Life processes are the maintenance processes essential for sustaining life, such as nutrition, respiration, transportation, and excretion, which together keep living organisms alive and functioning.

Source: Chapter 5, Section 5.1

The examiner expects the definition directly from the textbook: "The processes which together perform this maintenance job are life processes." You should also mention 1–2 examples (nutrition, respiration, etc.) to complete the answer. Avoid writing a long explanation for a 1-mark question.

(d) Locomotion

Locomotion is NOT a life process. Life processes include nutrition, respiration, transportation, and excretion — functions essential for body maintenance.

The textbook (Section 5.1) defines life processes as maintenance functions essential for survival, listing nutrition, respiration, transport, and excretion. Locomotion (movement from place to place) is not listed as a life process; movement may indicate life, but locomotion itself is not a maintenance function. Examiners expect students to distinguish between movement/locomotion and actual life processes.

The two types of nutrition are autotrophic nutrition (using simple inorganic substances like CO₂ and water to synthesise food) and heterotrophic nutrition (obtaining complex food from other organisms).

Source: 5.2 Nutrition, Chapter 5

The examiner expects both terms named correctly. A brief distinguishing phrase for each earns full credit. No elaboration needed for 1 mark.

The term used for such organisms is autotrophs. They prepare their own food using inorganic raw materials like CO₂ and water in the presence of sunlight.

Source: Chapter 5, Section 5.2 — Nutrition

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The examiner expects the specific term autotrophs to be stated clearly. Mentioning that they use inorganic sources (CO₂, water) and sunlight adds completeness for full marks. Green plants and some bacteria are examples, but naming examples is optional for a 1-mark answer.

Chloroplast is the organelle in plant cells that contains chlorophyll.

Source: Autotrophic Nutrition, Chapter 5

The passage from Chapter 5 explicitly states: "These green dots are cell organelles called chloroplasts which contain chlorophyll." For a 1-mark question, simply naming the organelle is sufficient. Do not confuse chloroplast (the organelle) with chlorophyll (the pigment inside it).

(b) Photosynthesis

Photosynthesis is the process by which green plants use sunlight, carbon dioxide, and water to synthesise carbohydrates (food) in the presence of chlorophyll.

Source: Life Processes, Section 5.2.1

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This is a direct one-mark MCQ. Simply state the correct option and give a one-line justification — examiners award the mark for the correct option, but a brief reason shows understanding. Do not write lengthy definitions for 1-mark questions.

Guard cells regulate the opening and closing of stomata, thereby controlling gaseous exchange (CO₂ and O₂) and transpiration (water loss) in the leaf.

Examiners expect two functions in one line: stomatal regulation and what that controls (gas exchange + water loss). Mentioning only "open and close stomata" without stating why it matters may cost half the mark. The source passages do not directly describe guard cells, so use standard NCERT Life Processes knowledge here.

The enzyme present in saliva is salivary amylase.

Function: It breaks down starch (a complex carbohydrate) into simple sugars. Thus, the chemical digestion of carbohydrates begins in the mouth itself.

Source: Life Processes, Section 5.2.4

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• 1 mark for naming the enzyme: salivary amylase (not just "amylase").
• 1 mark for its function: breaking down starch into simple sugars.
• Avoid vague answers like "it digests food" — be specific about the substrate (starch) and the product (simple sugar).
• The textbook explicitly states: "The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar." Stick close to this wording.

Complete digestion of carbohydrates, proteins, and fats takes place in the small intestine.

The small intestine receives secretions from the pancreas (pancreatic juice containing amylase, trypsin, lipase) and bile from the liver, which complete the digestion of all three food groups. The examiner expects a direct, single-line answer — just naming the small intestine earns full marks. Do not write stomach, as digestion there is only partial.

Hydrochloric acid (HCl) secreted by the gastric glands in the stomach serves two main functions:

1. It creates an acidic medium which is necessary for the activation and proper functioning of the protein-digesting enzyme pepsin.
2. It kills harmful bacteria and pathogens that may enter the stomach along with food.

