1.What are life processes? Name the four vital life processes necessary for maintaining the life of an individual organism.
2.Differentiate between autotrophic nutrition and heterotrophic nutrition, giving two examples of organisms showing each mode.
3.Write the balanced chemical equation representing the process of photosynthesis. List the three major events that occur during this process in green leaves.
4.Describe the structure and function of stomata in leaves. Explain how guard cells regulate the opening and closing of stomatal pores.
5.Explain with a neat description or experiment how you would prove that chlorophyll is absolutely necessary for photosynthesis to occur. (Variegated leaf experiment).
6.Why do desert plants take up carbon dioxide at night and prepare an intermediate compound, instead of taking it up during daytime? What is the survival advantage?
7.How do single-celled organisms like Amoeba obtain and digest their food? Explain with the help of a neat, step-by-step diagram showing pseudopodia formation.
8.Describe the human digestive system by tracing the path of a bolus of food from the mouth to the anus. List the enzymes secreted at each step and their functions.
9.What is the role of hydrochloric acid ($\text{HCl}$) in our stomach? How is the stomach lining protected from the corrosive action of this strong acid?
10.How is the small intestine designed to absorb digested food efficiently? Explain the structural importance of villi and their blood capillary network.
11.What is the function of bile juice secreted by the liver? Discuss its role in the digestion of fats (emulsification).
12.Why is the length of the small intestine longer in herbivorous animals (like cows) compared to carnivorous animals (like tigers)? Explain in terms of diet.
13.Define respiration. How is respiration different from breathing? Is cellular respiration exothermic or endothermic?
14.Draw a flowchart representing the three different pathways of the breakdown of glucose in living organisms (aerobic pathway in mitochondria, anaerobic pathway in yeast, and anaerobic pathway in muscle cells).
15.Differentiate between aerobic respiration and anaerobic respiration. Write the chemical equations representing both pathways.
16.Why do we get painful muscle cramps in our legs after running a very fast race or doing vigorous physical exercise? Explain the biochemistry involved.
17.What is ATP? Why is it called the "energy currency" of the cell? Explain how energy is released from ATP molecules when a cell needs it.
18.Why is the rate of breathing in aquatic organisms (like fish) much faster than in terrestrial organisms (like humans)? Explain in terms of dissolved gas concentrations.
19.Describe the design of the human respiratory system. Explain how the nasal passage, trachea, bronchi, and lungs are structured to ensure safe air filtration and gas exchange.
20.How are alveoli designed in our lungs to maximize the exchange of gases? State the approximate surface area they would cover if spread out.
21.What is the role of hemoglobin in human respiration? Why can diffusion alone not meet the oxygen requirements of large multicellular organisms like humans?
22.Explain what happens to our diaphragm and ribs during: (a) Inhalation (breathing in), (b) Exhalation (breathing out).
23.Why is a circulatory system necessary in multicellular organisms? Name the three main components of the human circulatory system.
24.Describe the internal structure of the human heart. Why is it divided into four separate chambers (two atria and two ventricles)? Explain in terms of oxygenated and deoxygenated blood separation.
25.Explain the mechanism of double circulation in human beings. Draw a neat block schematic diagram showing pulmonary and systemic circulation pathways.
26.Differentiate between arteries and veins based on: (a) wall thickness, (b) presence of valves, (c) direction of blood flow, and (d) nature of blood carried.
27.What are blood capillaries? Explain their structural importance in facilitating the exchange of nutrients and gases between blood and surrounding tissues.
28.What is blood pressure? Explain the terms: (a) Systolic pressure, (b) Diastolic pressure. What is the normal range of blood pressure in a healthy adult?
29.What is lymph (tissue fluid)? How is it formed? State two important functions of the lymphatic system in our body.
30.Why do mammals and birds have a four-chambered heart, whereas amphibians have a three-chambered heart and fish have only a two-chambered heart? Explain the evolutionary advantage.
31.How is water and minerals transported in plants? Explain the mechanism of water movement through xylem via root pressure and transpiration pull.
