1. Hemophilia-
Caused by a defect in a single gene cannot produce all the proteins necessary for blood clotting
Depend on expensive injections of clotting proteins to prevent uncontrolled bleeding

2. nuclear pore chromatin (DNA) nucleus nucleolus nuclear envelope
flagellum
intermediate
filaments
cytoplasm
plasma
membrane
rough endoplasmic
reticulum
ribosome
lysosome
Figure: 04-02
Title:
A generalized animal cell.
Caption:
microtubules
smooth endoplasmic
reticulum
Golgi
complex
free ribosome
vesicle
mitochondrion
vesicle

3. Protein Synthesis
Gene
Expression

4. The relationship of Chromosomes,
DNA, Genes & Proteins
The relationship of Chromosomes,
Genes, DNA & Proteins
Franklin's Legacy | PBS
DNA to Protein

5. Genes and Proteins Genes provide information to make proteins
Genetic information for protein synthesis is carried by RNA (ribonucleic acid) intermediates

6. The genetic code and codons
A sequence of nucleotide bases in DNA is translated into a sequence of amino acids in a protein.

7. Protein Synthesis Two-step process
Transcription and Translation
Transcription—nucleotide message sent from nucleus to cytoplasm
DNA nucleotide sequence "copied" (using complementary base pairing) as a "messenger" nucleotide sequence of RNA (mRNA)

8. Translation produces a protein molecule with an amino acid
gene 3
gene 1
DNA
gene 2
(nucleus)
(cytoplasm)
Transcription of
gene 1 produces an
mRNA with a
nucleotide sequence
complementary to
one of the DNA strands.
(a) TRANSCRIPTION
messenger RNA
Figure: 09-01
Title:
Genetic information flows from DNA to RNA to protein.
Caption:
After being transcribed, the mRNA molecule moves from the nucleus to the cytoplasm, where it is translated.
protein
(b) TRANSLATION
Translation produces a protein
molecule with an amino acid
sequence determined by the
nucleotide sequence in the mRNA.

9. Protein Synthesis 1. Transcription…
b. RNA polymerase catalyzes synthesis of mRNA; similar to DNA replication and DNA polymerase
Promoter sequence binds RNA polymerase
Termination signal is a sequence of nucleotides at end of genes that tell RNA polymerase to stop transcription

10. Translation produces a protein molecule with an amino acid
gene 3
gene 1
DNA
gene 2
(nucleus)
(cytoplasm)
Transcription of
gene 1 produces an
mRNA with a
nucleotide sequence
complementary to
one of the DNA strands.
(a) TRANSCRIPTION
messenger RNA
Figure: 09-01
Title:
Genetic information flows from DNA to RNA to protein.
Caption:
After being transcribed, the mRNA molecule moves from the nucleus to the cytoplasm, where it is translated.
protein
(b) TRANSLATION
Translation produces a protein
molecule with an amino acid
sequence determined by the
nucleotide sequence in the mRNA.

11. Protein Synthesis 1. Transcription…
c. The entire DNA molecule in a chromosome is not transcribed, only a specific gene or family of genes is transcribed

12. chromosome DNA gene 1 gene 2 gene 3 (a) initiation template strand
Figure: 09-03a
Title:
Initiation and elongation are the first two steps of transcription.
Caption:
(a) Initiation: The enzyme RNA polymerase binds to the promoter region of DNA near the beginning of a gene, forcing the DNA double helix to separate in front of it.
template strand
RNA polymerase

13. (b) elongation RNA Figure: 09-03b Title:
Initiation and elongation are the first two steps of transcription.
Caption:
(b) Elongation: RNA polymerase travels along the DNA template strand, catalyzing the formation of a complementary RNA molecule from free RNA nucleotides. As RNA polymerase moves along, the already transcribed portion of the DNA double helix begins to rewind.
RNA

14. direction of transcription beginning of gene growing RNA RNA molecules
Figure: 09-04b
Title:
RNA transcription in action.
Caption:
In each treelike structure, the central “trunk” is DNA and the “branches” are RNA molecules. RNA polymerase molecules are traveling along the DNA, synthesizing RNA as they go. The beginning of the gene is on the left, and the short RNA molecules on the left have just begun to be synthesized; the long RNA molecules on the right are almost finished.
growing
RNA
molecules
RNA
polymerase
DNA

15. Figure: 09-04a
Title:
RNA transcription in action.
Caption:
The images in this electron micrograph show RNA transcription. In each treelike structure, the central “trunk” is DNA and the “branches” are RNA molecules. RNA polymerase molecules are traveling along the DNA, synthesizing RNA as they go. The beginning of the gene is on the left, and the short RNA molecules on the left have just begun to be synthesized; the long RNA molecules on the right are almost finished.