Source: Life Processes, Chapter 5, Section 5.2.4

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The passage explicitly states: "The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin." The question in the passage also hints at another function — killing germs. Examiners expect both points for full 2 marks. Mention pepsin by name; that shows precise textbook knowledge. Do not confuse this with the role of mucus (which protects the stomach lining from the acid).

(c) Trypsin

Trypsin is secreted by the pancreas as part of pancreatic juice and is responsible for digesting proteins in the small intestine.

Source: Life Processes, Section 5.2.4 (Nutrition in Human Beings)

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The passage clearly states: "The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats." Pepsin is a protein-digesting enzyme but it is secreted by the stomach (gastric glands), not the pancreas. Amylase digests starch, and lipase digests fats. Examiners expect you to distinguish between the source (which organ) and the function (which nutrient) of each enzyme.

Villi are tiny, finger-like projections found on the embryo's side of the placenta. They are surrounded by blood spaces on the mother's side. Villi provide a large surface area for the transfer of glucose and oxygen from the mother's blood to the developing embryo, and for removal of waste substances from the embryo.

Source: Chapter 7, Section 7.3.3(b)

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• The question is directly answered from the placenta passage in Chapter 7.
• Examiners expect two things: what villi are (finger-like projections) and where they are found (embryo's side of the placenta) — one point each for 2 marks.
• Mentioning their function (large surface area for exchange) strengthens the answer and is often expected even in a "what/where" question.
• Do not confuse these with intestinal villi (Class 10 Life Processes chapter) — the source passage here refers only to placental villi.

Bread mould (Rhizopus) and mushroom are two organisms that break down food material outside their body and then absorb it (saprotrophic/extracellular digestion).

Source: Life Processes, Section 5.2.2

The passage explicitly lists "fungi like bread moulds, yeast and mushrooms" as examples. Name any two from this list. The examiner expects organisms from the textbook — do not write animals. The key phrase is "break down food outside the body then absorb it."

The first step in the breakdown of glucose during cellular respiration is glycolysis, in which glucose is broken down into pyruvate in the cytoplasm.

Examiners expect the term "glycolysis" and its location (cytoplasm). This is a 1-mark question, so one clear line naming the process is sufficient. Note: the passage (Exercise Q4) confirms that pyruvate breakdown occurs in mitochondria — implying the prior step, glycolysis, occurs in the cytoplasm, as taught in the chapter.

(d) Mitochondria

The breakdown of pyruvate using oxygen (aerobic respiration) takes place in the mitochondria.

This is directly supported by Exercise Q4 in Chapter 5, which states that breakdown of pyruvate to give carbon dioxide, water and energy takes place in the mitochondria. Cytoplasm is where glycolysis (breakdown of glucose to pyruvate) occurs — not the oxygen-dependent breakdown of pyruvate. Examiners expect the single correct option with its letter.

Anaerobic respiration is the breakdown of glucose in the absence of oxygen to release energy. It produces less energy compared to aerobic respiration. For example, in yeast, glucose is broken down to produce ethanol and carbon dioxide. In our muscles during heavy exercise, glucose breaks down to produce lactic acid, causing muscle cramps.

Source: Life Processes, Chapter 5

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• The examiner expects: definition (no oxygen), products (ethanol + CO₂ in yeast / lactic acid in muscles), and the fact that less energy is released.
• Mentioning both examples (yeast and human muscles) secures both marks.
• Do not confuse anaerobic with aerobic — aerobic uses oxygen and releases CO₂ + water + more energy.

When pyruvate is broken down anaerobically in yeast (fermentation), ethanol (alcohol) and carbon dioxide are produced.

Source: Chapter 5, Section 5.3 Respiration

The passage explicitly states: "pyruvate may be converted into ethanol and carbon dioxide. This process takes place in yeast during fermentation." Both products must be named for full marks. Writing only "ethanol" or only "CO₂" may result in losing the mark.

