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Protein Synthesis
Grade 10 EST
Recall: DNA
• DNA is deoxyribonucleic acid
• Composed of nucleotides
• Each nucleotide contains
– Deoxyribose sugar
– Phosphate group (PO4-1)
– Nitrogenous base (A, T, C, or G)
• Sequence of bases = gene
Recall: Proteins
• A gene is piece of DNA that codes to make a
protein.
• Proteins play specific roles in an organism.
– Support (elastin)
– Transport (hemoglobin)
– Control (hormones, insulin)
– Immunity (antibodies)
– Catalysis (enzymes)
Recall: Protein Structure
• Protein are made of amino acids.
• 20 different amino acids
• Average = 100-200 amino acids in a protein
chain
Protein Synthesis
• Protein synthesis is the creation of proteins by
cells.
• Instructions are in genes inside nucleus.
• Protein synthesis occurs in ribosomes, outside
the nucleus.
RNA
• DNA cannot leave the nucleus
• Messenger between nucleus and ribosome
• mRNA: messenger ribonucleic acid
• RNA is single-stranded
• Thymine (T)  Uracil (U)
• Ribose sugar
Two types of RNA
Messenger RNA
acts as a
messenger
between gene
and ribosome
(mRNA)
Transfer RNA
transfers amino acids
from cytoplasm to
ribosome
(tRNA)
1. Transcription of DNA into mRNA
2. Attachment of mRNA to Ribosome
3. Translation of mRNA into Protein
4. End of Protein Synthesis
UAA, UAG, or UGA nucleotide triplet
•
•
•
•
Chain is complete.
Protein is released.
Folds into functional shape.
Performs its role.
Notes
Video
HW pp. 181-182
due May 22