Chapter 5 (Part 2) Flashcards
the cell cycle is controlled by…
checkpoints
what is apoptosis?
programmed cell death
mutations are either _______ or ________
repaired or undergo apoptosis
3 principal checkpoints control the cycle in eukaryotes
G1, G2, and M checkpoints
G1 checkpoint
- Determines whether the cell should enter S phase for DNA replication and cell division
- Some cells never pass this point and are said to be in G0
G2 checkpoint
- Determine if mutations occurred in DNA replication
- Repair enzymes available to correct mutations.
M checkpoint
Occurs during metaphase and determines whether mitosis should proceed. Triggers exit from M phase
and entry into G1 phase
Cancer results from…
mutated cells growing unregulated by growth checkpoints
oncology
the study of cancer
the result of cancer is a growing cluster of cells is called a
tumour
Benign tumours
surrounded by a smooth layer of cells and do not spread to other areas
Malignant tumours
have irregular cell borders, are not encapsulated, and are invasive. cells leave and spread to other areas forming new tumours
new tumours are called
metastases ( or secondary tumours)
what are the two general classes of genes that are usually involved in cancer?
Proto-oncogenes, tumour-suppressor genes
Proto-oncogenes
*These genes encode proteins that stimulate the cell cycle.
*Mutations to these genes can cause cells to divide excessively.
*When mutated, they are called oncogenes.