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2.7 Cancer 🦀


Introduction to cancer

Cancer is a core JC1 topic in H2 BIO A levels. This topic covers the genetic basis of the disease where accumulations of mutations on cancer-related genes lead to transformation from a normal to a cancer cell. As such how this will impact the treatment and management of the cancer.

This is an extension from a previous topic of mutation and genetic diseases and will be helpful as a primer to the topic molecular techniques.

Materials for cancer

YouTube video
  • 👆🏻 an explanation of cancer development and potential early detection.
YouTube video
  • 👆🏻 a general overview of cancer.
YouTube video

Phrasing errors

  • p53 protein is an example of tumor suppressor gene.
  • Proto-oncogenes encode for proteins that control cell division.
  • Lengthening of telomeres is due to the high activity of telomerase.
  • p53 binds to certain part of DNA to inhibit the transcriptional genes that encode proteins that stimulate cell division. It binds to damaged part of DNA and repair damage.

Exam tips

  • When referencing RAS or p53, detail their primary functions before stating the effects and consequences of mutation.
  • When talking about angiogenesis, note that this applies to solid tumors and not to tumors that exist in the blood vessels.
  • Telomeres are lost after each cell cycle due to the end replication problem and they are replaced by the telomerase so that the telomere numbers are maintained. The enzyme does not prevent telomere lost.

BYang’s tough question bank

  • There are some organ systems where cancers rarely occur in stark contrast to circulatory system cancers such as T cell acute lymphoblastic leukemia. One such example is the nervous system. The underlying reason is because neurons are considered to be permanent cells that do not undergo cell division. Suggest how can cancer can arise in the nervous system despite this fact. [3m. Created 210926] (Hint ⌲ it is unlikely that one or few mutations were to occur to cause neurons to re-enter into cell cycle since typical cell cycles require exquisite control of numerous proto-oncogenes through numerous phases and these genes will likely be methylated with permanent silencing)
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