Download Protein Synthesis Notes - Winona Senior High School

Protein Synthesis Notes
Introduction to Biology
Protein Synthesis

DNA in the nucleus codes for the joining of
amino acids in a certain order to produce
specific proteins. The sequence of amino
acids determines the type of protein that is
made.
DNA
RNA
Sugar
deoxyribose
ribose
Bases
adenine, cytosine,
guanine, thymine
adenine, cytosine,
guanine, uracil
Structure
double stranded
single stranded
Found in
nucleus
nuclei, cytoplasm,
ribosomes
Base Pairing
In RNA uracil is found instead of thymine.
 Complementary bases:
A and T (or A and U), C and G

Triplet Code

There are about 20 different amino acids.
Three bases are needed to code for an
amino acid (triplet code). These three
bases together are known as a codon. The
sequence of bases is always read in one
particular direction.
Each amino acid has a different codon:




CAA stands for the amino acid valine
TTT stands for the amino acid lysine
CCC stands for the amino acid leucine
GGC stands for the amino acid glycine
Codons

There are also three codes for stopping the
formation of an amino acid chain. These are
UAA, UAC, or UGA. These are referred to
as stop codons or termination codons. They
act like the period at the end of the sentence
which tells the ribosome that the protein is
now complete.
Genes and Genomes

A length of DNA which codes for the whole
of one protein is called a gene. The total set
of genes in a cell is called the genome.
STEPS TO MAKING A PROTEIN


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DNA transcribes code onto mRNA in the nucleus.
mRNA travels from nucleus to the ribosomes.
mRNA codon is read by the ribosome and matches
with the proper tRNA anticodon. This is called
translation.
Amino acid attached to the tRNA connects to the
next amino acid in the ribosome. Only two tRNA
are in the ribosome at one time.
Stop Codon will cause the ribosome to release the
completed protein.