Question

Which organelle is composed of Cristae and a matrix?
A. Chloroplast
B. Nucleolus
C. Mitochondria
D. Central Vacuole

Answer 1

Hint: Cristae – Mitochondria is double membrane organelle, it has inner and outer membrane. The inner membrane forms a number of folding called the cristae. Cristae increase the surface area and have a variety of enzymes.
Matrix – it is the space between the cristae. It is filled with a mitochondrial matrix. Matrix contains proteins, lipids, some ribosomes, RNA, DNA, ions etc.

Complete answer
Membrane around the organelle is the characteristic of eukaryotic cells. These membrane help is compartmentalization within the cell.
Chloroplast is the organelle which is also known as the kitchen of the cell as it manufactures the food for plants. It is covered with a double membrane which acts as a protective layer around the cell. Chloroplast contains thylakoids which have green pigment chlorophyll. Chlorophyll traps the sunlight for photosynthesis.
Nucleolus is the dense sphere which is present in the Nucleus. Nucleus, the brain of the cell, is also surrounded by a double membrane known as the nuclear envelope and has pores in between. This outer layer at certain places is extended to form Endoplasmic reticulum. Nucleolus is the site of Ribosome synthesis which later helps in protein synthesis
Mitochondria is another organelle which is also double membranous structure but the inner membrane in mitochondria in folds to form cristae. Matrix is the inner space of the cristae which contain respiratory enzymes on its inner surface. In mitochondria – Mitochondria is the site for aerobic respiration. They produce ATP, hence called the powerhouse of the cell.
Central Vacuole is the characteristic of plant cells. The membrane which surrounds the vacuole is known as tonoplast. Vacuole is filled with cell sap which mostly contains dissolved salts, pigments, sugars etc.

Hence the correct answer is “C”, Mitochondria.

Note:(i) Mitochondria were first seen in 1880 by Kolliker. He isolated them from the muscle cells of insects. They were named mitochondria by Benda in 1898.
(ii) Mitochondria are self-replicating organelles. It divides by fission.
(iii) Mitochondria are absent in nature red blood cells.