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Amino Acid Structure:
Peptide bond Reaction:
Walk the Dogma:
Remember- DNA contains the instructions that tells the cell how to make PROTEINS
THE CENTRAL DOGMA OF CELL BIOLOGY:
Protein Synthesis has 2 main phases:
Transcription (DNA  RNA)
Translation (RNA  DNA)
DNA v. RNA
-Deoxyribose Sugar
-Double Stranded
- A binds to T
-Longer in length
-Location: nucleus
- 1 type
- Ribose Sugar
- Single- Stranded
- A binds to U (URACIL)
- Shorter in length
- Location: cytoplasm
- 3 types
Ribonucleic Acid (RNA):
There are 3 types of RNA:
1) Messenger RNA (mRNA)
- Structure- Linear single strand
- Function- Carries genetic info from the DNA in the nucleus to the cytoplasm
2) Transfer RNA (tRNA)
- Structure: Hairpin Loop
- Function: Binds and carries specific amino acids
3) Ribosomal RNA (rRNA)
- Structure: Globular
- Function: Combines with proteins to form ribosomes
Protein Synthesis: TRANSCRIPTION
Transcription: The process by which genetic information is copied from DNA to RNA
- DNA double- strand “unzips”
- RNA polymerase (an enzyme) binds to a specific region on DNA called a PROMTER
- RNA polymerase travels along the gene, creating a chain of mRNA that is complementary to
the strand of DNA
- RNA polymerase reaches the termination signal at the end of the gene & and falls off the DNA
strand.
DEFINITION: GENE
- A specific segment on a strand of DNA, which encompasses the space between a
promoter and a termination signal, that contains the instructions to make a single
polypeptide.
Post- Transcription Modification
- Occurs before translation can begin
- INTRONS are removed, EXONS are joined
o Intron: non- coding sections of a gene
o Exon: Region of a specific gene that does code for protein
- This process a.k.a. mRNA SPLICING
- Catalyzed by a spliceosome (RNA/ protein complex)