Download dna notes for protein synthesis and more Study notes Biology in PDF only on Docsity!
Protein Synthesis
Protein Synthesis
Protein synthesis
- Two step process by which an organism’s DNA is translated into proteins
(genes)
Why do we need proteins?
- Structure, repair, and growth
- Enzymes – control metabolism (sum of all life’s processes)
- Hormones & steroids – control growth and development
Protein Synthesis
Protein Synthesis
Protein synthesis involves 2 types of nucleic acids: DNA and RNA
DNA RNA
# of
Strands
Location in
cell
Nucleotide
Bases
Sugar
DNA RNA
# of
Strands
Doubled
stranded
Location in
cell
Cannot
leave the
nucleus
Nucleotide
Bases
ATGC
Sugar deoxyribos
e
DNA RNA
# of
Strands
Doubled
stranded
Single
Stranded
Location in
cell
Cannot
leave the
nucleus
Nucleus
and
Cytoplasm
Nucleotide
Bases
ATGC AUGC (uracil)
Sugars Deoxyribos
e
Ribose
Protein Synthesis
Occurs in 2 steps
Step 1: Transcription
Taking DNA and transcribing it into RNA
Occurs in the Nucleus
Step 2: Translation
Taking RNA and translating it into amino acids
(protein)
Occurs out in the cytoplasm in Ribosomes
(Transcription) (Translation)
After the mRNA is made it is
released and an enzyme zips
the DNA back up
Protein Synthesis-
Protein Synthesis-
Transcription
Transcription
Okay…we made
mRNA, now what?
mRNA takes the
genetic
information out of
the nucleus
through the
cytoplasm to a
ribosome
Protein Synthesis-
Protein Synthesis-
Transcription
Transcription
ribosome
cytoplasm
nucleus
Changing mRNA to proteins
How does it begin?
mRNA arrives at the ribosome
- tRNA brings amino acids to the ribosome to match up to the
mRNA according to Chargaff’s
Every three nucleotide bases on the mRNA represents a
(codon)…the tRNA that matches it is the anticodon and
brings in the appropriate amino acid
- Example: DNA: A A C T G A T G C
mRNA: U U G A C U A C G
Amino Acids: LEU- THR- THR
Protein Synthesis- Translation
Protein Synthesis- Translation
Transcription
Translation
Protein Synthesis- Translation
Protein Synthesis- Translation
There are 64 possible codons
Only 20 amino acids, therefore some amino acids
may be coded for more than one triplet codon
There are special start and stop sequences
(codons)
Start codon = AUG codes for the amino acid
methionine
stop codons = UGA, UAG, UAA
These are STOP codons and they signal the end of a
protein
They are also called termination codons (ter)
Protein Synthesis- Translation
Protein Synthesis- Translation
http://omega.dawsoncollege.qc.ca/
ray/protein/panim.htm
Protein Synthesis- Translation
Protein Synthesis- Translation
