Question

In which of the following parts of mitochondria succinic dehydrogenase enzyme is located?
A. Peri Mitochondrial space
B. Outer membrane
C. Matrix
D. Inner membrane

Answer 1

Succinate dehydrogenase (SDH) is part of both the citric acid cycle and respiratory electron transfer chain and it consists of four subunits (named A to D) encoded by the nuclear genome. Three additional proteins, including SDHAF1, are essential for the assembly and activity of SDH.

Complete answer:
Cell is the basic functional unit of the life, cells of living things perform different functions and help the living to grow, to develop, to reproduce, to perform all the biochemical reactions during their life cycle.
Cells are made up of different parts and each with different functions. One of the important parts of the Cell is cell organelles and these cell organelles perform different functions in coordination with each other.
Some of the major organelles animal cell contains:

Cytoplasm: It is made up of jelly-like fluid called cytosol. All the cell organelle, proteins, amino acids, ions, messenger molecules etc. are present in cytoplasm.
Cytoskeleton: It is a network of long fibers that help to make up the cell’s structural framework.
Endoplasmic reticulum (ER): This organelle helps in the processing of molecules created by the cell. And also transports these molecules to their specific destinations present inside or outside the cell.
Golgi apparatus: The Golgi apparatus packaging of molecules processed by the endoplasmic reticulum to be transported out of the cell.
Lysosomes and peroxisomes: These organelles are performing recycling in the center of the cell. They digest foreign substances that invade the cell, remove the toxic substances, and recycle worn-out cell components.
Nucleus: It contains genetic material of the cell (DNA) and it serves as the cell’s command center, sending directions to the cell to grow, mature, divide, or die.
Plasma membrane: It is the outer lining of the cell, separates the cell from its environment and allows materials to enter and leave the cell.
Ribosomes: These organelles that process the cell’s genetic instructions to create proteins. It is connected to the ER or can float freely in the cytoplasm.
Mitochondria: These are complex organelles that convert energy from food into a form that the cell can use. Mitochondria have their own genetic material, separate from the DNA in the nucleus, and can make copies of them. Generate energy in the form of ATP, outer membrane is with specialized function and exchange of ions.

Mitochondria are typically round to oval in shape and range in size from 0.5 to 10 μm. In addition to producing energy, mitochondria store calcium for cell signaling activities, generate heat, and mediate cell growth and death. The number of mitochondria per cell varies widely. In many bacterial cells and in the inner layer of mitochondria of eukaryotic cells contains the enzyme SDH or Succinate dehydrogenase or respiratory complex 2. This is the only enzyme which participates in both the citric acid cycle and the electron transport chain.

So, the correct answer is D, inner membrane.

Note: Mitochondria also known as “powerhouses of the cell”, was first discovered in 1857 by physiologist Albert von Kolliker. Later in 1886 it was termed as “bioblasts” (life germs) by Richard Altman. Then twelve years later the organelle was again renamed “mitochondria” by Carl Benda.