Flashcards
Structural Features of Nucleic Acids
Cards in this deck (19)
- 1What are purines?- 2 ring nitrogenous bases
- adenine and guanine - 2What are pyrimidines?- 1 ring nitrogenous bases
- thymine, cytosine, uracil - 3Describe the properties of bases.- many nitrogen and oxygen atoms
- multiple hydrogen bonds
- form glycosidic bonds
- react with carbohydrates
- planar - 4What are nucleosides? How are they formed?- base + sugar ring
- ribose or deoxyribose
- glycosidic bonds
- condensation reaction - 5What are nucleotides?- nucleosides + 3 phosphate groups
- ester formed with OH of sugar = phosphorylated
- phosphodiester groups link 3' and 5' carbons = backbone - 6What is the role of nucleoside triphosphates?- energy carriers
- phosphate carriers
- phosphoanhydride bonds - are easily hydrolysed
- important metabolic synthesis, redox and signalling roles - 7What is the role of NTPs in redox? Give an example.- coenzymes
- NAD, FAD, NADP
- have reactive sites = accept electrons
- oxidative metabolism and reductive biosynthesis - 8What is the role of NTPs in signalling ? Give an example.- coenzyme A, cAMP, cGMP
- signal transduction = 2nd messengers
- trigger cell reaction
- carrier for acetyl groups - 9Describe base pairing.- CG = 3 hydrogen bonds
- ATU = 2 hydrogen bonds - 10Describe the structure of DNA.- double helix
- 2 antiparallel strands
- right-handed double helix
- outside = hydrophilic
- inside = hydrophobic
- major and minor grooves - 11How is DNA stabilised?- hydrophobic effect
- hydrogen bonding
- VDW forces between bps - 12Why are the grooves important in DNA?- provide access to edges of bps
- for sequence dependant binding and reading of the sequence - 13Describe base pairing in RNA.- not as regular
- non Watson and Crick
- e.g. base triples
- self-complementary sequences = loop back to form helical domains
- non-helical
- important for termination - 14Describe tRNA.- resembles globular protein
- L-shaped
- highly folded
- many chemically modified bases = alter steric, polar and h-bonding properties - 15What is a ribozyme?- RNA with catalytic activity
- RNA can fold into tertiary structures
- binding sites - 16How do ribozymes work?- some can function without protein activity = self-splicing RNA introns
- most have accessory proteins = RNA is less chemically versatile and diverse than AAs
- proteins provide scaffold - 17What is the function of RNA in ribosomes?- rRNA determines = structure of ribosomes, position of tRNA and catalyses peptide bond formation
- 18What is the function of proteins in ribosomes?- stabilise RNA
- allow conformational changes for catalysis - 19Describe sncRNAs. Give their role.- small RNA molecules 20-29 nucleotides
- siRNA, miRNA, piRNA
- post-transcriptional regulation of gene expression
- developmental processes
- controlling transposon activity and viral infection
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- Prelims Cells Flashcards on Structural Features of Nucleic Acids , created by Kirstin Latimer on 06/01/2016.
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- Kirstin Latimer
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