Chapter 2 Mitosis Meiosis Flashcards
How prokaryotes reproduce, simple division, the separation of replicated circular chromosomes
Binary Fission
DNA and associated proteins of a chromosome
Chromatin
The number of chromosome sets
Ploidy
A cell having one set of chromosomes, one of each chromosome
Haploid (1n)
A cell having two sets of chromosomes, normally one from each parent
Diploid (2n)
A cell having more than two sets of chromosomes
Polyploid (3x, 4x, 5x, etc.)
Ploidy of humans
2n=46 (23 from mother, 23 from father)
A pair of chromosomes with the same genes on them (possibly not the same alleles), in 2n organisms usually one from the male parent and one from the female parent
Homologous Pairs
Chromosomes that carry different genes
Nonhomologous Chromosomes
The unpaired X and Y chromosomes
Sex Chromosomes
All the chromosomes except X and Y
Autosomes
A metaphase chromosome with centromere positioned so that there is a slightly shorter p arm and a longer q arm
Submetacentric
A metaphase chromosome with the centromere positioned right in the middle so that the two arms are the same length
Metacentric
A metaphase chromosome with the centrosome positioned basically at the end of the chromosome so that one arm is basically the whole length and the other is basically nonexistent
Telocentric
A metaphase chromosome with the centromere positioned so that there is one super long arm and one super tiny arm
Acrocentric
A complex of proteins that attaches to the centromere during cell division so that the spindle fibers can attach to them
Kinetochore
The protein that attach to the kinetochore and facilitate the movement of the sister chromatids to opposite sides of the cell in mitosis and meiosis
Spindle Fibers
The phase of the cell cycle in which the cell grows and carries on normal function, ~23 hours in a human cell in culture
Interphase
The phase of the cell cycle in which the cell divides ~1 hour in a human cell in culture
M phase
The part of interphase in which the cell has active gene expression and cell activity, and prepares for DNA synthesis, around 10 hours in a typical cell in culture
G1 phase
The part of interphase in which the cell replicates its DNA, about 9 hours in a typical cell in culture
S phase
The part of interphase in which the cell prepares everything it needs for cell division, around 4 hours in a typical cell in culture
G2 Phase
A kind of perpetual G1 phase in which a cell exits the cell cycle and does not divide, instead eventually dying (apoptosis)
G0 Phase
Identical copies of each chromosome present after each S-phase and held together at their centromeres
Sister Chromatids
The centromeres of sister chromatids
Sister Centromeres
Genes found on different chromosomes, that are independently assorting
Unlinked
The phase of mitosis in which chromosomes condense and the mitotic spindle forms
Prophase
The phase of mitosis in which that nuclear envelope disintegrates and the spindle fibers anchor to the kinetochores
Prometaphase
The part of mitosis in which the chromosomes align in the center, contains the spindle assembly checkpoint
Metaphase
The checkpoint in metaphase in which the cell checks to make sure that the chromosomes are lined up properly and the spindle fibers are attached correctly
Spindle-Assembly Checkpoint
The part of the cell where the chromosomes line up in metaphase
Metaphase Plate
The part of mitosis in which the sister chromatids separate and migrate toward the spindle points
Anaphase
The part of mitosis in which the chromosomes arrive at the spindle poles, the nuclear envelope reforms around them, and the chromosomes start to relax
Telophase
The part of the cell cycle in which the cytoplasm divides and the cell wall forms in plant cells
Cytokinesis
A microtubule based structure that is responsible for chromosome movement and separation
Spindle Apparatus (Mitotic Spindle)
One of the components of the cytoskeleton comprised of polymerized tubulin, a major component of the mitotic spindle that is also involved in cytokinesis and vesicle transport
Microtubules
The microtubule organizing center which localizes to the poles of the mitotic spindle and associates with the nuclear envelope during interphase
Centrosome
Part of the centrosomes, a pair of small bodies that is found only in animals and helps organize microtubules
Centrioles
The checkpoint in the cell cycle that confirms whether the cell has all the enzymes it needs to replicate it’s DNA
G1/S Checkpoint
The checkpoint in the cell cycle in which the cell makes sure all the DNA is replicated and undamaged
G2/M Checkpoint
The half of meiosis that is reduction division and contains the synapsis of homologous chromosomes, recombination, and the separation of homologous chromosomes
Meiosis I
The half of meiosis that is the equational division, and has the separation of sister chromatids
Meiosis II
The point at which homologous chromosomes remain in contact during late prophase I/metaphase I and where crossing over occurs
Chiasmata
The fusion of chromosome pairs at the start of meiosis I
Synapsis
The complex during meiosis that forms between non-sister chromatids during meiosis that contains multiple proteins that bind together homologous chromosomes to align them and facilitate crossing-over
Synaptonemal Complex
The formation of new combinations of alleles during crossing over
Recombination
The four synapsed chromatids for each homologous pair of chromosomes
Tetrads (Bivalents)
Aggregates of proteins that form in the Synaptonemal Complex and mediate crossing over
Recombination Nodules
A protein complex responsible for the condensation of chromosomes at mitosis
Condensins
A protein complex that holds the two sister chromatids together
Cohesin
An enzyme that cleaves one of the cohesion subunits, resulting in the release of sister chromatids that occurs in anaphase of mitosis and anaphase II of meiosis. It’s activity is controlled by the spindle assembly checkpoint
Separase
A protein that associates with cohesin during meiosis I to protect it from being cleaved by separase too early. It is degraded after anaphase I to allow separase to cleave cohesin in anaphase II
Shugoshin
All the cells other than germ cells, never go through meiosis, but can undergo mutations; however, these mutations are not passed on tho offspring because they are not in germ cells
The precursor cells to gametes located in the gonads (testis and ovary), go through mitosis and meiosis only at specific stages of development
Germ Cells
The process of gamete formation
Gametogenesis
The male sex cells that go through mitosis and cell division
Spermatogonia
The female sex cells that go through mitosis and cell division
Oogonia
The male sex cells that are in meiosis I
Primary spermatocytes
The female sex cells that are in meiosis I
Primary oocyte
The male sex cells that are the products of meiosis I and are in the process of meiosis II
Secondary Spermatocytes
The female sex cells that are the products of meiosis I and are in the process of meiosis II
Secondary oocyte and first polar body
The male sex cells that have completes meiosis II
Spermatids
The female sex cells that have completes meiosis II
Ovum and second polar body
The four female 1n cells that plants produce , three of them degenerate
Megaspores
The female cell that plants produce by having the surviving megaspore undergo 3 rounds of mitosis without actually dividing that has 8 genetically identical nuclei
Female Gametophyte
The four male 1n cells that plants produce
Microspores
The nucleus in a pollen grain that creates the pollen tube
Tube Nucleus
The nucleus in a pollen grain that produces two genetically identical sperm cells when it goes through mitosis
Generative Nucleus
The cell that forms form the cytoplasm of the female gametophyte dividing that has one nucleus and is eventually fertilized by one of the sperm
Egg
The cell after the division of the female gametophyte that ends up with two nuclei
Binucleate cell with polar nuclei
The cell that forms form the cell that has two nuclei after the division of the female gametophyte when it is fertilized by one of the sperm
Endosperm
