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Practice each question, then open the answer or worked solution.
What are the different ways in which glucose is oxidized to provide energy in various organisms?
Ans: The different ways in which glucose is oxidized to provide energy in various organisms are:
In mammals and birds, why is it necessary to separate oxygenated and deoxygenated blood?
Ans: In Mammals and birds it is important to separate the oxygenated and deoxygenated blood because they are homoeothermic and warm-blooded animals. Due to this character, they can maintain their temperature constant throughout and the changes in their environment do not affect their body temperature regulation. This process also results in a good supply of oxygen in the case of birds and mammals so that optimum oxidation of glucose can take place. So to supply the required amount of oxygen it is important to have separate oxygenated and deoxygenated blood.
List three characteristics of the lungs that make them an efficient respiratory surface.
Ans: The characteristics that make lungs an efficient respiratory surface are:
1. Thin: The walls of the alveoli or air sac are very thin resulting in the quick diffusion of gases. They help in the absorption of oxygen inside the blood by inhalation process and also remove the carbon dioxide from the lungs by exhaling it to the outside.
2. Moist: The air sacs are composed of mucus that makes them moist which helps the gases to dissolve easily before diffusing.
3. Large surface area: In the lungs of human beings, its surface area is almost similar to the surface area of the tennis court that helps in the diffusion of gases. The alveoli or air sacs results in increasing the surface area of the lungs for the absorption of oxygen.
4. Good blood supply: The air sacs or alveoli are composed of a large capillary network that helps in the exchange of large volumes of gases. Thus greater the flow of blood in the lungs the greater would be the exchange of gases.
What are the components of the transport system in human beings? What are the functions of these components?
Ans: The main components of the transport system in human beings are the heart, blood, and blood vessels and their function are as follows:
The heart helps in pumping the oxygenated blood throughout the body. From the various parts of the body the deoxygenated blood is accumulated in the heart and from there it goes to the lungs for oxygenation.
Blood is the main body fluid that helps in the transport of nutrients, oxygen, carbon dioxide, nitrogenous wastes, and hormones. Blood also consists of white blood cells (WBCs) thus making it the main component of our immune system. Blood also consists of platelets that cause the clotting of blood that helps in repairing the damaged blood vessels. Also, the temperature of the body is also maintained by transportation.
Blood vessels (arteries, veins, and capillaries) are responsible for blood transportation either from the heart to various other body organs or from various body organs to the heart. All arteries carry oxygenated except pulmonary arteries and they transport blood from the heart to various parts of the body while all veins carry deoxygenated blood except pulmonary veins. The material that exchanges between the blood and tissues takes place inside the capillaries.
What are the components of the transport system in highly organized plants?
Ans: In highly organized plants, the transport system consists of vascular tissues. These are also called conducting tissues that two are of different types which include − xylem and phloem. The water and mineral which is obtained from the soil through roots are conducted through the xylem tissues to various parts of the plant while the food materials are conducted through the phloem tissues from the leaves to different parts of the plant body.
How are water and minerals transported in plants?
Ans: The transportation of water and minerals in the plants occurs through the xylem tissues which is a part of the vascular system and occurs mainly in the upward direction that is from roots to the leaves while the other part of the vascular system includes phloem vessels which help in the transportation of the photosynthetic products within the plants, from leaves to all parts like the stem, roots, fruits, etc. and the transportation takes place in all directions.
How is food transported in plants?
Ans: The food is produced in the leaves of the plants through the process of photosynthesis and from leaves it is then transported to various parts of the body through phloem tissues. The phloem requires energy in the form of ATP for the transportation of food materials. This results in the development of osmotic pressure inside the tissue that increases the movement of water into the tissues. The osmotic pressure results in the movement of the material in the phloem to those tissues which have less pressure. This helps the tissue in moving the food materials according to the needs of the plant. Sucrose is a food material that requires energy in the form of ATP when it is transported into the phloem tissue.
Describe the structure and function of the nephron in the human body.
Ans: The structural and functional units of the kidney are Nephrons (filtration units). Each kidney consists of a large number of nephrons. Nephrons are composed mainly of two parts - renal corpuscle and renal tubule.
The renal corpuscle is composed of a cup-shaped structure called Bowman’s capsule which is surrounded by a cluster of capillaries that helps in the collection of filtered urine. The composition of urine changes as it passes through the tubular part of the nephron due to the reabsorption of amino acids, glucose, salts, and water. The reabsorption of the amount of water and other substances depends on their presence in the body. The urine then enters the collecting duct of the kidney from where it is then transported to the long tube called the ureter. Lastly, the urine is then collected in the urinary bladder.
What are the methods used by plants to get rid of excretory products?
Ans: The excretory products of the plants may either be excreted out or may be stored as per the need of the plant. The excess amount of water in the plants can be removed by transpiration while the waste materials may be stored in the cell vacuoles or especially in old xylem vessels such as gum and resin. If it is also stored in the leaves then they fall off later. By the process of diffusion through stomata, the waste products that are obtained at the end of photosynthesis (oxygen) and respiration (carbon dioxide) are released.
How is the amount of urine produced regulated?
Ans: The amount of urine that is regulated depends upon the amount of water and other substances that are present. The urine is composed mainly of water so water is the main component in its regulation. If the amount of water is more in the body then the water reabsorbed will be less and more water will be released from the body and vice versa. There are various other factors that are responsible for the regulation of urine hormone such as Antidiuretic hormone (ADH) and also the habitat of an organism that regulates the amount of urine produced.