Honor Bio 10.1 Flashcards
What are the stages of the cell cycle in order?
G1, S, G2, M, G0
What happens during the G1 phase?
The cell grows and carries out normal functions while preparing for DNA replication.
What happens during the S phase?
DNA replication occurs
What happens during the G2 phase?
The cell continues to grow and prepares for mitosis.
What happens during the M phase?
Mitosis occurs, leading to cell division.
What is the G0 phase?
A resting phase where cells exit the cycle and do not divide.
What is interphase?
The collective name for G1, S, and G2 phases, where the cell prepares for division.
What are examples of stimulatory proteins in the cell cycle?
Growth factors, cyclins, CDKs
What do growth factors do?
Signal cells to divide
What do cyclins and CDKs do?
Regulate cell cycle progression by forming cyclin-CDK complexes.
What is p53, and what does it do?
A tumor suppressor protein that halts the cell cycle if DNA damage is detected.
What is a proto-oncogene?
A normal gene that promotes cell division but can mutate into an oncogene.
What is a tumor suppressor gene?
A gene that prevents uncontrolled cell growth by regulating the cell cycle.
What is an example of a proto-oncogene?
RAS, MYC
What is an example of a tumor suppressor gene?
p53, RB
Compare and contrast proto-oncogenes and tumor suppressor genes.
Proto-oncogenes stimulate cell division, while tumor suppressor genes inhibit it. Both regulate the cell cycle, but mutations in proto-oncogenes lead to overactivation (cancer), whereas mutations in tumor suppressors lead to loss of control (cancer).
Compare the roles of stimulatory and inhibitory proteins in the cell cycle.
Stimulatory proteins (cyclins, CDKs, growth factors) promote progression through the cycle, while inhibitory proteins (p53, RB) prevent uncontrolled growth. Both are necessary for balanced cell division.
Why does a mutation in an oncogene lead to cancer?
Oncogenes are mutated proto-oncogenes that continuously signal the cell to divide, even without external signals, leading to uncontrolled growth.
Why does a mutation in a tumor suppressor gene lead to cancer?
Tumor suppressor genes normally prevent excessive cell division. When they are mutated and lose function, cells divide uncontrollably.
Why do mutations in both oncogenes and tumor suppressor genes often occur together in cancer cells?
Cancer typically arises from multiple mutations; activating oncogenes causes excessive growth, while inactivating tumor suppressor genes removes the brakes on cell division.
