Quiz: Life Processes and Human Physiology — 39 questions

1. Which combination best describes the roles of food in living organisms?

A. Transporting water, protecting organs, and transmitting nerve impulses

B. Removing waste, detecting stimuli, and controlling body temperature

C. Absorbing sunlight, producing oxygen, and eliminating carbon dioxide

D. Providing energy, raw materials for growth and repair, and materials for enzymes and hormones

Answer: (D)

Explanation

Food supplies energy for life processes, raw materials for growth and tissue repair, and materials needed to produce enzymes and hormones.

2. What does nutrition involve in a living organism?

A. Producing oxygen, removing waste, and responding to environmental changes

B. Taking in sunlight, releasing carbon dioxide, and storing minerals

C. Digesting waste materials, absorbing oxygen, and repairing damaged tissues

D. Obtaining food, converting it into absorbable forms, and using it to make needed substances

Answer: (D)

Explanation

Nutrition is the process of obtaining food, converting it into simple absorbable forms, and using it to make substances required by the body.

3. Which activity is an example of a life process?

A. Reflecting light from a nonliving surface

B. Responding to a change in the surrounding environment

C. Forming a mineral crystal without using energy

D. Changing shape because of physical pressure alone

Answer: (B)

Explanation

Life processes include obtaining food, deriving energy, removing waste, and responding to environmental changes.

4. What is the key difference between autotrophic and heterotrophic nutrition?

A. Autotrophs manufacture their own food, whereas heterotrophs obtain food from other organisms

B. Autotrophs live inside hosts, whereas heterotrophs absorb nutrients from dead matter

C. Autotrophs ingest solid food, whereas heterotrophs manufacture glucose in chloroplasts

D. Autotrophs digest food externally, whereas heterotrophs produce food using sunlight

Answer: (A)

Explanation

Autotrophic organisms make their own food, while heterotrophic organisms depend on other organisms for food. The reverse distinction is a common confusion.

5. Why are green plants, algae, and certain bacteria called producers?

A. They live on or inside hosts and absorb nutrients from them

B. They obtain all their food by eating other organisms

C. They decompose dead organisms into simple substances

D. They manufacture food that other organisms depend on

Answer: (D)

Explanation

Green plants, algae, and certain bacteria are autotrophs that produce their own food, supporting other organisms in the food supply.

6. Which statement correctly defines photosynthesis?

A. Green plants use oxygen and glucose to make carbon dioxide in darkness without chlorophyll

B. Green plants use carbon dioxide and water to make food in sunlight with chlorophyll, releasing oxygen

C. Green plants absorb ready-made food from soil and release nitrogen during digestion

D. Green plants convert starch into water and carbon dioxide using enzymes in their roots

Answer: (B)

Explanation

Photosynthesis is the process in which green plants manufacture food from carbon dioxide and water using sunlight and chlorophyll, with oxygen released as a by-product.

7. Which equation represents the overall process of photosynthesis?

A. 6H₂O + 6O₂ → 6CO₂ + C₆H₁₂O₆, in darkness

B. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O, in light and chlorophyll

C. 6CO₂ + 6O₂ → C₆H₁₂O₆ + 6H₂O, without water

D. 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6H₂O + 6O₂, in light and chlorophyll

Answer: (D)

Explanation

The stated overall equation uses carbon dioxide and water in the presence of light and chlorophyll to produce glucose, water, and oxygen.

8. A student compares the two simultaneous stages of photosynthesis. Which comparison is correct?

A. The light reaction stores starch, whereas the dark reaction breaks down chlorophyll

B. The light reaction captures light energy, whereas the dark reaction forms glucose

C. The light reaction forms glucose, whereas the dark reaction captures light energy

D. The light reaction absorbs carbon dioxide, whereas the dark reaction releases oxygen

Answer: (B)

Explanation

The light reaction captures light energy in chloroplasts, while the dark reaction forms glucose in chloroplasts. Confusing these roles reverses the process.

