class 10 biology chapter 10 mcqs

class 10 biology chapter 10 mcqs

Biology class 10

Chapter 10

Gaseous Exchange—MCQs (1–100)

What is the primary function of the respiratory system?
a) Digestion
b) Circulation
c) Gaseous exchange
d) Excretion
Answer: c
Which gas is taken in during inhalation?
a) Carbon dioxide
b) Oxygen
c) Nitrogen
d) Hydrogen
Answer: b
In humans, gaseous exchange occurs in:
a) Trachea
b) Bronchi
c) Alveoli
d) Larynx
Answer: c
What is the process of breathing in called?
a) Exhalation
b) Inhalation
c) Respiration
d) Ventilation
Answer: b
Which structure prevents food from entering the windpipe?
a) Glottis
b) Larynx
c) Epiglottis
d) Alveolus
Answer: c
What is the main respiratory pigment in humans?
a) Hemocyanin
b) Hemoglobin
c) Myoglobin
d) Chlorophyll
Answer: b
In plants, gaseous exchange occurs through:
a) Phloem
b) Stomata
c) Xylem
d) Cuticle
Answer: b
Which of the following is not a part of the human respiratory system?
a) Lungs
b) Trachea
c) Kidney
d) Bronchi
Answer: c
What is the main waste gas produced by respiration?
a) Carbon monoxide
b) Oxygen
c) Carbon dioxide
d) Nitrogen
Answer: c
Breathing rate is controlled by:
a) Lungs
b) Heart
c) Medulla oblongata
d) Cerebrum
Answer: c
Which disease is caused by inflammation of the bronchi?
a) Asthma
b) Pneumonia
c) Bronchitis
d) Tuberculosis
Answer: c
The trachea is also called the:
a) Food pipe
b) Windpipe
c) Voice box
d) Nose
Answer: b
Which process provides energy by breaking down glucose?
a) Breathing
b) Digestion
c) Respiration
d) Circulation
Answer: c
During inhalation, the diaphragm:
a) Relaxes
b) Contracts and moves upward
c) Contracts and moves downward
d) Stays static
Answer: c
The exchange of gases between blood and body cells is called
a) Internal respiration
b) External respiration
c) Inhalation
d) Ventilation
Answer: a
Which gas diffuses from blood into alveoli?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Methane
Answer: c
In plants, gaseous exchange mainly occurs during:
a) Day
b) Night
c) Both day and night
d) Only in winter
Answer: c
The breathing rate of a normal adult is
a) 5–10 breaths/min
b) 12–20 breaths/min
c) 25–30 breaths/min
d) 30–40 breaths/min
Answer: b
Fish perform gaseous exchange through
a) Lungs
b) Gills
c) Skin
d) Spiracles
Answer: b
Which one is not a respiratory disorder?
a) Emphysema
b) Asthma
c) Bronchitis
d) Anemia
Answer: d
In plants, the gaseous exchange occurs through:
a) Root hairs
b) Vessels
c) Stomata and lenticels
d) Cuticle
Answer: c
Which structure is responsible for producing voice?
a) Bronchi
b) Larynx
c) Trachea
d) Pharynx
Answer: b
The walls of alveoli are
a) Thick
b) Rigid
c) Permeable and thin
d) Made of cartilage
Answer: c
Hemoglobin carries
a) Carbon dioxide
b) Oxygen
c) Nitrogen
d) All gases
Answer: b
Which of the following connects the throat to the lungs?
a) Esophagus
b) Trachea
c) Artery
d) Vein
Answer: b

