Anticancer Drugs
o What is an anticancer drug?
An anticancer drug, also known as chemotherapy, are used for the treatment of malignant cancers. Some of the anticancer drugs include antimetabolites which block the cell’s metabolism, natural products that stop cells dividing, hormones and alkylating agents which damage the cell’s DNA.
o How do anticancer drugs work?
Anticancer drugs are designed to successfully stop cancer cells from spreading and growing – without affecting and damaging our normal, healthy cells. A characteristic of cancer cells is rapidly dividing, and so anticancer drugs target these cells.
o Paclitaxel
Paclitaxel, also known as Taxol, is a chemotherapy drug used to treat cancer in animal cells. Paclitaxel kills cancer cells by mitotic arrest – which stops the process of mitosis, therefore disabling the cell’s ability to reproduce.
A protein called tubulin is the main part of microtubules, a tubular structure present in the cells cytoplasm which often aggregates to form other complex structures. Microtubules are responsible for mitosis as well as many other vital things in order for a cell to function successfully. Paclitaxel stabilises these microtubules and reduces their ability to be active, therefore halting the process of mitosis.
Therefore, microtubules formed under paclitaxel are incredibly dysfunctional, causing death of the cell, through the disruption of vital mitosis processes.
To know that the paclitaxel is working and affecting the cell type (ie the mammalian cell) you would measure the mass of the five petri dishes every day once the chemical had been integrated with the cell type. The unknown cell type’s mass that is affected by the paclitaxel will stop increasing, or will decrease in size as the cells are dying.
The agar that is needed in order for the cancer cell to be maintained is that of a human blood agar – as cancer lives and grows in this condition.
Antibiotics
o What is an antibiotic?
An antibiotic is a substance that affects the growth of bacteria. They can help treat and prevent bacterial infections from occurring.
o How do antibiotics work?
Antibiotics work in two ways: kill the bacteria directly and/or prevent the bacteria from growing.
o Streptomycin
Streptomycin is an antibiotic that treats bacterial infection. Streptomycin works by affecting certain proteins in the bacteria that are vital for their survival. This antibiotic has to be given by injection into a muscle.
Streptomycin prevents bacteria from growing without having much effect on eukaryotic cells. It blocks protein synthesis by binding to the bacteria’s ribosomes.
Bacteria are incredibly adaptive, and can quickly create a resistance to the drug.
As a sign to see if the Streptomycin is affecting one of the unknown cell types (ie the bacteria cell), you would swab a person who is suffering from tuberculosis to gain a sample of the bacteria cells. You would place the variety of cells onto a nutrient agar, and place a certain number of drops of the streptomycin drug, and measure the ‘death zone’ around each drop. The one with the biggest amounts of ‘death zone’ on the agar could be confirmed as the bacteria cells.
Use of nutrient agar is important as it will keep the bacteria cells alive.
Fungicides
o What are fungicides and how do they work?
A fungicide is a chemical substance that kills fungi, fungal growth, spores and infections. Most fungicides work by damaging the fungi cell membrane or by disturbing the energy production of fungal cells.
o Amphotericin B
This drug is given by an injection into the vein. Amphotericin B binds with ergesterol which is a component of the fungal cell membrane. It slows the growth of the fungi.
A way that you could identify if the drug is working on the cell type is to measure the death zone around where you dropped a small amount of the drug. The correct chemical and cell combination can be confirmed when you recognise which cell type was affected the most.
Use of nutrient agar is important as it will keep the yeast cells alive.
Herbicides
o What is an herbicide?
Herbicides are a chemical substance used to kill weeds and unwanted plants. They are in two main categories: broad-spectrum and selective.
o Broad-spectrum and selective herbicides
Broad-spectrum herbicides kill all plants, weeds and lawn grass. An example of a broad-spectrum herbicide is roundup.
Selective herbicides are used for specific plants, causing hormonal disruption.
o Glyphosate (Roundup)
Glyphosate is a non-selective herbicide, it is applied to the leaves of a plant and kills the plant itself. It prevents the plants from making vital proteins that is needed for the plant to grow and flourish.
You can identify if the chemical is working on a cell type by observing how dead a plant is after applying the chemicals.