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33 Cards in this Set
- Front
- Back
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Life of a Cell
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Cell division is the reproduction of a cell
Apoptosis - genetiaclly controlled death of a cell (programmed cell death) Mitosis - nuclear division of somatic cells Meiosis - produces sex cells |
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The Cell Life Cycle
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see pic pg 12
Interphase Mitosis and cytokinesis |
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Interphase
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G0
G1 S Phase G2 Phase |
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G0 Phase
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Interphase
Indefinite period of time Not preparing for division Cell is performing other functions |
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G1 Phase
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Interphase
8 or more hours Normal cell functions plus growth and duplication of organelles |
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S Phase
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Interphase
6-8 hours DNA replication - cell duplicates its chromosomes Copies the gentic information of the cell |
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G2 Phase
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Interphase
2-5 hours Protein synthesis Cell enters M phase after this, and mitosis then begins |
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Mitosis
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Prophase
Metaphase Anaphase Telophase |
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Prophase
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Metaphase
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Spindle development complete
Alignment of chromosomes on spindle |
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Anaphase
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Replicated chromosomes divide - they move to polar regions
Each is attached to tubules of spindle |
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Telophase
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Cytoplasm cleaves (splits)
The membrane depresses on either side of cells Double the amount of information before cell splits |
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Cell Cycle
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G - generation
TG - total generarion; period of a cell 46 chromosomes - 23 pairs of homologous chromosomes 22 of the pairs are autosomal chromosomes 1 pair is sex chromosomes 2N - # of chromosomes - diploid |
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DNA Replication
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During S Phase of Interphase
Parent strand is the original DNA Leading strand - that strand manufactured by continuous synthesis Lagging strand - that strand manufactured by discontinous synthesis Okazaki fragment - section of RNA and DNA nucleotides manufactured as part of lagging strand |
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Helicase
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Unzips DNA
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DNA Polymerase I
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Synthesizes DNA in a C5 C3 direction
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RNA Primase
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Synthesizes starter fragment on DNA called an RNA primer
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DNA Polymerase II
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Cleans Okazaki fragment by removing RNA nucleotides or incorrect DNA nucleotides
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Ligase
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Ties okazaki fragments together in the direction that follow the Helicase
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DNA Replication
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see pic pg. 13
A-T; G-C DNA strands unwind DNA polymerase begins attaching DNA nucleotides along each strand On original strand a complementary copy is produced as a continuous strand Along the other original strand the copy begins as a series of short segments spliced together by ligases This produces 2 identical copies of DNA |
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The Human Chromosome
Somatic Cells |
Somatic (tissue) cells - 46 chromosomes; 23 homologous pairs; called 2n number (ploidy) of chromosomes - or diploid
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The Human Chromosome
Sex Cells |
Contain 23 chromosomes; or n number of chromosomes - expressed as haploid
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The Human Chromosome
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Each chromosome has 2 extremely long coiled chains of DNA nucleotides wound in a double helix
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The Human Chromosome
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Section of each coiled DNA strand contains information determined by the sequence of the nucleotides
A sequence of 3 nucelotides is a codon or triplet Sequences of triplets contain information as inheritance - called genes |
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Mitosis
Cell Division |
Karyokenesis - nuclear division
Cytokenesis division of the cytoplasm |
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Mitosis
Karyokenesis |
Prophase - chromosomes become visible/insoluble
Metaphase - chromatin becomes condensed; nuclear membrane disappears Anaphase |
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Mitosis
Cytokenesis |
Division of the cytoplasm
Restoration of the cell membrane Cell division ends Telophase - cleavage of the cytoplasm; nuclear membrane reforms |
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Mitotic Rate and Cancer
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Generally, the longer the life expectancy of the cell, the slower the mitotic rate
Stem cells undergo frequent mitoses; stem cells are embryonic cells that haven't specialized Growth factors can stimulate cell division Abnormal cell division produces tumors |
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Tumors (Neoplasms)
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Benign
Malignant - invasive; cancerous Tumors grow and invade healthy tissue |
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Malignant Tumors
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Spread by metastasis
Oncogenes - (onco - tumor) - cancer causing genese; when genes controlling cell division mutate they are called oncogenes |
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Nucleus and Transcription
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Transcription is the production of RNA, mRNA, and tRNA
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Nucleus and Transcription
mRNA |
DNA can not leave the nucleus so mRNA is needed to to carry the information to the cytoplasm
Metabolic analyte attaches to a gene RNA polymerase attaches and begins synthesis of mRNA When RNA polymerase arrives at the stop codon, the process terminates and the mRNA lifts off the DNA and travels out to the ribosome mRNA is manufactured from the antisense strand of DNA |
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Nucleus and Transcription
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Antisense strand is the strand opposite that which contains the sequence required
With transcription only a small section of DNA unzips at a time; with DNA the entire strand unzips at once with mRNA uracil, replace thymine |