During sudden intense activity, the muscle cells may not get enough oxygen. In the absence of oxygen, glucose is broken down anaerobically, producing lactic acid. This lactic acid accumulates in the muscle cells, causing cramps (pain and stiffness).

This question is from the chapter on Life Processes (anaerobic respiration in muscles), not directly from the provided passages on Control and Coordination. The examiner expects: (1) lack of oxygen during intense activity, (2) anaerobic breakdown of glucose producing lactic acid, and (3) lactic acid accumulation causing cramps. These three points cover both marks. Keep the answer concise and use correct terms: anaerobic respiration, lactic acid, accumulation.

ATP (Adenosine Triphosphate) is the energy currency of the cell. During cellular respiration, organic compounds such as glucose are broken down, and the energy released is stored in the form of ATP. This ATP is then used to provide energy for various other reactions in the cell, enabling life processes to continue.

Source: Life Processes, Chapter 5, Section 5.1 / What you have learnt

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• Examiners expect two clear points: (1) what ATP is, and (2) its role/importance — one point per mark.
• The phrase "energy currency of the cell" is a standard term that scores well.
• Directly quote or paraphrase the textbook line: "organic compounds such as glucose are broken down to provide energy in the form of ATP; ATP is used to provide energy for other reactions in the cell."
• Do not over-explain; keep it within 40–60 words.

The tiny balloon-like structures in the lungs where exchange of gases takes place are called alveoli (singular: alveolus).

The examiner expects the specific term "alveoli." This is a direct one-line factual answer worth 1 mark. The source passages reference lungs and capillaries in the context of gas exchange, and alveoli is the standard NCERT term from Chapter 5 (Life Processes). No further detail is needed for 1 mark.

(a) Haemoglobin, red blood corpuscles

Haemoglobin is the respiratory pigment in human blood that carries oxygen, and it is found in red blood corpuscles (RBCs).

Source: Life Processes, Section 5.4.1

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The passage clearly states: "Oxygen is carried by the red blood corpuscles" and Activity 5.7 directly references haemoglobin content in human beings. Chlorophyll is a plant pigment (photosynthesis), not a blood pigment. Plasma transports food and CO₂ in dissolved form, not oxygen. White blood cells (WBCs) are part of the immune system, not oxygen carriers. Platelets help in clotting. So option (a) is the only correct choice.

Carbon dioxide is mainly transported in dissolved form in the plasma of blood.

Source: Life Processes, Section 5.4.1

The textbook explicitly states: "Plasma transports food, carbon dioxide and nitrogenous wastes in dissolved form." Examiners expect this specific point. Avoid writing about haemoglobin here — that is for oxygen transport, not CO₂.

The four chambers of the human heart are: right atrium, right ventricle, left atrium, and left ventricle.

The textbook clearly states that the heart has different chambers to prevent mixing of oxygenated and deoxygenated blood. For a 1-mark question, simply naming all four chambers in one line is sufficient — no further description needed. Remember: upper chambers = atria (right and left); lower chambers = ventricles (right and left).

Double circulation is the process in which blood passes through the heart twice during each cycle of circulation through the body. In one cycle, deoxygenated blood goes from the heart to the lungs for oxygenation and returns to the heart; then oxygenated blood is pumped from the heart to the rest of the body. It occurs in mammals and birds.

Source: Chapter 5, Section 5.4.1 – Transportation in Human Beings

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• The key phrase examiners look for is "blood passes through the heart twice in one cycle."
• Briefly mention both loops: heart → lungs → heart (pulmonary), and heart → body → heart (systemic).
• Mentioning that it occurs in mammals/birds adds value and may fetch full marks.
• Avoid confusing this with the four-chambered heart description — focus on the circulation pattern, not the heart structure.

(c) Arteries

Arteries are blood vessels that carry blood away from the heart to various organs of the body.

