Why use microbes?
They have a simple biodiversity and so are easy to understand and control
They reproduce quickly
There are only a few different species
They can be genetically engineered to change their products
There is no ethical concerns about their treatment
They die quickly
In genetic modification (GM), a gene is transferred from one organism to another, where it continues to work.
Put the following statements in order:
1.The gene is then inserted into a suitable vector (eg a plasmid or virus).
2.The required gene is identified and isolated (cut out of the organism’s DNA using enzymes).
3.The vector is used to insert the gene into the host organism (eg bacteria or yeast).
4.Organisms that have been successfully modified are selected and then ‘cultured’ (grown in ideal conditions to increase their numbers).
5.The gene is then replicated to make many copies of it.
Genetic can be used to make crops to disease, which means that fewer pesticides need to be sprayed onto farmland. Other crops can be made resistant to , so that the field can then be sprayed with a herbicide to kill off all the , making the crop more and easier to harvest.
Genetic modification can also be used to manufacture human proteins which are used to treat medical conditions.
means manipulating and using particles of materials that are very small - between 1 and nm – about the size of some molecules.
Nanotechnology can be used in packaging. For example, silver nanoparticles are anti-microbial and can be used to prevent bacteria from growing inside food packaging. This extends the life of the food. It can also be used in medicines, for example nanoparticles can speed up the healing process and gold plated 'nano ' act as a concentrated treatment for by absorbing energy and then heating and killing the tumour.
Stem cells are...
... cells that can develop into any type of cell
... found in the stems of plants
... the most common type of cell in the human body
Choose the examples of stem cell sources.
Stem cells can be cultured outside the body.
Biomedical engineering involves...
...solving medical problems using new materials and man-made parts
...experimenting genetically on living organisms
...developing and improving existing medical knowledge with the use of plants
Examples of biomedical engineering include:
mechanical or biological heart valve replacements
stem cell development
using the genetic modification of bacteria to produce human insulin
Which of the following apply to mechanical heart valves?
likely to last for longer
need to be replaced quicker
more likely to be rejected by the body
Genetic testing may be used to find out if an has a genetic disease - a disease which they have and which is a result of a defect in their DNA.
To investigate a person’s DNA, blood cells are used because they are easy to obtain from a blood sample, and (unlike blood cells) they have a nucleus containing the DNA.
1. Isolation of DNA from white blood cells
A small quantity of blood has chemicals added to it. The chemicals split open the red cells. The sample is then put into a centrifuge and spun very rapidly so that the white cells form a at the bottom of the tube.
The pellet of white blood cells is then in a liquid. More chemicals are added which split open the cell membranes and release the DNA from the .
The DNA is collected and then (more copies of it are made) so that there is enough to test. The DNA is then broken up into smaller sections using and put onto a special gel. An electrical is applied, and the pieces of DNA separate out along the gel.
2. Gene Probe
A gene is a short section of single-stranded DNA that has a chemical attached to it which will glow under UV light. The chemical is added to a length of DNA which has the base sequence to the gene that codes for a particular disease, eg cystic fibrosis.
3. Adding the gene probe to the sample DNA
The separated pieces of DNA on the gel are ‘blotted’ to split the DNA into single strands. The gene probe is added and if the gene the scientist is searching for is present, the gene probe will to it because it has a complementary base sequence to the gene being .
4. Using UV light
The gel is then viewed under light. If the gene is present, the gel will glow at that point. The gene has therefore been identified as being in the person’s DNA.