Cellular death Flashcards
What happens when a gene is active and follow the process on from there?
RNA is transcribed. The mRNA then exits the nucleus to be translated on cytoplasmic ribosome. This forms proteins for structure and function.
Can you give an overview of how a protein is made and the name the processes that occur?
Transcription then translation
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Can genetic disorders be inheritable?
Yes, this is known as germ line. Genetic disorders that are not inheritable are known as somatic.
What are the three main ways that single gene disorders can occur?
- Missense mutation- When there is a different nucleotide produced resulting in a different protein.
- Silent mutation- Different nucleotide produced however coding for the same protein that was going to be produced
- Nonsense mutation- Different nucleotide producing a stop codon.
What is a frameshift mutation?
Where there is an addition or deletion of a number of bases that would result in a frame shift, which can result in different frame sequence downstream from the amino acid.
What can single gene disorders result in and the main one?
1. Enzyme defects
- Membrane R and transport systems
- Structure, function or quality of non-enzymes
- Unusual drug reactions
How does enzyme defects occur in single gene disorders?
- Accumulation of substrate and or/intermediate substrates that may be toxic in high concentration (lysosomal storage disease)
- Metabolic block (glycogen storage diseases)
- Failure to inactivate damaging substrates (anti-trypsin deficiency).
What other types of disorders can occur other than gene?
Chromosomal disorders and single gene disorders of the germ line.
- Chromosomal most often errors in cell division. (Downs)
- Germ lines- X linked, autosomal dominant, Huntingdons disease etc. Turners syndrome in mares, X monosomy, small uterus and fail to cycle as a result.
What is cellular ageing?
Cellular ageing is the result of a progressive decline in cellular function and viability caused by genetic abnormalities and the accumulation of cellular and molecular damage due to the effects of exposure to exogenous influences.
Can you show cellular ageing in a diagram?
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How can cell death occur?
Necrosis: A degradative reaction occurring after the death of a cell.
Apoptosis: A gene-directed programme of cell death- can be manipulated.
Can you show some features that illustrate necrosis in a cell?
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What are the two main changes in necrosis?
Cytoplasmic change and nuclear change
How does H and E show this and why?
- Eosin is negative and the protein tissues, collagen, and mitchondria are positive resulting in a more eosinophilic response.
- Haematoxylin is positive and the nucleic acids (DNA & RNA) are negative resulting in a more haematoxylin response when nuclear change occurs.
What are the features of nuclear change and what do they mean?
Pyknosis- shrinking of the nucleus to a more concentric form.
Karyorrhexis- fragmenting of the nucleus.
Karyolysis- Complete dissolution of the chromatin from the nucleus.