Protein Synthesis

DNA → mRNA → Protein

Genetic Code → triplets in DNA → the amino acids in proteins

The Players mRNA: messenger RNA - carries

protein recipe from the nucleus

tRNA: transfer RNA -brings amino acids to the

ribosome

Ribosome: the site of protein synthesis

- made of rRNA (ribosomal RNA )and Protein

Meet mRNA (ribonucleic acid)

mRNA (messenger RNA) made in nucleus serves as a template (pattern) of the DNA molecule.

Triplet or codon: grouping of 3 nitrogenous bases in DNA or RNA

molecules (each codon will code for a specific amino acid)

HOW DOES IT DIFFER FROM DNA?

1. The RNA molecule is a SINGLE nucleotide strand, not a double strand as in DNA.

2. The sugar molecule in RNA is RIBOSE -- not deoxyribose as in DNA.

3. The base URACIL (U) takes the place of thymine. (T)

There are twenty different amino acids that build proteins

There are 64 different triplets/codons Each amino acid is coded for by more than

one triplet/codon

Meet tRNA

each molecule of tRNA carries a specific type of amino acid -each tRNA molecule can only carry one type of amino acid

The tRNA has a group of 3 nucleotides at the base called the anticodon

DNA → mRNA → Protein

tRNA (transfer RNA) – reads the mRNA and transfers the amino acids into the correct order to make the protein

rRNA:(ribosomal RNA) found in the cytoplasm and is the site of protein synthesis

DNA serves as a template for the synthesis of mRNA from RNA nucleotides in the nucleus.

transcription: transfer of the genetic message from DNA to mRNA

How are proteins synthesized from a DNA template? (model)

The Process of Translation

mRNA takes recipe to the ribosome in cytoplasm

ribosome attaches to the mRNA

How does tRNA know which amino acid goes where?

The anticodon a sequence of 3 nucleotides

tRNA is complementary to a mRNA codon binds to matching codon specifies the next amino acid to be

attached during protein synthesis.

Example: mRNA codon = GAC = carries only

aspartic acid tRNA anticodon = UAC carries only

methionine

Begin Translation

The ribosome moves along the mRNA until it reaches the “Start” codon

Start codon = AUG signals the start of the recipe

AUG also codes for the amino acid methionine

mRNA molecules carrying a specific code move from the nucleus to the cytoplasm and attach to a ribosomes (rRNA)

mRNA leaves through nuclear pores

Different triplets

(codons) of nitrogenous bases in tRNA molecules pick up specific amino acids in the cytoplasm and carry them to mRNA at the ribosomes.

A molecule of transfer RNA brings the amino acid called for by the mRNA to the ribosome

transfer RNA = tRNA

A second tRNA brings the second amino acid to the ribosome

The amino acids are joined together to begin the protein

The ribosome moves over 1 codon (triplet) and another tRNA molecule brings another amino acid

The process continues until the stop codon on the mRNA is reached

The stop codon = the end of the protein recipe

These proteins are what directs the activity in each cell!

Basically, RNA translates the DNA information!

Translation: The genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a protein

gene: the sequence of nucleotides in a DNA molecule necessary to synthesize a protein (polypeptide)

** One gene codes for one protein

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DNA determines the sequence of amino acids in specific proteins.

The specific shape of the protein (ex:enzymes and hormones) determines the function of that protein

Offspring resemble their parents because they inherit: similar genes…that code for similar proteins… that have similar structure and function

Major Understandings:

Making the building(protein)