UNIT 6: CELL DIVISION AND REPRODUCTION
The Cell Cycle (Ch. 9)
● Phases of the cell cycle, and what occurs in each phase
- G1: cellular content is duplicated (excluding chromosomes); majority of cells in this stage have
the same amount of DNA
- S: Each of the chromosomes is duplicated by the cell
- G2: cell double checks the duplicated chromosomes for error, making any needed repair:
- Contd G2: nuclear envelope is still there with genetic material in a mess
- G0 = cell cycle arrest
● The structure of the chromosome - where are the chromatids, the centromere, etc.
Chromosome ⇒ group of supercoils ⇒ super coils are consists of coils of bunched nucelosomes
⇒ bunched nucelosomes are histones wrapped by DNA
● Phases of mitosis and what occurs in each phase
Mitosis:
- Prophase:Centrosomes with centriole pairs start creating early mitosis spindle; chromosomes
become visible and they consist of two sister chromatids
- Prometaphase:Nuclear envelope breaks (there are still fragments), spindles attach to kinetochore
- Metaphase: chromosomes line up in the middle of the cell and centrosomes are at opposite ends of
the cell ⇒ spindles attach to the kinetochores
- Anaphase:spindles separate the daughter chromosomes to opposite poles of the cell
- Telophase:A nuclear envelope starts forming around the daughter chromosomes
- Cytokinesis: cytoplasm splits and the nuclear envelope forms
● The general mechanism of binary fission, and what organisms it occurs in
- binary fission: occurs in prokaryotes: duplication of chromosome and separation of copies
(chromosomes are just messy coiled chromosomes) ⇒ elongation of the cell and movement of copies
⇒ division in two two daughter cells each with a messy knot of chromosomes
● Relationship between cancer cells and mitosis
- cancer cells replicate at high speeds allowing the cancer to spread extremely fast ⇒ the
checkpoints aren’t working ⇒ and cells with disease or mutations are being allowed to spread
- Cells never die in cancer
● The ability to recognize and predict patterns in pictures of mitosis
● How cytokinesis differs in animals vs. plant cells
- Cytokinesis in animals: regular cytokinesis ⇒ cytoplasm splits and separate to make two cells
with their own membrane
- Cytokinesis in plants: vesicles with cell wall components fuse, forming a new cell wall during
telophase and cytokinesis
● Checkpoints of the cell cycle
- After G1: check if there are enough nutrients and whether the cell grew properly
- After G2: check if there are mutations in the DNA and whether it replicated property
- After mitosis: check if the chromosomes attached the spindles and if the chromatids separated
evenly
● The fate of specialized cells and non-dividing cells in regards to the cell cycle
- Cells that never/rarely divide remain in G0 permanently ( can enter G0 if there isn’t enough
nutrients, unavailability of certain organelles, contact inhibition (defense in case of cancer)
Meiosis and Sexual Life Cycles (Ch. 10)
● Asexual vs. sexual reproduction
- Asexual reproduction: binary fission, budding, fragmentation
- Binary fission: bacteria/prokaryote splits into 2
- fragmentation/regeneration: planaria splits into pieces and regenerates parts of its body b/c of
stem cells
- Parthogenesis: doesn’t need a male, mostly occurs in female birds and reptiles (when females can
give birth to eggs without a male)
- Budding: growing off of one organism (ex: coral)
● Relationship between homologous chromosomes, sister chromosomes, and their locations on a
karyotype
The Cell Cycle (Ch. 9)
● Phases of the cell cycle, and what occurs in each phase
- G1: cellular content is duplicated (excluding chromosomes); majority of cells in this stage have
the same amount of DNA
- S: Each of the chromosomes is duplicated by the cell
- G2: cell double checks the duplicated chromosomes for error, making any needed repair:
- Contd G2: nuclear envelope is still there with genetic material in a mess
- G0 = cell cycle arrest
● The structure of the chromosome - where are the chromatids, the centromere, etc.
Chromosome ⇒ group of supercoils ⇒ super coils are consists of coils of bunched nucelosomes
⇒ bunched nucelosomes are histones wrapped by DNA
● Phases of mitosis and what occurs in each phase
Mitosis:
- Prophase:Centrosomes with centriole pairs start creating early mitosis spindle; chromosomes
become visible and they consist of two sister chromatids
- Prometaphase:Nuclear envelope breaks (there are still fragments), spindles attach to kinetochore
- Metaphase: chromosomes line up in the middle of the cell and centrosomes are at opposite ends of
the cell ⇒ spindles attach to the kinetochores
- Anaphase:spindles separate the daughter chromosomes to opposite poles of the cell
- Telophase:A nuclear envelope starts forming around the daughter chromosomes
- Cytokinesis: cytoplasm splits and the nuclear envelope forms
● The general mechanism of binary fission, and what organisms it occurs in
- binary fission: occurs in prokaryotes: duplication of chromosome and separation of copies
(chromosomes are just messy coiled chromosomes) ⇒ elongation of the cell and movement of copies
⇒ division in two two daughter cells each with a messy knot of chromosomes
● Relationship between cancer cells and mitosis
- cancer cells replicate at high speeds allowing the cancer to spread extremely fast ⇒ the
checkpoints aren’t working ⇒ and cells with disease or mutations are being allowed to spread
- Cells never die in cancer
● The ability to recognize and predict patterns in pictures of mitosis
● How cytokinesis differs in animals vs. plant cells
- Cytokinesis in animals: regular cytokinesis ⇒ cytoplasm splits and separate to make two cells
with their own membrane
- Cytokinesis in plants: vesicles with cell wall components fuse, forming a new cell wall during
telophase and cytokinesis
● Checkpoints of the cell cycle
- After G1: check if there are enough nutrients and whether the cell grew properly
- After G2: check if there are mutations in the DNA and whether it replicated property
- After mitosis: check if the chromosomes attached the spindles and if the chromatids separated
evenly
● The fate of specialized cells and non-dividing cells in regards to the cell cycle
- Cells that never/rarely divide remain in G0 permanently ( can enter G0 if there isn’t enough
nutrients, unavailability of certain organelles, contact inhibition (defense in case of cancer)
Meiosis and Sexual Life Cycles (Ch. 10)
● Asexual vs. sexual reproduction
- Asexual reproduction: binary fission, budding, fragmentation
- Binary fission: bacteria/prokaryote splits into 2
- fragmentation/regeneration: planaria splits into pieces and regenerates parts of its body b/c of
stem cells
- Parthogenesis: doesn’t need a male, mostly occurs in female birds and reptiles (when females can
give birth to eggs without a male)
- Budding: growing off of one organism (ex: coral)
● Relationship between homologous chromosomes, sister chromosomes, and their locations on a
karyotype
