Nucleic Acids

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What is a nucleic acid?
A large polymers in cell nuclei, there are 2 types, DNA and RNA.
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What are nucleic acids made up of?
nucleotides (monomers)
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What is the structure of a single nucleotide?
A pentose sugar (a 5 carbon sugar), a nitrogenous base (a single or double carbon ring structure with nitrogen) and a phosphate group ( a negatively charged inorganic molecule, -PO4 2-)
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How are nucleotides joined together to create a nucleic acid?
condensation reactions, joining the phosphate with the hydroxyl group on the 3rd carbon on the pentose sugar, water is given off and the bonds formed are phosphodiester bonds
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What is the sugar-phosphate backbone?
The single polymer of nucleotides joined by condensation reactions ( 2 sugar-phosphate backbones joined by hydrogen bonds creates a nucleic acid)
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What does DNA stand for?
Deoxyribonucleic Acid
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What is the sugar in DNA?
Deoxyribose (a sugar with 1 less oxygen than ribose, ribose and deoxyribose are both pentose sugars)
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Name the 4 nitrogenous bases
Cytosine, guanine, thymine and adenine
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Whats the name for the 2 groups the bases are split into?
Pyrimidines and purines
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Which bases are pyrimidines?
pYrimidines- cYtosine and thYmine
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Which bases are purines?
Guanine and Adenine
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Which bases bind to which? What is this called?
Cytosine and guanine, thymine and adenine, it is called complimentary base paring
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How many hydrogen bonds are formed when A and T join?
2 hydrogen bonds
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How many hydrogen bonds are formed when C and G join?
3 hydrogen bonds
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What is the DNA helix?
2 strands of polynucleotides coiled into a helix, held together by the hydrogen bonds formed between the bases
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Does the polynucleotides run parallel or anitparallel?
Antiparallel- the polynucleotides run in opposite directions
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Why are base paring rules important?
It allows DNA to be copied and transcribed
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What does complimentary base paring ensure?
A pyrimidine always binds to a purine so it maintains a constant distance between the 2 polynucleotides. In addition, it allows DNA to always have the same amounts of A and T and G and C
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What is the genetic code?
The sequence of nitrogenous bases
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What is RNA? How does it differ from DNA?
A nucleic acid with ribose as the sugar (instead of deoxyribose in DNA) and the base thymine is replaced with uracil in RNA
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What does RNA do?
DNA is too large to move out of the nucleus to carry out protein synthesis so it is transcribed into similarly short messages called messenger RNA, which can move out of the nucleus
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What happens to the RNA after protein synthesis?
The RNA comes away from the ribesome (the site of protein synthesis) and is hydrolysed in the cytoplasm, breaking the phosphodiester bonds and the RNA nucleotides are released and reused
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Other cards in this set

Card 2

Front

What are nucleic acids made up of?

Back

nucleotides (monomers)

Card 3

Front

What is the structure of a single nucleotide?

Back

Preview of the front of card 3

Card 4

Front

How are nucleotides joined together to create a nucleic acid?

Back

Preview of the front of card 4

Card 5

Front

What is the sugar-phosphate backbone?

Back

Preview of the front of card 5
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