The textbook explicitly states: "Arteries are the vessels which carry blood away from the heart to various organs of the body." Veins bring blood back to the heart; capillaries allow exchange at tissue level; lymph vessels carry lymph, not blood. This is a direct definition-based question — memorise the direction of flow for each vessel type.

Arteries carry blood away from the heart under high pressure. Thick, elastic walls help them withstand and maintain this high blood pressure without bursting.

The examiner expects two linked points: (1) arteries carry blood at high pressure from the heart, and (2) thick elastic walls withstand that pressure. Note: this topic is from the Life Processes chapter (Chapter 6, circulatory system), though the provided passages don't directly cover it — answer from core CBSE knowledge.

Platelets help clot the blood at points of injury, thereby plugging leaks in blood vessels and preventing excessive blood loss.

Source: Life Processes, Section 5.4.1 (Maintenance by platelets)

The passage directly states that platelet cells "circulate around the body and plug these leaks by helping to clot the blood at these points of injury." For 1 mark, simply state this clotting/plugging function — no extra detail needed.

Lymph is a fluid derived from blood plasma that leaks out through the pores of capillary walls into the surrounding tissues. It is a colourless fluid containing white blood cells (lymphocytes). It is formed when plasma, proteins, and blood cells are forced out of the blood capillaries into intercellular spaces, and is then collected by lymph capillaries.

This question is from Chapter 6 (Life Processes) — specifically the section on transportation in animals. The source passages provided are from Chapter 7 (Reproduction) and do not contain information about lymph, so this answer is based on the standard CBSE Class 10 NCERT textbook content for that topic. Key examiner expectations: define lymph, mention it is derived from plasma, state it contains WBCs/lymphocytes, and briefly describe its formation from capillary filtration into intercellular spaces. Do not confuse lymph with blood.

The two types of vascular tissue in plants are:

1. Xylem – transports water and minerals absorbed from the soil upward to all parts of the plant.
2. Phloem – transports soluble products of photosynthesis (such as sucrose) from leaves to other parts of the plant (translocation).

Source: Life Processes, Section 5.4.2

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• Examiners expect you to name both tissues and clearly state what each transports — that's 1 mark each.
• A common mistake is saying phloem transports "food upward only" — phloem moves material in both upward and downward directions, so avoid limiting its direction.
• Key terms to use: water and minerals for xylem; products of photosynthesis / sucrose / translocation for phloem.

Transpiration is the process by which plants lose excess water in the form of water vapour through their stomata (mainly from leaves).

Source: Life Processes, Section 5.5.2

The examiner expects a one-line definition mentioning: (1) loss of water, (2) in the form of water vapour/water, (3) from plants (through stomata/leaves). The textbook mentions transpiration under excretion in plants as a way to get rid of excess water. Do not confuse it with respiration.

(b) Translocation

The transport of soluble products of photosynthesis (food) in plants is called translocation. It occurs through the phloem, which is part of the vascular tissue.

Source: Life Processes, Chapter 5

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The examiner expects you to recall that xylem transports water and minerals, while phloem transports food (soluble products of photosynthesis) — this movement of food through phloem is called translocation. Do not confuse with transpiration (loss of water vapour) or osmosis (movement of water across a membrane). For a 1-mark MCQ, simply writing the option letter and term is sufficient.

Translocation of food in phloem requires ATP (energy), which is used to actively load solutes, creating an osmotic pressure difference that drives the movement of food.

Source: Life Processes, Section 5.2

The examiner expects the key term ATP as the energy currency used in phloem translocation. The active loading of sugars into phloem requires energy in the form of ATP. A one-mark answer needs only the energy source named, with minimal supporting context. Avoid lengthy explanations.

The human excretory system consists of the following components:

1. A pair of kidneys – filter nitrogenous waste (urea) from the blood.
2. A pair of ureters – carry urine from the kidneys to the urinary bladder.
3. Urinary bladder – stores urine until it is released.
4. Urethra – passage through which urine is expelled from the body.