9. Which classification correctly matches the major functions of these nutrients?

A. Carbohydrates and fats provide energy, proteins build body tissues, and vitamins and minerals regulate growth

B. Proteins and vitamins provide energy, fats regulate growth, and carbohydrates build body tissues

C. Vitamins and minerals provide energy, carbohydrates build body tissues, and proteins regulate growth

D. Carbohydrates and proteins provide energy, fats build body tissues, and minerals regulate digestion

Answer: (A)

Explanation

Carbohydrates and fats are energy-yielding nutrients, proteins are body-building nutrients, and vitamins and minerals regulate growth.

10. Which food group is primarily associated with supplying proteins for the growth of body tissues?

A. Salt, water, spices, and fruit juices

B. Oranges, carrots, leafy vegetables, and tomatoes

C. Rice, sugar, potatoes, bread, and cooking oils

D. Milk, pulses, eggs, meat, groundnuts, and soyabeans

Answer: (D)

Explanation

Proteins mainly support tissue growth and are found in foods such as milk, pulses, eggs, meat, groundnuts, and soyabeans.

11. Which meal plan best represents the meaning of a balanced diet?

A. A diet focused on proteins and vitamins while minimizing water and mineral intake

B. A diet containing adequate carbohydrates, fats, proteins, vitamins, minerals, and water in suitable proportions

C. A diet containing equal amounts of every nutrient regardless of a person's age or condition

D. A diet consisting mainly of carbohydrates and fats because they provide most of the body's energy

Answer: (B)

Explanation

A balanced diet provides all six listed components in proper proportions, and those proportions vary with age, sex, and pregnancy.

12. What is the main difference between digestion and ingestion?

A. Digestion stores unused nutrients, whereas ingestion eliminates undigested food from the body

B. Digestion converts complex food into absorbable substances, whereas ingestion takes food into the mouth

C. Digestion moves food through the oesophagus, whereas ingestion absorbs nutrients into blood capillaries

D. Digestion adds food to the mouth, whereas ingestion breaks proteins into smaller substances

Answer: (B)

Explanation

Digestion is the conversion of complex food into substances that cells can absorb; ingestion is the taking of food into the mouth.

13. Which sequence correctly lists the major stages of human nutrition?

A. Ingestion, digestion, absorption, assimilation, and egestion

B. Digestion, ingestion, assimilation, egestion, and absorption

C. Absorption, ingestion, digestion, assimilation, and egestion

D. Ingestion, absorption, digestion, egestion, and assimilation

Answer: (A)

Explanation

Human nutrition includes ingestion, digestion, absorption, assimilation, and egestion in that sequence.

14. A person has normal movement of food through the oesophagus but impaired starch digestion in the mouth. Which function is most directly affected?

A. Peristalsis moving food toward the stomach

B. Bile emulsifying fats in the small intestine

C. Villi absorbing digested food into blood capillaries

D. Salivary amylase breaking starch into sugar

Answer: (D)

Explanation

Salivary amylase begins starch digestion in the mouth, whereas the oesophagus mainly transports food by peristalsis without digesting it.

15. Which statement correctly describes the roles of stomach hydrochloric acid and pepsin?

A. Hydrochloric acid absorbs amino acids, while pepsin neutralizes the intestinal contents

B. Hydrochloric acid produces bile, while pepsin transports food through the oesophagus

C. Hydrochloric acid activates pepsinogen and kills bacteria, while pepsin breaks proteins into peptones

D. Hydrochloric acid emulsifies fats, while pepsin breaks starch into sugar

Answer: (C)

Explanation

Hydrochloric acid activates pepsinogen to pepsin and kills bacteria; pepsin then digests proteins into peptones.

16. What is malnutrition?

A. The intake of an improper or inadequate diet that may hinder children's mental and physical growth

B. The normal variation in nutrient needs caused by age, sex, or pregnancy

C. The inability to digest starch because salivary amylase is absent

D. The deliberate mixing of food with cheaper substances to increase its quantity

Answer: (A)

Explanation

Malnutrition results from an improper or inadequate diet and can retard the mental and physical growth of children.

