Mitosis And Cell Cycle Flashcards
(24 cards)
Somatic Cells
Body Cells
Diploid (2n): 2 of each chromosome
Divide by mitosis
Humans 2n=46
Gametes
Sex Cells (sperm/egg)
Haploid (n): 1 of each type of chromosome
Divide by meiosis
Humans: n=23
Interphase: G1
Cell grows
Interphase: S phase
Duplicates chromosomes
Interphase: G2
Prepares for cell division
Order of mitosis
Interphase—> prophase —> metaphase—> Anaphase—> telophase
Prophase
Chromosomes condense and become visible
Nucleoli disappear
Prometaphase
Nuclear envelope fragments
Each chromatid had kinetochore
Micro tubules attach to the kinetochores
Kinetochore
Specialized protein structure at the centromere
Centrioles
Organized mitotic spindles to pill chromosomes to opposite ends of cell
Centromere
Center, where two chromosomes come together
Metaphase
Chromosomes convene at the metaphase plate
Anaphase
Shortest stage
As the microtubules shorten, chromosomes are pulled to opposite ends of the cell
Telophase
-A nucleus forms in each daughter cell
-two nuclear envelopes form around the separated chromosomes
Cytokinesis
Cleavage furrow forms, pinching the cel into 2
Cytokinesis in plants vs animals
Animals: cleavage furrow
Plants: cell plate
Binary Fission
Asexual reproduction of single celled eukaryotes and prokaryotes
Cells grows to double its size, then divides into 2 cells
Check points
Control systems
Stop and go signals to regulate the cell cycle
Protein kinases
Enzymes that activate or inactivate proteins by phosphorylation them
Cyclin dependent kinases (CDK)
Protein kinases that drive the cell cycle. Always present, but often inactive.
The binding of cyclins activate CDKS
MPF
Cell passage past G2 and into M
External Regulatory Factors
Environmental factors that regulates if a cell divides. Problems in these result in tumors.
Density Dependent Inhibition
Crowded cells stop dividing.
Because cells have receptors on the membrane, they only divide when they sense there is space.
Anchorage dependence
Cells must be attached t a substratum to divide
