PROTEIN SYNTHESIS
Process whereby biological cells generate new proteins
PROCESS:
o Takes place in 2 steps!TRANSCRIPTION & TRANSLATION
o TRANSCRIPTION!process by which the DNA encodes/makes mRNA
o TRANSLATION!process by which information from DNA carried by mRNA is
used to form chains of amino acids=protein
TRANSCRIPTION:
• DNA double helix molecule unwinds
• Weak hydrogen bonds break!Double-stranded molecule unzips
• 2 separate strands of DNA are formed!1 strand is a template
• The template strand allows is the portion of DNA that codes for the needed
protein can be transcribed
• Since mRNA is a single-stranded molecule, only one of the two strands of
DNA is used as a template for the new RNA strand
• Template strand forms mRNA using free- oating nucleotides from the
nucleoplasm
• mRNA=complementary to DNA
BASE PAIRING:
❖ DNA cytosine pairs with RNA guanine
❖ DNA guanine pairs with RNA cytosine
❖ DNA thymine pairs with RNA adenine
❖ DNA adenine pairs with RNA uracil
• mRNA has coded message from DNA for protein synthesis
• mRNA strand is released and moves from the nucleus to the cytoplasm and
attaches to the ribosome, away from the DNA molecule
• Ribosome will build each protein step by step after reading the order of
codons as it moves along the mRNA strand
• DNA molecule rewinds in a double helix
TRANSLATION
• mRNA sent to cytoplasm!bonds to ribosomes
• Ribosomes=where protein synthesis occurs
• Ribosomes have building sites for mRNA and 2 sites for tRNA
• mRNA goes into place on ribosome
• tRNA binds to ribosome through polypeptide chains!the sequence is
determined by the mRNA code
• Anticodon on tRNA pairs with the complementary nitrogenous bases with
mRNA
• tRNA molecules each carry a speci c amino acid
• tRNA molecules with the same anticodon sequence will always carry the
same amino acids!ensures consistency of the proteins coded for in DNA
Process whereby biological cells generate new proteins
PROCESS:
o Takes place in 2 steps!TRANSCRIPTION & TRANSLATION
o TRANSCRIPTION!process by which the DNA encodes/makes mRNA
o TRANSLATION!process by which information from DNA carried by mRNA is
used to form chains of amino acids=protein
TRANSCRIPTION:
• DNA double helix molecule unwinds
• Weak hydrogen bonds break!Double-stranded molecule unzips
• 2 separate strands of DNA are formed!1 strand is a template
• The template strand allows is the portion of DNA that codes for the needed
protein can be transcribed
• Since mRNA is a single-stranded molecule, only one of the two strands of
DNA is used as a template for the new RNA strand
• Template strand forms mRNA using free- oating nucleotides from the
nucleoplasm
• mRNA=complementary to DNA
BASE PAIRING:
❖ DNA cytosine pairs with RNA guanine
❖ DNA guanine pairs with RNA cytosine
❖ DNA thymine pairs with RNA adenine
❖ DNA adenine pairs with RNA uracil
• mRNA has coded message from DNA for protein synthesis
• mRNA strand is released and moves from the nucleus to the cytoplasm and
attaches to the ribosome, away from the DNA molecule
• Ribosome will build each protein step by step after reading the order of
codons as it moves along the mRNA strand
• DNA molecule rewinds in a double helix
TRANSLATION
• mRNA sent to cytoplasm!bonds to ribosomes
• Ribosomes=where protein synthesis occurs
• Ribosomes have building sites for mRNA and 2 sites for tRNA
• mRNA goes into place on ribosome
• tRNA binds to ribosome through polypeptide chains!the sequence is
determined by the mRNA code
• Anticodon on tRNA pairs with the complementary nitrogenous bases with
mRNA
• tRNA molecules each carry a speci c amino acid
• tRNA molecules with the same anticodon sequence will always carry the
same amino acids!ensures consistency of the proteins coded for in DNA
