HIV (human immunodeficiency virus) is a virus which can eventually lead to development of AIDS (acquired immunodeficiency syndrome). However, it is not the virus itself which causes AIDS symptoms; HIV weakens the immune system, meaning other infections can take hold more easily. In this article we will look at HIV structure, replication, and development of... Continue Reading →
Electrophoresis – Gene Technologies Ep 4
Electrophoresis is a method used to separate fragments of DNA or RNA based on their size (length*) using an electric current. It has applications in processes such as genetic fingerprinting and disease diagnosis. DNA and RNA are negatively charged which means they will move towards a positive electrode. This technique can be used for proteins,... Continue Reading →
Transforming bacteria – Gene Technologies Ep 3
So far in the genetic engineering journey we have learnt how to isolate or produce a DNA fragment, and amplify it in vitro using PCR. Transforming bacteria is a method to amplify a DNA fragment in vivo (in a living organism), and to engineer bacteria to produce a protein. In this article we will look... Continue Reading →
Polymerase Chain Reaction (PCR) – Gene Technologies Ep 2
Once a DNA fragment has been isolated or produced (see the last article), the next step is often to produce many copies of it. One common way to do this is to use the polymerase chain reaction, which is a fairly simple process that can be automated. In this article we will look in detail... Continue Reading →
Producing DNA Fragments – Gene Technologies Ep 1
This article begins a new series about gene technologies. Many gene technologies, especially recombinant DNA technologies, begin with the need to isolate or make DNA fragments. We will look at three different ways that this can be achieved. Restriction endonuclease enzymes This method allows DNA fragments to be "cut out" of existing DNA. Restriction endonucleases,... Continue Reading →
Mutations – Variation and Biodiversity Ep 1
There is a huge variety of life on this planet. In this series we will look at how all that variation exists, from the DNA level to the population level. Today we are starting off with a source of variation at the DNA level. What are mutations? A genetic mutation occurs when the DNA base... Continue Reading →
Meiosis – Cell Division Ep 4
Meiosis is a little more complicated than mitosis, and has a different outcome. Meiosis is a method of nuclear division which only happens in the reproductive organs of organisms which reproduce by sexual reproduction. It produces genetically different gametes with half the number of chromosomes as the parent cell. These gametes (the egg cells and... Continue Reading →
Binary Fission – Cell Division Ep 3
In the last article we looked at mitosis as a method of cell division. However, mitosis can only take place in eukaryotic cells. Prokaryotic cells, which don't have a nucleus, divide by binary fission. This process produces two genetically identical daughter cells from the parent cell, and is a method of asexual reproduction. Binary fission... Continue Reading →
Mitosis – Cell Division Ep 2
Mitosis is a method of nuclear division used by multicellular organisms for growth and repair of tissues. Some plants and fungi (and rarely some animals) also use it for asexual reproduction - producing genetically identical offspring from one parent. Mitosis results in two daughter cells which are genetically identical to the parent cell. In this... Continue Reading →
The Cell Cycle and DNA Replication – Cell Division Ep 1
All the cells in multicellular organisms which are capable of division go through a cell cycle - a sequence of phases which incorporates cell growth, DNA replication, and division. However, remember that not all cells are capable of division e.g. red blood cells. The Cell Cycle The cell cycle begins just after mitosis with growth... Continue Reading →