17. Which pairing correctly matches a deficiency or nutritional disorder with its consequence?

A. Kwashiorkor in children up to one year and marasmus in children aged one to five years

B. Night blindness from protein deficiency and kwashiorkor from vitamin A deficiency

C. Marasmus in children up to one year and kwashiorkor in children aged one to five years

D. Goitre from iron deficiency and anaemia from iodine deficiency

Answer: (C)

Explanation

Protein-energy malnutrition commonly causes marasmus in children up to one year and kwashiorkor in children aged one to five years.

18. A nutrition worker compares two protein-energy malnutrition disorders in children. Which distinction is correct?

A. Marasmus commonly affects children up to one year, whereas kwashiorkor commonly affects children aged one to five years

B. Marasmus commonly affects children aged one to five years, whereas kwashiorkor commonly affects infants up to one year

C. Marasmus causes night blindness, whereas kwashiorkor causes excess haemoglobin production

D. Marasmus is caused by iodine deficiency, whereas kwashiorkor is caused by iron deficiency

Answer: (A)

Explanation

Protein-energy malnutrition commonly causes marasmus in children up to one year and kwashiorkor in children aged one to five years. The other options confuse these disorders with mineral or vitamin deficiencies.

19. Which plant tissues absorb water and minerals from the soil and transport them upward to the leaves?

A. Root hairs and xylem

B. Stomata and phloem

C. Root hairs and phloem

D. Stomata and xylem

Answer: (A)

Explanation

Root hairs absorb water and minerals from the soil, while xylem tracheids and vessels transport them upward to the leaves. Phloem transports food rather than water and minerals.

20. What creates the transpiration pull that draws water upward through the xylem?

A. Evaporation of water vapour from stomata

B. Contraction of phloem sieve tubes

C. Release of oxygen from leaf cells

D. Absorption of sugars by root hairs

Answer: (A)

Explanation

Evaporation of water vapour from stomata creates a vacuum, producing an upward force called transpiration pull that draws water through the xylem.

21. A plant produces sugars in its leaves that must reach its roots and developing fruits. Which process transports these sugars?

A. Transpiration through stomata

B. Ascent of sap through xylem

C. Translocation through phloem

D. Absorption through root hairs

Answer: (C)

Explanation

Translocation moves sugars and other food molecules from leaves to other parts of the plant through living phloem sieve tubes. Ascent of sap through xylem carries water and minerals.

22. Which combination correctly describes the main components and functions of the human circulatory system?

A. Kidneys, ureters, and urine that filter blood and store wastes

B. Bones, joints, and muscles that support movement and posture

C. Lungs, airways, and mucus that exchange gases and trap particles

D. Heart, blood vessels, and circulating fluids that distribute materials and remove wastes

Answer: (D)

Explanation

The circulatory system includes a muscular heart, blood vessels, and circulating fluids. Together they distribute nutrients and oxygen, remove wastes, and transport hormones.

23. Which statement correctly distinguishes arteries, veins, and capillaries?

A. Arteries carry blood away from the heart, veins carry it toward the heart, and capillaries allow exchange with tissues.

B. Arteries produce hormones, veins remove wastes, and capillaries carry blood toward the heart.

C. Arteries allow exchange with tissues, veins pump blood, and capillaries carry blood away from the heart.

D. Arteries carry blood toward the heart, veins carry it away, and capillaries produce blood cells.

Answer: (A)

Explanation

Arteries carry blood away from the heart, veins bring blood toward it, and capillaries are thin vessels where exchange occurs between blood and tissues.

24. Which chambers are found in a normal human heart?

A. Right and left atria and right and left ventricles

B. Right and left atria and one central ventricle

C. Right and left ventricles and two aortic chambers

D. One atrium, two ventricles, and one pulmonary chamber

Answer: (A)

Explanation

The human heart has four chambers: the right and left atria and the right and left ventricles.