16. (a) RNA polymerase termination signal Figure: 09-05a Title:
Termination is the third step of transcription.
Caption:
Elongation of the RNA molecule continues until (a) RNA polymerase encounters, at the end of gene, a termination signal.

17. Initiation, Elongation and Termination
(b)
Figure: 09-05b
Title:
Termination is the third step of transcription.
Caption:
(b) RNA polymerase detaches from the DNA and releases the RNA molecule, allowing the DNA double helix to completely rewind.
RNA
Initiation, Elongation and Termination

18. Translation produces a protein molecule with an amino acid
gene 3
gene 1
DNA
gene 2
(nucleus)
(cytoplasm)
Transcription of
gene 1 produces an
mRNA with a
nucleotide sequence
complementary to
one of the DNA strands.
(a) TRANSCRIPTION
messenger RNA
Figure: 09-01
Title:
Genetic information flows from DNA to RNA to protein.
Caption:
After being transcribed, the mRNA molecule moves from the nucleus to the cytoplasm, where it is translated.
protein
(b) TRANSLATION
Translation produces a protein
molecule with an amino acid
sequence determined by the
nucleotide sequence in the mRNA.

19. Protein Synthesis
2. Translation—nucleotide sequence of mRNA used to synthesize a sequence of amino acids (polypeptide or protein)
a. Occurs on the endoplasmic reticulum using ribosomes

20. rough endoplasmic reticulum smooth endoplasmic reticulum
ribosomes
0.5 micrometers
smooth endoplasmic reticulum
Figure: 04-07
Title:
Endoplasmic reticulum.
Caption:
There are two types of endoplasmic reticulum: rough ER, coated with ribosomes, and smooth ER, without ribosomes. Although in electron micrographs the ER looks like a series of tubes and sacs, it is actually a maze of folded sheets and interlocking channels.
0.5 micrometers
vesicles

21. Protein Synthesis 2. Translation…
b. mRNA codons are used to specify amino acids
c. Ribosomes "read" mRNA codons to synthesize a specific amino acid sequence

22. A Codon = three nucleotide bases
(a) messenger RNA
Figure: 09-02a
Title:
Cells synthesize three major types of RNA.
Caption:
(a) mRNA is a sequence of nucleotides that encodes a protein.
A Codon = three nucleotide bases

23. (b) ribosome (contains ribosomal RNA) catalytic site large subunit
tRNA/amino acid
binding sites
Figure: 09-02b
Title:
Cells synthesize three major types of RNA.
Caption:
(b) rRNA is a major component of the two subunits that join together to form a ribosome.
small
subunit

24. Protein Synthesis 2. Translation…
d. Each of the 20 amino acids has a specific "carrier" transfer RNA (tRNA) that brings the amino acid to the ribosome
e. Complementary base pairing between the mRNA and tRNAs determines the amino acid sequence

25. (c) transfer RNA attached amino acid anticodon Figure: 09-02c Title:
Cells synthesize three major types of RNA.
Caption:
(c) One side of tRNA contains an anticodon that is complementary to an mRNA codon; the opposite side binds an amino acid.
anticodon

26. (a) messenger RNA (b) ribosome (contains ribosomal RNA) catalytic site
large
subunit
tRNA/amino acid
binding sites
small
subunit
Figure: 09-02a-c
Title:
Cells synthesize three major types of RNA.
Caption:
RNA consists of a single strand of nucleotides whose sequence is complementary to that of the DNA from which it was transcribed. (a) mRNA is a sequence of nucleotides that encodes a protein. (b) rRNA is a major component of the two subunits that join together to form a ribosome. (c) One side of tRNA contains an anticodon that is complementary to an mRNA codon; the opposite side binds an amino acid.
(c) transfer RNA
attached
amino acid
anticodon

27. Protein Synthesis 2. Translation…
f. Ribosomes need to recognize the beginning and end of the mRNA message
1) Initiation (start) codon: AUG (methionine)
2) Stop codons: UAA, UAG, UGA

28. A tRNA with an attached methionine amino acid binds to small
initiation
complex
small
ribosomal
subunit
Figure: 09-06a
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(a)
A tRNA with an attached methionine
amino acid binds to small
ribosomal subunit, forming
an initiation complex.

