III. How a protein is made: Protein Synthesis

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III. How a protein is made Protein Synthesis
A. Why are proteins made and what does this
have to do with genetics? 1. DNA holds the
information to make proteins 2. A gene is a
segment of DNA that codes for 1 protein B.
DNA holds the recipes for making proteins. It
uses RNA (the chefs) to send these recipes to
the ribosomes (kitchen) so they can be
made. 1. The basic unit of a protein is an amino
acid a. we use 20 amino acids to make all
of our proteins 2. A chain of amino acids
together is a protein 3. Types of proteins
include hormones, enzymes, structural
proteins
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C. RNA ribonucleic acid 1. Similar
structure to DNA with a few differences DNA
RNA Basic unit nucleotide nucleotide 4
nitrogen bases A,T,C,G A,U,C,G
(uuracil) Sugar deoxyribose ribose Structure
double stranded single stranded
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D. There are 3 types of RNA each having a
different role in making a protein 1. mRNA
messenger RNA a. reads the information from
the DNA and carriers the message to the
ribosomes (this process is called
transcription DNA A T T G C C G A
T mRNA U A A C G G C U A
Codon Codon Codon
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2. tRNA Transfer RNA a. made in the
nucleus and reused in the cytoplasm b. reads
mRNA and brings the correct amino acid to
make a chain of amino acids (protein). This
process is called translation c.
The code is being translated into the language of
amino acids. d. structure looks
like an upside down t.
Anticodon that corresponds with the mRNA codon
UAC
Amino Acid
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tRNA
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3. rRNA Ribosomal RNA a. located in the
ribosome b. plays role in helping the
amino acids join together during
translation c. scientists are using this
sequence to classify organisms.
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E. The process of making a protein 1.
Transcription Making mRNA from DNA 2.
Translation Translating the mRNA code into a
chain of amino acids using tRNA to make a
protein
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1. Transcription making mRNA from DNA a.
enzyme RNA polymerase unzips DNA and
attaches corresponding RNA nucleotides DNA A
T T C G C G A T mRNA U A A G
C G C U A b. When RNA polymerase reaches the
sequence of DNA bases that tells it to
stop the RNA strand is released and
DNA zips back up c. mRNA strand carries the
message out of the nucleus
into the cytoplasm to the
ribosome
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2. Translation Translating the mRNA codons into
a chain of amino acids to make a protein
a. 2 subunits of a ribosome bind to mRNA
b. the 1st tRNA binds to the mRNA (the anticodon
corresponds with the codon) c.
the 2nd tRNA binds to the mRNA d. the amino
acid from the 1st tRNA binds to the amino
acid from the 2nd tRNA. e. the ribosome
moves down the mRNA and the 1st
tRNA is released (leaving a vacancy for the next
tRNA) f. The process continues
until the STOP signal codon is reached
and the protein is released.