During exhalation, the ribs:
a) Move upward and outward
b) Move downward and inward
c) Stay in place
d) Move only outward
Answer: b
The site of internal respiration in humans is
a) Alveoli
b) Tissues
c) Lungs
d) Heart
Answer: b
In amphibians like frogs, gaseous exchange occurs through:
a) Skin only
b) Lungs only
c) Gills only
d) Lungs, skin, and buccal cavity
Answer: d
Emphysema affects which part of the respiratory system?
a) Bronchi
b) Alveoli
c) Larynx
d) Diaphragm
Answer: b
The oxygen-rich blood is carried from the lungs to the heart by
a) Pulmonary vein
b) Pulmonary artery
c) Aorta
d) Vena cava
Answer: a
Which animal uses spiracles for gaseous exchange?
a) Fish
b) Frog
c) Earthworm
d) Insect
Answer: d
The presence of moisture in alveoli is essential for:
a) Movement of air
b) Sound production
c) Diffusion of gases
d) Digestion
Answer: c
Which respiratory disease is caused by bacterial infection?
a) Asthma
b) Tuberculosis
c) Emphysema
d) Lung cancer
Answer: b
What is the term for the sum of tidal volume and inspiratory reserve volume?
a) Total lung capacity
b) Vital capacity
c) Residual volume
d) Functional volume
Answer: b
In human respiration, oxygen moves from alveoli to:
a) Bronchi
b) Capillaries
c) Larynx
d) Trachea
Answer: b
Which of the following do not have lungs?
a) Birds
b) Amphibians
c) Fish
d) Mammals
Answer: c
Which plant structure is involved in gaseous exchange in woody stems?
a) Lenticels
b) Phloem
c) Cambium
d) Cortex
Answer: a
Which enzyme helps break down harmful particles in alveolar macrophages?
a) Pepsin
b) Amylase
c) Catalase
d) Lysozyme
Answer: d
What is the function of mucus in the respiratory tract?
a) Carry oxygen
b) Trap dust and microbes
c) Reduce surface tension
d) Aid digestion
Answer: b
Which muscle is primarily responsible for breathing?
a) Heart
b) Diaphragm
c) Abdominal muscle
d) Intercostal muscle
Answer: b
Which process is not part of respiration?
a) Glycolysis
b) Krebs cycle
c) Photosynthesis
d) Electron transport chain
Answer: c
The respiratory surface in earthworms is
a) Lungs
b) Skin
c) Gills
d) Spiracles
Answer: b
Which of the following organs is not involved in human respiration?
a) Nose
b) Trachea
c) Diaphragm
d) Liver
Answer: d
Which disease is caused by smoking and destroys alveolar walls?
a) Bronchitis
b) Emphysema
c) Tuberculosis
d) Asthma
Answer: b
Which gas binds with hemoglobin more strongly than oxygen?
a) Nitrogen
b) Carbon dioxide
c) Carbon monoxide
d) Ozone
Answer: c
In anaerobic respiration, the end products are
a) CO₂ and H₂O
b) Alcohol or lactic acid and CO₂
c) Glucose and oxygen
d) ATP and water only
Answer: b
The structure that divides the nasal cavity is called
a) Septum
b) Palate
c) Epiglottis
d) Pharynx
Answer: a
Stomatal pores are bordered by:
a) Phloem cells
b) Guard cells
c) Xylem vessels
d) Mesophyll cells
Answer: b
The part of the respiratory system that humidifies and filters the air is
a) Lungs
b) Trachea
c) Nasal cavity
d) Alveoli
Answer: c
The role of intercostal muscles is to:
a) Pump blood
b) Facilitate breathing
c) Digest food
d) Secrete hormones
Answer: b

