The molecular basis of inheritance is a totally conceptual chapter and there are many processes to learn here. It has experiments and name of scientists which need to be remembered.
You can begin this chapter by studying the structure of DNA and RNA and then proceed to replication, transcription, translation.
There are a total of four experiments which are there at the beginning of the chapter- Griffith’s Transformation Principle, Biochemical nature of transformation principle by Avery, McLeod and McCarty, Bacteriophage experiment by Hershey and Chase and Semi conservative replication by Meselson and Stahl. Try to remember the names of scientist, the materials which they used such as Escherichia coli by Meselson and Stahl. Try to understand the objective behind the aim of the experiments.
A scientist named Taylor conducted an experiment like the one carried by Meselson and Stahl but with Vicia faba.
Candidates must know the polarity of the DNA strands. This section is very scoring.
Study properly the last few sections of the chapter such as the human genome project or DNA fingerprinting.
The central dogma of life given by Crick does not explain reverse transcription. It was updated by Temin and Baltimore.
Beadle and Tatum, who propagated the one gene one enzyme hypothesis, worked with Neurospora.
What is meant by molecular basis of inheritance?
Molecular basis of inheritance can be described as the study of genes, hereditary and genetic variations which talks about how an offspring look like its maternal or paternal features. DNA, RNA and genetic code are the main components of the molecular basis of inheritance and they play the role of transmitting genes from parents to the offspring.
Importance of DNA
A cell has a nucleus which contains all genetic materials. The nucleus has nucleolus and chromatin which are thread-like structures. Chromatin become chromosomes located with genes. Each chromosome contains thousands of genes and each gene has a particular trait. The number of chromosomes of each cell of living organisms is fixed, for example, humans have 23 pairs of homologous chromosomes i.e., 46 in number. Whereas the number of genes in each chromosome is vast.
A gene consists of a double-stranded structure called DNA. Different portions of DNA exhibit different traits like skin color, hair color, eye color, etc. This proves that DNA is responsible for molecular inheritance.
Structure of DNA and RNA
A group of biomolecules has two types of nucleic acids, DNA and RNA, that are responsible for molecular inheritance.
DNA is Deoxyribonucleic acid and the structure is double-stranded helical and ribbon-like wrapped around each other. It is a polynucleotide or polymer. The monomer units are deoxyribonucleotides and the number of nucleotides determines the length.
RNA is Ribonucleic acid and its structure is like that of DNA but has a single strand. It is a polymer or polynucleotide, made up of many monomer units called ribonucleotides. The molecular basis of inheritance in few viruses is RNA. You can visit here to know about the abovethenews. On the other hand, you can also get more essential info on dbfile. Here is the best news portal thoughtco where you can get the latest news around the world.
Any nucleotide present in DNA or RNA has three parts.
- Pentose sugar
- Nitrogenous base
- Phosphate group
Pentose sugar– It is a monosaccharide having 5 carbon atoms. RNA contains ribose sugar and DNA contains deoxyribose sugar.
Phosphate group– It is an inorganic salt of phosphorous and pentose sugar and the phosphate group makes a backbone of the polynucleotide chain.
Nitrogenous base– It has nitrogen compounds with properties of a base. There are two kinds of nitrogenous bases – purines and pyrimidines.
How is a polynucleotide formed by joining nucleotides?
An N-glycosidic bond bonds with the nitrogenous base with pentose to form a nucleoside. A phosphate group connecting to this nucleoside through phosphoester linkage form a nucleotide. Many nucleotides combine together to make a polynucleotide through 3’-5’ phosphodiester bond. In this way, nuclei acid chains are formed in DNA or RNA.
Genetic code is a set of rules through which information encoded in the DNA or mRNA sequence is transferred into proteins by the living cells.
Human genome project
Human genome project was formed as an international scientific research project to determine the base pairs which make up human DNA. It covers identifying and mapping all the genes of the human genome in terms of physical features and functionalities. It is of immense value in the fields of life science, medicine and biotechnology.
Do you know the answer of the below question:
- Histone proteins are:
- A) basic, negatively charged
- B) basic, positively charged
- C) acidic, positively charged
- D) acidic, negatively charged.
What is molecular basis of inheritance?
DNA, which is the molecule of heredity and RNA are the two parts that form the molecular basis of inheritance. It allows organisms to inherit genetic information from parental genes. Genetic materials are passed to the progeny cell from the parent cell at each cell division.
What is meant by central dogma?
The protein synthesis begins from DNA. Replication helps in making many copies of DNA. Transcription is the process of copying one strand of DNA to from mRNA. This is known as the Central dogma theory.