1. RIBONUCLEIC ACID (RNA)
HOW IS RNA DIFFERENT FROM DNA??

2. Let’s review DNA Contains the sugar DEOXYRibose
ADENINE pairs with Thymine
GUANINE pairs with Cytosine
Double Stranded

3. RNA is different from DNA…
Contains the sugar Ribose
Uracil Substitutes for Thymine (A pairs with U)
Single stranded
DNA = A T T G C A C
RNA = U A A C G U G

4. Differences Between DNA and RNA:
Fill in Your Chart…
Differences Between DNA and RNA:
DNA
RNA
SUGAR
Deoxyribose
Ribose
NITROGEN BASES
A, T, C, G
A, Uracil, C, G
SHAPE
Double Helix
Single Strand

5. RNA and Protein Synthesis
Gene is a coded instruction, found in a segment of DNA that controls the production of a protein inside the cell.
Think of DNA as a prisoner inside the nucleus of the cell. DNA can never leave the nucleus as it must stay there to control all cell functions
To make a protein, DNA needs a helper called ribonucleic acid = RNA, which can enter and leave the nucleus

6. Three Types of RNA
Messenger RNA (mRNA) – transcribes or copies instructions from DNA for the assembly of amino acids into proteins. Remember, amino acids are the monomers of proteins.
Transfer RNA(tRNA) – translates the instructions by transferring amino acids from the cytoplasm to mRNA now in the ribosome
Ribosomal RNA (rRNA) – structural part of the ribosome that binds mRNA and tRNA together; makes up 80% of all RNA in the cell.

7. Through TRANSCRIPTION! Here’s a Summary:
How is RNA Made?
Through TRANSCRIPTION!
Here’s a Summary:
Transcription: RNA is made from DNA. Same process as replication, but only one side of the DNA strand is copied. This occurs in the nucleus. When RNA is made it leaves the nucleus (through nuclear pores in the membrane) and the DNA strand zips back up.

8. It contains the genetic code from DNA that is needed to make proteins!
Why is RNA Important?
It contains the genetic code from DNA that is needed to make proteins!

9. Organic Compounds that are made from amino acids linked together by peptide bonds
Ex. AA1 + AA2 + AA3 = a protein (or also known as a polypeptide)
Each polypeptide can have a combination of any or all of 20 different AA
One protein is different from another by the order in which the different AA are joined together to produce a polypeptide
What are Proteins?

10. Why are Proteins Important?
Help build cell organelles (remember that they are part of the cell membrane)
Are used as enzymes to promote reactions
Component in muscle, blood, skin and bone

11. Protein Synthesis – THE MAKING OF PROTEINS
2 Processes in Protein Synthesis
Transcription
Translation

12. Transcription
mRNA copies the code from DNA

13. TRANSCRIPTION – the details
Strands of DNA are separated by the enzyme RNA polymerase and a molecule of mRNA is produced by copying or transcribing one side of the DNA strand into a complementary sequence of RNA
So RNA polymerase uses one strand of DNA as a template/model to assemble a
strand of RNA

14. Transcription

15. LET’S DO TRANSCRIPTION!
If DNA = A G C T G A
Then mRNA= U C G A C U

16. How Does RNA Polymerase know where to start and stop making an RNA copy of DNA?
Well…….
RNA polymerase doesn’t bind to DNA anywhere but will bind only to regions of DNA called promoters that have a specific nitrogen base sequence. There is also a specific nitrogen base sequence on DNA called the terminator that causes transcription to stop.

17. The Genetic Code
The “language” of mRNA instructions is called the genetic code
Since RNA has only 4 nitrogen bases ( A, U, G, C), the code is written in a “language” that only has 4 letters
The genetic code is read 3 letters (nitrogen bases) at a time so each “word” in mRNA is known as a codon

18. TRANSCRIPTION
The sequence/order of bases in mRNA has a code that enables the tRNA to find the right amino acids and assemble them in the correct sequence to synthesize a protein.
Codon: Every combination of three “letters” (nitrogen bases or 3 nucleotides) on mRNA.
1 CODON will specify for 1 AMINO ACID

19. Translation
It involves the translation of the mRNA codons into amino acids that will make up a protein.
Ribosome attaches to the mRNA
tRNA picks up a specific amino acid in the cytoplasm and carries it to the mRNA at the ribosome
tRNA contains the anticodon which is 3 unpaired nitrogen bases which will pair with the mRNA codon

20. TRANSLATION— The Details
mRNA strand (made of codons) leaves the nucleus, enters the cytoplasm and attaches to a ribosome

21. 2. tRNA molecule picks up an amino acid in the cytoplasm and carries it to the ribosome

22. 3. tRNA anticodon pairs with mRNA codon and the two molecules join together

23. 4. When 2 amino acids are in place a peptide bond forms

24. Once an amino acid has joined a growing polypeptide chain, the tRNA detaches from the mRNA strand

25. 6. The process continues until a chain of amino acids is formed and stops once a STOP codon on the mRNA is reached. Translation is now
complete.
7. The chain of amino acids is called a protein (or polypeptide).

