Genetics – Chemistry – Flashcards
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Cytosine |
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Has Amine Group Has double bonded oxygen |
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Uracil |
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Has two bonded oxygens |
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Thymine |
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Has Two Double bonded oxygens Has one methyl group |
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Adenine |
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Has one Amine group |
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Guanine |
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Has double Bonded oxygen Has an amine group |
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Hypoxanthine |
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Has one double bonded oxygen |
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Purines make a glycosidic bond at |
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Nitrogen - 9 |
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Pyrimidines make a glycosidic bond at |
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Nitrogen - 1 |
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If the glycosidic bonds are pointing down, then the major groove is on which side of the base? |
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The major groove is at the top |
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What is a stem-loop? |
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Its a structural motif found in RNA |
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Double stranded DNA usually takes on which structural form? |
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Beta form |
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Double Stranded RNA is usually which structural form? |
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The alpha form. |
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Alpha helices of proteins can fit into which groove of DNA really well? |
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Major Grooves |
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Beta strands of Proteins work with which of the grooves of DNA really well? |
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Beta strands interact with BOTH major and minor grooves really well. |
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Herman Muller |
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Discovered That x-rays cause DNA mutations. |
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Frederick Griffith |
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Discovered that heat extracts from virulent S.pneumoniae causes virulence in nonpathogens of the same species. |
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Virulence as seen in S.pneumoniae is determined by |
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Whether the cell wall is rough (nonvirulent) or smooth. |
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Transformation |
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A process in which bacteria take up extracellular DNA and use it |
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Maclyn McCarty's Group |
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Discovered the transforming factor is DNA (not protein or RNA) |
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Alfred Hershey & Martha Case |
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Used radioactive tracers to show that DNA is the genetic component of bacteriophage. |
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S35 was a radioactive marker used for |
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Proteins |
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P32 was a marker used for |
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Nucleic Acids |
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Telomeres |
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Stabilize the ends of chromosomes and direct special steps for maintaining those structures. |
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Euchromatin |
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contains genes that are expressed |
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Heterochromatin |
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Genes that are suppressed |
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Human chromosomes range from... |
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250 - 50 Mb (Mega base pairs) 8.5 cm |
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Condensed Chromosomes have a size of... |
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5 um |
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As the length of chromosomes increases in Mb pairs (or complexity of organism increases)... |
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...the number of genes per Mb pairs decreases. |
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Chromatin |
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DNA wrapped into nucleosomes |
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Nucleosome |
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Two coils of DNA wrapped around a protein spool |
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Histone-DNA interactions are considered... |
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non-specific---any part of DNA can attach to any histone. |
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The core of the nucleosome is made of... |
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...an octomer of histone proteins. |
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Histone 1 |
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Outside of the core & binds linker DNA between nucleosomes |
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How many wraps of DNA go around the histone octomer? |
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2 |
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How many base pairs go around the histone octomer? |
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140 base pairs |
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Nucleosomes pack into a filament which has a diameter of ... |
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36 nanometers |
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The DNA wraps around the histone octomer contribute negative or positive supercoils? |
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Contributes negative supercoils |
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Acetylation, methylation, and other covalent attachments to histones can do what to DNA-histone interactions? |
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It can either tighten the DNA (lowering gene expression) or loosen the DNA (Increasing gene expression). |
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Why are some histones considered "loose"? Why are they loose? |
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"Loose" histones can slide along the DNA allowing control proteins to read indicator sequences. |
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The Cell uses what type of system for making enough nucleotides? |
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It is an on "demand system": only enough is made for that moment. |
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At any given time, how many nucleotide triphosphates are there in the cell? |
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Only enough to make 1% of the cell's nucleic acids |
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What are the two pathways for nucleotide synthesis? |
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Salvage & De novo |
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What is Salvage synthesis? |
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The recycling of purine bases (adenosine & guanine)from used nucleic acids. |
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What is de novo synthesis? |
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Synthesis from scratch of both purines and pyrimidines. |
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Kinases phosphorylate NMPs (nucleoside monophosphates) to make... |
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Nucleoside diphosphates (NDPs) |
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Nucleoside diphosphates (NDPs) are phosphorylated by kinases to make... |
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Nucleoside triphosphates (NTPs). |
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PRPP stands for... |
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5-Phosphoribosyl-1-pyrophospate |
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Purine salvage starts with... |
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PRPP (5-phosphoribosyl-1-phosphate) |
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The enzyme that catalyzes the reaction of Hypoxanthine and Guanine with PRPP to make monophosphates is... |
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Hypoxanthine-Guanine Phosphoribosyl transferase (HGPRTase) |
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HGPRTase can make these two monophosphates... |
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Inosinate (IMP) and Guanylate (GMP) |
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IMP can be modified to make... |
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GMP (guanylate) and AMP (adenosine monophosphate) |
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The enzyme that catalyzes the reaction between PRPP and adenine to make a nucleotide monophosphate is... |
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Adenine Phosphoribosyl Transferase |
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Adenine Phosphoribosyl Transferase is involved in the reaction between _______ & ________ in order to make _________. |
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PRPP & Adenine , AMP (adenosine monophosphate) |
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De novo pathways can make which type of nucleotides? |
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Both pyrimidines and Purines. |
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Amino acids, C1-THF, and carbamoyl phosphate are used to assemble the... |
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Pyrimidine Rings. |
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The Ribose in the De novo pathway is derived from... |
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PRPP |
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Pyrimidine de novo synthesis makes... |
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UTP |
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UTP can be covalently changed in what way to make CTP (Cytidine Triphosphate)? |
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Through Amination. |
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Tetrahydrofolate is used in which pathways? |
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De novo synthesis of purines and dTTP formation. |
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Tetrahydrofolate provides... |
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one carbon units. |
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Tetrahydrofolate is derived from... |
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Vitamin folate. |
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Methylation of homocysteine makes... |
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methionine. |
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Deoxynucleotides can only be made from the reduction of... |
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ribonucleoside DIphosphates. |
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The source of reduction power of ribonucleotide reductase is derived from... |
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NADPH. |
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Hydroxyurea is a chemotherapy drug that is involved in the... |
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...inhibition of Ribonucleotide reductase. |
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Fluorouracil (or fluorouridylate) is a chemotherapy drug that inhibits... |
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thymidine synthase. |
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Methotrexate & aminopterin are chemotherapy drugs which inhibit... |
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...dihydrofolate reductase. |
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What is the helix diameter of RNA (alpha form helix)? |
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25.5 Angstroms |
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What is the helix diameter of DNA (Beta form helix)? |
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23.7 Angstroms |
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How many base pairs are there for every helical turn of RNA? |
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11 base pairs |
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How many base pairs are there for every helical turn of DNA? |
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10.4 bases |
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When relaxed, Linking Number is equal to... |
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#bp/10.4 |
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Linking nummber is equal to... |
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Twists + Writhes |