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Cell: The Unit of Life

Mitochondria Practice Questions

19 free Mitochondria practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.

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Question 1 of 19 Medium

Which organelle is known as the powerhouse of the cell?

  1. A Mitochondria
  2. B Nucleus
  3. C Ribosome
  4. D Golgi apparatus

Correct answer: Mitochondria

Mitochondria are called the powerhouse because they produce ATP. ATP is the main energy currency of the cell.

Question 2 of 19 Medium

Mitochondria have how many membranes?

  1. A Two
  2. B One
  3. C Three
  4. D Four

Correct answer: Two

Mitochondria are double-membrane bound organelles. They have an outer membrane and a highly folded inner membrane.

Question 3 of 19 Medium

The inner space of mitochondria is known as:

  1. A Matrix
  2. B Cytosol
  3. C Stroma
  4. D Lumen

Correct answer: Matrix

The mitochondrial matrix contains enzymes, DNA, and ribosomes. It is the site of several metabolic reactions.

Question 4 of 19 Medium

Which process occurs in the mitochondrial matrix?

  1. A Krebs cycle
  2. B Glycolysis
  3. C Photosynthesis
  4. D Transcription

Correct answer: Krebs cycle

The Krebs cycle occurs in the matrix. It generates high-energy electron carriers.

Question 5 of 19 Medium

Where does the electron transport chain occur in mitochondria?

  1. A Inner membrane
  2. B Outer membrane
  3. C Matrix
  4. D Intermembrane space

Correct answer: Inner membrane

The electron transport chain is located on the inner membrane. It is involved in ATP production.

Question 6 of 19 Medium

ATP is synthesized in mitochondria by which process?

  1. A Oxidative phosphorylation
  2. B Photophosphorylation in chloroplasts
  3. C Cytoplasmic glycolysis
  4. D Anaerobic fermentation

Correct answer: Oxidative phosphorylation

Oxidative phosphorylation occurs in mitochondria. It uses energy from electrons to produce ATP.

Question 7 of 19 Medium

Which molecule acts as the main energy currency of the cell?

  1. A DNA
  2. B RNA
  3. C ATP
  4. D Glucose

Correct answer: ATP

ATP stores and provides energy for cellular activities. It is produced mainly in mitochondria.

Question 8 of 19 Medium

Mitochondria contain their own:

  1. A Chlorophyll pigments
  2. B DNA and ribosomes
  3. C Cell wall
  4. D Nucleus

Correct answer: DNA and ribosomes

Mitochondria have their own DNA and ribosomes. This supports the endosymbiotic theory.

Question 9 of 19 Medium

Which of the following best explains the role of mitochondria?

  1. A Protein synthesis
  2. B Energy production
  3. C Lipid synthesis
  4. D Waste removal

Correct answer: Energy production

Mitochondria generate ATP through respiration. They are essential for energy supply.

Question 10 of 19 Medium

Which membrane of mitochondria is permeable to small molecules?

  1. A Inner membrane
  2. B Outer membrane
  3. C Cristae
  4. D Matrix

Correct answer: Outer membrane

The outer membrane is relatively permeable due to porins. The inner membrane is selectively permeable.

Question 11 of 19 Medium

Which structure increases the surface area for ATP synthesis?

  1. A Matrix
  2. B Cristae
  3. C Outer membrane
  4. D Cytoplasm

Correct answer: Cristae

Cristae provide more surface area for enzymes of the electron transport chain. This enhances ATP production.

Question 12 of 19 Medium

Which process generates NADH and FADH2 in mitochondria?

  1. A Glycolysis
  2. B Krebs cycle
  3. C Fermentation
  4. D Photosynthesis

Correct answer: Krebs cycle

The Krebs cycle produces NADH and FADH2. These molecules donate electrons to the electron transport chain.

Question 13 of 19 Medium

Which of the following is NOT a function of mitochondria?

  1. A ATP production
  2. B Cellular respiration in eukaryotic cells
  3. C Protein synthesis for secretion
  4. D Energy metabolism

Correct answer: Protein synthesis for secretion

Protein synthesis for secretion occurs in the rough ER. Mitochondria mainly produce energy.

Question 14 of 19 Medium

Which region of mitochondria contains enzymes for respiration?

  1. A Outer membrane
  2. B Inner membrane
  3. C Matrix compartment
  4. D Intermembrane space

Correct answer: Matrix compartment

The matrix contains enzymes for the Krebs cycle. It is a major site of metabolic activity.

Question 15 of 19 Medium

Which theory explains the origin of mitochondria?

  1. A Cell theory
  2. B Endosymbiotic theory
  3. C Gene theory
  4. D Darwinian evolution theory

Correct answer: Endosymbiotic theory

The endosymbiotic theory suggests mitochondria evolved from free-living bacteria. They became part of eukaryotic cells.

Question 16 of 19 Medium

Which type of respiration occurs in mitochondria?

  1. A Anaerobic respiration
  2. B Fermentation
  3. C Photosynthesis
  4. D Aerobic respiration

Correct answer: Aerobic respiration

Mitochondria carry out aerobic respiration. Oxygen is required for efficient ATP production.

Question 17 of 19 Medium

Which component of mitochondria is responsible for ATP synthesis?

  1. A Cristae enzymes
  2. B DNA
  3. C Matrix fluid
  4. D ATP synthase

Correct answer: ATP synthase

ATP synthase is an enzyme embedded in the inner membrane. It synthesizes ATP using a proton gradient.

Question 18 of 19 Medium

Which gradient drives ATP synthesis in mitochondria?

  1. A Glucose gradient
  2. B Oxygen gradient
  3. C Carbon dioxide gradient
  4. D Proton gradient

Correct answer: Proton gradient

A proton gradient across the inner membrane drives ATP synthesis. This is called chemiosmosis.

Question 19 of 19 Medium

Which space lies between the inner and outer mitochondrial membranes?

  1. A Mitochondrial matrix
  2. B Cytoplasm
  3. C Intermembrane space
  4. D Stroma

Correct answer: Intermembrane space

The intermembrane space lies between the two membranes. It plays a role in proton accumulation during respiration.

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