Biology links: 2014

Thursday, 13 November 2014

Endocrine System Questions and Answers

Tuesday, 6 May 2014

Genetic Engineering (Notes)

Genetic Engineering

In this process, the genes of organisms are manipulated by geneticists.

This manipulation may require any one, or all, of the following actions:
1.    Restriction Enzymes ( a.k.a. restriction endonucleases, or biological scissors)
       These are enzymes that find specific nucleotide sequences on the DNA, and cut the DNA into smaller         segments wherever/whenever that sequence is found.

2.    Recombinant DNA
       This is the result of splicing (joining) together the DNA from 2 or more organisms.

3.    DNA Amplification

       This is the process of taking a particular segment of DNA and generating multiple copies of it so that        there is sufficient amounts for the various procedures that need to be done.

      This may be done by:
     (a) cloning vectors
     (b) PCR - Polymerase Chain Reaction

4.    Gel Electrophoresis (See diagram p. 617)

       In this process, a DNA sample which has been cut in segments by restriction enzymes are allowed
      to pass through a gel medium using an electrical current. Using this method, DNA segments of
      different sizes will separate out according to size, with the smallest sections moving furthest, the next
      smallest sections move slightly less, and so on, with the largest sections moving the least within the gel.

5. DNA Sequencing

    This refers to a process used to determine the exact sequence of nucleotides that make up the DNA of a     particular gene or chromosome, or even a whole organism. This was the goal of the HUMAN GENOME     PROJECT.

Options for Treating Genetic Disorders

1. Screening and Prevention: People with potential genetic disorders may decide not to have children.
Or they may decide to do in vitro fertilization, and genetically testing the embryos before deciding to implant.

2. Surgery: Some genetic disorders, such as cleft palate, can be surgically corrected after the birth.
3. Environmental Control: Some diseases, such as PKU only become severe if the child is exposed to certain proteins. Parents can control this by limiting the child's exposure to those proteins.
4. Gene Therapy: In this process, the damaged gene is excised (cut out) and replaced by a functional gene (possibly from another species!) This may be able to reverse the damage caused by the defective gene.