BIOL 118: Test 2
54 Cards in this Set
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Nucleous
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where ribosomes are made contains DNA in chromosomes has double membrane = nuclear envelope, is not homogenius
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Nuclear Lamina
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anchors chromosomes, mantians overall shape and structure of the nucleous
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Cell Division in Animals
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anchors chromosomes, mantians overall shape and structure of the nucleous
daughter cells are genetically identical to the parent
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Cytokinesis
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division of cytoplasm into two daughter cells
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The Cell Cycle: mitotic Phase
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when the cells actually divide apart
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Interphase
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non dividing phase, cells spend most of their time in interphase, chromosomes are coiled during interphase
made of lamins (intermediate filaments)
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Lamins
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intermediate filaments
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Nuclear Envelope
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Contains thousands of openings called pores
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Binary Fission
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Prokaryotes reproduce via cell division through the process off binary fission
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Chromatin
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DNA protein complex
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Histones
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proteins in a chromosome
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Chromatid
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DNA strands in a replicated chromosome
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Sister Chromatids
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exact copies of the same genetic information encoded in one long DNA double helix
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Centromere
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A constriction of the joined sister chromatids
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Order of meiosis
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Prophase, Prmetaphase, Metaphase, Anaphase, telophase
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Prophase
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Microtubules begin to form the mitotic spindle
Spindle fiber microtubules attach to the chromosomes
Chromosomes become visible in light
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Prometaphase
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nucleous disappears and the nuclear envelope breaks down during during prometaphase
Spindle fibers attach to each sister chromatid at kinetochores, located at chromosome centromeres
Kinetochore microtubules begin moving chromosomes toward the middle of the cell
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Metaphase
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Centrosomes rach opposite poles of the cell in nimals, chromosomes are pulled by the kinetochore microtubules, reach the middle of the cell. The imaginary plane where the chromosomes line up is called the metaphase plate. the mitotic spindle is now complete-stretching from each kinetochor…
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Anaphase
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kinetochores spindles shorten, pulling apart sister chromatids to create seoarate chromosomes that are oulled toward microtubule organizing centers at opposite cell poles
chromatid separation ensures that each daughter cell reives ne copy of each parent chromosome
motor proteins also p…
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Telophase
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a new nuclear envelope begins to form around each set of chromosomes. the spindle dissintegrates, and the chromosomes become less compact and less visible as they de condense
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Cytokinesis
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division to form two daughter cells typically occurs immediately after mitosis
Plant cell cytokinesis occurs as vesicles are transpoted from the Golgi apparatus to the middle of the dividing cell. The vesicles fuse to form a cell plate
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M- Phase promoting Factor
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induces mitosis in all eukaryotes, protein kinase catalyzes a protein phosphorlation reaction that transgers a phosphate group from ATP to a target protein
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cyclin and the M-phase promoting factor
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subunit cyclin concentration increases during interphase
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Factors that affect whether cell pass the g1 checkpoints
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cell size
nutrient conditions- in unicellular organisms
signaling molecules from other cells o multicellular organisms
tumor suppressors- regulatory proteins that can stop the cell cycle
two types of cell cycle defects cause cancer
defects that cauuse continuous activation of protei…
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Benign Tumors
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non cancerous
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Malignant Tumors
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cancerous and can spread throughout the whole body
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metastasis
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detachment from original source of the tumor to another area
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Meiosis I
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involves the complex mechanism of crossing over in prophase I and the separation of homologous chromosomes into two separate cells
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Meiosis II
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repeats the steps of meiosis I , difference is the physical separation of the sister chromatids and the migration of each into a gamete cell that will contain one copy of each chromosome
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Prophase I
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chromosomes condense into tightly wound balls of DNA, condensation is mediated to small histone proteins that bind to the chromosomal DNA and wrap the DNA around their surgace, Crossing Over occurs, key in recombination of DNA for the production of genetically diverse gametes
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Metaphase I
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condensed chromosomes migrate to the mideline of the cell and form a line. Homologous chromosomes are adjacent to each other at the mideline, cytoskeletal proteins known as microtubules mediate this migration
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Anaphase I
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paired homologues are separated from each other, migrating to opposite ends of the cell, following migration each pole of the cell contains one complete set of chromosomes
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Telophase I
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chromosomes complete their migration and are enclosed in two newly formed daughter cells
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Aneuploidy
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fragmented chromsomes that were damaged some point during meiosis, also known as mistakes in meiosis, example Down syndrome
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Semi conservative Replication
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the double helix separates, and each old strand is copied to generate two new chromosomes. Thus each new chromosome is composed of one strand of old DNA and one strand of newly synthesized DNA
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Conservative Replication
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during replication the original chromosome is copied but remains unchanged Both of the original strands would remain at the end of this replication and the new ribosome will be completely new
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Dispersive Replication
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the replication process generates two new chromosomes with new and old sections of DNA mixed together randomly this model is complex and would require a great deal of cutting and splicing of DNA strands
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DNA polymerase II
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preformed the bulk of DNA replication during bacterial cell division while DNA polymerase I performed a key role in the repair of mutation
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DNA polymerase I
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isolated from E coli.
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How does DNA REplication get started
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DNA polymerase II catalyzes DNA synthesis in the 5’ to 3’ direction
On a circular prokaryotic chromsome DNA replication starts at specific sites and proceeds in both directions from the starting point. this bidirectional DNA replication proceeds in each directions with the advancement of…
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How does the fork originate?
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with the action of a DNA helicase, and enzyme that opens the double helix to allow enzymes to attach to each strand . small proteins known as single stranded DNA and keep it from reforming double-stranded DNA
DNA polymerization requires a primer on which to add nucleotides. the primase e…
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Where are the leading Strand and Lagging Strand Found
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Replication Fork
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DNA Polymerase II
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mediate the leading and lagging strand synthesis reactions
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telomeres
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ends of each chromosomes, they contain many repeats of a six base sequence TTAGGG (repeated 1000 times)
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Telemerase
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an enzyme that mediates the replication of telomeres, solving the problem of the single stranded DNA ( dna is degraded and the telomere shortens by the length with each cell division
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Helicase
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catalyzes the breaking of hydrogen bonds between these pairs and at the opening of the double helix
Single-stranded DNA binding proteins- stabilize single stranded DNA
topotsomerase- breaks and rejoins the DNa double helix to relieve twisting forces caused by the opening of the helix
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Leading Strand
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Primase- catalyzes the synthesis of the RNA primer
DNA polymerase II- extends the leading strand
Sliding clamp- holds DNA polymerase in place during strand
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Lagging Strand
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primase- catalyzes the synthesis of the RNA primer on the okazaki fragment
DNA polymerase II- establish an Okazaki fragment
Sliding Clamp- holds DNA polymerase in place during strand extraction
DNA polymerase I- removes the RNa primer and replaces it with Dna
DNA ligase- catalyzes th…
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Xeroderma pigmentation
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inherited disease in humans , it results in sensitivity to UV light.
this disease is caused by mutation of one of several excision repair enzymes utilized by humansa, diminished excision repair enzymes result in a defficient cellular capacity to repair damaged DNA, excision repair involv…
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Chromosome Replication
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occurs only during interphase not during m phase, dna synthesis occurs in the s phase of interphase
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Interphase
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includes two gap phases
no dna synthesis occurs in these
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G1
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prepares for DNA synthesis, occurs before S phase takes 6-8 hours
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G2
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after DNA synthesis prepares for mitosis, 4 hours
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What happens during Gap phases?
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organelles replicate and additional cytoplasm is made
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BIOL 118: Test 2