1. Unit 4 Inheritance of Traits
Part 2: How DNA codes for Proteins

2. DNA carries the info to make Proteins. How does it work?
DNA RNA Proteins
Starts with DNA….transcribed into mRNA…..translated into proteins by tRNA
This process is known as:
Central Dogma of Molecular Biology
How does the DNA get made into RNA and that made into Protein???.

3. When DNA inside the nucleus is This strand then leaves the nucleus.
Transcription
When DNA inside the nucleus is
TRANSCRIBED (re-written)
Into mRNA.
This strand then leaves the nucleus.

4. DNA Deoxiribonucleic acid
1.sugar=deoxyribose
2.bases = A, T, G, C
3.double strand
4.stays in nucleus
RNA Ribonucleic acid
1.sugar = ribose
2.Bases=A, U, G,C
3.single strand
4.leaves nucleus

5. What are the three main differences between DNA and RNA?

6. There are three main differences between RNA and DNA:
The Structure of RNA
There are three main differences between RNA and DNA:
The sugar in RNA is ribose instead of deoxyribose.
RNA is a single-stranded polymer molecule
RNA contains the base: uracil, in place of thymine.
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7. 3 Types of RNA are made from DNA
1. mRNA  “messenger”
made from DNA in nucleus…travels out of nucleus and finds a ribosome.
2. tRNA “transfer”
brings amino acids to the ribosomes; found in cytoplasm
3. rRNA  “ribosomal”
part of the ribosome; this is where proteins
are made

8. Types of RNA
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.
Messenger RNA (mRNA) carries copies of instructions for assembling amino acids into proteins.
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9. Types of RNA
Ribosome
Ribosomal RNA
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA. Ribosomal RNA is combined with proteins to form ribosomes.
Ribosomes are found in all Eukaryotic and Prokaryotic organisnms and are made up of proteins and ribosomal RNA (rRNA).
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10. Amino Acids are monomers (subunits) of proteins
Types of RNA
Amino acid
Amino Acids are monomers (subunits) of proteins
The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.
Transfer RNA
During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome.
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11. Lets watch:

12. Transcribe this…… TACAGTACCATAATC AUGUCAUGGUAUUAG

13. Is ALL the DNA transcribed into mRNA?
NO!!!
Only certain sections of the DNA (GENES) are made (transcribed) into message (mRNA)

14. Now…to make proteins from the mRNA
This is called: Translation
Translation is the decoding of an mRNA message into a an amino acid acid chain creating a (protein).
The mRNA goes into the Ribosome and a tRNA molecule brings amino acids.

15. Codon A grouping of 3 mRNA bases
This tells the TRNA what amino Acid to bring

16. Translation
The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.
Lysine
Phenylalanine
tRNA
Methionine
Ribosome
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
Start codon
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17. Copyright Pearson Prentice Hall
Why do we need Proteins?
1. Proteins give certain traits and capabilities to organisms
Ex: lots of the protein melanin leads to darker pigment
EX: Production of insulin helps in glucose metabolism
2. Proteins act as enzymes to make reactions go faster, act as parts of muscle, skin, bone,& organs!!
Proteins are hormones & cell signalers
Organisms are dependent on proteins in order to function!
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18. Translation :Decoding the Message
FOR REVIEW
mRNA leave nucleus and enters ribosome
mRNA codons read & tRNA brings matching amino acid to the ribosome
Amino acids are strung together like beads on a necklace
Amino Acids are held together by peptide bonds
1000 or more Amino Acids = protein

19. Lets watch!

20. Use the RNA Codon Chart to decode RNA into amino acids.
The Genetic Code
Use the RNA Codon Chart to decode RNA into amino acids.
The genetic code is the “language” of mRNA instructions.
The code is written using four “letters” (the bases: A, U, C, and G).
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21. WHEN WE DECODE DNA Example: AUG= Methylamine (Start)
Use the “Genetic Code” 
Convert mRNA 3 letter groupings called codons
Example:
AUG= Methylamine (Start)
The mRNA Code tells us what amino acid each codon codes for.

22. The Genetic Code
The genetic code shows the amino acid to which each of the 64 possible codons corresponds. To decode a codon, start at the middle of the circle and move outward.
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24. Protein Synthesis Translation direction Translation Lysine tRNA mRNA
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
Translation direction
Ribosome
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25. The process continues until the ribosome reaches a stop codon.
Translation
The process continues until the ribosome reaches a stop codon.
Polypeptide
Ribosome
tRNA
During translation, or protein synthesis, the cell uses information from messenger RNA to produce proteins. The cell uses all three main forms of RNA during this process.
mRNA
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27. REVIEW! Watch these: https://www.youtube.com/watch?v=gG7uCskUOrA

29. Transcribe and Translate this DNA Strand without looking at your notes
TACAGTACCATAATC
NOW, Label the DNA, mRNA, amino acid,
Which part is transcription
Which is translation ?

30. DNA TACAGTACCATAATC mRNA AUGUCAUGGUAUUAG AA: MET-SER-TRP-TYR-STOP
Codon
Amino Acid