cell cycles and divisions Flashcards
evelyn jensen (14 cards)
what is binary fission?
prokaryotic replication of the entire single celled organism
what are cell division signals?
external factor such as nutrient concentration n environmental conditions
-> optimum conditions = more fission
what is the ori part of a chromosome?
“origin” where replication starts
what is the ter region of a chromosome?
“terminus” where replication ends
what is DNA segregation?
when replication is complete, ori regions move to opposite ends of the cell -> segregates daughter chromosomes
what occurs in the G1 phase?
- chromosomes are single
-> unreplicated - duration variable, minutes to years
- ends at G1-to-S transition
-> commitment made to DNA replication n cell division
what occurs during the S phase?
- DNA replicates
- sister chromatids remain together till mitosis
what occur during the G2 phase
- cell prepares for mitosis
-> synthesizes the structures that move chromatids
what occurs during the M phase?
mitosis n cytokinesis
what is mitosis?
production of 2 nuclei that are genetically identical to each other and nucleus of cell that entered cell cycle in G1
what are the 5 phases of mitosis?
- prophase
- prometaphase
- metaphase
- anaphase
- telophase
what are examples of chromosome structural rearrangements?
intrachromosomal: inversions, duplications, terminal and interstitial deletions
interchromosomal: translocation, dicentric and acentric fragments
what are advantages of being diploid?
- can repair DNA damage using other chromosome copy
- recessive mutations can be masked
- more rapid evolution possible
- greater diversity of immune cells
what are advantages of being haploid?
- more efficient cell cycle -> faster division
- more rapid growth
- survival in resource poor conditions
