Respiration MCQs

1. What is respiration?
A. Digestion of food
B. Release of energy from food
C. Absorption of nutrients
D. Transportation of oxygen
Answer: B
Which gas is taken in during respiration?
A. Carbon dioxide
B. Oxygen
C. Nitrogen
D. Hydrogen
Answer: B
Which gas is released during respiration?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Hydrogen
Answer: C
Where does cellular respiration occur?
A. Nucleus
B. Ribosome
C. Mitochondria
D. Cell wall
Answer: C
Which molecule is broken down in respiration?
A. Protein
B. Lipid
C. Glucose
D. Vitamin
Answer: C
What is the end product of aerobic respiration?
A. Lactic acid
B. Ethanol
C. Carbon dioxide and water
D. Oxygen
Answer: C
What is anaerobic respiration?
A. Respiration with oxygen
B. Respiration without oxygen
C. Respiration in plants only
D. Respiration in animals only
Answer: B
Which organ is responsible for breathing in humans?
A. Heart
B. Lungs
C. Kidney
D. Liver
Answer: B
What is the process of inhaling air called?
A. Exhalation
B. Ventilation
C. Inspiration
D. Expiration
Answer: C
What is the process of breathing out called?
A. Inspiration
B. Expiration
C. Ventilation
D. Diffusion
Answer: B
Which structure helps in gas exchange in lungs?
A. Bronchi
B. Alveoli
C. Trachea
D. Diaphragm
Answer: B
What is produced during anaerobic respiration in muscles?
A. Ethanol
B. Lactic acid
C. Oxygen
D. Water
Answer: B
Which process releases more energy?
A. Anaerobic respiration
B. Aerobic respiration
C. Photosynthesis
D. Diffusion
Answer: B
Which organ controls breathing?
A. Brain
B. Heart
C. Liver
D. Kidney
Answer: A
Which enzyme starts glycolysis?
A. Amylase
B. Hexokinase
C. Lipase
D. Protease
Answer: B
Glycolysis occurs in:
A. Mitochondria
B. Cytoplasm
C. Nucleus
D. Ribosome
Answer: B
How many ATP are produced in glycolysis?
A. 2
B. 4
C. 36
D. 38
Answer: A
What is the first step of respiration?
A. Krebs cycle
B. Glycolysis
C. Electron transport chain
D. Fermentation
Answer: B
Which cycle occurs in mitochondria?
A. Calvin cycle
B. Krebs cycle
C. Glycolysis
D. Nitrogen cycle
Answer: B
What is another name for the Krebs cycle?
A. Glycolysis
B. Citric acid cycle
C. Carbon cycle
D. Water cycle
Answer: B
What is the role of oxygen in respiration?
A. Energy source
B. Final electron acceptor
C. Enzyme
D. Product
Answer: B
Which part of cell produces most ATP?
A. Cytoplasm
B. Nucleus
C. Mitochondria
D. Cell membrane
Answer: C
What is ATP?
A. Protein
B. Energy currency of cell
C. Lipid
D. Vitamin
Answer: B
Which organ carries oxygen in blood?
A. Plasma
B. Red blood cells
C. White blood cells
D. Platelets
Answer: B
Which pigment carries oxygen?
A. Chlorophyll
B. Hemoglobin
C. Melanin
D. Carotene
Answer: B
What is the function of diaphragm?
A. Pump blood
B. Help breathing
C. Digest food
D. Filter blood
Answer: B
What happens to diaphragm during inhalation?
A. Relaxes
B. Contracts
C. Stops
D. Breaks
Answer: B
What is breathing rate?
A. Heart beats
B. Number of breaths per minute
C. Oxygen level
D. Blood pressure
Answer: B
What is fermentation?
A. Aerobic respiration
B. Anaerobic respiration
C. Photosynthesis
D. Digestion
Answer: B
Which organism performs fermentation?
A. Human
B. Yeast
C. Fish
D. Bird
Answer: B
What is produced in yeast fermentation?
A. Lactic acid
B. Ethanol and CO₂
C. Water
D. Oxygen
Answer: B
Which structure connects nose to lungs?
A. Esophagus
B. Trachea
C. Intestine
D. Vein
Answer: B
What is tidal volume?
A. Total lung capacity
B. Air inhaled/exhaled in normal breath
C. Residual air
D. Dead air
Answer: B
What is residual volume?
A. Air after forceful exhalation
B. Air left in lungs
C. Fresh air
D. Expired air
Answer: B
Which gas diffuses into blood?
A. CO₂
B. O₂
C. N₂
D. H₂
Answer: B
Which gas diffuses out of blood?
A. O₂
B. CO₂
C. N₂
D. H₂
Answer: B
What is the main function of lungs?
A. Pump blood
B. Exchange gases
C. Digest food
D. Produce hormones
Answer: B
What controls respiration rate?
A. Kidney
B. Brain stem
C. Liver
D. Heart
Answer: B
What increases breathing rate?
A. Sleep
B. Exercise
C. Rest
D. Meditation
Answer: B
What is aerobic respiration?
A. Without oxygen
B. With oxygen
C. Only in plants
D. Only in bacteria
Answer: B
Which step produces most ATP?
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
D. Fermentation
Answer: C
Where does electron transport chain occur?
A. Cytoplasm
B. Inner mitochondrial membrane
C. Nucleus
D. Ribosome
Answer: B
What is produced in ETC?
A. CO₂
B. ATP
C. Glucose
D. Protein
Answer: B
What is oxidation?
A. Gain of electrons
B. Loss of electrons
C. Gain of oxygen only
D. Loss of hydrogen only
Answer: B
What is reduction?
A. Gain of electrons
B. Loss of electrons
C. Gain of oxygen
D. Loss of oxygen
Answer: A
Which compound enters Krebs cycle?
A. Pyruvate
B. Acetyl-CoA
C. Glucose
D. ATP
Answer: B
What is produced in glycolysis?
A. Oxygen
B. Pyruvate
C. CO₂
D. Water
Answer: B
Which system helps in breathing?
A. Digestive system
B. Respiratory system
C. Circulatory system
D. Nervous system
Answer: B
What is hyperventilation?
A. Slow breathing
B. Fast breathing
C. No breathing
D. Deep sleep
Answer: B
50. What is hypoventilation?
A. Fast breathing
B. Slow breathing
C. No breathing
D. Deep breathing
Answer: B