Last Updated on May 24, 2023 by Nourhan Essam
Molecular biology of the cell involves different macromolecules or biomolecules like proteins, carbohydrates, lipids, DNA and RNA (nucleic acids) and amino acids. It focuses on studying their chemical and physical structures, compositions, modification, mechanisms, interactions, and functions which are essential and vital to life processes.
In this article, you will learn more about what is molecular biology, its techniques, how does it provide evidence for evolution, what is molecular biology central dogma? and a list of more than 35 molecular biology virtual lab experiments introduced by PraxiLabs.
Table of Contents
What is Molecular Biology?
In simple words, molecular biology definition is the branch of science that is interested in studying various biological activities at the molecular level (between or in the cells).
To know what is molecular biology? Let’s take an overview at the science of molecular biology.
In 1945, the term molecular biology was used by the physicist William Astbury. In 1953, Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at the Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Rosalind Franklin and Maurice Wilkins. This research then led to finding DNA material in other microorganisms, plants and animals.
What is the Central Dogma of Molecular Biology?
The central dogma of molecular biology is a theory that explains that the flow of genetic information (from DNA to RNA to protein) occurs only in one direction to make a functional product. The central dogma of molecular cell biology says that our DNA contains the needed information to make all of our proteins, and the role of RNA is a messenger that carries this information to the ribosomes. The role of these ribosomes is that they act as cell factories where the process of information translation from a code into the functional (final) product happens.
The process of gene expression has 2 stages that are called transcription and translation. In the transcription stage, the information which is found in the DNA of the cell is converted into messages that are portable and small. However in translation, the messages travel or translate from where the DNA is in the cell nucleus to the ribosomes to make specific proteins.
The central dogma of molecular biology states that the pattern of information that occurs in our cells is:
- DNA replication: From existing DNA to make new DNA.
- Transcription: From DNA to make new RNA.
- Translation: From RNA to make new proteins.
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Molecular Biology Techniques
Molecular biology techniques are the methods used in molecular biology and other related branches like genetics, biochemistry and biophysics which generally involve processes like modification, interaction, manipulation and analysis of DNA , protein, RNA and lipid.
Let’s put a spotlight on some of the most common molecular biology techniques:
Polymerase Chain Reaction (PCR)
Polymerase chain reaction or PCR is one of the most important methods in molecular biology. It is basically a test tube system for DNA replication that is used to copy DNA and allows a target DNA sequence (single) to be amplified into millions of DNA molecules folds in just a few hours. PCR can also be used to introduce and detect mutations within the DNA or the sites of special restriction enzymes. PCR is also used to detect whether a certain DNA fragment exists in a cDNA library.
In addition, PCR is used widely in the medical and biological fields for a variety of applications such as DNA cloning for sequencing, functional gene analysis, and the diagnosis and detection of hereditary and infectious diseases.
There are many different types of PCR like:
- Real-time PCR
- Nested PCR
- Multiplex PCR
- Quantitative PCR
- Long-range PCR
- Hot start PCR
- Arbitrary Primed PCR
- Single-cell PCR
- Methylation-specific PCR (MSP)
- Fast-cycling PCR
Gel electrophoresis is an important molecular biology method used to separate mixtures of DNA, RNA, and proteins depending on their molecular size. In this technique, the molecules to be separated are run by an electric field through agarose gel that contains small pores and that allows you to differentiate between DNA fragments of different lengths.
There are many applications of gel electrophoresis like:
- Crime scenes investigation by separating DNA fragments for DNA fingerprinting.
- Polymerase chain reaction (PCR) results analysis.
- In taxonomy studies, for distinguishing different species by DNA profiling.
- Gene analysis (genes that are associated with a particular illness).
DNA cloning is a molecular biology technique that is used to make several identical copies of a piece of DNA, such as a gene or other DNA pieces. DNA cloning is done by inserting a target gene into a circular piece of DNA which is called “plasmid”. Then, through the transformation process, the plasmid is introduced into bacteria (selected by using antibiotics). These bacteria are used to make more plasmid DNA or, induced to express the gene and make protein.
The cloned DNA can be used to:
- Detect and identify the function of the gene.
- Investigate the characteristics of the gene like size, expression, and tissue distribution.
- Make big protein concentrations that are coded by the gene.
- Learn how mutations can affect the function of a gene.
Cell culture is one of the most important molecular cell biology techniques as it provides a platform to investigate the biology, physiology (e.g., aging), biochemistry, and cells and diseased cells metabolism. It is also used to study mutagenesis, carcinogenesis, the effects of drugs and toxic compounds on the cells, and the route of infection and interaction between wild-type cells and pathogenic agents (e.g., fungi, bacteria and viruses).
Cell culture is the process by which human, animal, or plant cells are removed and grown in an artificial environment under controlled condition. For example, cultured animal cells are used in the production of viruses, and these viruses are used to produce vaccines. For example, vaccines for diseases like rabies, chicken pox, polio, measles and hepatitis B are produced using culture of animal cell.
We can define DNA extraction as the technique that is used to isolate DNA by breaking the cell and nuclear membrane with the help of some chemical substances or enzymes or physical disruptions. DNA extraction has been the target of a lot of research, as it has many applications like genetic modification of plants, detecting bacteria, and viruses in the environment, altering animals, medical diagnosis, paternity tests, identity verification, pharmaceutical products, and hormone production.
The extraction of DNA is critical to molecular cell biology and biotechnology. It is considered the first step of different applications, varying from routine diagnostic and therapeutic decision-making to fundamental research. The importance of DNA extraction and purification is that they are vital and essential for defining the unique characteristics of DNA, such as its shape, size, and function.
