exam 2 Flashcards
(147 cards)
what are the general phases of the cell cycle
- interphase
2. M phase
interphase
- normal cell activity
- majority of cell’s lifetime
- prep for cell division
- DNA is loose chromatin
what are the three stages in interphase?
- G1 aka gap 1
- S aka synthesis
- G2 aka Gap 2
G1
- cell growth
- protein synthesis
- water intake
S stage
- DNA replication
G2
- organelle replication
- chromosomes begin to condense into tight chromatids
M phase
division phase
what two events divide the entirety of the cell content in M phase
- mitosis
2. cytokinesis
what is mitosis
Nuclear division
what is Cytokinesis
cytoplasmic division
what happens during mitosis
- plant growth
- replacement
what are the 4 phases in the M phase
- Prophase
- metaphase
- anaphase
- telophase
Prophase (mitosis)
- chromosomes finish condensing
- sister chromatids are connected at centromere
- nuclear envelope fragments and dissociates
- spindle fibers attach at centromeres
metaphase (mitosis)
- chromosomes line up at spindle equator
anaphase (mitosis)
- sister chromatids separate
- pulled to opposite ends of the cell
telophase (mitosis)
- nuclear envelope reforms
- chromosomes decondense (return to chromatin)
- cell plate begins to form
when does cytokinesis begin?
- late anaphase/telophase
What occurs during cytokinesis
- telophase golgi vesicles create cell plate → becomes cell wall
- small bits of ER between vesicles → plasmodesmata
meiosis
- aka reduction division
- only occurs in specific cells of sporophyte
what happens during meiosis
- Start: parent cell with 2 sets of chromosomes
- End: 4 daughter unique daughter cells with half chromosome number of parent cell
zygote
- egg+ sperm
what are the 4 stages in meiosis I?
- Prophase I
- metaphase I
- anaphase I
- telophase I
Prophase I
- chromosomes condense
- synapsis (pairing of homologous chromosomes)
- nuclear envelope dissociates
- crossing over
Metaphase I
- homologous chromosomes line up at spindle equator (independent assortment)