P ROTEIN SYNTHESIS

The base sequence of DNA codes for the amino acids that make up a protein (one gene codes for one polypeptide).

P ROTEIN SYNTHESIS The base sequence of DNA codes for the amino acids that make up a protein (one gene codes for one polypeptide). A sequence of 3 bases in DNA, a triplet, codes for an amino acid.

P ROTEIN SYNTHESIS The base sequence of DNA codes for the amino acids that make up a protein (one gene codes for one polypeptide). A sequence of 3 bases in DNA, a triplet, codes for an amino acid. Protein synthesis takes place in cell organelles called ribosomes, which are found in the cytoplasm.

P ROTEIN SYNTHESIS The base sequence of DNA codes for the amino acids that make up a protein (one gene codes for one polypeptide). A sequence of 3 bases in DNA, a triplet, codes for an amino acid. Protein synthesis takes place in cell organelles called ribosomes, which are found in the cytoplasm. A carrier molecule takes the code from DNA in the nucleus to the ribosomes in the cytoplasm.

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA)

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA) RNA are nucleic acids like DNA but there are some key differences: -

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA) RNA are nucleic acids like DNA but there are some key differences: - There are 3 different forms on RNA – messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). They each have a different function.

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA) RNA are nucleic acids like DNA but there are some key differences: - There are 3 different forms on RNA – messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). They each have a different function. - RNA is single stranded – though folding can make RNA appear double stranded at times.

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA) RNA are nucleic acids like DNA but there are some key differences: - There are 3 different forms on RNA – messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). They each have a different function. - RNA is single stranded – though folding can make RNA appear double stranded at times. - The sugar in RNA is ribose

P ROTEIN SYNTHESIS The carrier molecule is messenger ribonucleic acid (mRNA) RNA are nucleic acids like DNA but there are some key differences: - There are 3 different forms on RNA – messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). They each have a different function. - RNA is single stranded – though folding can make RNA appear double stranded at times. - The sugar in RNA is ribose - The base uracil (u) replaces the base thymine (T) found in DNA.

S TAGES OF PROTEIN SYNTHESIS Transcription: Every gene has 3 regions. - The promoter which turns the gene ‘on’ and ‘off’ and signals the site of transcription

S TAGES OF PROTEIN SYNTHESIS Transcription: Every gene has 3 regions. - The promoter which turns the gene ‘on’ and ‘off’ and signals the site of transcription - The coding region which has the base sequence for the protein

S TAGES OF PROTEIN SYNTHESIS Transcription: Every gene has 3 regions. - The promoter which turns the gene ‘on’ and ‘off’ and signals the site of transcription - The coding region which has the base sequence for the protein - The terminator which signals the end point of transcription.

S TAGES OF PROTEIN SYNTHESIS Transcription: Every gene has 3 regions. - The promoter which turns the gene ‘on’ and ‘off’ and signals the site of transcription - The coding region which has the base sequence for the protein - The terminator which signals the end point of transcription. o In transcription, the enzyme RNA polymerase binds to the promoter and the DNA ‘unwinds’ and ‘unzips’ here.

T RANSCRIPTION CONT. Only one of the two strands of DNA (the template strand) is copied to become mRNA in transcription.

T RANSCRIPTION CONT. Only one of the two strands of DNA (the template strand) is copied to become mRNA in transcription. A now pairs with U (uracil) in mRNA instead of T.

T RANSCRIPTION CONT. Only one of the two strands of DNA (the template strand) is copied to become mRNA in transcription. A now pairs with U (uracil) in mRNA instead of T. When RNA polymerase reaches the terminator sequence, transcription is completed; mRNA detaches, the 2 DNA strands re-join and the helix reforms. **Drawing on board**

T RANSCRIPTION CONT The mRNA is the primary transcript and is ‘edited’.

T RANSCRIPTION CONT The mRNA is the primary transcript and is ‘edited’. There are regions of the DNA (introns) which are NOT needed to make the protein.

T RANSCRIPTION CONT The mRNA is the primary transcript and is ‘edited’. There are regions of the DNA (introns) which are NOT needed to make the protein. The introns are cut out of the mRNA and the regions that ARE needed for the formation of the protein (exons) are spliced (pushed) together to give the final transcript (version) of mRNA.

T RANSCRIPTION CONT The mRNA is the primary transcript and is ‘edited’. There are regions of the DNA (introns) which are NOT needed to make the protein. The introns are cut out of the mRNA and the regions that ARE needed for the formation of the protein (exons) are spliced (pushed) together to give the final transcript (version) of mRNA. Depending on what exons are pushed together, there can be more than one version of the final transcript.

T RANSCRIPTION CONT The mRNA is the primary transcript and is ‘edited’. There are regions of the DNA (introns) which are NOT needed to make the protein. The introns are cut out of the mRNA and the regions that ARE needed for the formation of the protein (exons) are spliced (pushed) together to give the final transcript (version) of mRNA. Depending on what exons are pushed together, there can be more than one version of the final transcript. Therefore, there can be one gene coding for more than one polypeptide.