1. Unit 7 RNA, Protein Synthesis & Gene Expression Chapter 10-2, 10-3
(page 190 – 197)
Chapter 11
(pg 203 – 214)

2. Unit 7 Lecture 1 Topics: Covers: DNA vs RNA Chapter 10-2
Pages

3. RNA Introduction
RNA (Ribonucleic Acid) is another type of nucleic acid.
Nucleic Acid – Organic compound, polymer made up of monomers known as nucleotides
RNA uses the genetic information stored in DNA to create proteins. Remember:
DNA stores genes and is kept in the nucleus
Gene – code for a protein
Ribosomes (outside nucleus) make proteins
Protein synthesis – process where a cell makes a protein

4. Protein Review A chain of many amino acids is known as a polypeptide
Proteins are polymers made up of monomers known as amino acids 
A chain of many amino acids is known as a polypeptide
Once a polypeptide is folded/coiled into its final shape, then it is called a protein
The shape (and function) of each protein is very different
A gene codes for the order of amino acids in a protein
The sequence of amino acids determines how the polypeptide will eventually coil/fold on itself (determines final shape of protein)
There are twenty different kinds of amino acids
Each amino acid is coded for by a specific combination of nucleotides
DNA Review:
DNA is polymer made up of monomers known as nucleotides
Shape of DNA is a double helix
DNA is made up of two parallel strands of nucleotides
The strands (left and right side of helix) are thousands of nucleotides long
The left and right strands are connected in the middle of the helix because certain nucleotides pair together
DNA is made up of four types of nucleotides
Adenine (a purine) pairs with Thymine (a pyrimidine)
Guanine (a purine) pairs with Cytosine (a pyrimidine)
The sequence (order) of nucleotides in the DNA molecule is very important 
DNA sequence is a code for a protein, it codes for the order of amino acids in the protein chain

5. Protein Review

6. Comparison of DNA and RNA
Nucleotide Components
Function
Structure
Varieties
Sugar
Nitrogen Base
DNA
Deoxyribose
Adenine
Guanine
Cytosine
Thymine
Stores genetic information (genes)
Double helix (two strands connected in center of helix)
Only one type
RNA
Ribose
Uracil (a pyrimidine)
Uses genetic information to make proteins
Single helix (single strand of nucleotides)
Three types
rRNA
mRNA
tRNA
Remember: a gene is a code for a protein

8. Comparison of Three types of RNA
rRNA (Ribosomal RNA)
Makes up part of a ribosome
Remember:
Ribosomes are made up of RNA and proteins
Ribosomes are organelles that make proteins

9. Comparison of Three types of RNA
mRNA (Messenger RNA)
Brings the genetic message from DNA to a ribosome
DNA gene (protein message) copied into mRNA

10. Comparison of Three types of RNA
tRNA (Transfer RNA)
Used during protein synthesis
Transfers amino acids to their proper place in the amino acid chain  
has a triplet of  
nucleotides that is complementary to a certain codon
 * Known as an ANTICODON

11. END OF LECTURE 1

12. Unit 7 Lecture 2 Topic: Covers: Introduction to Protein Synthesis
Chapter 10-2 and 10-3
Pages 191 – 195

13. Protein Synthesis
DNA (Chromosomes) store genetic information. Each strand of DNA stores hundreds of genes
The order (sequence) of nucleotides in the gene codes for the order of amino acids in the protein
A mutation that occurs in a gene could affect the protein code
Mutation – change in the order of nucleotides (DNA or RNA)
A gene mutation could change the order of amino acids in the protein or could prevent the protein from being made

14. Protein Synthesis To make a protein:
1. A copy of a gene is made (DNA copied into mRNA)
This mRNA template serves as the code for the protein, instructions for how to make the protein
2. mRNA carries the protein code from the nucleus to a ribosome
Protein synthesis takes place outside the nucleus by a:
Bound ribosome – makes proteins to leave the cell
Free ribosome – makes proteins to be used in the cell
3. Ribosome translates mRNA sequence into an amino acid sequence
4. The chain of amino acids will fold into final protein product
Brings the genetic message from DNA to a ribosome
DNA gene (protein message) copied into mRNA
mRNA carries the protein code from the nucleus to a ribosome.
Protein synthesis takes place outside the nucleus by a:
The mRNA message is translated into amino acids
A combination of three nucleotides (in mRNA) translated into one amino acid
CODON – three nucleotide sequence that codes for an amino acid

16. Protein Synthesis The Genetic Code
The order of nucleotides in the mRNA template codes for the order of amino acids in the protein chain
Ribosome translates the information from mRNA into amino acids
mRNA is made up of nucleotides; Proteins made up of amino acids
Brings the genetic message from DNA to a ribosome
DNA gene (protein message) copied into mRNA
mRNA carries the protein code from the nucleus to a ribosome.
Protein synthesis takes place outside the nucleus by a:
The mRNA message is translated into amino acids
A combination of three nucleotides (in mRNA) translated into one amino acid
CODON – three nucleotide sequence that codes for an amino acid

17. Protein Synthesis The Genetic Code
A combination of three nucleotides codes for one amino acid
CODON – Three nucleotide sequence that codes for an amino acid
64 codons, but there are only 20 amino acids
Some amino acids have more than one codons
Important codons: START (AUG), and STOP (UAA, UAG, UGA)
Brings the genetic message from DNA to a ribosome
DNA gene (protein message) copied into mRNA
mRNA carries the protein code from the nucleus to a ribosome.
Protein synthesis takes place outside the nucleus by a:
The mRNA message is translated into amino acids
A combination of three nucleotides (in mRNA) translated into one amino acid
CODON – three nucleotide sequence that codes for an amino acid

