AP Bio // chromosomes and cell division
how does the cell pass the metaphase checkpoint
-all chromosomes are attached to the mitotic spindle
how does the cell pass the g2 cycle
-cell size is large enough -chromosomes have successfully been completed
how does the cell pass the g1 checkpoint
-large enough -sufficient nutrients are available -signals from other cells have been recieved
state two important changes that chromosomes must undergo before cell division can take place
DNA must be replicated, chromosomes must condense to avoid tangling
protein kinase (CDK)
MPF subunit that activates proteins by transferring a phosphate group from ATP to protein
cyclin
MPF subunit that activates the first subunit
m-phase promoting factor (MPF)
Substance found in mitotic cells that contains two subunits that when combined, causing proteins to activate
gamete
a mature haploid germ cell (Male- sperm, Female- egg)
what does synapsis do?
allows the homologous, non-sister chromatids to exchange segments
what happens in G1?
cell growth and development
what happens in S?
chromosome replication (DNA synthesis)
what can happen during prophase one that aids in genetic change
crossing over- the chromosome legs can become exchanged
What is formed when the sperm and egg fertilize?
diploid zygote
in eukaryotes, what follows the replication of the cell's DNA?
division of the nucleus
what happens if genetic mistakes occur in meiosis of sex organs in plants and animals?
genetic mutation gets inherited
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budding
how yeasts reproduce
how does gametogenesis differ between humans and flowering plants?
humans- gametes are produced through meiosis plants- gametes produced through mitosis of haploid cells
at what stage do gene mutations occur in meiosis
interphase- when the chromosomes replicate
which process involved a reduction reaction?
meiosis
which process produces haploid gametes for sexual reproduction?
meiosis
which process results in a change of chromosomal numbers?
meiosis
what process produces gametes?
meiosis- division that reduces the number of chromosomes by half that of a somatic (body) cell
which process is responsible for growth and repair in multi-cellular organisms, and reproduction in single celled and asexual organisms?
mitosis
what is meiosis 2 also known as?
mitotic division
how does cancer arise
pathways regulating the checkpoints in mitosis fail so the mutated cell enters the next phase without reference to the correct completion or functioning of cellular processes
What do the remainder of cytoplasm and nuclei form in oogenesis?
polar bodies- futile
what happens in G2?
rapid cell growth and protein synthesis, cell prepares for mitosis
what is meiosis 1 also known as?
reduction division
what does meiosis 1 do?
separate the homologous chromosomes into two intermediate cells
when does cytokineses occur?
shortly after the sister chromatids have seperated in anaphase of mitosis
non-disjunction
sister chromatids fail to separate during meiosis 2 OR during anaphase in meiosis 1. causes abnormal numbers of chromosomes to be passed to the gamete
independent assortment
the bivalents line up in random order in the middle of the cell, mixing maternal and paternal chromosomes in Metaphase 1
where does synapsis occur?
the chiasmata of the chromatids
what does meiosis 2 do?
the chromatids are pulled apart and large numbers of gametes can be produced
recombination
the new allele combinations created when crossing over occurs
what does it mean that cdks are kinases
they are enzymes that phosphorylate (attach a phosphate group to something)
why are the chromosomes not visible in a non-dividing cell?
they are uncoiled to make DNA information available for protein synthesis
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aneuoloidy
when an aberrant gamete unites with a normal one at fertilization and the offspring has an abnormal number of chromosomes
synapsis
when two sister chromatids pair up to form bivalents
