Lecture 8 Cell cycle Oncogene TS Flashcards
Describe how cancer develops through various mechanisms.
Cancer develops through processes like unlimited growth, evasion of checkpoints, resistance to apoptosis, immortality, promotion of blood vessel growth, and overcoming density dependence.
What lifestyle factors can cause mutations leading to cancer?
Lifestyle factors like tobacco use, bodyweight, physical inactivity, diet choices, sunlight exposure, and certain occupations can contribute to mutations that lead to cancer.
Define Proto-oncogenes and their role in normal cell function.
Proto-oncogenes are genes that regulate cell division and differentiation under normal conditions.
How does a Proto-oncogene mutate into an oncogene, leading to cancer?
Proto-oncogenes can mutate through amplification, translocation, or point mutation, becoming permanently activated and causing uncontrolled cell division.
Describe the process of RAS mutation and its role in cancer development.
Mutation of RAS can lead to its permanent activation, causing uncontrolled cell proliferation and potentially contributing to cancer development.
Explain the function of tumour suppressor genes in the cell cycle.
Tumour suppressor genes encode proteins that regulate cell division, repair DNA errors, and induce apoptosis to prevent uncontrolled cell growth.
What is the significance of P53 in cancer development?
P53 is a crucial tumour suppressor gene frequently mutated in human cancers, leading to increased cell proliferation and reduced DNA repair mechanisms.
Describe the stages of the cell cycle, including G1, S, G2, M, and C.
The cell cycle consists of phases like G1 (growth), S (DNA synthesis), G2 (further growth), M (mitosis), and C (cytokinesis) for cell division and replication.
Describe positive regulation of the cell cycle.
Positive regulation involves promoting the progress of the cell to the next phase through Cyclins and Cyclin-dependent kinases (Cdk).
What are some examples of negative regulators of the cell cycle?
Negative regulators include Retinoblastoma, P53, and cyclin-dependent kinase inhibitor 1 or P21.
How is the cell cycle regulated by DEAB?
DEAB regulation involves cyclin D in G1, cyclin E in later G1 phase, cyclin A in S-phase, and cyclin B in G2 + M phase.
Define internal checkpoints in the cell cycle.
Internal checkpoints in the cell cycle include G1 (cell size, nutrients, growth factors, DNA damage), G2 (cell size, DNA damage), and M phase (chromosome attachment to spindle).
What are some positive cues for cell cycle progression?
Positive cues include the presence of growth factors, nutrient richness, space availability, Proto-Oncogenes ‘on’, and tumour suppressor genes ‘off’.
Describe the role of P53 in stalling the cell cycle.
P53, a tumor suppressor gene, is activated by damaged DNA, leading to upregulation of p21. P21 then inhibits CDK2/CyclinE and Cdc2/cyclinB, halting cell cycle progression and coordinating DNA repair or apoptosis.
