SET 2 - Omar Eldakar PDF

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Omar Eldakar...

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SET 2 Chromatid a complex of DNA and protein.

Cohesin complex of proteins holding replicated chromosomes together

Diploid 2n - somatic cells

Haploid n - sex cells or Gametes

Karyotype the particular array of chromosomes of an organism

Mitosis Division of the nucleus. results in daughter cells with identical DNA.

Cytokinesis Division of the cytoplasm, cleavage of the cell into equal halves

Meiosis is a special division that can produce sperm and egg cells.

Prokaryotic cells the genome consists of a single circular DNA molecule.

Eukaryotic cells the genome consists of a number of DNA segments or linear chromosomes.

Somatic cells (nonreproductive cells) have two sets of chromosomes.

Gametes (reproductive cells: sperm and eggs) have half as many chromosomes as somatic cells.

Replicated chromsomes are connected to each other at their kinetochores

sister chromatids 2 copies of the chromosome within the replicated chromosome

Interphase includes G1 phase ("first gap"), S phase ("synthesis"), G2 phase ("second gap")

Interphase makes up 90% of the cell cycle

G1 phase gap one - growth by synthesizing proteins and producing organelles,

S phase DNA synthesis - chromosomes duplicated

G2 phase

gap two - growth by synthesizing proteins and producing organelles in preparation for M phase. The chromosomes undergo condensation, Centrioles (microtubule-organizing centers) replicate and one centriole moves to each pole.

Prophase most complex, Nucleolus disappears, Chromosomes condense, Spindle begins to form, Centosomes move to opposite poles, Asters around centrioles in animal cells

Prometaphase Nuclear membrane disappears, Chromosomes condense even more, Spindle completed, Asters around centrioles in animal cells, kinetichores mature and attach to spindle microtubules.

Metaphase The chromosomes are all lined up at the metaphase plate, Centomeres begin to divide

metaphase plate an imaginary structure at the midway point between the spindle's two poles.

Anaphase Removal of cohesin proteins causes the centromeres to separate, Microtubules pull sister chromatids toward the poles, The microtubules shorten by depolymerizing at their kinetochore ends

Telophase spindle apparatus disassembles nuclear envelope forms around each set of sister chromatids, chromosomes begin to uncoil, nucleolus reappears in each new nucleus

in animal cells - constriction of actin filaments produces a

cleavage furrow

in plant cells - plasma membrane forms a ______ between the nuclei cell plate

Bacteria divide by binary fission

binary fission the single, circular bacterial chromosome is replicated, replication begins at the origin of replication and proceeds bidirectionally, new chromosomes are partitioned to opposite ends of the cell, a septum forms to divide the cell into 2 cells

cell cycle control system The sequential events of the cell cycle are directed by this, regulated by both internal and external controls

The three checkpoints: G1/S checkpoint, G2/M checkpoint, late metaphase (spindle) checkpoint

cyclins proteins produced in synchrony with the cell cycle, regulate passage of the cell through cell cycle checkpoints

cyclin-dependent kinases (Cdks) enzymes that drive the cell cycle

anaphase-promoting complex (APC) the signal for anaphase to proceed is transmitted through

platelet-derived growth factor (PDGF) triggers cells to divide during wound healing

Cancer is a failure of cell cycle control.

tumor-suppressor genes prevent the development of many cells containing mutations

proto-oncogenes some encode receptors for growth factors, some encode signal transduction proteins...