Understanding Molecular Biology

This free online course introduces you to the world of molecular biology. We explore the role of the ‘polymerase chain reaction’ technique that uses an enzymatic method and cycling condition to ‘amplify’ many double deoxyribonucleic acid (DNA) molecules that have the same size and sequence. DNA is a nucleic acid that is composed of two complementary nucleotide building blockchains. These ‘nucleotides’ are made up of a phosphate group, five-carbon sugars and a nitrogen base. We explain the concept of ‘DNA replication’, which is a process of duplication of the entire genome before the division of cells. We then examine the four nitrogen bases that are found in DNA and are linked in a repeated pattern by hydrogen bonding between the nitrogen bases. The linking of the two complementary strands is called ‘hybridization’. Demonstrations, problems, examples and assessment questions in this instructor-led video-based course are designed to provide you with a comprehensive foundation that enables you to take serious steps into this field.

The course begins by examining DNA replication and PCR setup. Primers are short DNA stretches that serve as a starting point for DNA synthesis. We study their secondary structures and explain how they are created by intra- or intermolecular attraction within the primer, which eventually reduces the yield of amplification as the availability of single-stranded primers is limited for the PCR. We showcase the use of the thermal cycler, an instrument that carries out the amplification of DNA using the PCR. We clarify that primers should be designed in such a way that there should be no homology, which is similarity borne of shared ancestry, within the template other than the target site. This results in non-specific binding and amplification. This course teaches you to recognize the advantages of using the PCR technique: speed, ease of use, sensitivity and robustness when compared to other techniques used in clinical diagnostic tests.

PCR technology has become the basis for a broad spectrum of clinical diagnostic tests for various infectious agents and can detect the presence of infectious diseases in blood samples. We show you how the appearance of a smear that has visible bands indicates that the genomic DNA has been completely digested and is suitable for ‘Southern’ blotting, in contrast to the Northern blotting that is used to detect RNA. We provide two examples of methods that are used in DNA sequencing: Sanger and Maxam Gilbert. We wrap up with more attention to PCR techniques, sequencing and blotting methods, DNA amplification and the location of PCR in the tissue culture. This course suits aspiring biotechnology students, people looking to work as a biologist or even those who simply want to understand how our bodies work at their most fundamental level.