What is a gene?

1. Protein Synthesis What is a gene? A specific sequence of nucleotides on DNA (chromosome) that contains the information to make proteins.

2. What is an amino acid? The building blocks of proteins.

3. What are the three types of RNA? Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)

4. What is protein synthesis? The process by which proteins are made in the body.

5. What are the two major steps of protein synthesis? Step 1: Transcription: occurs in the nucleus of the cell

6. Steps of transcription: a. RNA is made from the DNA gene DNA gene: T A C CC A G C CCG A T G A T T A C G C C A G A C C A C T RNA: A U G GG U C G GG C U A C U A A U G C G G U C U G G U G A

7. DNA splits into two strands Transcription: RNA complementary bases attach to the bases on one side of the strand.

8. Why does DNA need mRNA to carry the message to the ribosome to make proteins? The DNA is too big and cannot pass through the nuclear membrane b. The RNA is modified Exons - parts of the gene that stay Introns - lie between exons and are cut out- do not code for proteins

9. Write the modified RNA below. Label the introns and exons from the original RNA strand. intron intron DNA gene: T A C CC A G C CCG A T G A T T A C G C C A G A C C A C T Modified RNA: A U G GG U C G GG C U A A U G C G U G A

10. Once modified, the RNA is now known as mRNA c. mRNA is broken down into codons (3 nucleotides or letters) mRNA codons: A U G - G G U - C G G - G C U - A A U - G C G - U G A

11. What does each codon stand for?

12. Step 2: Translation: occurs in the ribosome

13. Steps of Translation: a. mRNA leaves the nucleus and attaches to a ribosome (ribosome is made up of rRNA) b. Each codon is translated and an amino acid is matched with the codon.

14. mRNA codons: A U G - G G U - C G G - G C U - A A U - G C G - U G A Meth/start – Gly – Arg – Ala – Asn – Ala - stop Amino acids:

15. c. tRNA picks up the amino acid transports the amino acids to the mRNA codon. It contains anti-codons Anti-codon simply means opposite of the codon. The anti-codon also contains 3 bases and they are the compliment to the codon on the mRNA.   mRNA codons: A U G - G G U - C G G - G C U - A A U - G C G - U G A tRNA anti-codons: U A C – C C A – G C C – C G A – U U A – C G C – A C U

16. What is the purpose of the start codon? • It tells where to start making the protein.  What is the purpose of the stop codon? • It tells where to stop making the protein.  What is made once all the amino acids are linked together? • Protein What bond links the amino acids together? • Peptide Bond