26. TRANSLATION (tRNA) DNA = A T G C T A mRNA = U A C G A U (Codon)
tRNA = A U G C U A
(Anticodon)

27. summarize Protein synthesis!
Takes place in the nucleus
Moves out of the nucleus into the cytoplasm & attaches to the ribosome
Transcription
Takes place in the nucleus
Translation
Moves out of nucleus into the cytoplasm & attach to ribosome

28. SUMMARY: Steps of Protein Synthesis
Transcription: DNA makes RNA (in the nucleus)
RNA now becomes mRNA which will leave the nucleus (take the genetic code to ribosome)
mRNA tells ribosomes what proteins to make
mRNA attaches to ribosome and forms a pattern called a codon to make a protein
tRNA in cytoplasm comes to ribosome. It “translates” the code (codon=three base pairs on mRNA) and gets the specific amino acid that matches up with the codon. This is the anticodon. When amino acids are combined together (by peptide bonds) they break off and form the specific protein needed by the cell. This part is called translation.

29. Steps to figure out the genetic code
A row of DNA bases
Transcribe DNA into mRNA
Translate mRNA into tRNA
Use the codons (mRNA) to translate into amino acids

30. Why do some amino acids have more than one code?
4 nucleotide bases, 3 at a time = 43 = 64
20 different amino acids and 64 code words, so some AA are specified by more than one code word.

31. let’s practice! ATG UAC AUG Tyrosine DNA mRNA (Codon) tRNA (anticodon)
Amino Acids
UAC
AUG
Tyrosine

32. More practice DNA= TAC -GAT-GCC-ATC mRNA= ________________
tRNA= ________________
Amino Acids= _________________
AUG -CUA- CGG-UAG
UAC -GAU-GCC-AUC
START-LEU-ARG-STOP

33. Overview

34. When Something Goes Wrong…A Mutation
What would happen if nucleotides did not pair correctly?
What would happen if a nucleotide got squeezed out?
What would happen if an extra nucleotide got put in?
These are all types of DNA, RNA, or protein sequence mutations.
Mutations are changes in the genetic material

35. * NOT ALL MUTATIONS CHANGE THE FINAL OUTCOME*
Types of Mutations
Point Mutations- a single base (letter) on a strand gets replaced with another letter. Remember that the genetic code is read in three-base codons
Normal RNA: ACC CUG UAC GGU ACU
Protein: thr leu tyr gly thr
Mutated RNA 1: ACC CUG UCC GGU ACU
Protein: thr leu ser gly thr
Mutated RNA 2: ACC CUG UAU GGU ACU
Protein: thr leu tyr gly thr
* NOT ALL MUTATIONS CHANGE THE FINAL OUTCOME*

36. Mutations
Mutations
Frame Shift- a single base (letter) on a strand either gets squeezed out (deletion) or an extra base gets added in (insertion) this causes the whole sequence to “shift”. By shifting the sequence, every amino acid will be changed following the point of the mutation.
Normal RNA: ACC CUG UAC CGU ACU
Protein: thr leu tyr gly thr,
Mutated RNA 1: ACC UGU CCG GUA CU deletion of C & A
Protein: thr cys pro val
Mutated RNA 2: ACC CUG UAC UCG UAC U insertion of U
Protein: thr leu tyr try tyr

37. Chromosomal Mutations Mutationshromosomal Mutations
- A chromosome is found in the nucleus of a cell and it contains all the genetic information that is passed down from one generation of cells to the next
Chromosomal mutations involve changes in the number or structure of chromosomes
Types of Chromosomal Mutations:
Deletions – loss of all or part of the chromosome
A B C D E F original chromosome
A C D E F deletion of B

38. Mutations Continued Mutations Continued
2. Duplication – produce extra copies of parts of a . chromosome A B C D E F original chromosome A B C D D E F duplication of an extra D 3. Inversion – reverse the direction of parts of a chromosome A E D C B F inversion of B C D E 4. Translocation – part of one chromosome breaks off and attaches to another A B C D E F original chromosome A B C J K L translocation of J K L from another completely different chromosome

39. Significance of Mutations
Harmful Mutations
- cause of many genetic disorders and cancer
- these types of mutations will cause changes in protein structure or gene activity
2. Neutral Mutations
- they have no effect on the function of the protein which they code or the expression of genes
3. Provide a Source of Genetic Variability
- produce proteins with new or altered activities that can be helpful to organism in different or changing environments
- mutations are one source of evolution
- responsible for developing new and better varieties of crops