Cell Division Flashcards
What is the purpose of cell division in multicellular and unicellular organisms? (2 life processes)
Multicellular: growth, make new cells to replace dead or damaged cells.
Unicellular: asexual reproduction
What is the mode of cell division in prokaryotic and eukaryotic cells?
Prokaryotic: binary fission
Eukaryotic: mitosis
What is semi-conservative replication in binary fission?
Splits DNA into 2 strands, each one creates a complimentary strand, resulting in 2 complete sets of DNA
What are the 3 steps of binary fission?
- Semi-conservative replication of DNA into 2 chromosomes.
- Cell elongates, each chromosome is pulled to the poles at either end of the cell.
- Cytokinesis: clevage forms, the two daughter cells become independent from each other
What are the two process that must occur during interphase for mitosis to occur?
Growth of the cell and replication of DNA
How do cells prepare to divide during interphase? (4 things)
ATP accumulates.
Organelles are made.
DNA replicates.
Cells grow in volume.
What occurs in prophase?
Cells prepare for division: chromatin condenses into visible chromosomes, nucleus starts to break down (nuclear membrane and nucleoli disappear), spindle fibres form and attach to chromosomes
What occurs in metaphase?
Chromosomes are fully condensed, and line up along the equator of the cell
What occurs in anaphase?
Spindle fibres contract and pull apart chromosomes to opposite ends of the cell (chromosomes become single-stranded as one chromatid moves to each daughter cell)
What occurs in telophase?
Two nuclei form, each with an identical set of DNA
What occurs in cytokinesis?
Division of the cytoplasm (cleavage forms), chromosomes unwind into chromatin
How can you tell when the cells have settled back into interphase after cell division?
When you can no longer see the chromatids in the nucleus, the nucleus and its membrane is fully formed, and nucleoli may also be observed
