Substitution
A type of mutation where one base is swapped with another base, this could result in three possible consequences:
- Stop codon is no longer
... [Show More] coded for, allowing for continued protein formation
- No change, the genetic code is degenerate so coded for the same amino acid
- A different amino acid is coded for, producing a unique and non-functional protein
Deletion
A type of mutation where one base is removed from the DNA sequence. This causes a frameshift mutation to the left. As a result all codons from this point onwards has changed, resulting in a non-functional protein. Unless three bases are removed at once, therefore one amino acid in the sequence would not be coded for
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Addition
A type of mutation where one base is added to the DNA sequence. This causes a frameshift to the right. As a result all codons from this point onwards has changed, resulting in a non-functional protein. Unless three bases are added at once, therefore there will be one extra amino acid coded for
Duplication
A type of mutation where one or more bases are repeated, producing a frameshift to the right. As a result all codons from this point onwards has changed, resulting in a non-functional protein. Unless three bases are repeated at once, therefore there will be one extra amino acid coded for
Inversion
A type of mutation where a group of bases become separated from the DNA sequence, then rejoin to the sequence in reverse order. The base sequence of this portion is therefore reversed, coding for a different amino acid, producing a non-functional protein
Translocation
A type of mutation where a group of bases become separated from the DNA sequence on one chromosome, re-attaching to the DNA sequence on another chromosome. This leads to significant effects on gene expression and can lead to the development of cancer and can reduce fertility
Mutagenic Agents
External factors that can cause a mutation. These include toxic chemicals or highly ionising radiation
Specialisation
The process by which only some genes are expressed in a cell through stopping unnecessary transcription and translation
Stem Cells
Undifferentiated cells which are often replaced with identical copies of themselves self-renewal. There are numerous types of these
Totipotent
A type of stem cell that is found in a zygote. These can differentiate to any type of cell
Pluripotent
A type of stem cell that is found in the embryo. These can differentiate into most types of cell
Multipotent
A type of stem cell that is found in adults and in umbilical cord blood. These can only differentiate into a small range of cell types
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Unipotent
A type of stem cell that is found in adults (such as bone marrow). These can only differentiate into one type of cell. These are derived from multipotent cells and are comprised of adult tissue
Induced Pluripotent
Unique stem cells which are produced from unipotent stem cells. These are genetically altered to give characteristics of pluripotent stem cells (specifically, embryonic). These stem cells only differ to embryonic stem cells in the sense that they can undergo self-renewal
Benign
A type of tumor that:
- Has controlled growth. Cells produce adhesion molecules making them stick together
- Known as primary tumours
- Nucleus has a relatively normal appearance
- Cells are very well specialised
- Tumours surrounded by a capsule of dense tissue to remain a compact structure
- Less likely to be life threatening
- Localised effects on the body
- Can usually be removed by surgery alone
- Rarely reoccur
Malignant
A type of tumor that:
- Has uncontrolled growth. Cells have no adhesion molecules so can spread throughout the body in metastasis
- Forms secondary tumours
- Nucleus is larger and darker from abundance of DNA
- Cells become de-differentiated
- No capsule so produce finger-like projections into the surrounding tissue
- More likely to be life threatening (abnormal tissue replaces normal tissue)
- Systematic effects on the body (weight loss/fatigue)
- Removal often includes chemo/radio therapy along with surgery
- Frequently reoccur
Metastasis
A process where a tumour spreads to numerous parts of the body. Often in secondary tumours
Smoking
A factor that increases the risk of cancer. Doing this regularly will increase the volume of tar in the lungs, which is carcinogenic. Other risks include that a product of tar BP will bind to genes and increase the likelihood of mutation [Show Less]