Question

(a) Expand DNA and RNA. (b) In which part of the cell it is found? State its function. (c) In which form is DNA present in (1) dividing cell (2) non-dividing cell?

Answer 1

DNA and RNA are the nucleic acid which is present in the living cell. It is made up of nitrogenous base, ribose sugar and phosphate. The DNA and RNA are responsible for carrying out all the physiology in our body.

Complete answer:
a) DNA stands for Deoxyribose nucleic acid and RNA stands for ribonucleic acid. They are made up of deoxyribose sugar in case of DNA and ribose sugar in case of RNA, nitrogen bases- Adenine, guanine, cytosine and thymine in case of DNA and thymine is replaced by uracil in case of RNA.

b) DNA is present in the nucleus of the cell in case of eukaryotes and in the cytoplasm in case of prokaryotes. In case of eukaryotes the DNA is linear and double stranded whereas in case of prokaryotes it is circular. DNA is also found in organelles like mitochondria, chloroplast. RNA is produced by the DNA by the process of transcription. Function of DNA is it controls the body’s activities. It is the unit of heredity. The DNA contains genes which are responsible for the characteristics of the organism. RNA is single stranded found in the ribosomes. The function of RNA in our body is protein synthesis. The RNA synthesized amino acids by the process of translation.

c) The long strands of DNA are compactly packed around the histones and are present inside the nucleus. In case of dividing cells, the DNA coils and forms the chromosome. Each chromosome contains DNA. In case of non-dividing cells, it is present as the chromatin in the free form.

Note: There are three types of RNA. mRNA, tRNA and rRNA. The transcription is the process by which DNA is converted into RNA. The RNA further converts into amino acid by the process of translation.