Reproduction Flashcards
(4 cards)
Cell Division
Cell doubles organelles and cytoplasm
Replicates DNA and divides
Unicellular: reproduction
Multicellular: growth, development, replacement
Mitosis
division and distrubition to 2 daughter cells- each recieve exact copy of orginal genome
nuclear division(karyokinesis) and cellular division(cytokenisis)
INTERPHASE: (90% of cell division)
chromosomes replicated- growth period
phases: G1: growth peroid
S Phase: DNA synthesizes
G2: cell prepares to divide, grows/synthesizes proteins
M phase: cell division (MITOSIS) –> 2 daughter cells
PROPHASE: chromosome condenses, centrioles pair up and seperate. spindle apparatus forms, nuclear membrane dissolves
METAPHASE; chromosomes align at centromere
ANAPHASE: centromeres split; sister chromatids pull to oposite polls
TELOPHASE: spindle apparatus dissapears; nuclear membrane forms around new chromosomes; each nucleus contains diplid number of chromosomes
CYTOKENISES: cell splits into 2 daughter cells
*plant cells lack centrioles- spindle apparatus synthesized by microtubule organizing center. and no cleveage furrow (cell plate)
Meiosis
production of sex cells - haploid # (1/2 number of chromosomes)
2 divisions of primary sex cells- 4 haplid cells (gametes)
INTERPHASE: parent cell’s choromosomes replicate w/ 2N sister chromatids
PROPHASE 1: chromatin condenses, spindle apparatus forms,
*synapsis: homologs intertwine
tetrad: pair of homologs w/ 4 chromatids
crossing over: excahgne of DNA on chiasmata*
METAPHASE 1: tetrads allign
ANAPHASE 1: homologs seperate (dijunction), random distribution of DNA
TELOPHASE1: nuclear membrane forms, cell splits
MEIOSIS II = MITOSIS… except new cells have haploid #
Asexual Reproduction (Animals)
- production of offspring w.out fertilization
- single division of parent cell
Fission: DNA replication
budding: replication of nucleus- unequal cytokenisis - small daugter cell grows to adult size (yeast)
regeneration: regrowth of lost/injured body part (mitosis)
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