Source: Life Processes, Section 5.5.1

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• The question is worth 2 marks, so simply naming all four components with a one-line function for each is sufficient — no detailed description needed.
• Examiners expect all four organs to be listed; missing even one can cost a mark.
• The textbook lists them in order: kidneys → ureters → urinary bladder → urethra. Following this order shows clarity.
• Avoid writing about nephrons here; the question asks for organs of the excretory system, not the internal structure of the kidney.

The basic filtration unit of the kidney is called the nephron.

Source: Life Processes, Section 5.5.1

The examiner expects the single term "nephron." The passage clearly states: "Each kidney has large numbers of these filtration units called nephrons packed close together." No further detail is needed for a 1-mark question — just name it correctly.

(c) Bowman's capsule

The cup-shaped end of a coiled tube associated with the capillary cluster in the kidney that collects the filtrate is called Bowman's capsule.

The passage directly states: "Each capillary cluster in the kidney is associated with the cup-shaped end of a coiled tube called Bowman's capsule that collects the filtrate." A nephron is the entire filtration unit; ureter and urethra are tubes for urine transport — not collecting structures for filtrate. Bowman's capsule is the only cup-shaped structure collecting filtrate.

The two nitrogenous waste products removed from the blood by the kidneys are urea and uric acid.

Source: Life Processes, Section 5.5.1

The textbook explicitly states: "nitrogenous waste such as urea or uric acid are removed from blood in the kidneys." Just name both — no extra detail needed for 1 mark.

Plants store their waste products using several methods:

• Waste products like resins and gums are stored in old xylem.
• Wastes are stored in cellular vacuoles.
• Some waste products are stored in leaves that fall off.
• Plants also excrete some waste substances into the surrounding soil.

Source: Chapter 5, Section 5.5.2 – Excretion in Plants

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The examiner expects students to name specific storage methods — vacuoles, resins/gums in old xylem, falling leaves, and excretion into soil. Simply writing "plants store waste in vacuoles" alone will fetch only 1 mark. For 2 marks, give at least two distinct methods. Avoid writing about oxygen/CO₂/transpiration here, as those deal with gaseous wastes, not stored wastes. The key section is 5.5.2.

Artificial Kidney: An artificial kidney is a device used to remove nitrogenous waste products (such as urea) from the blood when the kidneys fail. This process is called haemodialysis.

Principle: It works on the principle of dialysis (diffusion through a semi-permeable membrane). The device contains tubes with a semi-permeable lining suspended in dialysing fluid, which has the same osmotic pressure as blood but is devoid of nitrogenous wastes. The patient's blood is passed through these tubes, and waste products diffuse from the blood into the dialysing fluid. The purified blood is then pumped back into the patient. Unlike the kidney, no reabsorption is involved.

Source: Chapter 5, Section 5.5.1 (More to Know — Artificial Kidney)

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• Examiners expect two parts: definition (what it is) and principle (how it works).
• Key terms to include: dialysis, semi-permeable membrane, diffusion, dialysing fluid, no reabsorption.
• Mentioning that dialysing fluid lacks nitrogenous wastes (creating a concentration gradient for diffusion) is a scoring point.
• The last line about no reabsorption distinguishes it from a natural kidney — include it for full marks.

Bile juice is secreted by the liver and acts on fats in the small intestine. It makes the acidic food coming from the stomach alkaline, enabling pancreatic enzymes to function. Bile salts break large fat globules into smaller ones (emulsification), which increases the efficiency of enzyme action on fats.

Source: Chapter 5, Section 5.2.4 – Nutrition in Human Beings

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Examiners look for two roles of bile for 2 marks:

1. Making the medium alkaline (neutralising acid from stomach so pancreatic enzymes can work).
2. Emulsification of fats (breaking large fat globules into smaller ones to increase surface area for enzyme action).

Don't confuse bile with a digestive enzyme — it contains no enzymes. Mentioning that bile is produced by the liver adds accuracy. Keep the answer within 50–60 words for a 2-mark question.

