GN 301 Module 3: The Genetic Code and Translation

tRNA

carries the amino acid to the site of the ribosome.

pattern of degeneracy

The ________ allows one to organize the codons into "families "and "pairs ..

stop codons

UAA, UAG, or UGA

Elongation

amino acids are brought to the ribosome by tRNAs and linked together to form a chain.

mRNA

contains the codon, which are 3 bases that specify an amino acid for protein synthesis.

Amino acids

joined by peptide bonds to make proteins.

tRNA

transport RNA

Initiation

the ribosome gets together with the mRNA and the first tRNA so translation can begin

Elongation

amino acids are brought to the ribosome by tRNAs and linked together to form a chain

Termination

when a stop codon in the mRNA (UAA, UAG, or UGA) enters the A site

(Hint

First find the start codon and split the RNA into codons and then translate each codon)

**Properties of the genetic code**

* universal
* degenerate
* start-stop function
* polarity
* triplet code

**How many amino acids have exactly 1 codon? Which are they?**

2 amino acids (Met and Trp)

**How many amino acids have exactly 4 codons? Which are they?**

5\. 1) Val, 2) Pro, 3) Thr, 4) Ala, 5) Gly

**What is the highest number of codons for one amino acid? Which are they?**

6 codons. (Leu, Ser, Arg)

**Is there a pattern to the degeneracy of the code?**

Yes. The pattern of degeneracy allows one to organize the codons into "families" and "pairs.”

mRNA is read from

5’ to 3’

Determine the sequence of the protein translated from this mRNA.

5’ – G G G C A A A U G A C A G U U C C G G A A U A A G G C U G A – 3’

Met, Thr, Val, Pro, Glu, STOP

The template strand of DNA is given below.

3’ – A T T A C G C C G G T T A G A C T T T – 5’

**What is the sequence of the mRNA formed from this strand?**

5’ - U A A U G C G G C C A A U C U G A A A - 3’

**What is the process of forming mRNA called?**

Transcription

**What is the process of making protein from mRNA called?**

transcription

**Where does translation take place?**

in ribosomes

**What is the role of tRNA in translation?**

brings proper amino acids to ribosomes

**What is the sequence of the protein made from this mRNA sequence?** (Hint: First find the start codon and split the RNA into codons and then translate each codon)

5’ - U A A U G C G G C C A A U C U G A A A - 3’

Met, Arg, Pro, Ile, STOP