Health and Disease Flashcards
What is cancer caused by?
An uncontrolled division of abnormal cells in a part of the body.
What is metastasis?
The development of secondary malignant growths from the primary site of cancer.
What is the difference between malignant growths and benign growths?
Malignant growths are tumours caused by cancerous cells dividing uncontrollably. They could spread to other parts of the body and form metastatic growths.
Benign growths are non-cancerous growths. They will not spread to other parts of the body or invade nearby tissue.
What is gene therapy?
The placement of fultl-functioning alleles into a cell which contains a faulty allele for the same gene.
What are some problems with gene therapy?
- The healthy allele may not reach all the target cells, so some cells will go untreated.
- The healthy allele may join with chromosomes in random places, meaning it will not function correctly.
- Treated cells may be naturally replaced over time by the patient’s own unhealthy cells, so treatment is only temporary.
Outline the process of gene therapy.
- A healthy allele (coding for the same thing as the unhealthy allele in the patient) is cut out of a healthy person using a restriction enzyme.
- The DNA is amplified, producing multiple copies of the healthy allele.
- A virus is modified to carry the healthy allele within its genetic code. It acts as a vector.
- The virus is injected into the patient with the genetic disorder and infects their cells.
- The virus then inserts the healthy copies of the allele into the patient’s cells with the faulty allele.
What are some risk factors for cancer?
- Genetic inheritance
- Exposure to ionising radiation
- Mutations
What are 3 things cells do while in interphase?
- Normal cell functions
- DNA replication
- Cell growth
What is meant by “mitotically active” cells?
Cells that regularly undergo mitosis, e.g. root hair cells or cancer cells
What is a tumour?
A swelling of a body part caused by abnormal growth of tissue.
What hormones are cancer cells able to produce? Why is this dangerous?
Growth hormone. This means that malignant tumours are able to divert blood vessels to the cancerous ces to give ethene more nutrients to grow. It also prevents healthy cells from gaining those nutrients in the process.
Outline how to grow bacterial colonies in a lab.
- Sterilise every surface and petri dish to kill any unwanted microorganisms.
- Bacteria is spread across the agar plate using an inoculating loop; before this happens the inoculating loop must be dipped in ethanol and flamed with a Bunsen Burner to kill any unwanted microorganisms.
- Spread the bacteria across the agar plate in long strips with the sterilised inoculating loop.
- Seal the agar plate with adhesive tape - but not completely. The bacteria must be kept in aerobic conditions, as anaerobic conditions can prompt the growth of harmful pathogens.
- Place the agar plate in the incubator upside-down to prevent moisture from dripping down onto the bacterial colonies and disturbing them.
- Incubate at 25°C. This temperature usually prevents any harmful bacteria from forming.
- After incubating overnight, remove the agar plate from the incubator and view the colonies formed.
Why must the agar plate be kept upside down when incubating?
It prevents moisture from dripping down onto the bacterial colonies and disturbing them.
What steps must be taken to ensure nothing contaminates the bacterial colonies in aseptic technique?
- All surfaces must be sprayed with disinfectant to kill unwanted microorganisms.
- Inoculating loop must be dipped in ethanol and flamed with a Bunsen Burner to kill unwanted microorganisms.
- The lid of the agar plate must only be partially sealed, as harmful pathogens form in anaerobic conditions.
