The Cell Cycle & Cancer Flashcards
What are the four phases of the Cell Cycle? Which of these are considered Interphase?
G1, S, G2, M
(G1, S, G2 are considered interphase)
What are the 2 phases within M phase? What are their functions?
Mitosis: division of the nucleus
Cytokinesis: division of the cytoplasm
What are the functions of the different phases within interphase?
G1: regular cellular activity
S: copying (synthesizing) DNA
G2: regular cellular activity + making proteins for replication
What are chromosomes? How many do humans have?
Single strand of DNA
Humans have 46 chromosomes
How are sister chromatids created?
During S phase chromosomes are copied and paired together to form sibling chromatids.
What is centromere? Where are they located?
The centromere is the site of separation during M phase. (it helps cells divide) Sibling chromatids are joined at the centromere.
T/F sibling chromatids are considered a chromosome?
True
What are telomeres?
Telomeres are repetitive ends of chromatids or chromosomes. Each time a cell replicates it loses a bit of telomere, once telomere is lost the cell fails to divide.
What are telomerase?
Telomerases are enzymes that add more telomeres to chromosomes so that the cells can continue to divide.
(present in stem cells)
Why do cells need to divide?
Growth
Repair
Replenishment
What sub-phases are within M phase?
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens in Prophase?
- Spindle fiber formation. (made of microtubules)
- Centromosomes (organizing proteins) move to opposite sides of the cell.
- Chromatin condenses.
What is chromatin made up of? What are there functions?
Histone: a protein that binds DNA
Nucleosome: DNA would twine around histone.
What happens in Prometaphase?
- The nuclear membrane breaks down
- Spindle fibers begin to attach to the centromere of chromosomes
- Kinetochore: proteins at centromere that attach microtubules - Tugging begins from each centrosome
What happens in Metaphase?
Chromosomes align along metaphase plate (in the middle of the cell)
What happens in Anaphase?
Chromatids are pulled apart towards opposite sides of the cell
What happens in Telophase?
Spindle fibers break down. Nuclear membrane reforms.
(2 separate nuclear membranes on each side of the cell)
How is cytokinesis different between animal and plant cells?
Animal cells: cleavage furrow
Contractile ring made of proteins ACTIN & MYOSIN
Plant cells: new cell plate formed
Vesicles deliver new cell wall material to the middle of the cell
What are some characteristics that define cancer?
- Uncontrolled growth
- Infinite number of divisions
- Less prone to apoptosis (a process to keep certain cells from taking over): Intention death of cells
- Genetically unstable: Different numbers of chromosomes or chromosomes being in incorrect places.
- Metastis: when cancer cells invade & colonize distant tissues
What are the different types of tumors, how are they different?
Benign: Uncontrolled cell division
Not invasive => cells don’t migrate and colonize
Malignant (cancer): Uncontrolled cell division
Migrate and invade
(Surgery alone can only cure benign tumors)
What are the different types of cancer genes and their functions?
Proto-oncogenes: Stimulate cell division
- Mutation can turn this gene into an oncogene (gene never turns off)
Tumor Suppressor Genes: Inhibit cell division
- Mutation can turn this gene off
Genome Stability Genes: DNA repair genes
- Mutation can turn this gene off
T/F You only need one mutation to create cancer?
False, you need multiple mutations to create cancer.
