Biochem
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| DNA contains what sugar? | 2-deoxyribose | ||||
| Purines. Contains ______ rings in their structure | Adenine and guanine. 2 rings | ||||
| Pyrimidines. Contain ______ rings in their structure | Cytosine, Uracil, Thymine. 1 ring | ||||
| A nucleoside is made up of: | one of the bases covalently attached (via glycosidic bond) to the 1' carbon of one of the sugar residues. | ||||
| The 5' carbon of the sugar residue attaches to: | phosphate group | ||||
| List what attaches to the 1' carbon in DNA | 1' - glycosidic bond, | ||||
| List what attaches to the 2' carbon in DNA | 2' - no hydroxy group, | ||||
| List what attaches to the 3' carbon in DNA | 3' - hydroxyl group is required for polymerization. Forms phosphodiester bond with carbon 5 of adjacent molecule. | ||||
| List what attaches to the 4' carbon in DNA | nothing | ||||
| List what attaches to the 5' carbon in DNA | linked to one or more phosphates, joined to carbon 3 of an adjacent nucleotide in nucleic acids through a phosphodiester bond | ||||
| A DNA sequence is always written in what direction? | 5' to 3' | ||||
| DNA is antiparallel and complimentary. Define these terms. | Antiparallel - the two strands are in opposite directions. Complimentary - A pairs with T, G pairs with C. | ||||
| What is the complimentary sequence of AGCTCCTTAGG? | CCTAAGGACCT | ||||
| What is Chargaff's rule? | The amount of A always equals T, and G equals C. Can use this to figure out the total percent of a given nucleotide in a sequence. | ||||
| The sugar phosphate backbone is on the outside of the double helix and contains a ______ charge | negative | ||||
| The core of the double helix is: | hydrophoebic. | ||||
| Why is DNA an amphipathic molecule? | Because of the hydrophilic sugar phosphate backbone and hydrophoebic core. | ||||
| A-T base pairs contain ____ hydrogen bonds, and G-C base pairs contain _____ hydrogen bonds. | 2, 3 | ||||
| Methods that can be used to separate double stranded DNA | heat, alkali pH, certain chemicals | ||||
| Define Tm | the temperature required to melt 50% of DNA, or the temperature that results in the DNA being half denatured | ||||
| What change will you notice in Tm of a DNA strand with high AT content versus high GC content | High GC content will have a much higher Tm | ||||
| What does Topoisomerase I do? | remove negative supercoils to result in relaxed DNA. | ||||
| What does Topoisomerase II (DNA gyrase) do? | induce negative supercoils | ||||
| What does the antibiotic class of quinolones do? | Inhibits prokaryotic DNA gyrase. | ||||
| DNA in the nucleus of eukaryotes is packaged in _______, which is made up of packaging units called ________ | chromatin, nucleosomes | ||||
| What amino acids primarily make up histones and why? | Lysine and arginine. They are positively charged | ||||
| A group of free nucleosomes in the absense of H1 is sensitive to ____________ | nuclease degredation | ||||
| What is the significance of H1? | Associates with DNA to further condense it to a nucleofilament. | ||||
| RNA basepairing back on itself can impart unique properties. When RNA exhibits enzymatic activity, what is called? What is its usual activity? | ribozyme. Hydrolyze phosphodiester bonds within RNA | ||||
| What are the three major types of RNA? | mRNA, rRNA, tRNA | ||||
| Heterogenious is size. Essentially correlated to the protein for which it encodes. Eukaryoctic version contains a m7G-cap and poly-A tail | mRNA | ||||
| What is the function of the G-cap structure | Is to allow ribsomes to bind and to protect against nuclease degredation. | ||||
| What is the function of the poly-A tail? | Protects against nuclease degredation. Is an importain signal for transport out of the nucleus. | ||||
| How many molecues make up prokaryotic and eukaryotic rRNA? | Prokaryotic - 3. Eukaryotic - 4 | ||||
| tRNA is approximately how large? | 4S or 80 nts | ||||
| tRNAs are covalently linked to what? | amino acid | ||||
| What is the attachment site for amino acids on tRNA? | CCA-3' terminus | ||||
| What causes the cloverleaf-like structure of tRNA? | extensive intrachain base-pairing. | ||||
| The ______ determines the amino acid specificity by base-pairing with mRNA during translation. | Anticodon loop | ||||
| Two examples of other RNAs found only in the nucleus of eukaryotes | hnRNA, snRNA |
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Created by:
addimatteo
on 2008-10-05