Protein Synthesis Chapter 12 3 The basic Review

Protein Synthesis Chapter 12 -3

The basic Review 1. 2. 3. 4. 5. 6. 7. 8. Where is the code for proteins stored? Answer: In the Nucleus What organelle makes proteins? Answer: Ribosomes What are proteins made out of? Answer: Amino Acids How do we get the “code” for the proteins out of the nucleus and onto the ribosome? Answer: It must be carried out by a special molecule; m. RNA

DNA vs. RNA DNA n Double stranded n N-bases: n n n n Adenine Thymine Cytosine Guanine 5 -C sugar = Deoxyribose Huge molecule Stays in nucleus RNA n Single stranded n Three types n N-bases: n n n n Adenine URACIL Cytosine Guanine 5 -C sugar = Ribose Small molecule Can travel from nucleus to cytoplasm

The Three Types of RNA n m. RNA Messenger RNA (m. RNA) n n n Transfer RNA (t. RNA) n n This RNA is a copy of 1 gene of the DNA and is made in the nucleus m. RNA leaves the nucleus and goes to a ribosome This RNA transfers Amino Acids to the ribosome and m. RNA Ribosome RNA (r. RNA) n This RNA makes up a small portion of the ribosome and is not that important

Codons on m. RNA n n n A “codon” is a group of 3 nitrogen bases that codes for a specific amino acid This allows for 20 different amino acids to exist Each t. RNA molecule has an “anticodon” that matches each codon (a sequence of 3 n-bases that are complimentary to the codon)

STEP 1: Transcription – takes place in nucleus -DNA is a code for proteins -Each gene on DNA codes for 1 protein a) DNA is unzipped and a small portion (1 gene) is copied as m. RNA -m. RNA is the cruddy copy of one gene b) m. RNA is small enough to leave the nucleus while DNA is not

STEP 2: Translation – takes place in cytoplasm -m. RNA leaves the nucleus and attaches to a ribosome a) The ribosome “reads” the codons of m. RNA b) t. RNA transfers amino acids from the cytoplasm to the codons c) amino acids are linked together with peptide bonds d) t. RNA leaves to pick up another amino acid

Video of Protein Synthesis n http: //www. youtube. com/watch? v=983 lhh 20 r. GY&feature=related