Every question from this NCERT chapter, with a detailed explanation.
Which enzyme, present in saliva and pancreatic juice, is primarily responsible for the breakdown of starch into simpler sugars?
The accumulation of which compound in muscle cells leads to cramps during sudden physical activity or anaerobic respiration?
Which hair-like structures lining the upper respiratory tract help in filtering air by trapping dust and particles?
In the circulatory system of fishes, the heart is characteristically composed of how many chambers?
With reference to maintenance functions in organisms, consider the following statements: 1. The transfer of energy source from outside to inside is referred to as respiration. 2. These processes require energy sourced from outside the body. 3. All organisms obtain energy directly from sunlight. Which of the statements given above is/are correct?
Consider the following in the context of body design and exchange with the environment: 1. In single-celled organisms, the entire surface can handle intake and waste removal. 2. In multicellular organisms, simple diffusion is sufficient for all cells. 3. Increased body size and complexity necessitate specialised organs. Which of the statements given above are correct?
Regarding modes of nutrition, consider the following statements: 1. Autotrophs utilise complex organic substances as raw materials. 2. Heterotrophs require enzymes to break complex food into simpler forms. 3. Heterotrophs are directly or indirectly dependent on autotrophs for survival. Which of the statements given above are correct?
Which of the following is/are correct about autotrophic energy storage? 1. Carbohydrates formed are utilised for energy and stored as starch. 2. In humans, energy derived from food is stored in cells as starch. 3. Chlorophyll is not required for the formation of carbohydrates. Select the correct answer using the code below:
Assertion (A): The opening and closing of the stomatal pore is a function of the guard cells. Reason (R): The guard cells swell when water flows out of them, causing the stomatal pore to open.
Regarding raw material uptake by terrestrial plants, consider the following statements: 1. Water is absorbed from the soil by the roots. 2. Nitrogen is taken up by plants exclusively in the form of atmospheric gas. 3. Phosphorus is absorbed from the soil along with water. Which of the statements given above are correct?
Match the following organisms with their nutritive strategies: List I (Organism) | List II (Nutritive Strategy) A. Bread mould | 1. Parasitic on plants B. Cuscuta | 2. Ingestive internal digestion C. Leech | 3. External digestion and absorption D. Lion | 4. Ectoparasite on animals Select the correct answer using the code given below
Match the unicellular organism features with their descriptions: List I (Feature/Organism) | List II (Description) A. Amoeba feeding mechanism | 1. Cilia move food to a specific spot B. Paramoecium feeding mechanism | 2. Variable and irregular C. Amoeba body shape | 3. Temporary finger-like extensions (pseudopodia) D. Paramoecium body shape | 4. Definite and fixed Select the correct answer using the code given below
Assertion (A): Starchy foods like bread or rice begin to taste sweet after they are chewed thoroughly. Reason (R): Saliva contains an enzyme called salivary amylase that breaks down starch into simple sugars.
Match the gastric secretion/structure with its primary role: List I | List II A. Hydrochloric acid | 1. Protects inner lining of stomach B. Pepsin | 2. Regulates release of food to small intestine C. Mucus | 3. Facilitates protein digestion D. Sphincter muscle | 4. Creates acidic medium Select the correct answer using the code given below
In the context of animal physiology and diet adaptation, which of the following animals possesses the longest small intestine relative to its body size to facilitate the digestion of cellulose?
Consider the following statements about fat digestion and small intestinal milieu: 1. Bile makes the intestinal content acidic for the action of pancreatic enzymes. 2. Bile salts emulsify fats into smaller globules. 3. Lipase in pancreatic juice acts on emulsified fats. Which of the statements given above are correct?
In the process of cellular respiration, the metabolic pathway of glycolysis, which converts glucose into pyruvate, takes place in which cellular compartment?
Assertion (A): During heavy physical exercise, muscle cells in humans perform fermentation to produce ethanol and carbon dioxide. Reason (R): In the absence of oxygen, yeast cells convert pyruvate into ethanol and carbon dioxide.
Consider the following statements about anaerobic conditions in human muscles: 1. The product formed has two carbon atoms. 2. Pyruvate is converted into lactic acid. 3. The pathway yields significantly more energy than aerobic respiration. Which of the statements given above is/are correct?
Which cellular activities commonly draw upon ATP? 1. Muscle contraction 2. Protein synthesis occurs without energy expenditure. 3. Conduction of nervous impulses Select the correct answer using the code below:
Consider the following statements about gaseous exchange in plants: 1. At night, elimination of carbon dioxide predominates. 2. During the day, carbon dioxide release is the major event. Which of the statements given above is/are correct?
Assertion (A): The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms. Reason (R): The amount of dissolved oxygen in water is fairly low compared to the amount of oxygen in the air.
Assertion (A): The lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed. Reason (R): This residual volume allows the lungs to completely empty of carbon dioxide during each exhalation cycle.
