1. 2/27/12
Grab your clicker
Objective: Explain the concept of the genetic code
Warm-Up: Why does splicing occur during mRNA processing?
Congrats to science fair winners:
3rd:Katie, Alex & Zain
5th: Cuinn & Kenny, Woudese & Mariam, Elizabeth & Marina, Sabrina & Edward & Madison, Charlie & Paul

2. Which of the following is true about mRNA?
It is a double helix
It never leaves the nucleus
It uses the same nucleotides as DNA
It is synthesized by RNA polymerase
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[MC Any]
[MC All]

3. Exons… Are spliced out of the DNA Code for amino acids
Are spliced out of the mRNA
Are not transcribed
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[MC Any]
[MC All]

4. What is the function of the GTP cap and the poly-A tail?
Differentiate DNA from mRNA
Make the mRNA longer
Protect the mRNA from being degraded
Code for different amino acids
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[MC Any]
[MC All]

5. Retroviruses… Have an RNA genome Use the enzyme reverse transcriptase
Can insert their genetic information into the host DNA
All of the above
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[MC Any]
[MC All]

6. What is splicing? The process of removing non-coding sequence from DNA
The process of removing non-coding sequence from mRNA
The process of deleting genes
The process of mutating DNA sequence
[Default]
[MC Any]
[MC All]

7. The Problem Nucleotide sequences correspond to amino acids
Each amino acid has a unique nucleotide codon
There are four different nucleotides: A, C, G, T/U
There are 20 different amino acids
What is the minimum length of a codon? How many nucleotides are used to specify one amino acid, given that 1:1 won’t work?

8. The Genetic Code
The code is based on three-letter “words” called codons
A codon is made up of 3 nucleotide bases
Each codon corresponds to a single amino acid
tRNA “reads” the mRNA codons and translates those codons into amino acids
There are codons that signal “start” and “stop” to begin and end translation
The code is universal—every organism with DNA uses the same code