Mutation, Cancer, Epigenetics & Stem Cells

• Explain how a single base substitution causes a change in the structure of this polypeptide. Do not include details of transcription and translation in your answer?

  1. Change in primary structure/sequence of amino acids
  2. Change in hydrogen/ionic bonds
  3. Alters tertiary structure
• What is a substitution mutation?

  1. Replacement of a base by a different base (in DNA)
• The males in Group T had thymine at nucleotide position 16 519. The males in Group C had a mutation resulting in cytosine at nucleotide position 16 519. The control regions of Group T and Group C were the same length. Name the type of gene mutation that is most likely to have occurred at nucleotide position 16 519?

  1. Substitution
• Describe how alterations to tumour suppressor genes can lead to the development of tumours?

  1. Increased methylation of tumour suppressor genes
  2. Mutation in tumour suppressor genes
  3. Tumour suppressor genes are not transcribed/expressed
  4. Results in uncontrollable cell division
• Define what is meant by epigenetics?

  1. Heritable changes in gene function
  2. Without changes to the base sequence of DNA
• Explain how increased methylation could lead to cancer?

  1. Methyl groups added to both copies of a tumour suppressor gene
  2. The transcription of tumour suppressor genes is inhibited
  3. Leading to uncontrolled cell division
• Give one way in which benign tumours differ from malignant tumours?

  1. Cells of benign tumours cannot metastasise/spread to other parts of the body
• Explain how the methylation of tumour suppressor genes can lead to cancer?

  1. Methylation prevents transcription of gene
  2. Protein not produced that prevents cell division
  3. No control of mitosis
• Testosterone is a steroid hormone that belongs to a group of male sex hormones called androgens. Steroid hormones are hydrophobic. Explain why steroid hormones can rapidly enter a cell by passing through its cell-surface membrane?

  1. Lipid soluble
  2. Diffuse through phospholipid bilayer
• Define the term stem cell?

  1. A cell that can replicate indefinitely
  2. An undifferentiated cell
• Why is the use of embryonic stem cells more controversial than the use of adult stem cells?

  1. Adults can consent to the use of their stem cells
  2. Many believe that an embryo is a potential human and therefore has human rights
• Define the term induced pluripotent stem cell?

  1. An adult cell that can differentiate into many cell types
• Distinguish between totipotent, multipotent and pluripotent cells?

  1. Totipotent cells can differentiate into any type of cell in the body
  2. Multipotent cells can differentiate into a limited number of cell types
  3. Pluripotent cells can differentiate into almost any/most cell type