Question

Which of the following sets of cell organelles contain DNA?
A. Mitochondria, peroxisome
B. Plasma membrane, ribosome
C. Mitochondria, chloroplast
D. Chloroplast, dictyosome

Answer 1

Hint:A cell consists of a central double-membrane organelle called the nucleus which houses nuclear DNA. DNA stands for Deoxyribonucleic acid which stores information for encoding proteins required for several cellular functions. There exist two semi-autosomal organelles that contain their own DNA as well as ribosomes. Both are sites for energy production for cells.

Complete answer:
The DNA is the genetic material of cells which consists of long sequences of nucleotide base pairs. These base pairs form three-member codons that encode for several proteins required by the cell. Proteins form several enzymes and other molecules required for metabolic functions of the cell. The cellular DNA which is the main regulatory DNA is present inside the nucleus. The DNA in the nucleus regulates and controls the majority of cellular functions.
Mitochondria and chloroplast are two organelles that contain their own DNA except for the nucleus. These are semi-autonomous organelles that mean that only some of the proteins are made by their DNA. The majority of proteins for mitochondria and chloroplast are made by nuclear DNA. They have distinct DNA as compared to nuclear DNA. The organelle DNA resembles prokaryotic DNA and thus is either a circular or open thread structure.
The human mitochondrial DNA is called mtDNA and is 16 kb each. Dozens of copies of mtDNA are present inside the mitochondria. It is double-stranded DNA and is circular without any membrane covering. The chloroplast DNA or ctDNA is 120-170 kb. Multiple copies of ctDNA exist. The DNA is present in the nucleoid region of the chloroplast.

Hence, option C) is the right answer.

Note: The organelle DNA is devoid of histone proteins. The histone proteins are binding proteins for DNA. They make DNA compact and turn around them to form chromatin. Also, organelle DNAs are generally AT-rich genomes and they lack introns.