3.5 Transcription And Translation Flashcards Preview

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Flashcards in 3.5 Transcription And Translation Deck (5)
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1

Compare the structure of DNA and RNA

DNA
• Deoxyribose pentose sugar
• Thymine base
• Double stranded
• Long molecule
RNA
• Ribose pentose sugar
• Uracil
• Single stranded
• Shorter molecule
Both
• Both have a pentose sugar, a phosphate group and a nitrogenous base

2

List the three forms of RNA

• Messenger RNA (mRNA)
• Transfer RNA (tRNA)
• Ribosomal RNA (rRNA)

3

Describe a 'codon' and outline its function

• A codon is a triplet of bases which codes for a particular amino acid
• The order of codons determines the amino acid sequence for a protein
• The coding region always begins with the START codon (AUG) and terminates with a STOP codon

4

Describe the genetic code

• Universal - every living thing uses the same code (there are a few rare and minor exceptions)
• Degenerate - more than one codon may code for the same amino acid
– e.g. GGT and GGG = glycine

5

Explain the relationship between one gene and one polypeptide

• One gene codes for one polypeptide
• The gene sequence is converted into a polypeptide via translation (mRNA synthesis) and transcription (polypeptide synthesis)
• Some proteins consist of a number of polypeptide chains, and so will need multiple genes