The three events that occur during photosynthesis are:

1. Absorption of light energy by chlorophyll – Chlorophyll present in the chloroplasts of plant cells absorbs sunlight.

1. Conversion of light energy to chemical energy and splitting of water molecules – The absorbed light energy is converted into chemical energy, and water molecules are split into hydrogen and oxygen.

1. Reduction of carbon dioxide to carbohydrates – The hydrogen produced is used to reduce CO₂ to form carbohydrates, which store energy for the plant.

Source: Life Processes, Section 5.2.1 Autotrophic Nutrition

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• The examiner expects all three events listed exactly as given in the textbook — one point per mark.
• Use the correct scientific terms: "absorption," "conversion," "splitting of water," and "reduction of CO₂."
• Do not confuse the order; examiners check that all three are mentioned clearly.
• Avoid adding unnecessary detail (e.g., light vs. dark reactions) — it goes beyond the textbook scope for this question.

Herbivores eat grass and plant material, which contains cellulose — a complex carbohydrate that is difficult to digest and requires more time and a longer digestive tract to break down completely. Meat (eaten by carnivores) is easier to digest, so carnivores like tigers have a shorter small intestine.

Source: Chapter 5, Section 5.2.4 – Nutrition in Human Beings

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• The textbook directly states this fact: "Herbivores eating grass need a longer small intestine to allow the cellulose to be digested. Meat is easier to digest, hence carnivores like tigers have a shorter small intestine."
• For 2 marks, examiners expect two points: (1) herbivores need to digest cellulose → longer intestine, and (2) meat is easier to digest → carnivores have shorter intestine.
• Always mention cellulose by name — it is the key term that earns marks.

The heart needs separate chambers for oxygenated and deoxygenated blood to prevent mixing of the two. If they mixed, the tissues would not receive pure oxygen-rich blood, reducing efficiency of oxygen supply to the body.

Deoxygenated blood must be sent to the lungs to release CO₂ and collect oxygen, while oxygenated blood from the lungs must be pumped to the rest of the body. Separation ensures this double circulation works efficiently.

This is especially important for birds and mammals, which have high energy needs and must maintain constant body temperature. A highly efficient oxygen supply is essential for this purpose.

Source: Life Processes, Chapter 5, Section 5.4.1

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• The examiner expects three points for 3 marks: (1) mixing is prevented, (2) efficient oxygen supply is maintained, and (3) it is essential for warm-blooded animals (high energy needs / thermoregulation).
• Use the textbook phrase "highly efficient supply of oxygen" — it signals you've read the source.
• Avoid writing about all four chambers in detail; the question is specifically about why separation is necessary, not how the heart works.

Two functions of transpiration in plants:

1. Absorption and upward movement of water and minerals — Transpiration creates a suction pull (transpiration pull) that helps transport water and dissolved minerals from roots to leaves through xylem.

1. Cooling effect — Evaporation of water through stomata during transpiration helps cool the plant surface, preventing overheating.

Transpiration is the loss of water vapour through stomata. Examiners expect two distinct, clearly stated functions — "transpiration pull" for water transport is the most important point. The cooling function is the second commonly accepted answer. Write each as a separate point for easy mark allocation. Avoid vague statements like "it helps the plant" without explaining how.

Mucus protects the inner lining of the stomach from the action of the hydrochloric acid secreted by the gastric glands under normal conditions.

Source: Life Processes, Section 5.2.4

The examiner expects a direct, one-line functional statement. The key phrase from the textbook is "protects the inner lining of the stomach from the action of the acid." Avoid vague answers like "it helps digestion" — mucus is not an enzyme and does not digest food.

Nutrition in Amoeba:

Amoeba is a unicellular organism that follows holozoic nutrition. It captures food using pseudopodia — temporary finger-like extensions of the cell surface. These pseudopodia surround the food particle and fuse over it, forming a food-vacuole.

