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DNA/ RNA. DNA. De oxyribo N ucleic A cid Made up of Nucleotides Contains deoxyrib ose sugar Contains the genetic (hereditary) code for all living organisms. Provides a “blueprint” or directions for all cellular processes. Nucleotide. DNA. DNA is found in the nucleus in Eukaryotic cells - PowerPoint PPT Presentation
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DNA/ RNA
DNA• DeoxyriboNucleic Acid• Made up of Nucleotides• Contains deoxyribose sugar• Contains the genetic
(hereditary) code for all living organisms.
• Provides a “blueprint” or directions for all cellular processes
Nucleotide
DNA• DNA is found in the nucleus in Eukaryotic cells• DNA is found in Chromosomes• In order of decreasing size– Nucleus Chromosome Gene DNA
DNA
• Discovered by Watson and Crick
• They determined that DNA was in the form of a double helix (twisted ladder)
• Sides of the ladder are made of sugar and phosphorous
• Steps (rungs) made of nitrogenous base pairs
DNA base pairs
• Adenine• Thymine• Guanine• Cytosine
• What are the base pair rules?
DNA base pair rules
• Adenine always attaches to Thymine• Guanine always attaches to Cytosine
Example:• A-T and T-A• G-C and C-G
DNA base pair practice
A-G-G-C-T-A-
Fill in the correct base pair sequence for the following:
A-TG-CG-CC-GT-AA-T
More Practice
TTACGTCAG
T-AT-AA-TC-GG-CT-AC-GA-TG-C
What would happen if the code was altered?
Mutation: any change or alteration in the sequence of DNA (genetic material)
Types:Deletion: one or more bases are removed(deleted)Example: AATCG AACG The T was deleted
More Mutations
• Addition (aka Insertion): One or more bases are added
• Example:AATTCGC AATTCCGC A “C” was added
Substitution: A base is replaced with a new baseAATTGCG AATGGCG The “T” was replaced with a “G”
RNA
• RiboNucleic Acid• Made of nucleotides• Contains Ribose sugar• Contains Uracil instead of
Thymine• Is vital in making proteins• Is single stranded
RNA base pair rules• There is only one difference in pairing the
bases• Adenine always pairs with Uracil• Thymine still pairs with Adenine• Guanine still pairs with Cytosine• Example:
A-U T-AG-C or C-G
Protein Synthesis
RNA
• Two types– mRNA- • messenger RNA• translates the DNA code into codons
– tRNA- • Transfer RNA• lines up amino acids in order of codons
• Both used in protein synthesis at the ribosome
Protein Synthesis• Protein Synthesis: The process of making proteins• Remember proteins are made from long chains of amino
acids• The sequence(order) of the amino determines what type
of protein is being made• This process will need:
– DNA– RNA
• mRNA• tRNA• Ribosome
Protein Synthesis Steps• DNA Replication:
DNA will “unzip” and copy itself
• It will then “unzip” again to make a single strand that can make a strand of RNA
• Transcription: The process of making an RNA sequence based on the DNA sequence.
Transcription practice
DNA Unzipped DNA mRNA (transcription)A-T A UT-A T AG-C G CG-C G CT-A T AA-T A U
More Practice
DNA mRNAAAGTTC
A-UA-UG-CT-AT-AC-G
Protein Synthesis
• Translation: The process by which mRNA “translates” the genetic code into triple letter combinations that represent the key to figuring out the correct order of amino acids
Protein Synthesis• Codon: The triple letter combination of nitrogenous
bases
(DNA Template) AATTTAAAGCCGGAT(mRNA) UUAAAUUUCGGCCUA
Codons UUA AAU UUC GGC CUA
Hint: to make codons, just break up the mRNA code into three letters
Protein Synthesis• The codons will then
be used to code for a particular Amino Acid
• A chart will be used to determine the Amino acid
• The first 3 letters are used to represent the Amino Acid
• Always use mRNA for chart
More Practice
DNA mRNA Codon Amino AcidA UA U UUCG CT AT A AAGC G
Phe
Lys
• Use this chart with your mRNA codons to determine amino acids
• Start from the center and work your way out
• AAG Asp
• This chart can also be used to code for amino acids
Protein Synthesis• Once codons are
determined mRNA brings the information to the Ribosome.
• It is there that the tRNA will transfer or bring the correct amino acid into place.
Protein Synthesis• Transfer RNA (tRNA) will bring
the correct amino acid into place
• tRNA will match its code (anti-codon) to the mRNA codon
• This will provide the correct sequence needed to make a protein
• Remember: the sequence of Amino Acids determines what protein is being made
The anti codon AAG matches up to the codon UUCThis combination will always bring Phe into place
STEP 1DNA Replicates and mRNA created in the Nucleus
STEP 2 mRNA leaves the nucleus bringing codon information to the ribosome
tRNA
Random single amino acids
STEP 3tRNA brings the correct amino acid in to place based on the mRNA code
Protein synthesis
• STEPS• DNA copies itself (replicates)• mRNA matches up to DNA code following the
rules of the base pairing (transcription) • mRNA translates DNA code into codons (triple
letters) brings it to the ribosome• tRNA then “transfers” the amino acids into the
correct order.
Protein Synthesis
• (DNA) AATTTAAAGCCGGAT• (mRNA) UUAAAUUUCGGCCUA
Codons UUA AAU UUC GGC CUA
tRNA AAU UUA AAG CCG GAUAmino Acids Leu Asp Phe Pro Asp A
Mutations re-visited
DNA code:AATGGCCCTAAT
mRNA (codons): UUA CCG GGA UUA
Amino Acids:Leu Pro Gly Leu
Mutations re-visited• What happens if the DNA code on the previous
slide has a substitution of a “G” at the first “T”DNA (with mutations):
AAGCCGCCTAATRNA:
UUC GGC GGA UUAAmino Acids:
Phe Gly Gly LeuOne simple change makes a completely different protein!!!!!!