Biochemistry: Macromolecules: Nucleic Acids – Flashcards
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What is a nucleotide?
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A nucleotide is one of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a nitrogenous base (one of four chemicals: adenine, thymine, guanine, and cytosine) a molecule of sugar (deoxyribose or ribose) and a phosphate group.
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What is the difference between a nucleotide and a nucleoside?
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A nucleotide contains a sugar, nitrogenous base and phosphate group; whereas a nucleoside is just a sugar and nitrogenous base. When a phosphate group of a nucleotide is removed by hydrolysis, the structure remaining is nucleoside.
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Why is NTP called "nucleoside triphosphate" and not "nucleotide triphosphate"?
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Nucleoside indicates that there is no phosphates already attached to the group, so when "triphosphate" is indicated, you know there is three phosphates. Nucleotide indicates already that there is a phosphate group, so it's redundant to indicate "triphosphate".
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What are the functions of nucleic acids?
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Nucleic acids have two main functions:
1) Storing hereditary information in the DNA polymers
2) Coding for protein synthesis in the RNA
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What are the 3 key differences between RNA and DNA?
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1) The pentose sugar for a DNA nucleotide is deoxyribose; whereas it is ribose for RNA.
2) The nitrogenous base Thymine is only found on DNA nucleotides; whereas only Uracil is found on RNA
3) DNA have two strands and coil to form a double-helix structure; RNA only has one strand but still coils
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