Q.Assertion (A) : Mitochondria and chloroplast are semi-autonomous organelles.
Reason (R) : They are formed by division of pre-existing organelles and contain DNA but lack protein synthesizing machinery.

Mitochondria are the site of aerobic respiration, and the ATP generated there powers the cell's energy needs.

Each mitochondrion has a double membrane: a smooth outer membrane, and an inner membrane thrown into folds called cristae, which greatly increase the surface area available for the electron transport chain. The fluid matrix enclosed by the inner membrane contains the enzymes of the Krebs (citric acid) cycle.

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Mitochondria are double membrane-bound organelles, so the answer is (C).

Membrane organisation of organelles:

• Mitochondria — double membrane (outer smooth membrane and inner membrane folded into cristae); the site of aerobic respiration.
• Lysosome and Golgi apparatus — single membrane-bound.
• Ribosome — not membrane-bound at all. …

Mitochondria are called the power house of the cell because they are the primary site of aerobic cellular respiration and ATP synthesis.

Mitochondria are double membrane-bound organelles. Their inner membrane is folded into cristae, which house the electron transport chain and ATP synthase enzyme complexes. The matrix contains enzymes of the Krebs cycle. Through oxidative phosphorylation, mitochondria convert the chemical energy of food (via pyruvate and acetyl-CoA oxidation) into ATP, the energy currency of the cell.

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Mitochondria and chloroplasts are semi-autonomous because they contain their own circular DNA, ribosomes (70S type) and RNA, allowing them to synthesise some of their own proteins — they do not lack protein-synthesising machinery, they simply cannot function fully independently of the nucleus.

The Assertion — that mitochondria and chloroplast are semi-autonomous organelles — is true. They are called 'semi-autonomous' because they have some genetic autonomy but are not completely independent of nuclear control.

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Mitochondria generate the ATP that powers the cell, earning the nickname 'powerhouse of the cell'.

Mitochondria are double-membrane-bound organelles; the inner membrane is folded into cristae that increase surface area for the electron transport chain and ATP synthase. Through the processes of the Krebs cycle and oxidative phosphorylation, mitochondria oxidise pyruvate (derived from glucose) in the presence of oxygen to release large amounts of energy, most of which is captured as ATP. Because ATP is the cell's usable energy currency and mitochondria are the primary site of its aerobic pro …

The mitochondrion is the "power house of the cell" because it is the main site of aerobic cellular respiration, where most of the cell's ATP is generated.

Every living cell needs a continuous supply of energy in a usable form, and that form is ATP (adenosine triphosphate). Among the four options:

• Ribosome: builds proteins from amino acids; it does not generate energy.
• Vacuole: mainly a storage sac (water, ions, waste products); no major role in energy release.
• Chloroplast: traps light energy and makes food (glucose) by photosynthesis, but this is energy CAPTURE, not the day-to-day energy-currency-generating engine common to all cells (plant and animal alike). …