PROTEIN SYNTHESIS

The overall goal of protein synthesis is to make proteins, which are needed everywhere in our body in order to function. Protein Synthesis Intro (3:35)

There are 2 parts to Protein Synthesis Transcription Translation

DNA is a blueprint that makes you who you are. More specifically DNA is a blueprint to make RNA or Ribonucleic Acid. Ameoba Sisters DNA vs RNA (4:43) RNA Brain Pop

DNA vs. RNA Double Stranded Single stranded Adenine – Thymine Adenine – Uracil (thymine is replaced by uracil) Cytosine – Guanine Deoxyribose sugar Ribose sugar

Transcription: The copying (or writing) of DNA to form mRNA

Types of RNA mRNA – messenger RNA, carries the DNA code for the protein to the ribosome. tRNA – transfer RNA, carries amino acids to ribosome to construct the protein rRNA- Ribosomal RNA, makes up ribosomes

Transcription: occurs in the nucleus of Eukaryotic cells. Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase DNA RNA

DNA cannot leave nucleus because of its size, therefore genetic information must be copied into smaller pieces These small sections of DNA are called genes and are copied into single strands of RNA.

Steps in Transcription Helicase: unwinds DNA helix RNA Polymerase: finds and matches free floating RNA nucleotides to DNA. These free nucleotides once put in order forms the RNA. - When it reaches the stop sequence, polymerase detaches and RNA is free.

Steps cont. 3. Ligase: seals back the bases in the DNA Helix with hydrogen bonds The RNA strand, now called mRNA, leaves the DNA molecule and the nucleus. 4. Gyrase: winds up the DNA strand. Transcription Animation

Transcribing rules: DNA to mRNA A to U T to A C to G G to C

Let’s Practice DNA AAT CCG GCG TAT mRNA UUA GGC CGC AUA Transcription - DNA Learning

Now that the RNA strands are written (transcribed) they are sent out of the nucleus and into the cytoplasm of the cell. Once in the cytoplasm, the mRNA finds a ribosome - our protein making factories.

Translation: mRNA is used as a written code to form proteins.

During translation mRNA works with other types of RNA to build proteins by joining amino acids.

The Genetic Code The genetic code is the connection between nucleotide triplets in DNA to amino acids to proteins.

Codons Every three nucleotide bases in mRNA specify a particular amino acid. This nucleotide triplet is called a codon. 9 bases= 15 bases= 3 bases= 3 codons = 3 Amino Acids 5 codons = 5 Amino Acids 1 codon= 1 Amino Acid

The Genetic Code The order of bases in a codon determines an amino acid. The specific order of amino acids in the amino acid chain will determine the PROTEIN.

Codon Video There are 64 possible codons but only 20 different amino acids. More than one codon may specify an amino acid. “STOP” codons specify the end.

The 20 Amino Acids

Circular Codon Chart TRY ISO

Rectangular Codon Chart

tRNA Transfer RNA or tRNA , carries amino acids to the ribosome. The tRNA has an anticodon, which is a three nucleotide sequence and is complementary to mRNA codons.

tRNA If the anticodon on the tRNA is a match to the codon on the mRNA, the tRNA drops off the amino acid attached to it. Amino acids are continuously added for as many codons that the mRNA contains When the stop codon is reached, the amino acid chain detaches as a finished protein. Translation - DNA Learning

Translation

Translation Cont.

Translating Rules mRNA to tRNA U to A A to U C to G G to C

Let’s Practice DNA TAC AAT CCG GCG TAT ACT mRNA AUG UUA GGC CGC AUA UGA Amino Acids Met – Leu – Gly – Arg – Ile – STOP tRNA UAC AAU CCG GCG UAU ACU

Label the following Pictures as DNA Replication, Transcription, Translation

TRANSLATION DNA REPLICATION TRANSCRIPTION

TRANSCRIPTION TRANSLATION TRANSLATION TRANSLATION

TRANSCRIPTION TRANSCRIPTION DNA REPLICATION DNA REPLICATION

TRANSLATION TRANSCRIPTION

AMINO ACIDS DNA t-RNA PROTEIN RIBOSOME m-RNA CODON ANTI- CODON WORD BANK: *Ribosome *Anti-Codon *Codon *DNA *Protein * Amino Acids *mRNA *tRNA

Clips Practice Transcription and translation animation Amoeba Sisters Protein Synthesis (7:07)