1. What is the difference between autotrophic and heterotrophic nutrition?
Autotrophic nutrition involves organisms making their own food from simple inorganic substances (like plants using photosynthesis). Heterotrophic nutrition involves organisms obtaining complex organic food substances from other organisms or sources.
2. Explain the process of nutrition in Amoeba.
Amoeba feeds through phagocytosis. It engulfs food particles with its pseudopodia, forming a food vacuole. Digestive enzymes are released into this vacuole, breaking down the food. Nutrients are absorbed into the cytoplasm, and undigested waste is expelled.
3. What are the main steps in human nutrition?
The main steps in human nutrition are: ingestion (taking in food), digestion (breaking down food), absorption (nutrients entering the bloodstream), assimilation (cells using the nutrients), and egestion (removal of undigested waste).
4. How does the small intestine adapt itself for absorbing nutrients?
The small intestine adapts for nutrient absorption through: increased surface area (villi and microvilli), thin epithelial lining for easy diffusion, rich blood supply for quick nutrient transport, and presence of specific transport proteins in the membrane.
5. What is the role of saliva in the digestion of food?
Saliva contains the enzyme amylase, which begins the digestion of carbohydrates. It also moistens food for easier swallowing, helps in tasting food, and has antibacterial properties to protect the mouth.
6. Describe the structure and function of the human heart.
The human heart is a four-chambered muscular organ. It has two atria (upper chambers) and two ventricles (lower chambers). Its function is to pump blood throughout the body, delivering oxygen and nutrients to tissues and removing waste products.
7. What is the difference between arteries and veins?
Arteries carry blood away from the heart under high pressure, have thick walls, and no valves (except the pulmonary artery). Veins carry blood towards the heart under low pressure, have thinner walls, and contain valves to prevent backflow of blood.
8. Explain the process of breathing in humans.
Breathing involves inhalation and exhalation. During inhalation, the diaphragm contracts and moves down, the rib cage expands, increasing lung volume and decreasing air pressure, causing air to rush in. During exhalation, these processes reverse, pushing air out.
9. What is the role of hemoglobin in respiration?
Hemoglobin is the oxygen-carrying pigment in red blood cells. It binds with oxygen in the lungs and carries it to body tissues. It also helps in transporting some carbon dioxide back to the lungs. This makes it crucial for efficient gas exchange in the body.
10. How do plants get rid of their waste products?
Plants get rid of waste products through various methods: gaseous wastes (like oxygen) are released through stomata, excess water is lost through transpiration, and some waste products are stored in leaves that eventually fall off. Some wastes are also stored in vacuoles or converted into harmless substances.
11. What is the importance of diffusion in living organisms?
Diffusion is crucial for living organisms as it allows the movement of substances across cell membranes without energy expenditure. It’s important for gas exchange in respiration, absorption of nutrients in the small intestine, and the exchange of water and minerals in plant roots.
12. Describe the process of double circulation in humans.
Double circulation in humans involves two separate circuits: pulmonary circulation (between heart and lungs for oxygenation of blood) and systemic circulation (between heart and rest of the body to supply oxygenated blood). This ensures efficient oxygen supply to body tissues and separation of oxygenated and deoxygenated blood.
13. What are the main components of the human alimentary canal?
The main components of the human alimentary canal are: mouth, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum), and anus. Each part plays a specific role in the digestion and absorption of food.
14. How do plants obtain nitrogen for protein synthesis?
Plants obtain nitrogen mainly from the soil in the form of nitrates. Some plants have symbiotic relationships with nitrogen-fixing bacteria in their root nodules. These bacteria convert atmospheric nitrogen into a usable form for the plant. Plants then use this nitrogen to synthesize amino acids and proteins.
15. What is the role of pancreas in digestion?
The pancreas plays a dual role in digestion. It produces digestive enzymes (like amylase, lipase, and trypsin) that break down carbohydrates, fats, and proteins respectively. It also produces hormones like insulin and glucagon that regulate blood sugar levels.
16. Explain the process of photosynthesis and its importance.
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to produce oxygen and energy in the form of sugar. It occurs in the chloroplasts, specifically using the green pigment chlorophyll. The process can be summarized as: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂. It’s crucial for life on Earth as it provides food and oxygen for many organisms.
17. What is the function of nephrons in the human excretory system?
Nephrons are the functional units of the kidney. They filter blood, reabsorb useful substances, and secrete wastes to form urine. Each nephron consists of a glomerulus for filtration and a series of tubules for reabsorption and secretion, ultimately regulating the body’s water and solute balance.
