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39 Cards in this Set
- Front
- Back
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Cell Cycle Includes... |
-Interphase -Cell division (mitotic phase) |
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Interphase Subphases |
-G1 -S -G2 *ADD PICTURE* |
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G1 |
Vigorous growth and metabolism |
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S (synthetic) |
DNA replication |
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G2 |
Preparation for division |
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Helicase |
ENZYME that untwists the double helix and exposes complementary chains |
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The Y-shaped site of replication is the... |
replication fork |
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DNA polymerase |
-Works in one direction -Discontinuous lagging strand is synthesized in segments -Is an Enzyme |
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Nucleotide strand |
serves as a template for building a new complementary strand
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DNA ligase |
splices together short segments of discontinuous strand |
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Mitotic phase |
-Includes Mitosis and Cytokinesis -Essential for tissue repair also -Does not occur in most mature cells of nervous tissue, skeletal muscle and cardiac muscle |
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Mitosis stages |
-Prophase -Metaphase -Anaphase -Telophase |
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Cytokinesis |
-Division of cytoplasm by cleavage furrow -Begins during late anaphase -Ring of actin microfilaments contracts to form cleavage furrow -Two daughter cells are pinched apart, each containing a nucleus identical to the original |
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Prophase |
-Chromosomes become visible, each with two chromatids joined at a centromere -Centrosomes separate and migrate toward opposite poles -Mitotic spindles and asters form -Nuclear envelope fragments -Microtubules attach to centromeres and draw them toward the equator of the cell |
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Metaphase |
-Centromeres of chromosomes are aligned at the equator |
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Metaphase plate |
The plane midway between the poles of the cell |
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Anaphase |
-Shortest phase -Centromeres of chromosomes split -Each chromatid becomes a chromosome -Chromosomes are pulled toward poles by motor proteins -Polar microtubules continue forcing the poles apart |
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Telophase |
-New nuclear membrane forms around each chromatin mass -Nucleoli reappear -Spindle disappears |
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Protein Synthesis |
-DNA is the master blueprint -Triplets of nucleotide bases form genetic library -Each triplet specifies coding for an amino acid |
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Gene |
Segment of DNA with blueprint for one polypeptide |
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Main types of RNA |
-mRNA (Messenger) -rRNA (Ribsomal) -tRNA (Transfer) |
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Messenger RNA (mRNA) |
Carries instructions for building a polypeptide from gene in DNA to ribosomes in cytoplasm |
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Ribosomal RNA (rRNA) |
A structural component of ribosomes that along with tRNA helps translate message from mRNA |
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Transfer RNA (tRNA) |
Bind to amino acids and pair with bases of codons of mRNA at ribosome to begin process of protein synthesis |
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Transcription |
-Transfers DNA gene base sequence to a complementary base sequence of an mRNA |
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Transcription factor |
-Loosens histones from DNA in area to be transcribed -Binds to promoter, a DNA sequence specifying start site of gene to be transcribed -Mediates the binding of RNA polymerase to promoter |
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RNA polymerase |
-Enzyme that oversees synthesis of mRNA -Unwinds DNA template -Adds complementary RNA nucleotides on DNA template and joins them together -Stops when it reaches terminal signal -mRNA pulls off the DNA templates, is further processed by enzymes, and enters cytosol |
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Translation |
-Converts base sequence of nucleic acids into the amino acid sequence of proteins -mRNA attaches to a small ribosomal subunit that moves along the mRNA to start codon -Large ribosomal unit attaches, forming a functional ribosome -Anticodon of a tRNA binds to its complementary codon and adds its amino acid to the forming protein chain -New amino acids are added by other tRNA as ribosome moves along rRNA until stop codon is reached |
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Genetic code |
-Each three-base sequence on DNA is represented by a codon |
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Codon |
complementary three-base sequence on mRNA |
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Role of Rough ER in protein synthesis |
-mRNA-ribosome complex is directed to rough ER by a signal-recognition particle (SRP) -Forming protein enters the ER -Sugar groups may be added to the protein and its shape may be altered -Protein is enclosed in a vesicle for transport to golgi apparatus |
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Intron ("junk") regions of DNA |
Code for other types of ENA |
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Antisense RNA |
Prevents protein-coding RNA from being translated |
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Micro RNA |
Small RNA that interfere with mRNA made by certain exons |
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Riboswitches |
Folded RNA that act as switches, regulating protein synthesis in response to environmental conditions |
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Cystolic Protein Degradation |
-Nonfunctional organelle proteins are degraded by lysosomes |
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Extracellular Materials |
-Body fluids (interstitial fluid, blood plasma, and cerebrospinal fluid) -Cellular secretions (Intestinal and gastric fluids, saliva, mucus, and serous fluids) -Extracellular matrix (abundant jellylike mesh containing proteins and polysaccharides in contact with cells) |
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Developmental Aspects of Cells |
-All cells of the body contain the same DNA but are not identical -Chemical signals in the embryo channel cells into specific developmental pathways by turning some genes off -Development of specific and distinctive features in cells is called cell differentiation -Elimination of excess, injured, or aged cells occurs through programmed rapid cell death (apoptosis) followed by phagocytosis |
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Theories of Cell Aging |
-Wear and tear theory: Little chemical results and free radicals have cumulative effects -Immune system disorders: Autoimmune responses and progressive weakening of the immune response -Genetic theory: Cessation of mitosis and cell aging are programmed into genes |