Which respiratory disease involves narrowing of the bronchi?
a) Tuberculosis
b) Bronchitis
c) Asthma
d) Pneumonia
Answer: c
Which structure warms, moistens, and filters inhaled air?
a) Trachea
b) Nasal cavity
c) Bronchi
d) Lungs
Answer: b
What is the total lung capacity in average adults?
a) 1 liter
b) 2 liters
c) 4 liters
d) 5 to 6 liters
Answer: d
Which part of the brain controls involuntary breathing?
a) Cerebrum
b) Medulla oblongata
c) Cerebellum
d) Hypothalamus
Answer: b
What is formed when oxygen combines with hemoglobin?
a) Carbaminohemoglobin
b) Carboxyhemoglobin
c) Oxyhemoglobin
d) Myoglobin
Answer: c
Lungs are covered by:
a) Diaphragm
b) Pericardium
c) Pleural membrane
d) Mucosa
Answer: c
During vigorous exercise, breathing becomes:
a) Slower
b) Shallow
c) Faster and deeper
d) Irregular
Answer: c
Which of the following is a symptom of asthma?
a) High fever
b) Joint pain
c) Wheezing
d) Muscle weakness
Answer: c
Which organ regulates the amount of CO₂ in blood?
a) Kidney
b) Brain
c) Liver
d) Lungs
Answer: d
Which of the following does not breathe through skin?
a) Earthworm
b) Frog
c) Human
d) Leech
Answer: c
Which of these increases the surface area in alveoli?
a) Cilia
b) Folds
c) Capillaries
d) Septa
Answer: b
Pneumonia affects:
a) Kidneys
b) Alveoli
c) Bronchi
d) Liver
Answer: b
Which gas is toxic and reduces oxygen-carrying capacity of blood?
a) CO₂
b) CO
c) N₂
d) SO₂
Answer: b
Vital capacity does not include:
a) Tidal volume
b) Residual volume
c) Expiratory reserve volume
d) Inspiratory reserve volume
Answer: b
What enables exchange of gases in leaves?
a) Palisade cells
b) Stomata
c) Xylem
d) Cuticle
Answer: b
Which part of plant lacks stomata?
a) Leaves
b) Flowers
c) Roots
d) Fruits
Answer: c
Respiration that occurs in absence of oxygen is called:
a) External
b) Anaerobic
c) Aerobic
d) Internal
Answer: b
During aerobic respiration, glucose is broken down into:
a) Lactic acid
b) Carbon dioxide and water
c) Alcohol
d) Pyruvic acid
Answer: b
The thin layer of water in alveoli helps in:
a) Movement of cilia
b) Diffusion of gases
c) Sound production
d) Air filtration
Answer: b
Air enters the lungs due to:
a) Contraction of ribs
b) Increase in chest volume
c) Movement of blood
d) Decrease in lung capacity
Answer: b
Which gas is released during cellular respiration?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: c
The primary source of energy for respiration is:
a) Oxygen
b) Glucose
c) Protein
d) Water
Answer: b
Gaseous exchange in plants occurs via:
a) Osmosis
b) Active transport
c) Diffusion
d) Transpiration
Answer: c
The trachea divides into:
a) Two lungs
b) Two bronchi
c) Two alveoli
d) Two arteries
Answer: b
Oxygen transport in blood is mainly done by:
a) Plasma
b) White blood cells
c) Hemoglobin
d) Platelets
Answer: c
What is the flap that covers the trachea when swallowing?
a) Larynx
b) Pharynx
c) Epiglottis
d) Uvula
Answer: c
Which structure filters air in the nasal cavity?
a) Cilia and mucus
b) Alveoli
c) Diaphragm
d) Pleura
Answer: a
Which plant structure closes the stomata?
a) Epidermis
b) Guard cells
c) Mesophyll
d) Veins
Answer: b
Which condition is associated with fluid in alveoli?
a) Asthma
b) Emphysema
c) Pneumonia
d) Tuberculosis
Answer: c
In humans, gaseous exchange is efficient due to:
a) Small lungs
b) Thick alveolar walls
c) Large surface area of alveoli
d) Muscular bronchi
Answer: c
The voice box is also called:
a) Larynx
b) Trachea
c) Epiglottis
d) Bronchi
Answer: a
Carbon dioxide is mostly transported in blood as:
a) Free gas
b) Bicarbonate ions
c) Carbamino compounds
d) Bound to hemoglobin
Answer: b
Plants produce CO₂ during:
a) Photosynthesis
b) Respiration
c) Transpiration
d) Germination only
Answer: b
Which cells control opening/closing of stomata?
a) Mesophyll
b) Phloem
c) Guard cells
d) Cortex
Answer: c
Which part of the respiratory system branches into alveoli?
a) Bronchi
b) Bronchioles
c) Trachea
d) Larynx
Answer: b
Alveoli are surrounded by:
a) Arteries
b) Veins
c) Capillaries
d) Bronchi
Answer: c
Air moves into lungs because:
a) Lung pressure increases
b) Lung pressure decreases
c) Blood pressure increases
d) Blood pressure decreases
Answer: b
Which condition causes narrowing of airways due to allergens?
a) Asthma
b) Bronchitis
c) Emphysema
d) Lung cancer
Answer: a
Lung cancer is most commonly caused by:
a) Dust
b) Smoking
c) Pollution
d) Fungal infection
Answer: b
Which gas is a by-product of anaerobic respiration in yeast?
a) Oxygen
b) Water vapor
c) Alcohol
d) Carbon monoxide
Answer: c
Respiration occurs in:
a) Nucleus
b) Mitochondria
c) Cytoplasm
d) Cell wall
Answer: b
Which system works closely with respiratory system?
a) Skeletal
b) Nervous
c) Circulatory
d) Digestive
Answer: c
What maintains the trachea’s shape?
a) Muscles
b) Cartilage rings
c) Ligaments
d) Bone plates
Answer: b
Which process is directly responsible for energy release?
a) Breathing
b) Digestion
c) Respiration
d) Excretion
Answer: c
Smoking affects gaseous exchange by:
a) Increasing cilia
b) Enlarging alveoli
c) Damaging alveoli walls
d) Increasing mucus production
Answer: c
The number of alveoli in human lungs is approximately:
a) 1,000
b) 10,000
c) 1 million
d) 300 million
Answer: d
Spiracles are found in:
a) Mammals
b) Birds
c) Insects
d) Reptiles
Answer: c
What is the correct sequence of air passage in humans?
a) Nose → Trachea → Bronchi → Lungs
b) Nose → Bronchi → Trachea → Lungs
c) Nose → Lungs → Trachea → Bronchi
d) Lungs → Trachea → Nose → Bronchi
Answer: a
In mammals, exchange of gases occurs by:
a) Active transport
b) Osmosis
c) Diffusion
d) Filtration
Answer: c
Which structure allows diffusion of oxygen into blood?
a) Bronchi
b) Capillaries of alveoli
c) Trachea
d) Diaphragm
Answer: b

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