Cell cycle Flashcards
What is oriC
Single origin of replication
How does replication occur in prokaryote
Has single circular chromosomes
Two DNA strands
Replication forks move bidirectionally to terminus - away from oriC in bigger loops
What triggers chromosome replication
Cell growth
Cells can sense when cell DNA:mass very low - new chromosome replication triggered
What happens when chromosome replication has occured
DNA doubles
Cell must double in size before divides again
How long does the replication of a chromosome take, what is this period called
40 mins
C period
What occurs after chromosome replication, how long it takes and the name of this period
20 minute preparation to divide
D period
Why may a cell take over 60 minutes to double in size
Resting period B will occur between divisions and next DNA synthesis
Why does E. coli have a generation time of less than 60 minutes
Cell cycles overlap
What are the two goals that eukaryotes must alternate between for controlled cell cycle
Growth - copying cellular components (interphase)
Division - dividing cell so components distributed evenly to daughter cells (mitosis)
What does the cell check before divisions
All chromosomes at cell centre
Centromeres attached to microtubules
What happens if some chromosomes not attached by microtubules
Chromosomes may not separate as need to - one daughter cell may get an extra chromosome
Cytokinesis in animal cells
Cell membrane pulls inward from edges and pinches off
Cytokinesis in plant cells
Phragmoplast grows out from cell centre, form new cell membrane, cell wall - combine with existing cell wall
Where is the DNA replication check point
Between G2 and M
Where is the spindle check point
Between M and G1