32.What is transpiration? State two important roles that transpiration plays in the physiology of plants.
33.Define translocation. How is food and other substances transported in plants through phloem? Explain why phloem transport requires energy (ATP) unlike xylem transport.
34.What is excretion? Why is it essential for living organisms to remove metabolic wastes from their bodies?
35.Name the organs of the human excretory system. State one function of each organ.
36.Draw a neat, labelled diagram of a nephron. Name its key structural parts (Bowman's capsule, Glomerulus, tubular duct).
37.Explain the step-by-step mechanism of urine formation in the human kidney. Discuss the three key processes: (a) Ultrafiltration, (b) Selective reabsorption, (c) Tubular secretion.
38.How is the amount of water reabsorbed in the nephron tubules regulated in our body? State two factors that determine water reabsorption.
39.What is hemodialysis (artificial kidney)? Explain how it works to save the life of a patient suffering from kidney failure. What is the key difference between an artificial kidney and a natural kidney?
40.Describe the various strategies and methods used by plants to get rid of their waste products (gaseous wastes, solid wastes, storage in leaves/bark).
A group of Class 10 students performs a starch test on a variegated Money Plant leaf after keeping it in sunlight for 6 hours. They trace the green and non-green parts, decolourise the leaf by boiling it in alcohol in a water bath, rinse it, and dip it in dilute iodine solution. They observe that only the green parts turn blue-black.
41.Based on Case Study 1, answer the following:
- Why did only the green parts of the leaf turn blue-black after treating with iodine? What does this confirm?
- Why is the leaf boiled in alcohol before testing with iodine? Why is a water bath used instead of direct heating?
- Write the balanced equation for the chemical reaction occurring in the leaf during those 6 hours.
In a biology lab, Ravi sets up a test tube containing fruit juice mixed with a small amount of active yeast powder. He fits a cork with a delivery tube onto the test tube and passes the evolved gas into a second test tube filled with lime water. Within 15 minutes, lime water turns milky and a pungent alcoholic smell is detected.
42.Based on Case Study 2, answer the following:
- Name the biological process taking place in the first test tube. Is it aerobic or anaerobic?
- Write the balanced chemical equation for the breakdown of glucose occurring inside the yeast cells in this setup.
- What gas caused the lime water to turn milky? Write the equation for the milkiness reaction.
Ramesh visited a doctor for a routine checkup. The doctor wrapped an inflatable cuff around Ramesh's upper arm and used a mercury sphygmomanometer along with a stethoscope to measure his blood pressure. The reading recorded was 145/95 mm Hg. The doctor advised Ramesh to reduce salt intake and exercise.
43.Based on Case Study 3, answer the following:
- What do the two numbers 145 and 95 represent in Ramesh's blood pressure reading? What are their normal values?
- What is Ramesh's medical condition called based on this reading? What are the long-term health risks of this condition if left untreated?
- Why does high salt (sodium) intake raise blood pressure? Explain based on osmosis.
Mrs. Sharma has chronic kidney disease and undergoes hemodialysis twice a week. During dialysis, blood from her radial artery is pumped into a dialyzer containing semi-permeable cellophane tubes immersed in a dialysing fluid. Cleaned blood is then returned to her vein.
44.Based on Case Study 4, answer the following:
- What is the composition of the dialysing fluid used in the artificial kidney? How does it differ from Mrs. Sharma's blood?
- What specific metabolic waste is removed from Mrs. Sharma's blood during this process, and by what physical mechanism?
- Why is Mrs. Sharma's urine output extremely low? Why does an artificial kidney not require selective reabsorption?
A student sets up two conical flasks A and B. In Flask A, he places germinating seeds. In Flask B, he places dry, boiled seeds. In both flasks, he suspends a small test tube containing a solution of potassium hydroxide (KOH). A delivery tube connects each flask to a beaker of water. After 2 hours, the water level in the delivery tube of Flask A rises significantly, while Flask B shows no change.
45.Based on Case Study 5, answer the following:
- Why was potassium hydroxide (KOH) placed inside the flasks? What is its chemical role?