18. Phenylalanine (Phe), Leucine (Leu), Isoleucine (Ile), Methionine (Met), Valine (Val), Serine (Ser), Proline (Pro), Threonine (Thr), Alanine (Ala), Tyrosine (Tyr), Histidine (His), Glutamine (Gln), Asparagine (Asn), Lysine (Lys), Aspartic acid (Asp), Glutamic acid (Glu), Cysteine (Cys), Tryptophan (Trp), Arginine (Arg), Glycine (Gly)

19. Protein Synthesis The Genetic Code
Each amino acid is carried through the cell and to the ribosome by a specific tRNA (Transfer RNA)
tRNA is shaped like a “t”
One end (end of chain) bonds to a specific amino acid
Opposite end (bottom loop end) attaches to mRNA
This section is known as the ANTICODON
Anticodon is complementary to each mRNA codon
Example: Amino Acid – Serine
CODON – “AGU”
Serine transferred to amino acid chain by tRNA with the ANTICODON – UCA

20. End of Lecture 2

21. Unit 7 Lecture 3 Topic: Covers: Protein Synthesis Transcription
Translation
Covers:
Chapter 10-3
Pages 193 – 196

22. Protein Synthesis Protein Synthesis is a two part process
Transcription
This is when a gene is transcribed (copied)
DNA gene copied into mRNA
Translation
This is when the genetic code is translated into a protein
mRNA message translated into amino acids
Amino acid chain shaped into final protein product

23. Transcription 1. RNA Polymerase (an enzyme) binds to a gene on the DNA
RNA polymerase separates the two strands of DNA

24. Transcription 2. One of the separated DNA strands is copied
This DNA strand is known as the TEMPLATE
3. RNA Polymerase moves along the DNA template and adds the complementary RNA nucleotide
DNA
RNA
Complementary Base
Guanine
Cytosine
Thymine
Adenine
URACIL

25. Transcription
4. RNA polymerase continues until it reaches the end of the gene
5. RNA Polymerase releases DNA and gene copy (mRNA template)
DNA strands bond back together, goes back to double helix
mRNA template will leave the nucleus and go to a ribosome

26. Transcription

27. Translation
Once the mRNA reaches a ribosome, the genetic message will be translated into a protein
The ribosome will scan down the mRNA strand, translating each codon into an amino acid
tRNA transfers each amino acid into the proper place based on the mRNA message
Remember:
A CODON (in mRNA) codes for one amino acid
Each amino acid is transferred in place by tRNA
ANTICODON – in tRNA, complementary to codon
PROTEIN – polymer made up of monomers of amino acids

28. Translation

29. Translation
mRNA leaves nucleus and goes to a ribosome to begin protein synthesis
Ribosome will attach to the end of the mRNA. The ribosome will begin to move down the mRNA template.
tRNA will also begin to transport amino acids (floating in cytosol) to ribosome
Each amino acid is carried by a different tRNA

30. Translation
3. The ribosome will "scan" down the mRNA template until the ribosome reaches the start codon of mRNA.  
When the ribosome reaches the start codon (AUG), the ribosome will stop moving.
tRNA with the anticodon (UAC) can bond with the start codon.
tRNA adds first amino acid of the chain: methionine (MET)

31. Translation
4. After the first amino acid is attached, the ribosome will move down to the next codon. The next codon will be translated.
tRNA will attach the amino acid
MET and the second amino acid will bond together
Peptide bonds hold the amino acids together
Peptide Bond – covalent bond between amino acids
5. Ribosome will continue to move down the mRNA strand, stopping at each codon.
tRNA attaches to each codon and adds the correct amino acid.
The amino acids are attached in a chain by peptide bonds.

33. Translation
6. When the ribosome reaches the “STOP” codon, no more amino acids are added
"STOP" codons (UAA, UAG, UGA) don’t code for an amino acid
7. Long chain of amino acids is released
Long chain of amino acids – Polypeptide
8. Ribosome separates from the mRNA strand.
9. Polypeptide will coil/fold into its final shape, it will then be known as a protein

34. End of Lecture 3

35. Unit 7 Lecture 4 Topic: Covers: Cell Differentiation Gene Expression
Chapter 11
Page 209

36. Cell Differentiation
Only certain sections of the DNA molecule code for a gene
A gene is a section of DNA that codes for a protein
The longer the strand of DNA, the more genes it can store
Non-coding Region – Sections of DNA that do not code for proteins

37. Cell Differentiation
In a multicellular organism, every cell in the body has the same DNA
Every cell in the body came from one cell – a fertilized egg (embryo)
Embryo divides numerous times to add new body cells
Uses process of mitosis to add new body cells (Somatic Cells)
This means that every cell in our body has the same genes
In humans, each somatic cell is a diploid cell and has 46 chromosomes

38. Cell Differentiation
Every cell in a multicellular organism contains all of the organism’s genes
But, each cell does not need to use every gene to function properly.
Differentiated (specialized) cells only use the genes necessary for that cell type to function
Only makes the necessary proteins for that cell type
Cells can regulate which proteins they make by controlling which genes are activated and used to make proteins.

39. Gene Expression
GENE EXPRESSION - activation of a gene that results in the formation of a protein.
A gene is expressed when it is copied into RNA
Control of gene expression is very important in embryo development and as cells are becoming specialized
Before cells become specialized, they are known as Stem Cells
Stem cells activate certain genes & begin to become specialized
This causes the cell to change its shape to take on its final specialized form and function
Remember: Our body is made up of over 200 different types of cells! Each cell/tissue type has its own unique form & function
As multicellular organisms grow and develop, organs and tissues develop
Development of a cell into a specialized form based on its specialized function is known as MORPHOGENESIS
Cells develop their specialized form by expressing certain genes, which will produce certain proteins

41. End of Lecture 4