Which of the following statements are correct regarding respiratory gases and blood? 1. Haemoglobin in red blood corpuscles has no affinity for oxygen. 2. Carbon dioxide is mostly transported dissolved in plasma. 3. Carbon dioxide is more soluble in water than oxygen. Select the correct answer using the code below:
Which component of human blood is primarily responsible for the transport of oxygen to tissues via the pigment haemoglobin?
Match the cardiac chamber with its function: List I | List II A. Left atrium | 1. Pumps deoxygenated blood to lungs B. Left ventricle | 2. Pumps oxygenated blood to body C. Right atrium | 3. Receives oxygenated blood from lungs D. Right ventricle | 4. Receives deoxygenated blood from body Select the correct answer using the code given below
Consider the following statements: 1. Atria have thicker muscular walls than ventricles. 2. Valves in the heart prevent backflow during chamber contractions. Which of the statements given above is/are correct?
Consider the following statements about vertebrate circulation: 1. Separation of sides in the heart is unnecessary for animals that maintain body temperature. 2. Amphibians generally have three-chambered hearts and tolerate mixing of blood. 3. In fish, blood passes through the heart twice in one systemic cycle. Which of the statements given above is/are correct?
Match the term related to blood pressure with its description: List I | List II A. Systolic pressure | 1. 120/80 mm Hg B. Diastolic pressure | 2. Instrument used to measure blood pressure C. Normal blood pressure | 3. Pressure during ventricular contraction D. Sphygmomanometer | 4. Pressure during ventricular relaxation Select the correct answer using the code given below
With reference to the human circulatory system, which statement correctly describes the structure or function of capillaries?
Consider the following about lymph: 1. It is similar to plasma but colourless and contains less protein. 2. It drains into lymphatic vessels and finally into larger veins. 3. It carries absorbed fat from the intestine. 4. It increases blood pressure in arteries. Which of the statements given above are correct?
Match the vascular tissue or process with its description: List I | List II A. Xylem | 1. Translocation of products of photosynthesis B. Phloem | 2. Transport of water and minerals C. Root pressure | 3. Loss of water in the form of vapour D. Transpiration | 4. Push effect on water column at night Select the correct answer using the code given below
Assertion (A): Root pressure alone is sufficient to move water over the heights of tall trees. Reason (R): Active absorption of ions into the vascular tissue of roots causes water to flow in continuously, creating a pushing pressure.
Match the structure of the human excretory system with its role: List I | List II A. Kidney | 1. Conducts urine to the exterior B. Ureter | 2. Stores urine C. Urinary bladder | 3. Forms urine by filtration D. Urethra | 4. Conveys urine from kidney to bladder Select the correct answer using the code given below
Consider the following statements: 1. In a healthy adult, initial filtrate volume per day is about 180 L. 2. Only 1-2 L is excreted as urine due to reabsorption in tubules. Which of the statements given above is/are correct?
Which organ in the human body is responsible for the secretion of bile, which aids in the emulsification of fats?
Which molecule is universally referred to as the 'energy currency' of the cell?
Assertion (A): The nephron is the structural and functional unit of the kidney. Reason (R): Urine formation involves three main processes: filtration, reabsorption, and secretion.
The physiological process involving the intake of oxygen for the enzymatic breakdown of food sources to release energy is known as:
In the context of plant physiology, which carbohydrate serves as the primary storage form of energy?
Assertion (A): Visible molecular movement is not a defining characteristic of life, yet invisible molecular movements are necessary for existence. Reason (R): Viruses do not show any molecular movement in them until they infect some cell.
Which enzyme is active in the acidic environment of the human stomach to initiate protein digestion?
Which proteolytic enzyme is secreted by the pancreas and acts in the small intestine?
The finger-like projections found in the lining of the small intestine, which increase the surface area for absorption, are known as:
The rhythmic contraction and relaxation of muscles in the alimentary canal that pushes food forward is termed:
Which medical instrument is standardly used to measure arterial blood pressure?
Which class of blood vessels generally carries blood away from the heart to various parts of the body?
Which component of blood plays a pivotal role in the coagulation process at the site of injury?
Which fluid is primarily responsible for carrying digested and absorbed fats from the intestine to the blood?
Which vascular tissue in plants is responsible for the unidirectional transport of water and minerals from roots to stems?
Which organism is widely used in the fermentation process to produce ethanol and carbon dioxide?
What is the basic functional and structural unit of the human kidney?
Which tubular structure transports urine from the kidneys to the urinary bladder?
Which of the following is produced as a by-product during the process of photosynthesis in plants?
Assertion (A): Transpiration helps in the absorption and upward movement of water and minerals dissolved in it. Reason (R): Evaporation of water molecules from the cells of a leaf creates a suction which pulls water from the xylem cells of roots.