Protein Synthesis

Cards (90)

  • Protein synthesis is the process which produces proteins from the information in the DNA code.
  • What is protein synthesis?
    The process which produces proteins from the information in the DNA code
  • What are the two stages of protein synthesis?
    Transcription and Translation
  • Transcription is when the DNA code is copied (transcribed) into a single strand of RNA called messenger RNA
  • Translation is when the mRNA is read by a ribosome and the code is translated into a polypeptide chain.
  • What is transcription?

    The process by which genetic information is encoded in the DNA is copied into a complementary RNA molecule
  • Where does protein synthesis occur?
    In the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells
  • Where does protein synthesis occur in eukaryotic cells?
    In the nucleus
  • Where does protein synthesis occur in prokaryotic cells?

    In the cytoplasm
  • Why is transcription necessary?
    The DNA molecule itself is too large to fit through the nuclear pores, so the smaller mRNA is used to ‘copy’ a section of DNA which codes for a protein.
  • If a gene codes for a certain protein, it needs to be able to make all of the amino acids which make up that protein, therefore, each section of the gene (called a codon) codes for a different amino acid.
  • The genome is a complete set of genes in an individuals DNA
  • What is the genome?

    The complete set of genes in an individuals DNA
  • The genes in the genome encode for the different proteins a cell needs
  • The proteome is the full range of proteins an individual can produce
  • What is the proteome?

    The full range of proteins that an individual can produce
  • Every three bases on a gene are known as a codon
  • What is the name for every three bases on a gene?
    A codon
  • Each codon encodes for a specific amino acid.
  • What does each codon encode for?
    A specific amino acid
  • A single gene is essentially a sequence of codons
  • Codons are non-overlapping, meaning that each codon codes for only its particular amino acid, and does not specify the positions of the other amino acids on the final protein
  • Codons are degenerate, meaning that some of the amino acids in our body can be specified by more than one codon
  • There are a total of 64 codons in most organisms, this is referred to as the genetic code.
  • How many codons are there in most organisms?
    64
  • Three of the 64 codons in organisms are STOP codons, which signals the end of a polypeptide chain.
  • How many codons are STOP codons?
    Three
  • What are STOP codons?
    Codons that signal the end of a polypeptide chain
  • One of the 64 codons is called a START codon, and has the sequence ATG, this signals the start of the polypeptide chain.
  • What is the sequence for the START codon?
    ATG
  • What is a START codon?
    A codon that signals the start of the polypeptide chain
  • The remaining 60 codons (not STOP or START) encode for the 20 amino acids that our cells are able to use to make proteins.
  • The genetic code is universal, being the same in all living organisms, providing indirect evidence for evolution
  • The genetic code provides indirect evidence for?
    Evolution
  • RNA is a single stranded nucleic acid molecule that is made from the same bases as DNA, except for the bases Uracil, which replaces Thymine.
  • What are the two types of RNA?
    Messenger and transfer
  • Messenger RNA is transcribed from the DNA in the nucleus to produce a single stranded RNA, which is complementary to the DNA base sequence it has been transcribed from.
  • Messenger RNA travels from the nucleus to the ribosomes in the cytoplasm, which are proteins that translate mRNA into amino acids and synthesise the polypeptide.
  • Transfer RNA forms a clover-like shape and is vital for translation, it reads the mRNA codons and brings the corresponding amino acids into the ribosomes.
  • Each tRNA molecule has an anticodon, which is complementary to a specific codon on the mRNA. The amino acid that corresponds to a specific anticodon binds to a specific attachment site on the tRNA molecule.