RNA and Protein Synthesis

1. RNA and Protein Synthesis

2. From Genes to PRoteins

3. All of the 100 trillion cells in your body came from one original cell: thefertilized eggthat grew intoYOU! And all of those 100 trillion cells have exactly the same DNA in them. So how come there are so many different kinds of cells in your body? How did they get so specialized?

4. The answer is… Different genes are turned on in different types of cells. Each gene carries the instructions for making a protein, which does the work of the cell. Different cells make different proteins. For example, liver cells make different proteins than nerve cells, or eye cells, or stomach cells. DNAis the “boss” or manager of each cell. It’s the DNA that has the instructions for making the proteins. So what are the “workers” of the cells? The answer: RNA

5. Here’s what happens… DNA RNA Protein Trait transcription translation

6. RNA RNA is very similar in structure to DNA with 3 main differences.  RNA contains the sugar ribose instead of deoxyribose  RNA has the base uracil (U)instead of thymine (T).

7. RNAIsSingle-Strandedinstead of Double-Stranded like DNA

8. There are Different RNAs with Different Functions Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Recently, a new class of RNA, microRNA, has been shown to regulate gene expression.

9. deoxyribonucleic acid ribonucleic acid DNA/RNA deoxyribose ribose double-helix (twisted ladder) one-sided ladder adenine adenine cytosine cytosine guanine guanine thymine uracil travels between nucleus & cytoplasm stays in nucleus 3 types: mRNA tRNA, rRNA 1 type forms genetic code that specifies what proteins are produced by a cell carries genetic code from nucleus to the ribosomes; directs production of the proteins

10. Transcription RNA polymerase acts here makes an RNA copy of DNA The enzyme RNA polymerase opens the DNA strands and makes an RNA copy of one of the DNA strands.

11. The Genetic Language Uses 4 Letters Written Into 3-Letter Words

12. Amino Acids– What the Genetic Code Specifies There are 20 different amino acids Two examples Amino acids are the building blocks of proteins. A protein is made up of many amino acids bonded together. It’s the proteins that carry out every function in all your cells. It’s the proteins that give an organism its traits.

13.  The 4 nitrogen bases (A, C, G, T) are read in groups of three.  Each group of 3 bases is called acodon.  Each codon stands for 1 of the 20 amino acids.  Since there are 64 possible combinations of 3 and only 20 amino acids, some amino acids have more than one codon. For example, AAA and AAG both code for lysine.  There are also codes for “Start” and “Stop”.

14. Ribosomesare Complicated Protein-Synthesizing Machines Ribosomes are located in two places:  attached to the ER(Endoplasmic Reticulum), or  floating in the cytoplasm.

15. Protein Synthesis 1.DNAmolecule unzips and makes a single-stranded copy of itself(mRNA) 1 2.mRNAleaves the nucleus and attaches to aribosome. 3.Ribosomemoves along themRNAand “reads” it. 2 4 4.tRNAbrings amino acids to ribosome and attaches them to theprotein chain. 3 5.Theribosomereleases theprotein. 5

16. Protein Synthesis Protein Synthesis

17. Protein Synthesis Protein Synthesis (tRNA) (mRNA) Protein synthesis

18. Protein Synthesis Protein Synthesis

19. A U G G G C U U A A A G C A G U G C A C G U U This is a molecule of messenger RNA. It was made in the nucleus by transcription from a DNA molecule. codon mRNA molecule

20. ribosome A U G G G C U U A A A G C A G U G C A C G U U A ribosome on the rough E.R. attaches to the mRNA molecule.

21. Amino acid tRNA molecule anticodon U A C A U G G G C U U A A A G C A G U G C A C G U U • A transfer RNA molecule arrives. • It brings an amino acid to the first three bases (codon) on the mRNA. • The three unpaired bases (anticodon) on the tRNA link up with the codon.

22. U A C C C G A U G G G C U U A A A G C A G U G C A C G U U • Another tRNA molecule comes into place, bringing a second amino acid. • Its anticodon links up with the second codon on the mRNA.

23. Peptide bond C C G U A C A U G G G C U U A A A G C A G U G C A C G U U • A peptide bond (chemical bond) forms between the two amino acids.

24. C C G U A C A U G G G C U U A A A G C A G U G C A C G U U • The first tRNA molecule releases its amino acid and moves off into the cytoplasm.

25. C C G A U G G G C U U A A A G C A G U G C A C G U U • The ribosome moves along the mRNA to the next codon.

26. C C G A A U A U G G G C U U A A A G C A G U G C A C G U U • Another tRNA molecule brings the next amino acid into place.

27. C C G C C G A U G G G C U U A A A G C A G U G C A C G U U • A peptide bond joins the second and third amino acids to form a polypeptide (protein) chain.

28. G U C A C G A U G G G C U U A A A G C A G U G C A C G U U • The process continues. • The polypeptide (protein) chain gets longer. • This continues until a termination (stop) codon is reached.

29. G U C A C G A U G G G C U U A A A G C A G U G C A C G U U • The process continues. • The polypeptide (protein) chain gets longer. • This continues until a termination (stop) codon is reached.

30. A U G G G C U U A A A G C A G U G C A C G U U • The polypeptide (protein) is then complete, and is released from the ribosome.