What are double ringed nitrogenous bases called, and what are they? |
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Purines/ guanine and adenine |
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What are single ringed nitrogenous bases called, and what are they? |
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Pyrimidines/ cytosine and thymine (they all have ''y's") |
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What is the name of the rule that refers to the complementary nature of DNA? (Number of Adenine = Number of Thymine and Number of Cytosine = Number of Guanine) |
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Chargaff's Rule |
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The process of DNA making a copy of itself is called |
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Replication; average speed: 20 nucletides per second are added to new strand |
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When replication is completed, each molecule will have one original template strand. This is called |
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Semi-conservative replication |
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In DNA replication, new strands always begin at its __ end and nucleotides are added to its __ end. |
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5' , 3' |
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Enzymes responsible for building a DNA polymer; there are more than one kind; they catalyze the addition of nucleotides to the 3' end of the strand and cannot start the strand |
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DNA polymerases |
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Molecules in the nucleus that provide the substrates to build a new strand of RNA or DNA; have 3 phosphate groups |
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free nucleotides |
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Specific sequences on the DNA template strand where replication begins |
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origin of replication |
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Giant cloud of molecules that contain all enzymes, all substrates, and everything needed for replication --moves along the DNA molecules--replication only occurs where this is |
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DNA replication machine |
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Enzyme responsible for pulling the DNA helix apart; breaks hydrogen bonds |
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DNA helicase |
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Proteins that bind to the strands, keeping them apart so replication can occur |
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Single-strand binding proteins |
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Point where the two template strands of DNA are being pulled apart (y-shaped structure) |
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Replication fork |
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New strand built in the same direction that the replication fork is moving |
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Leading strand |
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New strand built in the opposite direction of the movement of the replication fork |
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Lagging strand |
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Built first, at the 5' end about 10 nucleotides long; synthesized at the point where replication begins |
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RNA primer |
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Responsible for building primers, made of RNA; digested and replaced with DNA nucleotides |
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Primase enzymes |
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Gets rid of primers and joins strands together |
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DNA ligase |
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100 to 2000 nucleotides pieces (short fragments of DNA) that must be joined by DNA ligase to form the lagging strand in DNA replication |
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Ogazaki fragments |
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A mistake that happens in replication |
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Mutation |
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One molecule of DNA with proteins attached; organized into nucleosomes; condensed chromatin |
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chromosome |
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Cells that lack membrane-bound organelles (no nucleus); generally have only ONE CIRCULAR CHROMOSOME; only one origin of replication (bidirectional); cell division is unique |
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Prokaryotic cells |
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Cells that have membrane-bound organelles, including nucleus; chromosomes are linear; more than one chromosome per nucleus (each species has a specific number of chromosomes) |
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Eukaryotic cells |
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Actual material in the nucleus; 40% DNA, 60% protein |
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Chromatin |
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Nonhistone proteins that help maintain chromosome structure |
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Scaffolding proteins |
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Structures of which the inside is made of 8 histone protein molecules; length of DNA (wrapped twice) is 146 base pairs long; positively charged |
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Nucleosome |
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Two types of Eukaryotic Cells |
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Germ cells- very specialized cells involved in sexual reproduction
Somatic cells- majority of eukaryotic cells; nuclear division |
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Phase in cell division when chromatin is not condensed into chromosomes; no cell division; no nuclear division; majority of the time in the life of the cell |
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Interphase |
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Phase in cell division when no DNA synthesis occurs; growth and metabolism take place; usually the longest phase |
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G1 phase (gap) |
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Phase in cell division when DNA replication occurs, chromosomes are duplicated |
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S phase (synthesis) |
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Phase in cell division when there is alot of protein synthesis; the cell gets ready for division |
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G2 phase (gap) |
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Phase in cell division when the nucleus divides; nuclear divison; cytoplasm divides (cytokinesis); forms two daughter cells |
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M phase (mitosis) |
