Unit 5: Cell Division and Cancer Flashcards
Definition of Mitosis
The division of the nucleus and DNA into two daughter cells
Cytokinesis
The division of the cytoplasm and organelles into two daughter cells
How do plant cells divide?
- the vesticles fuse together to create a disc-shaped structure called the “cell plate” –> made up of Golgi bodies
- the cell plate extends until it fuses with the sides of the parent cell
How do animal cells divide?
Contractile proteins form rings at the equator of the cell. They pull the membrane inwards to form a cleavage furrow
–> it pinches until the cell is split into two
- the nucleus, ER, GB disassemble and then are reformed during cytokinesis
Budding
asymmetric division used by most yeast to reproduce asexually
Oogenesis
is the production of an egg (ovum) cell
*one large egg, 3 small polar bodies
What are processes that require cell proliferation
1) organism growth
2) cell replacement
3) tissue repair
What happens in the G1 phase?
- the cell starts to get bigger, tries to double, replicating organelles for 2nd cell
What happens during S phase?
DNA is replicated, organelles are doubled, and new proteins are made
What happens during G2?
Final prep before cell divides
- replenishes energy by obtaining nutrients
- synthesizing proteins needed for division
- dismantling the cytoskeleton that is holding organelles in place
- growing size by increasing cytoplasm volume
How does cancer initiation begin?
1) Random errors in DNA replication
2) A mutagen which causes a mutation to the DNA
What is a mutagen?
Anything that changes genetic material
Proto-Oncogenes
Code for proteins that make the cell “go”
- such as the genes that code for cyclin proteins
Oncogene
- it becomes a cancer causing allele called an oncogene.
They are permanently activated even when they are not supposed to, causing the cell to grow out of control
- when activated it will cause cells to divide
Slamming the gas
Tumor Suppressor Genes
- Code for proteins that make the cell cycle “stop”
- slows down cell division
- repairs mistakes
Mutated Tumor Suppressor Gene
- Don’t work properly and cells can grow out of control
- Stops making the protein that inhibits cell division
Benign Tumor
The cells in the tumor adhere to each other and remain in a single mass
Doesn’t cause cancer
Malignant Tumor
The cells in the tumor can detach and invade neighboring tissues, lymph vessels, or blood vessels
Causes cancer
Cancer development stages
What is initiation?
- a normal cell is transformed into a cancerous cell as a result of mutations to genes that regulate the cell cycle
Cancer development stages
What is promotion?
- the initiated cell divides, giving rise to a large # of daughter cells containing the mutation(s)
–> these cells are the primary tumor
Cancer development stages
What is progression?
the cancerous cells often become aneuploid (having the wrong number of chromosomes) and invade surrounding tissues
Cancer development stages
What is metastasis?
- Cancer cells break away from where they first formed, travel through the blood of the lymph system to form new tumors in other parts of the body.
What is cancer?
- is the result of the accumulation of multiple mutations to a cell’s genetic code
Kinetochore
- Microtubule attachment for movement of chromosomes
-Protein complex that assembles at the centromere - each sister chromatid has its own
- links chromatids to microtubule