Investigation of the DNA sequence and structure that are related to diseases helped in finding out the molecular basis and cure for various diseases. DNA extraction also allowed the scientists to produce many vaccines, enzymes, and hormones. As well as it was also very beneficial and important in the forensic/medico legal entities.
To study DNA, it must be extracted out of the cell. Hence, DNA extraction technique is widely used in research labs.
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How does Molecular Biology Provide Evidence for Evolution?
According to evolution theory, evolution refers to the alteration in a species’ traits over a big number of generations and depends on a method called “the natural selection”. The theory said that “All species are related to one another and change over time”.
The science of molecular biology provides data that supports the evolution theory. In particular, the DNA universality and the genetic code near universality for proteins show that all the living organisms once shared a common ancestor. DNA also provides clues and data about how evolution may have happened. The process of gene duplications allows one copy to undergo mutational events without harming an organism, as one copy continues to produce functional protein.
DNA sequences have also shed light on some mechanisms of evolution . In general, the similarity of DNA sequence between groups of organisms shows their relatedness.
What’s “Nature Structural & Molecular Biology”?
Nature Structural & Molecular Biology is a monthly peer-reviewed scientific journal publishing research articles, reviews, news, and commentaries in structural and molecular biology, with an emphasis on papers that show “functional and mechanistic”understanding of how molecular components in a biological process work together”.
It is published by the Nature Portfolio and was established in 1994 under the title Nature Structural Biology. Later, it obtained its current title in January 2004. Like other Nature journals, there is no external editorial board, with editorial decisions being made by an in-house team, although peer reviewing by external expert referees forms a part of the review process.
According to the Journal Citation Reports, the journal had a 2020 impact factor of 15.369, ranking it the 13th out of 298 journals in the category “Biochemistry & Molecular Biology”, the 1st out of 72 journals in the category “Biophysics”, and the 16th out of 195 journals in the category “Cell Biology”.
So, if you are interested in Molecular biology news and articles, you can follow the Nature Structural & Molecular Biology journal.
More than 35 Molecular Biology Experiments by PraxiLabs
PraxiLabs provides a vast and exceptionally diverse collection of important molecular biology experiments with awesome features to improve students’ learning experience and outcomes.
Let’s take a look at some of PraxiLabs molecular biology virtual lab simulations!
The DNA extraction virtual lab from PraxiLabs lets students practice basic laboratory techniques and understand the protocol and principle involved in DNA extraction well. Students also will identify the role of reagents, techniques and equipment in the extraction of DNA. They will also know more about the importance and applications of DNA extraction.
After conducting the conventional PCR virtual experiment, students can demonstrate proficiency with the principle and protocol involved in PCR technique. They conclude downstream applications of conventional PCR.
Agarose Gel Electrophoresis
In agarose gel electrophoresis simulation, students will learn how to identify and separate DNA or RNA molecules by size, the process of separation achieved by placing the molecules in a gel made up of small pores and setting an electric field across the gel. They will learn how to prepare an agarose gel properly, understand and visualize the precautions required during sample application in the gel. Students also will identify the role of reagents, techniques and equipment in the agarose gel electrophoresis experiments.
In DNA sequencing virtual lab, students will understand and learn:
How to apply a DNA sample purification using exosap IT..
Also how to apply library preparation step by step.
How to apply DNA fragmentation, amplification and, clean up of fragmented DNA and adapter ligation.
How to practice library normalization, dilution and denaturation.
How to perform the protocol of AMPure beads for DNA libraries purification.
In cDNA synthesis virtual lab, students will learn how to synthesize cDNA from RNA templates using the enzyme of reverse transcriptase.
By the end of the experiment, students will be able to understand the cDNA Synthesis protocol well, practice the basic laboratory techniques proficiency, and identify the role of specific equipment and reagents that are used in cDNA Synthesis.
Bacterial Plating out Technique (Streak Plate Method)
In the plating out technique experiment (streak plate method) virtual lab, students will learn how to isolate bacteria from a mixed population into a pure culture of the organisms by streak plate method. They also will become proficient at doing streak plate method accurately and consistently, produce isolated organism colonies on an agar plate, and learn organism identification by performing biochemical tests to identify bacteria (organism) that are only valid when performed on pure cultures.
DNA Fingerprinting Using Gel Electrophoresis
By the end of DNA fingerprinting using gel electrophoresis simulation, students will be able to:
Mention and list the preparation of an optimum agarose gel steps accurately.
Understand the value and role of chemicals and reagents that are used in the experiment.
Study the factors which lead to successful sample uploading into the gel Visualize DNA fragments.
Identify and detect DNA molecules that have been processed by methods such as enzymatic digestion and PCR.
Identify the restriction sites characteristics that are found in a DNA sequence.
In the oxidase test virtual lab, students will learn how to detect if an organism possesses the cytochrome oxidase enzyme. By conducting this test they will be able to differentiate between oxidase positive species like Moraxella, Neisseria, Campylobacter, Pasteurella, and pseudomonads species.
Antibiotic Sensitivity Test Disc Diffusion Method
In antibiotic sensitivity test disc diffusion method simulation, the students will learn how to determine the susceptibility of a microbial species against different antibiotic agents, to utilize specific monitoring techniques to evaluate the susceptibility of a microbe to different antibiotics species, and to detect the range of antibiotic activity.
Check our Biology Portfolio and Explore More than 35 Virtual Molecular Biology Experiments to Enhance your Students’ Learning Experience and Outcomes!