Inside the food-vacuole, complex substances are broken down into simpler ones, which then diffuse into the cytoplasm for use. The remaining undigested material is moved to the cell surface and thrown out.

Source: Chapter 5, Section 5.2.3

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• Examiners expect four key steps: pseudopodia formation → food-vacuole formation → digestion inside vacuole → egestion of undigested matter.
• Use correct terms: pseudopodia, food-vacuole, diffuse into cytoplasm — these are direct marks triggers.
• Do not confuse with Paramoecium (uses cilia + fixed spot); Amoeba uses pseudopodia over the whole surface.
• 3 marks = roughly one mark per step, so covering all four steps briefly is safer than elaborating on one.

The normal systolic blood pressure is 120 mm of Hg and the normal diastolic blood pressure is 80 mm of Hg.

Source: Life Processes, Section 5.4.1 (Blood Pressure – More to Know)

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The examiner expects both values stated clearly with correct units (mm of Hg). Remember: systolic = pressure during ventricular contraction; diastolic = pressure during ventricular relaxation. A common error is omitting the unit or swapping the two values. For 1 mark, simply stating both figures correctly is sufficient.

Structure of the Human Respiratory System:

Air enters through the nostrils, passes through the nasal cavity (where it is filtered and warmed), down the pharynx and larynx, into the trachea (windpipe). The trachea divides into two bronchi, one entering each lung. Inside the lungs, bronchi branch into smaller bronchioles, which end in tiny air sacs called alveoli.

Alveoli are the functional units of the lungs. They have:

• Extremely thin, moist walls
• Rich network of blood capillaries
• Large surface area (millions of alveoli)

Function:
Oxygen from inhaled air diffuses across the thin alveolar walls into the blood capillaries. Simultaneously, carbon dioxide from the blood diffuses into the alveoli and is expelled during exhalation. This process is called gaseous exchange. The diaphragm and rib muscles create breathing movements that ventilate the lungs, ensuring a continuous supply of fresh air to the alveoli.

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• Examiners expect you to cover both structure and function — name the organs in sequence (nostrils → alveoli) and then explain gaseous exchange.
• Key terms to include: alveoli, bronchi, bronchioles, trachea, diffusion, gaseous exchange, diaphragm.
• The alveolar features (thin walls, large surface area, capillary network) are high-value points — always mention all three.
• Avoid writing a long essay; structured points or short paragraphs score well for a 5-mark question.

Transport of Water from Roots to Leaves in Tall Plants:

1. Absorption by roots: Root hair cells absorb water from the soil by osmosis. The large surface area of root hairs increases the efficiency of absorption.

1. Movement across root: Water moves from root hair cells into the root cortex and then into the xylem vessels present in the root.

1. Role of xylem: Xylem is the vascular tissue responsible for the transport of water and dissolved minerals from roots to all parts of the plant, including leaves.

1. Transpiration pull: Water evaporates from the leaves through stomata — a process called transpiration. This creates a suction force (transpiration pull) that pulls water upward continuously through the xylem.

1. Cohesion of water: Water molecules are held together by cohesive forces, forming a continuous water column in the xylem from roots to leaves.

Thus, water travels upward against gravity through a combination of root pressure, capillary action, and transpiration pull.

Source: Chapter 5, Transportation in Plants

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• The examiner expects you to cover: root absorption → xylem pathway → transpiration pull as the driving force. These are the key steps for full marks.
• Mention xylem by name — it's directly tested in the MCQs of this chapter ("The xylem in plants are responsible for transport of water").
• Transpiration pull is the most important mechanism for tall plants; always name it explicitly.
• Do not confuse xylem (water transport) with phloem (food transport) — a common error that costs marks.

Mouth: Food is crushed by teeth and mixed with saliva secreted by salivary glands. Saliva contains salivary amylase which breaks down starch into simple sugars. The tongue helps mix food thoroughly.

