The structure of DNA

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  • Created by: zoolouise
  • Created on: 28-03-16 15:45
What is DNA made up of?
Two polynucleotide strands - double helix. Pentose sugar - deoxyribose. Two purines adenine and guanine. Two pyrimidines cytosine and thymine.
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What maintains the shape of the double helix?
Hydrogen bonds join the bases in their complementary pairs and these maintain the shape of the double helix.
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What are some factors of DNA?
It's very long and thin. It's tightly coiled within a chromosome and the double helix is 2nm. A DNA molecule in a human chromosome is about 85mm long. The strands are antiparallel.
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How is DNA suited to its function?
It's a very stable molecule, it's content passes down generations with no change. It's a large molecule carrying a large amount of genetic information. Two strands can separate by breaking hydrogen bonds. Genetic information is protected.
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What is RNA made up of?
It's a single-stranded polynucleotide. It's pentose sugar is ribose. It's purine bases are adenine and guanine and it's pyrimidine bases are cytosine and uracil.
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What are the three types of RNA?
mRNA, rRNA and tRNA
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What is mRNA?
It's a long, single-stranded molecule synthesised in the nucleus. It carries the genetic code from the DNA to the ribosomes in the cytoplasm.
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It's a large, complex molecule found in the cytoplasm. It's ribosomes are made of rRNA and proteins. It's the site of translation of the genetic code into the protein.
What is rRNA?
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What is tRNA?
It's a small, single-stranded molecule. It has folds which cause complementary pairs to form between some of the bases. Molecules of tRNA transport specific amino acids to the ribosomes in protein synthesis
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What happens at the end of the molecule with 3' end in tRNA?
The end of the molecule with 3' end has the base sequence CCA this is where the specific amino acid the molecule carries is attached.
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What happens at the other end of the tRNA molecule?
The other end of the tRNA molecule has a sequence of there bases called the anticodon - this is complementary to the codon of DNA.
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Who proposed the molecular structure of DNA and when?
Watson and Crick in 1953
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What information did Watson and Crick use?
They used information from Franklin and Wilkins to build a 3D model of DNA.
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Other cards in this set

Card 2

Front

What maintains the shape of the double helix?

Back

Hydrogen bonds join the bases in their complementary pairs and these maintain the shape of the double helix.

Card 3

Front

What are some factors of DNA?

Back

Preview of the front of card 3

Card 4

Front

How is DNA suited to its function?

Back

Preview of the front of card 4

Card 5

Front

What is RNA made up of?

Back

Preview of the front of card 5
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