IB Biology HL D1.2.18 Hl Polypeptide Modification Questions

Explore how inactive precursor polypeptides are cleaved or activated into functional proteins while preventing autodigestion in IB Biology HL D1.2.18.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Explain that precursor polypeptides can be cleaved to produce active proteins, using proinsulin cleavage to form insulin.
  • Explain that pepsinogen and trypsinogen are inactive protease precursors activated in their digestive locations.
  • Relate precursor inactivation before secretion to prevention of autodigestion, then identify the activation condition or enzyme.

IB Biology HL D1.2.18 Hl Polypeptide Modification Questions question 1

[Maximum number: 2]

Type I diabetes is a leading cause of death in advanced countries and is associated with various severe or fatal complications, including blindness, kidney failure, heart disease, stroke, neuropathy, and amputations. Embryonic stem cells are considered to be a powerful tool in the treatment of diabetes.

In a study, embryonic stem cells were grown in culture and tested for insulin mRNA. A drug was injected into two groups of healthy mice in order to simulate type I diabetes 15 days prior to the transplant of embryonic stem cells. The mice in the transplant group received embryonic stem cells that produce insulin mRNA. The control group did not receive the transplant. The graph shows the blood glucose concentration in both groups.

Figure for Question IB Biology HL D1.2.18 Hl Polypeptide Modification Questions question 1 — IB Biology HL

Insulin is produced by cutting C -peptide from the precursor molecule proinsulin. Suggest why group 1 has a greater level of C-peptide than group 2.

All question bank results loaded