CELL CYCLE AND CELL DIVISION Flashcards
(14 cards)
What 3 phases make up interphase
G1
2
G2
What 4 happens in G1 phase
Organelle replication
Growth in cell size
Protein synthesis
Respiration
What happens at S phase
DNA replication
What happens at G2 phase
Organelles replicate
Protein synthesis
Respiration
Cell size increase
Describe the 4 things that happen in prophase
- DNA supercoil and condenses
- Nuclear envelope disintegrates
- Centrioles divide and move to opposite poles
- Spindle apparatus is formed from spindle fibres and centrioles
Describe the 2 things that happen in metaphase
- Spindle fibres attach onto centromeres of chromosomes
- Chromosomes are pulled to the equator to the cell and line up
What 2 things happen during anaphase
- centromeres split
- chromtids move to seperate poles now called chromosomes
What happens at telophase
Nucleus reappears and chromosomes become invisible
Difference between plant and animal centrioles
Plants don’t have them
Animals use them in mitosis
Difference between plant and animal cytokinesis
Plant - cell plate forms from inside
Animal - membrane folds inside
Difference between plant and animal spindle fibres
Animal - disintegrates in telophase
Plant - stays for cell wall formation
Define crossing over in meiosis
Exchange dna between chromatids on homologous chromosomes in Prophase1
What does crossing over allow
Exchange in alleles, variation
Define independent assortment
Chromosome are randomly organised on either side of the equator