Hence, deoxyribose is more precisely called 2-deoxyribose. A labeled deoxyribose, which is derived from ribose sugar is shown in figure 1. Adenine and guanine are purine bases whereas cytosine and thymine are pyrimidine bases.
These are briefly discussed below: Nucleotides are also known as nitrogenous bases or DNA bases. Nitrogenous base are of two types, viz. The features of pyrimidines and purines are given below.
Main features of pyrimidines are given below: Main features of purines are given below: Thus, in RNA there are four different types of nitrogenous bases, viz. In DNA, the pyrimidine base uracil is replaced by thymine.
The purine and pyrimidine bases always pair in a definite fashion. Adenine will always pair with uracil and guanine with cytosine. Adenine and thymine are joined by double hydrogen bonds while guanine and cytosine are joined by triple hydrogen bonds. Both are pentose sugar having five carbon atoms.
The four carbon atoms are inside the ring and the fifth one is with CH2 group. This has four OH groups on 1, 2, 3 and 5 carbon positions. Hydrogen atoms are attached to carbon atoms one to four.
The phosphate molecule is arranged in an alternate manner to ribose sugar. Thus there is ribose sugar on both sides of phosphate. The phosphate is joined with carbon atom 3 of ribose at one side and with carbon atom 5 of ribose on the other side.
In RNA, nucleoside is a combination of ribose sugar and nucleotide is a combination of nucleoside and phosphate. Thus, a nucleotide is a nucleoside with one or more phosphate groups covalently attached to it.
Nucleosides differ from nucleotides in that they lack phosphate groups. The RNA backbone is a polymer with an alternating sugar-phosphate sequence. RNA as Genetic Material: In such cases, RNA is the genetic material. Fraenkel Conract and Singer Experiment : They conducted their experiments with tobacco plant.
The experiment is based on the principle of transformation. They isolated RNA and protein from the tobacco plants infected with tobacco mosaic virus [TMV] and used the isolated RNA, protein and their mixture to develop TMV symptoms in the healthy plants of tobacco and recorded the observations after a definite period.
When only protein extract was applied, the symptoms did not develop. The details of the experiment are given below. They used Holmes Ribgrass Virus [HRV] which was isolated from Plantango lanceolata plant and used to develop symptoms in healthy tobacco plant.
RNA from one virus and protein from other virus were mixed together and used to develop infection on healthy tobacco plants and observations were recorded.
The symptoms resembled the virus from which RNA was used.Examine three (3) differences between DNA and RNA then explain two (2) main reasons why DNA is the most favorable molecule for genetic material.
DNA and RNA are somewhat similar organic molecules, both involved in the storage and transfer of genetic information. According to rutadeltambor.com, DNA’s primary function is to store genetic information over the long term, while RNA’s primary function is to transfer this information to the ribosomes.
DNA vs. RNA – The Comparison. Characteristics. DNA. RNA. Sugar Molecules: Deoxyribose (this sugar molecule is the same as ribose, however it has an additional OH) Ribose: Appearance: DNA appears as a Double Helix. It appears like a twisted ladder. Within the structures are rungs represented by Four-letter DNA alphabet.
The spiral is also made. Start studying Compare and contrast DNA and RNA. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Essay # 1. Meaning of DNA: A nucleic acid that carries the genetic information in the cell and is capable of self-replication and RNA synthesis is referred to as DNA.
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