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Nuclear division that produces two nuclei containing chromosomes identical to the parental nucleus; begins at the end of the G2 phase; occurs in 4 phases |
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Mitosis |
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1st stage of mitosis; nuclear membrane starts to fall apart; pieces are stored in vesicles (can be recycled); centrioles move up the sides; mitotic spindle forms |
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Prophase |
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Identical, double-stranded DNA sequences; linked by cohesin (ring shaped protein) |
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Sister chromatids |
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Specialized constricted region of a chromatid; contains kinetochore (a multiprotein complex to which micrtotubules can bind) |
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Centromere |
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2nd phase of mitosis; mitotic spindle is complete; sister chromatids line up at the midplane (metaphase plate) |
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Metaphase |
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Mitotic spindle's two types of microtubules: |
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Polar microtubules- run from the poles and overlap at the metaphase plate
Kinetochore microtubule- run from the micrtobule organizing centers and bind to the kinetochores of sister chromatids |
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Other type of mictotubule that runs from the centrioles toward the outside of the cell |
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Astral microtubules |
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3rd stage of mitosis; sister chromatids pulled apart; make daughter chromatids, which head to the poles; kinteochore MT get shorter and pull daughter chromatids in; polar MT get longer, pushing the 2 poles of cell apart; oblong mother cell with copy of each chromatid at each pole |
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Anaphase |
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Final stage of mitosis; nuclei are starting to reform; spindle fibers disintegrate; reforming nuclear envelope; chromosomes start to disorganize; cytokinesis begins |
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Telophase |
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Division of the cytoplasm to yeild two daughter cells;
IN ANIMALS- microfilaments pinch (cleave) cell and form 2 cells
IN PLANTS- occurs intially by building cell plate at metaplate; new cell wall and plasma membrane
BOTH- mitochondria and chloroplasts each copy itself and DNA |
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Cytokinesis |
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Why do somatic cells divide? |
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Growth
Repair/replacement
Maintenance
NOT for sexual reproduction |
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What regulates the cell cycle? |
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Proteins (cyclins-regulatory proteins produced by cells); accumulation in cells
Cyclin-dependent kinases (cdks)- protein kinases involved in controlling the cell cycle |
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Sequence of the DNA molecules that holds the information to build a specific product (protein and RNA products) |
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Gene |
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A complex series of events in which the info in DNA directs production of specific proteins coded in genes |
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Gene expression |
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The process of building an RNA molecule that is complementary and antiparallel to a small portion of a DNA template; occurs in the nucleolus; also know as RNA synthesis |
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Transcription |
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Process of building a protein polypeptide using the code on an mRNA; the small subunit of the ribosome binds to mRNA, allowing this process to occur; occurs at the ribosomes |
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Translation; occurs 20 amino acids per second |
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What do these characteristics describe?
5 Carbon sugar is ribose
4 bases are adenine, uracil, cytosine, and guanine
single stranded
shorter than DNA molecule
has covalent bonds (phosphodiester bonds)
has 5' and 3' ends
C1 holds the nitrogenous bas |
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RNA |
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Enzyme used to build RNA polymers; must be present; bind to promoter (specific DNA sequence that is the starting point of a gene)after the gene is turned on |
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RNA polymerase |
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The direction of transcription is always |
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DOWNSTREAM (toward the 3' end of the RNA or 5' end of the template strand) |
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Single strand of RNA that carries the information for making a protein; "intermediate molecule"; intiated at 5' end |
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mRNA |
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Each 3 nitrogenous bases on the mRNA |
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codon (ONLY on mRNA) |
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Amino acid that always initiates a polypeptide chain |
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Met (AUG) |
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Single strand of RNA that folds back on itself to form a specific shape; transfers amino acid to ribsomes; has the anti-codons |
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tRNA |
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tRNA that has an amino acid binded to its 3' end |
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Amino-acyl tRNA |
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Made of proteins bound to rRNA (ribosomal RNA) no membrane; 40% protein and 60% rRNA; split into large subunits (has 3 tRNA biding sites---E,P, and A) and small subunit (has a small mRNA binding site) |
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Ribosome |
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Large subunit binding sites |
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A site (aminoacyl site) the aminoacyl tRNA delievering the next amino acid in the sequence binds at this location.
P site stands for polypeptide. It holds polypeptide chain being builit.
E site stands for exit. tRNAs that have given up their amino acids to the growing polypeptide chain exit the ribsome. |
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The anticodon that is complementary to the codon attaches with ________ bonds. |
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Hydrogen |
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