Section 4 Protein Synthesis Chapter 10 Section 4 Protein Synthesis

What is the importance of synthesizing protein? Our hair, skin, nails, muscle fibers, and enzymes are made of protein. Proteins protect us from infections and allow our blood to carry oxygen.

Protein Synthesis Forming proteins based on information in DNA and carried out by RNA Proteins are made in the organelles called ribosome.

RNA is the second type of nucleic acid Differences between DNA and RNA Double-stranded Thymine nitrogen base, not uracil Sugar; dexoyribose Longer Single-stranded Uracil nitrogen base, not thymine Sugar; ribose Shorter *3 types of RNA

Types of RNA: mRNA (Messenger RNA) Transcribes instructions from DNA in the nucleus tRNA (transfer RNA) Transfers amino acids to the ribosome to make a protein rRNA (ribosomal RNA) Makes up the ribosomes

1st step- Transcription This occurs in the nucleus The process of making an mRNA strand using the DNA in the nucleus as a template

Steps of transcription: RNA polymerase attaches to DNA causing the DNA strands to unwind and separate RNA polymerase adds free nucleotide s to one side of the DNA molecule If DNA reads… GGCTATACGTAC What would the mRNA read? 3) RNA polymerase reaches a termination signal to stop transcription and RNA and DNA are released from the polymerase

2nd Step Translation This occurs in the ribosome. Translation involves putting together amino acids according to the base sequence of mRNA transcribed from DNA

The Genetic Code -the term for the rules that relate how a sequence of nitrogen bases in nucleotides corresponds to a particular amino acid, Every 3 letters of mRNA is called a codon.

Each codon “codes” for a certain amino acid Ex. GGU CUA

tRNA -has a 3-letter anti-codon on one end and is attached to an amino acid on the other -brings the amino acid to the ribosome where it is attached to another amino acid by a peptide bond to form a polypeptide