Protein Synthesis Study Guide

Exons

Coding regions of mRNA

Translation

RNA to protein

Codon

Set of 3 nucleotides on mRNA

Summarize, in detail, the steps of transcription and translation. Include the location of each process and the enzymes involved.

Transcription: 1. RNA polymerase binds to the DNA promoter where transcription is to begin and unzips the gene that needs to be copied. 2. RNA polymerase uses complementary base-pairing rules to match RNA nucleotides with the exposed DNA nucleotides. 3. Release the completed mRNA molecule. 4. DNA zips back up and the mRNA leaves the nucleus and enters the cytoplasm. Translation: 1. mRNA attaches to the small subunit of the ribosome. 2. Ribosome reads the mRNA codons, always in the 5' to 3' direction, starting at the AUG codon. 3. tRNAs act like taxis to pick up and drop off the amino acids that match with each codon. 4. tRNAs continue to drop off amino acids, and the ribosome binds the amino acids together with peptide bonds. 5. When the stop codon is reached, the ribosome releases the completed polypeptide chain.

Transcribe and translate the following strand of DNA: TACACCGGAGCGTTTATT

5' AUGUGGCCUCGCAAAUAA 3' UACACCGGAGCGUUUAUU

Polypeptide

A chain of amino acids

Anticodon

Complimentary nucleotides on tRNA

Explain the central dogma and why a two-step process is necessary in order to make proteins.

DNA is changed to mRNA through transcription, then mRNA is changed to protein through translation It has to be a two step process because DNA needs to leave the nucleus, but it is too big to do that

Transcription

DNA to RNA

Describe an example of how gene expression is regulated.

Depressors and activators

Explain the difference between epigenetics and mutations.

Epigenetics is the study of changes in gene expression, while mutation is change in the DNA sequence

Genetic code

Instructions for making a protein

Amino acid

Monomer of protein

Introns

Non-coding regions of mRNA

Protein synthesis

The process of reading instructions in DNA to make a polypeptide

Epigenetics

The study of changes in gene expression

Describe the roles of the three essential types of RNA in protein synthesis. Include a sketch to represent each one.

mRNA copies instructions from DNA and carries them to the cytoplasm. tRNA binds and carries specific amino acids to ribosomes. rRNA makes up the ribosome along with protein and helps catalyze the formation of peptide bonds. See email for sketches

Translation

mRNA to polypeptide