25. Which statement correctly describes red blood cells?

A. They form clots, release hormones, and contain haemoglobin.

B. They contain haemoglobin, transport respiratory gases, and lack a nucleus.

C. They produce antibodies, engulf germs, and contain a large nucleus.

D. They return tissue fluid to circulation and have irregular shapes.

Answer: (B)

Explanation

Red blood cells contain haemoglobin and transport oxygen to tissues and carbon dioxide back from tissues. They lack a nucleus, unlike many other cells.

26. How do white blood cells help protect the body?

A. They engulf germs or produce antibodies.

B. They transport oxygen using haemoglobin.

C. They release sugars into the bloodstream.

D. They form the main pathway for tissue fluid.

Answer: (A)

Explanation

White blood cells fight infection by engulfing germs or producing antibodies. Gas transport is primarily performed by red blood cells.

27. Which statement best distinguishes lymph from blood?

A. Lymph circulates through the heart and vessels, whereas blood flows one way from tissues to the heart.

B. Lymph is pumped from the heart to tissues, whereas blood is produced in capillaries.

C. Lymph transports most respiratory gases, whereas blood mainly returns proteins from tissues.

D. Lymph flows one way from tissues to the heart and returns fluid and proteins, whereas blood circulates through the heart and vessels.

Answer: (D)

Explanation

Lymph flows one way from tissues to the heart and returns tissue fluid and proteins to circulation. Blood circulates through the heart and blood vessels and transports gases, nutrients, hormones, and wastes.

28. Which ABO blood-group rule is correctly stated?

A. Group O can receive only from group AB, and group AB can donate only to group O.

B. All blood-group combinations are safe because ABO compatibility does not affect transfusions.

C. Group AB can donate to all four groups, and group O can receive from all four groups in every transfusion.

D. Group O can donate to all four groups, and group AB can receive from all four groups when blood is compatible.

Answer: (D)

Explanation

In the ABO system, group O can donate to all four groups and group AB can receive from all four groups, but transfusions are safe only when donor and recipient blood are compatible.

29. Which statement correctly distinguishes breathing from cellular respiration?

A. Breathing occurs in mitochondria, whereas cellular respiration occurs only in the alveoli.

B. Breathing transports ATP through the blood, whereas cellular respiration moves air into the lungs.

C. Breathing releases energy from food in cells, whereas cellular respiration exchanges gases with the environment.

D. Breathing exchanges gases with the environment, whereas cellular respiration releases energy from food in cells.

Answer: (D)

Explanation

Breathing is the physical exchange of respiratory gases between an organism and its environment. Cellular respiration oxidizes food in cells to release energy and form ATP.

30. Why are alveoli well suited for gas exchange?

A. They have thin walls and many surrounding capillaries, creating a large diffusion surface.

B. They have thick walls and few blood vessels, slowing diffusion.

C. They actively pump oxygen into the blood using muscular walls.

D. They contain cartilage rings that keep the air sacs open.

Answer: (A)

Explanation

Alveoli have thin walls and many surrounding capillaries, providing a large surface across which oxygen and carbon dioxide can diffuse efficiently.

31. Which sequence lists respiratory passages in the human respiratory system?

A. Nostrils, esophagus, stomach, trachea, bronchi, and alveoli

B. Nostrils, nasal cavities, pharynx, trachea, bronchi, bronchioles, and alveoli

C. Mouth, larynx, diaphragm, bronchioles, kidneys, and alveoli

D. Nasal cavities, pharynx, heart, trachea, bronchi, and capillaries

Answer: (B)

Explanation

The human respiratory passages include the nostrils, nasal cavities, internal nostrils, pharynx, trachea, bronchi, bronchioles, and alveoli.

