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Cancer Investigation Lessons

Cancer Investigation Lessons

Lesson 1: Who gets cancer and why?

  • Cancer is more common in:

    • Taller people

    • Older people

    • Females

    • People who live on the East Coast of the US

    • Individuals with less p53 (observed in animals)

Lesson 2: What is cancer?

  • Cancer is a disease of unregulated cell growth.

  • Tumors can form when too many cells grow in a specific area.

  • Cancer cells look very different from non-cancer cells (irregular shape, no spacing between cells).

Lesson 3: How do non-cancer cells become cancer cells?

  • The cell cycle is broken into four phases: G1, S, G2, and M.

    • G1 is growth.

    • S is DNA replication.

    • G2 is growth.

    • M is cell division.

  • Cell division leads to a cell split in half, producing genetically identical cells.

  • p53 is a protein that regulates the cell cycle.

    • If cells don’t have the necessary nutrients or are damaged, p53 prevents the cell from proceeding through cell division.

    • If p53 doesn’t function properly, cancer can form.

Lesson 4: Why are some kinds of cancer more common than others in taller and older people?

  • Taller people have more cells, leading to more cell divisions, which increases the risk of DNA mutations that can lead to cancer.

  • Older people's cells have undergone the cell cycle more often, increasing the chance of DNA mutations and, therefore, a higher cancer risk.

Lesson 5: How do cells end up with differences in their chromosomes and what is the role of p53 in preventing the differences?

  • Genes are made up of sequences of DNA.

  • Chromosomes contain thousands of genes.

  • DNA mutations can occur during DNA replication.

  • p53 can correct those mutations (changes in base pairs) if it is working properly.

  • Non-cancer cells will have identical chromosomes, but cancer cells can have differences.

Lesson 6: How do we make p53, and why is it sometimes different?

  • DNA codes for proteins.

  • Proteins are made through the process of transcription (DNA to RNA) and translation (RNA to protein).

  • Mutations in DNA can lead to changes in proteins.

    • The amino acid sequences may be incorrect, leading to a misshapen protein or a protein that is not made at all.

Lesson 7: What is the genetic basis of cancer?

  • This lesson revisits the driving question board and the model.

Lesson 8: Why do some cancers appear to run in families?

  • Pedigrees can be used to look at familial inheritance of a specific gene or trait.

  • Punnett squares can be used to determine the probability of inheriting a specific genotype.

  • Li-Fraumeni is a syndrome that causes one p53 allele to be missing, leading to a decrease in the amount of p53 protein made, resulting in a higher cancer risk.

  • Crossing over is a situation during meiosis (prophase I) where alleles between homologous chromosomes (mom and dad) can switch, leading to new allele combinations.

Lesson 9: How do genes interact with the environment to affect who gets cancer?

  • UV radiation can cause mutations in DNA, which can lead to changes in protein structure.

  • Melanin is a protein that protects skin cells from UV radiation.

    • Individuals with higher melanin levels (darker skin tones) have more protection from UV radiation, leading to less chance of mutations that lead to cancer.