- Why did the water level rise in the delivery tube of Flask A? Explain the physical mechanism.
- Why did Flask B show no rise in water level? What does this experiment prove?
A potted plant is kept inside a sealed transparent glass bell jar A, and another identical bell jar B is placed next to it containing only dry soil in a pot. Both jars are kept in bright sunlight. Within 30 minutes, large water droplets cover the inner walls of Jar A, while Jar B remains dry.
46.Based on the Transpiration Challenge, answer the following:
- What biological process in the plant caused the droplets to form in Jar A? Define this process.
- Explain how this process helps in the upward movement of water from the roots to the topmost leaves of a tall tree.
- State two environmental factors that would increase the rate of this process in sunlight.
An organ 'X' in the human body acts as a central pump. It receives oxygen-rich fluid 'Y' from the lungs through a tube 'A', and pumps it to all parts of the body through tube 'B'. It also receives carbon dioxide-rich fluid 'Z' from body tissues through tube 'C' and pumps it to the lungs through tube 'D' for purification.
47.Based on the puzzle description, answer the following:
- Identify organ 'X', fluid 'Y' / 'Z', and the four tubes 'A', 'B', 'C', and 'D'.
- Why is the left ventricle wall of organ 'X' much thicker and more muscular than the right ventricle wall?
- What would happen if the valves in organ 'X' fail to function properly?
48.Explain the mechanism of gaseous exchange in plants. Discuss how carbon dioxide and oxygen diffuse in and out of leaves during: (a) daytime, (b) nighttime, based on the rate of photosynthesis vs respiration.
49.What is emulsification of fats? Why is it necessary before lipase enzyme can act on fats? Name the organ and gland responsible for fat digestion in humans.
50.Describe the role of the following glands/juices in human digestion:
- Salivary gland (Salivary amylase)
- Gastric glands (Pepsin, Mucus)
- Pancreas (Trypsin, Lipase)
51.What happens to the rate of photosynthesis when: (a) light intensity increases, (b) carbon dioxide concentration drops, (c) temperature rises extremely high? Explain.
52.Why is the breakdown of glucose in the cytoplasm called glycolysis? What is the product formed at the end of this step, and how many carbon atoms does it contain?
53.Describe the respiratory surface of a human lung. Explain how the enormous surface area of alveoli helps in rapid diffusion of gases.
54.What is the difference between single circulation and double circulation? Name one animal group showing single circulation and explain how gas exchange occurs in them.
55.Why do plants have a much slower transport system and lower energy needs compared to animals? Explain in terms of their cellular composition (dead cells vs living cells).
56.Explain how transpiration pull is created. Discuss why transpiration is considered a "necessary evil" for plants.
57.Differentiate between excretion and egestion in animals. Name the major nitrogenous wastes excreted by: (a) aquatic animals, (b) birds, and (c) mammals.
58.Explain the structure and filtering function of the Glomerulus in Bowman's capsule. What prevents large blood proteins and cells from entering the filtrate?
59.What is selective reabsorption in urine formation? Name three substances present in the initial filtrate that are completely reabsorbed by the tubular cells, and explain why.
60.How does the plant get rid of its gaseous wastes ($\text{O}_2$ and $\text{CO}_2$) during different periods of a 24-hour cycle? Write the equations.
61.A student performs a starch test on a leaf of a potted plant that was kept in a dark room for 3 days. What will be the observation, and why was the plant kept in the dark first? (Destarching).
62.Why is lymph clear or light-yellow in colour and does not contain red blood cells? Explain its origin and filtration in capillaries.
63.Explain the mechanism of opening and closing of stomata in terms of osmotic pressure, water movement, and turgidity of guard cells.
64.Why does breathing become difficult and faster at high altitudes? Explain how our body adapts to low oxygen concentrations over a few weeks.
65.A patient is diagnosed with high blood urea levels (uremia). Evaluate the medical treatment options available (hemodialysis vs kidney transplant) in terms of efficacy, lifestyle impact, and risks.
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