32. What happens during inhalation as air enters the alveoli?

A. The diaphragm contracts into a dome, thoracic volume decreases, and pressure rises.

B. The diaphragm contracts and flattens, thoracic volume increases, and pressure falls.

C. The ribs move downward and inward, increasing pressure and drawing air inward.

D. The diaphragm relaxes, thoracic volume decreases, and pressure rises.

Answer: (B)

Explanation

During inhalation, the diaphragm contracts and flattens while the ribs move upward and outward. This increases thoracic volume, lowers pressure, and draws air into the alveoli.

33. Which combination describes normal exhalation?

A. The diaphragm contracts, the ribs move upward, and carbon-dioxide-rich air enters the lungs.

B. The diaphragm relaxes into a dome, the ribs move downward and inward, and pressure rises.

C. The diaphragm flattens, thoracic volume increases, and pressure falls as air leaves.

D. The diaphragm relaxes, the ribs move outward, and oxygen-rich air enters the alveoli.

Answer: (B)

Explanation

During exhalation, the diaphragm relaxes into a dome shape and the ribs move downward and inward. Thoracic volume decreases, pressure rises, and carbon-dioxide-rich air leaves the lungs.

34. In which direction do the respiratory gases diffuse during gas exchange?

A. Oxygen moves from alveoli to blood capillaries, while carbon dioxide moves from blood to alveoli.

B. Oxygen moves from blood to alveoli, while carbon dioxide moves from alveoli to blood.

C. Both oxygen and carbon dioxide move from blood capillaries into the alveoli.

D. Both oxygen and carbon dioxide move from alveoli into blood capillaries.

Answer: (A)

Explanation

Oxygen diffuses from the alveoli into blood capillaries, while carbon dioxide diffuses from tissue blood into the alveoli to be exhaled.

35. Where does cellular respiration occur, and what role does oxygen play in it?

A. It occurs in mitochondria, where oxygen acts on glucose to release energy and carbon dioxide.

B. It occurs in red blood cells, where glucose is stored as oxygen-rich ATP.

C. It occurs in the diaphragm, where oxygen drives the movement of the ribs.

D. It occurs in alveoli, where oxygen is converted directly into carbon dioxide.

Answer: (A)

Explanation

Cellular respiration occurs in mitochondria. Oxygen acts on glucose there, releasing energy and producing carbon dioxide.

36. What is excretion?

A. The removal of unnecessary or harmful products of chemical reactions from the body

B. The removal of undigested food from the alimentary canal

C. The movement of oxygen from the lungs into the bloodstream

D. The absorption of useful substances from the kidney tubules

Answer: (A)

Explanation

Excretion is the removal from the body of products of chemical reactions that would be unnecessary or harmful if they accumulated.

37. Which structures make up the human urinary system?

A. Two kidneys, a small intestine, a urinary bladder, and a urethra

B. One kidney, two ureters, two bladders, and a urethra

C. Two kidneys, two ureters, a urinary bladder, and a urethra

D. Two kidneys, two bronchi, a urinary bladder, and a trachea

Answer: (C)

Explanation

The human urinary system consists of two kidneys, two ureters, a urinary bladder, and a urethra.

38. What is a nephron?

A. The structural and functional unit of the kidney

B. The storage chamber that holds urine before excretion

C. The blood vessel that carries filtered urine to the urethra

D. The muscular tube that carries urine from a kidney to the bladder

Answer: (A)

Explanation

A nephron is the structural and functional unit of the kidney. It includes Bowman’s capsule, the glomerulus, and sections of the renal tubule.

39. Which statement correctly describes filtration and reabsorption in a nephron?

A. Filtration occurs in the glomerulus and Bowman’s capsule, whereas reabsorption returns useful substances from the renal tubule to blood.

B. Filtration occurs in the bladder, whereas reabsorption occurs in the urethra.

C. Filtration returns useful substances to blood, whereas reabsorption removes them from blood.

D. Filtration produces urine from the bladder, whereas reabsorption moves urine into the kidneys.

Answer: (A)

Explanation

Blood is filtered in the glomerulus and Bowman’s capsule. Useful substances, excess water, and salts are then reabsorbed from the renal tubule into surrounding capillaries, leaving mainly urea to form urine.