Molecular Genetics:

I. Chromosome

A. 23 pairs (46) in humans.

B. Located in the nucleus of every cell.

C. Contains minimum of 150,000 genes, however only some genes are expressed in a particular cell determining its unique qualities.

D. contains deoxyribunocleic acid (DNA) and ribonucleic acid (RNA).

II. DNA

A. Located inside the chromosome.

B. Function is to regulate cellular activity by protein synthesis. It is also necessary for cell division, DNA replication, transcription and production of RNA.

C. Contains 2 sugar molecules formed in double helix. The sugar molecules have one of adenine, guanine, cytosine, thymine and are linked to one another by hydrogen bonds. Adenine has 2 hydrogen bonds with thymine and guanine has 3 bonds with cytosine.

III. Nucleotide

A. consists of sugar molecule, phosphate and either adenine, guanine, cytosine and thymine.

B. group of 3 nucleotides (codon) indicates a specific amino acid.

C. due to pairing of adenine-thymine and cytosine-guanine, nucleotide sequences of one strand of DNA dictate the sequences of the other strand.

IV. Gene

A . parts of DNA (made up of a number of nucleotides).

B. coding a specific protein.

V. Transcription

A. A process where DNA is transcribed to mRNAvia RNA polymerase.

B. One of steps in protein synthesis-important in regulation of cell activity.

VI. Translation

A. a process of sequencing amino acids (which are coded bymRNA) in order to build protein.

VII. Regulating DNA

A. gene promoter: initiate transcription.

B. consensus sequences: binding sites for regulatory proteins.

C. gene enhances: binding sites for transcription proteins.

VIII. Biogenetic techniques

A. Restriction enzymes: cut DNA at a location determined by a specific nucleotide sequences. The resulting fragments are called restriction fragments.

B. Agarose gel electrophoresis: negatively charged DNA fragments are put in a gel and exposed to electrical field. As a result, there is separate of DNA fragments based on size - the smaller the gragments, the closer they are to the positive pole of electrical field.

C. DNA ligation: attached human genes to plasmids in order to study the genes.

D. Plasmid vectors: so called for the human genes about to be ligated to plasmids. The products of DNA ligation is called recombinant plasmid.

E. Transformation: insertion of recombinant plasmid into bacteriuym which then replicates the recombinant plasmid hence increases the amount for study.

F. Genomic library: a library of the entire genome, in the form of recombinant DNAs. Acheived by restricting the genes, which is then ligated with plasmid and transformed into E.coli which amplify the amount of recombinant genes and the genes are then isolated from the bcterial colony.

G. Transgenic animals: animals with foreign genes in every cells of their body due to insertion and incorporation into chromosomes of those foreign genes into a single cell embryo.

H. Southern Hybridization: technique to find a particular DNA sequence in mixed DNA.

I. Northern Hybridization: technique to find a particular RNA in mixed RNA.

J. Polymerase Chain Reaction (PCR) amplification: to increase the amount of specific DNA sequence in vivo by repeatedly synthesizing it. Used to screen DNA for gene mutation.

IX. Effects on orthopaedics

A. screening of genetic diseases such as osteogenesis imprefecta, Marfan syndrome, chondrodystrophies, Vitamin D-resistant rickets and familial aortic aneurysm.

B. bone tumours are a result of failure in regulating cell growth due to gene mutation.

Immunology:

I. Nonspecific Immune response

A. inflammatory responses following a recognition of a foreign antigen. It consists of Histamine release (cause vasodilation) and phagocytic cells that only recognize the antigen as non-self (macrophage, neutrophil, etc.) and respond by enzymatically digesting the foreign materials.

B. It can be enhanced by complement system or subsided by anti- flammatory medication.

II. Specific immune responses

A. cell mediated and humoral immune responses.

B. antigens: when recognized as foreign, starts an immune response.

C. macrophages: eat the foreign body and presents antigen on its surface to T lymphocytes.

D. T lymphocytes: originate in bone marrow but mature in thymus. It consists of helper T cells, suppressor T cells and killer T cells. Helpter T cells produce cytokines to stimulate B cells, macrophages, killer T cells and suppressor T cells. Killer T cells also produce cytokines to stimulate supporessor T cells. Suppressor T cells are then damped down the immune response once the antigens are cleared.

E. B lymhocytes: orginate and mature in bone marrow. Differentiate into plasma cells and memory cells upon stimulation. Plasma cells roduce immunoglobulins (lg) against specific antigens.

F. Immunoglobulins: 5 types-IgA (releases to and acts on mucosal surfaces), lgM (only inside blood circulation, largest, produced earliest by foetus and plasma cells at first encounter with new antigen), lgG (commonest, produced after lgM in response to new infection), lgD (acts as a receptor), lgE (attach to mast cells, involved in allergic reactions).

G. Cytokines:

a) glycoproteins produced by cell in response to foreign antigen.

b) role in regulation of inflammatory and immune reaction.

c) they are interferons, growth factors, colony stimulating factors, interleukins.

H. Complement system

a) 25 proteins.

b) acts in sequence to amplify immune response.

I. Immunogenetics

a) located on the short arm of chromosome 6 called Human Leucocyte antigens (HLA).

b) make up the specificity of immune recognition.

c) 6 class I loci and 14 class II loci.

J. Transplantation

a) allogenic grafting: tissue transplanted to another non genetically identical of the same species.

b) xenografting: tissues transplanted to another of different species.

c) graft prepration:

reduce cellular response by freezing.

eliminate cellular response by freeze-drying (lyophilization)

K. Oncology-tumour cells have cell surface antigens that are:

a) identical to the ones on normal cells indicating their origin, however they may lose some of these.

b) maybe identical to those on ftal cells.

c) tumour associated.