Oesophagus: Food is pushed down to the stomach by rhythmic peristaltic movements of the canal muscles.

Stomach: Gastric glands secrete hydrochloric acid, enzyme pepsin, and mucus. HCl creates an acidic medium for pepsin to digest proteins. Mucus protects the stomach lining from acid damage.

Small Intestine: The food (now acidic) receives bile juice from the liver, which makes it alkaline and emulsifies fats. The pancreas secretes trypsin (proteins) and lipase (fats). Intestinal glands secrete intestinal juice that finally converts proteins → amino acids, carbohydrates → glucose, fats → fatty acids and glycerol.

Source: Chapter 5, Section 5.2.4

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• Award marks are typically split: 1 mark each for mouth, oesophagus, stomach, small intestine (role of bile + pancreas), and small intestine (final digestion/absorption).
• Always name the specific enzyme and its substrate — examiners look for this.
• "Emulsification" is a key term for bile's action on fats; don't miss it.
• Keep absorption (villi) brief or skip if word count is tight — the question asks about digestion, not absorption.

| Basis | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| (i) Presence of oxygen | Takes place in the presence of oxygen | Takes place in the absence of oxygen |
| (ii) Products formed | Carbon dioxide and water | Ethanol + CO₂ (in yeast) OR lactic acid (in muscle cells) |
| (iii) Energy released | Much greater amount of energy released | Less energy released |
| (iv) Location in cell | Cytoplasm (glycolysis) + Mitochondria (breakdown of pyruvate) | Cytoplasm only |

Organisms using anaerobic respiration: Yeast (fermentation), some bacteria, and human muscle cells (during sudden/intense activity).

Note: In both types, the first step — breakdown of glucose (6-carbon) into pyruvate (3-carbon) — occurs in the cytoplasm.

Source: Life Processes, Section 5.3 Respiration

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• Examiners award one mark per comparison point; the table format makes this clear and easy to mark.
• Mention both anaerobic products (ethanol/CO₂ for yeast AND lactic acid for muscles) — missing one costs a mark.
• Stating that aerobic respiration also begins in the cytoplasm (glycolysis) and continues in the mitochondria shows complete understanding.
• The textbook explicitly states "the release of energy in the aerobic process is a lot greater than in the anaerobic process" — use this language.
• Naming organisms that use anaerobic respiration (yeast, bacteria, muscle cells) is often asked as a follow-up; including it here covers Exercise Q.8.

The nephron is the basic structural and functional unit of the kidney. Each kidney contains a large number of nephrons packed together.

Structure: Each nephron consists of a cup-shaped structure called the Bowman's capsule, which surrounds a cluster of thin-walled blood capillaries called a glomerulus. The Bowman's capsule leads into a long, coiled tubule.

Filtration: Blood entering the glomerulus is filtered under pressure. Water, glucose, amino acids, urea, salts, and other small molecules pass into the Bowman's capsule as the initial filtrate. Blood cells and large proteins remain in the blood.

Reabsorption: As the filtrate moves along the tubule, useful substances — glucose, amino acids, salts, and a large amount of water — are selectively reabsorbed back into the blood. The amount of water reabsorbed depends on the body's needs.

Urine formation: What remains after reabsorption — mainly urea and excess water — forms urine. Normally, about 180 L of filtrate is produced daily, but only 1–2 L is excreted as urine. Urine from each kidney passes into the ureter, then the urinary bladder, and is expelled through the urethra.

Source: Chapter 5, Section 5.5.1

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• Examiners expect: structure of nephron (Bowman's capsule + glomerulus + tubule), the process of filtration, selective reabsorption, and final urine formation — all four aspects for full marks.
• Quote the 180 L vs 1–2 L figure; it shows textbook accuracy and is often directly awarded a mark.
• Use bold/underline key terms like Bowman's capsule, glomerulus, selective reabsorption — examiners check for correct terminology.
• Do not pad with unrelated content (e.g., artificial kidney) unless specifically asked.