dna and rna chapter 12

The histone coat protecting the DNA double helix of the gene to be transcribed is removed, on a signal from the cytoplasm, exposing the polynucleotide sequences in this region of DNA. The RNA polymerase enzyme binds to a specific site, called promoter, in the DNAh..

RNA Types - The three different types of RNA, namely, messenger RNA (mRNA), ribosomal RNA (rRNA) and transfer RNA (tRNA) are transcribed from different regions of the DNA molecule. Three different RNA..

The three different types of RNA, namely, messenger RNA (mRNA), ribosomal RNA (rRNA) and transfer RNA (tRNA) are transcribed from different regions of the DNA molecule. Three different RNA polymerases: I, II a..

It represents about 5 to 10% of the total RNA. It is synthesised from DNA as and when necessary. It carries the genetic information in the form of a specific sequence of nitrogen bases arranged in triplet codons, which are copies from the code in DNA..

It represents nearly 80% of the total RNA in the cell. It always occurs bound to basic proteins in ribosomes. It takes part in assembling the amino acids brought by tRNA, into a polypeptide chain, based on the sequence of codons in mRNA. RNA serves the follo..

DNA serves the following functions. It is the genetic material in all prokaryotes and eukaryotes. It is capable of replication by which it can be faithfully passed on to successive generations. It is involved in the synthesis of RNA. It provides the code for protein ..

It is the DNA synthesised on RNA template with the help of the enzyme reverse transcriptase and necessary nucleotides. The DNA strand is isolated from the hybrid RNA-DNA complex by using alkaline phosphatase enzyme. A complementary DNA strand is th..

The RNA polymerase moves along the DNA and causes local unwinding and splitting of the DNA double helix into two chains in the region where the gene to be transcribed is located. This exposes the A, T, C and G bases that project into the karyoplasms from the phosphated..

RNA molecule is a single stranded structure made of ribonueleotides. RNA contains the pyrimidine uracil instead of thymine in DNA. RNA is of 3 types, based on the cellular compositio..

The DNA, that controls protein synthesis, is located in the chromosomes within the nucleus, whereas the ribosomes, on which the protein synthesis actually occurs, are placed in the cytoplasm. Therefore, some sort of agency must exist to carry instructions from the DNA to the ri..