Eukaryotic Cell cycle 11/11/19
- Unicellular organisms = 1 cell = reproduction of entire organism
- Multicellular eukaryotes need cell division for growth, repair, development of fertilized egg
Cell cycle = series of events in eukaryotic cell – resulting in reproduction
Mostly – mitosis = 2 daughter cells – with identical genetic info (DNA)
- Meiosis = nonidentical daughter cells – half the chromosomes as parent cell
Genome = cell’s DNA – DNA = chromosomes – (with histones and proteins) – complex = chromatin
- All human cells apart from gametes = somatic cells = 46 chromosomes
- Gametes = 23 chromosomes
Cell cycle = Interphase and mitotic phase
- Interphase = G1 (gap1 phase), S (synthesis), G2 (gap2 phase)
- Mitotic = prophase, metaphase, anaphase, telophase
- During interphase – cell grows – produces more proteins/organelles – e.g. – mitochondria
- Duplication of chromosomes = S phase
- G2 phase = formation of centrosomes- organize formation of mitotic spindle – each one = 2
centrioles
Prophase:
- Chromatin = tightly coiled
- Each duplic. chrom. = 2 sister chromatids – joined at centromere
- Mitotic spindle forms, with centrosomes and microtubules
- Centrosomes = move away from each other – as microtubules increase in length
Prometaphase:
(interlude between prophase and metaphase)
- Nuclear env. breaks down – allows microtubules to enter nuclear area
- Chromosomes = more condensed
- Some microtubules attach to centromere – moves chromosomes
- Cell = lengthened
Metaphase:
- Centrosomes = at opposite poles of cell
- Chromosomes = at metaphase plate – equator of cell
Anaphase:
- Shortest stage of mitosis
- Unicellular organisms = 1 cell = reproduction of entire organism
- Multicellular eukaryotes need cell division for growth, repair, development of fertilized egg
Cell cycle = series of events in eukaryotic cell – resulting in reproduction
Mostly – mitosis = 2 daughter cells – with identical genetic info (DNA)
- Meiosis = nonidentical daughter cells – half the chromosomes as parent cell
Genome = cell’s DNA – DNA = chromosomes – (with histones and proteins) – complex = chromatin
- All human cells apart from gametes = somatic cells = 46 chromosomes
- Gametes = 23 chromosomes
Cell cycle = Interphase and mitotic phase
- Interphase = G1 (gap1 phase), S (synthesis), G2 (gap2 phase)
- Mitotic = prophase, metaphase, anaphase, telophase
- During interphase – cell grows – produces more proteins/organelles – e.g. – mitochondria
- Duplication of chromosomes = S phase
- G2 phase = formation of centrosomes- organize formation of mitotic spindle – each one = 2
centrioles
Prophase:
- Chromatin = tightly coiled
- Each duplic. chrom. = 2 sister chromatids – joined at centromere
- Mitotic spindle forms, with centrosomes and microtubules
- Centrosomes = move away from each other – as microtubules increase in length
Prometaphase:
(interlude between prophase and metaphase)
- Nuclear env. breaks down – allows microtubules to enter nuclear area
- Chromosomes = more condensed
- Some microtubules attach to centromere – moves chromosomes
- Cell = lengthened
Metaphase:
- Centrosomes = at opposite poles of cell
- Chromosomes = at metaphase plate – equator of cell
Anaphase:
- Shortest stage of mitosis
