"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 06
LIFE PROCESSES
INTEXT QUESTIONS AND ANSWERS (PART 02)
NCERT INTEXT QUESTIONS (PAGE NO. 110)
Q.01:- What are the components of the transport system in human beings? What are the functions of these components?
Ans:- The transport system (called circulatory system) in human beings mainly consists of heart, blood and blood vessels.
Functions of components of circulatory system :-
(ⅰ) Heart :- The heart is a muscular organ which is a big as our first. Heart is a pumping organ to push blood around the body. It receives deoxygenated blood from the body parts and pumping organ to push blood around the body parts and pump it to lungs for enriching with oxygen. It receives purified blood from lungs and pumps it around the body.
(ⅱ) Blood :- Blood is a fluid connective tissue, it consists of a fluid medium known as plasma in which the cells are suspended, such as white blood cells and red blood cells. Plasma transports food, carbon dioxide and nitrogenous wastes (urea and uric acid) in dissolved form. Red blood cells transport Oxygen. Blood also transports many other substances like hormones, salt etc. Platelets present in the blood stop bleed from injuries by forming blood clots.
(ⅲ) Blood vessels :- Blood vessels form a closed network of tubes to reach all the tissues. Thus, the blood vessels (arteries) and also comes back to the heart in the blood vessels (veins).
Q.02:- Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans:- Separation of oxygenated and deoxygenated blood allows a highly efficient supply of oxygen to the body. This system is useful in animals that have high energy need. Mammals and birds constantly need oxygen to obtain energy to maintain body temperature constant.
Q.03:- What are the components of the transport system in highly organized plants?
Ans:- The transport system in highly organized plants consists of two pathways as independently organized conducting tubes. One is xylem and phloem.
(ⅰ) Xylem :- Consists of vessels, tracheids and other xylem tissues. The interconnected vessels and tracheids form a continuous system of water conducting channels reaching all parts of the plant. Xylem conducts water and dissolved minerals absorbed form the soil.
(ⅱ) Phloem :- Consists sieve tubes and companion cells which conduct soluble products of photosynthesis from leaves to different parts of the plant body. This transportation of prepared food material through phloem is called translocation.
Q.04:- How are water and minerals transported in plants?
Ans:- Water and dissolved minerals are transported through xylem tissues. Xylem vessels and tracheids of roots, stems and leaves are interconnected to form a continuous system of water and dissolved minerals conducting channels reaching all the parts of the plants.
The roots cells in contact with the soil actively take up ions from the soil. This creates a difference in the concentration of these ions between the root and the soil. Therefore, there is a steady movement of water into the xylem. This creates a column of water that is steadily pushed upward, called root pressure. However, this pressure is not enough to push water and dissolved minerals to leaves in the tall trees.
There is continuous loss of water through stomata of the leaves in the form of water through stomata of the leaves in the form of water vapour. This process is called transpiration. The water lost due to transpiration is taken up from the xylem vessels and tracheids in the leaves. This suction pressure which pulls water from the xylem cells of root.
As a result, there is enhanced absorption and upward movement of water and dissolved minerals from roots to the leaves due to transpiration.
The effect of root pressure in transport of water is more important at night when stomata are closed.
When the stomata are open during the day, the transpiration pull is the major force in the movement of water and dissolved minerals in the xylem, especially in trees.
Q.05:- How is food transported in plants?
Ans:- Plants transport soluble product of photosynthesis like carbohydrates, amino acids and other substances through phloem to storage organs of roots, fruits and seeds also to growing organs. This transport of soluble products of photosynthesis through phloem is known as translocation.
The transport of prepared food and other substances takes place both in upward and downward directions. This movement of food materials is carried out in phloem by sieve tubes with the help of companion cells.
Mechanism of translocation :- Translocation is an active process and utilizes energy. Material like sucrose is transferred from leaf cells or form the site of storage into the phloem tissue. This process requires energy which is provided by ATP (adenosine triphosphate) molecules. Entry of sucrose into phloem tissues causes increase in osmotic pressure, as a result water from outside moves into phloem. The osmotic pressure transports the dissolved material in the phloem to tissues which have less pressure. Thus, material moves in phloem, mainly in sieves tubes, to place of need in the plant body. For example, sugar is translocated from its storage organ. root or stem to growing buds which need energy.
NCERT INTEXT QUESTIONS (PAGE NO. 112)
Q.01:- Describe the structure and functioning of nephrons.
Or
(a) Draw the structure of a nephron and label on it the following parts:-
(ⅰ) Glomerulus
(ⅱ) Bowman's capsule
(ⅲ) Renal artery
(ⅳ) Collecting duct
(b) What happens to glucose, amino acids, salts and water that enter the nephron along with filtrate?
Ans:- Structure of Nephron :- Nephron is the filtration unit of kidney. It consists of a tubule which is connected with collecting duct at one end and a cup shaped structure at the other end.
(ⅰ) Functioning of nephron :- Filtration of blood takes place in Bowman's capsule from the capillaries of glomerulus. The filtrate passes into the tubular part of the nephron. This filtrate contains glucose, amino acids, urea, uric acid, salts and a major amount of water.
(ⅱ) Reabsorption :- As the filtrate flows along the tubule, useful substances such as glucose, amino acids, and water are selectively reabsorbed into the blood by capillaries surrounding the nephron tubule. The amount of water reabsorbed depends on the need of the body and also on the amount on the amount of wastes to be excreted.
(ⅲ) Urine :- The filtrate which remained after reabsorption is called urine. Urine contains dissolved nitrogenous waste i.e., urea and nitric acid, excess salts and water. Urine is collected from nephrons by the collecting duct to carry it to the ureter.
Q.02:- What are the methods used by plants to get rid of excretory products?
Ans:- To get rid of excretory products plants use the following ways :-
(ⅰ) In many plants waste products are stored in vacuoles of the cells. Plant cells have comparatively large vacuoles.
(ⅱ) Some waste products are stored in the leaves. They are removed as the leaves fall off.
(ⅲ) Some waste products such as resins and gums are stored, especially in non-functional old xylem.
(ⅳ) Some waste products such as tanins, resins, gums are stored in bark, thereby removed as the peeled off.
(ⅴ) Plants also excrete some waste substances through roots into the soil around them.
Q.03:- How is the amount of urine produced regulated?
Ans:- The amount of urine largely depends on the amount of water reabsorbed. The amount of water reabsorbed by the nephron tubule depends on :-
(ⅰ) How much water is in excess in the excess in the body need to be removed? when water is abundant in the body tissues, large quantities of dilute urine is excreted out. When water is less in quantities in the body tissues, a small quantity of concentrate urine is excreted.
(ⅱ) How much dissolved wastes, especially nitrogenous wastes, like urea and uric acid and salts needs to be exerted from the body ?
When there is more quantity of dissolved wastes in the body, more quantity of water is required to excrete them. So, the amount of urine produced increases.
The amount of urine produced is also regulated by certain hormones which control the movement of water and Na+ ions into and out of the nephrons.
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