18. How do fish carry out gaseous exchange?
Fish use gills for gaseous exchange. Water flows over the gills, and oxygen diffuses from the water into the blood in the gill filaments. At the same time, carbon dioxide diffuses from the blood into the water. The large surface area of the gills and the countercurrent flow of blood and water maximize the efficiency of this exchange.
19. What is the significance of transpiration pull in plants?
Transpiration pull is the main force driving the upward movement of water in plants. As water evaporates from the leaves, it creates a negative pressure (tension) in the xylem vessels. This tension pulls water up from the roots, allowing tall plants to transport water and minerals to their uppermost parts against gravity.
20. Describe the structure and function of the human respiratory system.
The human respiratory system consists of the nose, pharynx, larynx, trachea, bronchi, and lungs. Air enters through the nose or mouth, travels down the trachea, which branches into bronchi leading to the lungs. In the lungs, bronchi further divide into bronchioles ending in alveoli, where gas exchange occurs. The diaphragm and intercostal muscles facilitate breathing. The main functions are to supply oxygen to the blood and remove carbon dioxide from it.
1. (2022) Explain the process of nutrition in Amoeba with the help of a labeled diagram.
Amoeba feeds through phagocytosis. It extends pseudopodia to engulf food particles, forming a food vacuole. Digestive enzymes break down the food, and nutrients are absorbed into the cytoplasm. Undigested waste is expelled through exocytosis. A labeled diagram would show the amoeba’s cell membrane, cytoplasm, nucleus, food vacuole, and pseudopodia.
2. (2021) Describe double circulation in human beings. Why is it necessary?
Double circulation in humans involves two separate circuits: pulmonary (heart to lungs and back) and systemic (heart to body and back). It’s necessary to ensure efficient oxygenation of blood and its distribution to body tissues. This separation allows for high-pressure systemic circulation without damaging the lungs, and ensures that oxygenated and deoxygenated blood don’t mix.
3. (2020) What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Aerobic respiration uses oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and produces less ATP. Aerobic respiration fully breaks down glucose, while anaerobic respiration results in incomplete breakdown. Organisms using anaerobic respiration include some bacteria, yeast, and muscle cells during intense exercise.
4. (2019) Explain the mechanism of photosynthesis in plants.
Photosynthesis occurs in two stages: light-dependent reactions and light-independent reactions (Calvin cycle). In light-dependent reactions, chlorophyll absorbs light energy, which is used to split water and produce ATP and NADPH. In the Calvin cycle, CO2 is fixed using the energy from ATP and NADPH to produce glucose.
5. (2018) Describe the structure and functioning of nephrons.
Nephrons consist of a glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct. They function by filtering blood in the glomerulus, reabsorbing useful substances in the tubules, and secreting wastes. This process regulates blood composition, removes waste products, and maintains water-salt balance in the body.
6. (2017) Explain the process of breakdown of glucose in a cell in aerobic respiration.
Aerobic respiration breaks down glucose in three main stages: glycolysis (in cytoplasm), Krebs cycle (in mitochondrial matrix), and electron transport chain (on inner mitochondrial membrane). Glycolysis produces pyruvate, which enters the Krebs cycle. The Krebs cycle generates NADH and FADH2, which donate electrons to the electron transport chain, ultimately producing ATP through oxidative phosphorylation.
7. (2016) Describe the structure and function of the human heart with a labeled diagram.
The human heart is a four-chambered muscular organ with two atria and two ventricles. It pumps blood throughout the body. The right side pumps deoxygenated blood to the lungs, while the left side pumps oxygenated blood to the body. Valves ensure unidirectional blood flow. A labeled diagram would show the four chambers, major blood vessels, and valves.
8. (2015) What is transpiration? Explain its importance in plants.
Transpiration is the loss of water vapor from plant leaves and stems. It’s important for several reasons: it creates transpiration pull, which helps in water and mineral transport; it cools the plant; it maintains cell turgidity; and it influences stomatal opening and closing, which affects gas exchange for photosynthesis.
9. (2014) Describe the process of digestion in the human alimentary canal.
Digestion begins in the mouth with mechanical breakdown and salivary amylase. In the stomach, pepsin breaks down proteins. The small intestine is the main site of digestion and absorption, with enzymes from the pancreas and intestinal walls breaking down carbohydrates, proteins, and fats. The large intestine absorbs water and forms feces for excretion.
10. (2013) Explain how plants and animals respond to stimuli.
Plants respond to stimuli through tropisms (growth responses) and nastic movements. For example, phototropism (response to light) or thigmotropism (response to touch). Animals respond through their nervous system and hormones. Stimuli are detected by sensory receptors, processed by the nervous system, and result in appropriate responses through muscles or glands.