29. The initiation complex binds to the end of an mRNA and
tRNA
mRNA
Figure: 09-06b
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(b)
The initiation complex binds
to the end of an mRNA and
travels along the mRNA until
it encounters an AUG codon.
The anticodon of the tRNA
pairs with the AUG codon.

30. The large ribosomal subunit binds to the small subunit, with the
second binding site
catalytic site
large
ribosomal
subunit
first
binding
site
Figure: 09-06c
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(c)
The large ribosomal subunit binds
to the small subunit, with the
mRNA between the two subunits.
The methionine tRNA is in the first
binding site on the large subunit.

31. A second tRNA enters the second binding site. Its
catalyic site
Figure: 09-06d
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(d)
A second tRNA enters the
second binding site. Its
anticodon pairs with the codon
in the mRNA. The tRNA
carries an attached amino
acid.

32. The catalytic site catalyzes the formation
peptide
bond
Figure: 09-06e
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(e)
The catalytic site catalyzes the formation
of a peptide bond that links the two
amino acids. Both amino acids are now
attached to the tRNA in the second
binding position.

33. ribosome moves one codon to right
catalytic site
tRNA detaches
Figure: 09-06f
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
ribosome moves one codon to right
(f)
The “empty” tRNA is released and
the ribosome moves one codon to the
right. The tRNA with the two amino
acids is now in the first tRNA binding
site. The second tRNA binding site
is empty.

34. Another tRNA, with an anticodon complementary to the next mRNA
catalytic site
Figure: 09-06g
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(g)
Another tRNA, with an anticodon
complementary to the next mRNA
codon, enters the second binding
site. This tRNA carries the next
amino acid to be added to the chain.

35. The catalytic site forms a peptide bond that attaches the new amino
Figure: 09-06h
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(h)
The catalytic site forms a peptide
bond that attaches the new amino
acid at the end of the chain. The
chain of three amino acids is now
attached to the tRNA in the second
binding site. The empty tRNA in the
first site will be released and the
ribosome will move one codon to
the right.

36. Binding of tRNAs and formation of peptide bonds between amino acids
completed
peptide
stop codon
Figure: 09-06i
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
(i)
Binding of tRNAs and formation of
peptide bonds between amino acids
continues until the ribosomes reaches
a stop codon. No tRNA binds to stop
codons. Instead, protein “release
factors” signal the ribosome to release
the newly made protein. The mRNA is
also released, and the subunits separate.

37. tRNA detaches catalytic site catalytic site catalytic site
second binding site
large
ribosomal
subunit
amino acid
catalytic
site
methionine
tRNA
tRNA
initiation complex
first
binding
site
small
ribosomal
subunit
mRNA
(a)
(b)
(c)
tRNA detaches
catalytic
site
catalytic
site
peptide
bond
ribosome moves one
codon to the right
(d)
(e)
(f)
Figure: 09-06A-I
Title:
Translation: the base sequence of an mRNA is translated into the amino acid sequence of a protein.
Caption:
catalytic
site
completed
peptide
stop
condon
(g)
(h)
(i)

38. gene (a) gene in DNA (template strand) codon (b) mRNA (codons)
anticodon
Figure: 09-07a-d
Title:
Complementary base pairing is critical at each step in decoding genetic information
Caption:
(a) DNA contains two strands. One of them, the template strand, is used to synthesize an RNA molecule. (b) Bases in the template strand are transcribed into complementary mRNA codons. (c) Unless it is a stop codon, each mRNA codon forms base pairs with the anticodon of a tRNA molecule that carries a specific amino acid. (d) The amino acids are linked together, forming a protein.
(c)
tRNA
(anticodons)
amino acids
(d)
protein
(amino acids)

39. Review Protein Synthesis
Two Major Steps of Protein Synthesis Transcription & Translation
Initiation, Elongation and Termination