically found on the surface of leaves, stems, and other organs of plants. They are surrounded by specialized cells called guard cells, which control their opening and closing.

Two main functions of stomata are:

1. Gas Exchange: Stomata allow for the exchange of gases between the plant's internal tissues and the external atmosphere. This is vital for photosynthesis, as they take in carbon dioxide (CO2) needed for the process, and release oxygen (O2) as a byproduct.
2. Transpiration: Stomata are the primary sites for transpiration, which is the process of water vapor being released from the plant into the atmosphere. Transpiration helps in the upward movement of water and dissolved minerals from the roots to the leaves and also helps in cooling the plant.