6. What is gene expression?

8. Gene Expression and Protein Synthesis
The Genetic Code
Gene-a section of DNA that codes for an amino acid sequence (on RNA), which is a building block for proteins.

9. Amino Acids and Codons

10. These three letter words are called codons
Genes can be made up of 20 different amino acids made up of three letter words (four letters to choose from-nitrogenous bases of RNA [A, U, G, C]).
These three letter words are called codons
Example: Codon AUG, codes for methionine.

12. 50 Cents favourite codon: UAG

14. Simple Summary DNA produces an RNA strand in the nucleus
RNA single strand leaves the nucleus through a nuclear pore
RNA enters cytoplasm
RNA attaches to a ribosome
RNA molecule is decoded/”read” and produce a protein

16. From DNA RNA Protein Step One: Transcription
-RNA molecule is made that is complimentary to DNA molecule
DNA sequence: AAGCT
RNA complimentary sequence: UUCGA
-RNA polymerase is the enzyme used to split apart the DNA and join the RNA nucleotides together
-messengerRNA (mRNA ) is released into the cytoplasm and reaches a ribosome

18. transcription

19. 2. Step Two: Translation:
-The information on the mRNA is translated and codes for a specific amino acid (needed to make the polypeptide protein)
Transfer RNA (tRNA)-attach to an amino acid and brings it to the ribosome (containing rRNA)

23. Steps of Translation Initiation:
A start codon on mRNA, AUG methionine, allows translation to begin
mRNA codon pairs with the complimentary tRNA anticodon
Example codon on mRNA: AUG
Anticodon on tRNA: UAC

25. Amino Acid tRNA Anticodon mRNA strand codon
tRNA synthetase helps bind the amino acid to the tRNA molecule
tRNA
Anticodon
mRNA strand codon

26. II. Elongation-polypeptide gets longer one amino acid at a time
III. Termination-synthesis stops due to a stop codon
The three stop codons on the mRNA strand are: ___, ____, ____
Refer to page 330 (or 299)

28. Just like a recipe that you follow…instead of eggs, its amino acids…instead of samosas, it’s proteins (gene expression)

31. DNA RNA Double strand Single strand Helix (spiral) Straight
(Deoxyribonucleic Acid)
RNA
(Ribonucleic Acid)
Double strand
Single strand
Helix (spiral)
Straight
Sugar present: deoxyribose
Sugar present: ribose
Nitrogen bases:
Adenine, Thymine, Guanine, Cytosine
Adenine, Uracil, Guanine, Cytosine
(Uracil replaces thymine)
Found in the nucleus
Found in the nucleus and the cytoplasm (not confined in the nucleus)

32. Three Classes of RNA Messenger RNA (mRNA):
Takes a message made from DNA in the nucleus to a ribosome in the cytoplasm

33. Ribosomal RNA (rRNA):
A part of/embedded in the ribosome
and the site in which polypeptides are made. (two subunits: small and large ribosome)

34. Transfer RNA (tRNA):
Transfers amino acids to the ribosome (helps translate the message)

35. The tRNA synthetase (enzyme) recognizes which amino acid belongs to which tRNA molecule