Central Dogma

Central dogma- DNA→ mRNA→ protein

-is that information held in DNA is transcribed into messenger RNA (mRNA) & translated into proteins. This way, the information held in the DNA bases is turned into a functional product.

Gene: a certain stretch of chromosomes

Genes may be short (500 bp) or long (2.3 million bp)

bp: base pair

DNA: letters, ordered into genes

RNA: specific letters to make a sentence- needs editing

Protein: turn letters into a functional product you can see

transcription (DNA→ mRNA)

transcription: synthesis of single stranded messenger RNA

mRNA that carries DNA info to the ribosomes to make proteins

-making an mRNA copy of DNA

-occurs in the nucleus

Transcription important enzyme

RNA polymerase: an enzyme that binds DNA and regulates mRNA synthesis; works 5´ to 3´ and adds the RNA nucleotides to the growing mRNA

• start with DNA that has exons and introns

• make a full copy of mRNA with exons and introns

• exons are coding sequences of DNA= will be turned into protein

• introns are non-coding sequences of DNA that will NOT be turned into protein

  *INTron go IN the Trash*

  What is translation?

  -process where mRNA is ´read´ 3 nucleotides at a time (codon) and turned into a protein

  -occurs on ribosomes in the cytoplasm (free ribosomes or ribosomes on the rough er)

  Ribosome is made of ribosomal RNA (rRNA) plus protein

Transfer RNA (tRNA)

¨reads the codons with an anticodon and transports amino acids to ribosome

There are only 4 bases but 20 amino acids….

-the genetic code is degenerate because different codons can specify the same amino acid