Presentation Transcript

1. Protein Synthesis

2. Definitions • Protein Synthesis: the construction of proteins directed by DNA ---------Consists of 2 steps, which are----------- • Transcription: copying DNA in the nucleus to mRNA • Translation: using mRNA as a guide to form a polypeptide (protein)

3. What part of the cell cycle? Mitosis S Phase G2 Phase

4. Definitions 4. rRNA: ribosomal RNA 5. mRNA: messenger RNA 6. tRNA: transfer RNA

5. Where does protein synthesis happen? • The ribosomes!

6. What are the monomers ribosomes use to build proteins? • Amino acids

7. What are proteins used for?

8. How does protein synthesis happen? This is known as the central dogma of Biology.

9. DNA: Deoxyribose sugar Contains thymine (T) A-T and C-G Double-stranded RNA: Ribose sugar Contains uracil (U) instead of thymine A-U and C-G Single strand 3 Differences between DNA & RNA

10. 3 Types of RNA • rRNA • Location: nucleus and ribosomes • Function: combines with proteins to make ribosomes

11. 3 Types of RNA 2. mRNA a. Location: nucleus and cytoplasm b. Function: brings instructions from DNA in nucleus to ribosomes in the cytoplasm mRNA

12. 3 Types of RNA 3. tRNA a. Location: nucleus and cytoplasm b. Function: brings amino acids to ribosome to build polypeptides (proteins) tRNA

13. How are proteins made? • Step 1: Transcription – RNA polymerase splits open DNA and copies it to form a strand of mRNA. mRNA leaves the nucleus.

14. How are proteins made? • Step 2: Translation – mRNA in the cytoplasm binds to a ribosome. Ribosome reads it 3 bases at a time, and matches these with bases on tRNA attached to an amino acid. An amino acid chain is formed from many peptide bonds.

15. How are proteins made? • Step 3: Protein folding – polypeptide is folded, and combined with other polypeptides to form a protein.

17. What is a codon? • mRNA is read 3 bases at a time – a codon is the 3 base code, or triplet code, of mRNA.

19. What is a polypeptide? • A long chain of amino acids linked by peptide bonds

20. How many different amino acids can each codon specify? • Only one (CUC only codes for leucine)

21. Can an amino acid have more than one codon? • Yes! (ex.: phe, leu, pro, thr, ala, val, gly, etc.)

24. Transcribe the DNA into mRNA, then translate it into amino acids.

26. Animations of Protein Synthesis http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html http://www.wisc-online.com/objects/index_tj.asp?objID=AP1302 GAME: http://library.thinkquest.org/20465/g_DNATranscription.html http://learn.genetics.utah.edu/content/begin/dna/transcribe/