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Where is Cytochrome C?
What is the role? Where does it come from?
Evolutionary Biology
of Cytochrome C
• Cytochrome c is a highly
conserved protein.
• Its primary structure consists of a
chain of 100 aa.
• Both chicken and turkeys have the
identical molecule whereas ducks p
differ by one amino acid.
• Similarly, both humans and
chimpanzees have the identical
molecule.
Where does protein come from?
The information for building proteins is
stored in our DNA. DNA codes for
proteins like cytochrome C.
DNA  RNA Protein
Gene for Cytochrome C
Cytochrome C
Gene expression
If the DNA in a single human cell were stretched out and laid end-to-end, it would
measure approximately 6.5 feet. The average human body contains 10 to 20
billion miles of DNA distributed among trillions of cells.
Understanding How Cells Build
Essential Proteins
DNA Structure
Double helix
WC Base pair
Structure of a
Gene
Understanding how
genes are expressed
DNA RNAProtein
DNA is a double-stranded helix
James Watson and Francis Crick
Worked out the three-dimensional structure of
DNA, based on work by Rosalind Franklin
http://www.dnai.org/
Figure 10.3A, B
Twist
DNA is a nucleic acid
• Made of long chains of nucleotide monomers
• Remember that ATP was a nucleotide
Sugar-phosphate backbone
Phosphate group
Nitrogenous base
A
C
A
Sugar
DNA nucleotide
C
Nitrogenous base
(A, G, C, or T)
Phosphate
group
O
H3C
C
O
T
T
O
P
O
CH2
O–
G
G
H
N
C
N
C
O
Thymine (T)
O
C H
H C
H C
C H
O
H
C
H
Sugar
(deoxyribose)
T
T
DNA nucleotide
Figure 10.2A
DNA polynucleotide
Double Helix Structure
Major/minor groove
Anti-parallel strands
DNA has four kinds of nitrogenous bases
• A, T, C, and G
H
O
H3C
H
C
C
C
H
H
N
C
H
N
C
N
C
C
C
N
H
O
H
H
Thymine (T)
Cytosine (C)
Pyrimidines
Figure 10.2B
N
H
N
H
O
N
H
O
C
C
N
C
C
N
H
C
N
N
H
N
C
C
N
H
Adenine (A)
Guanine (G)
Purines
H
C
N
H
C
C
N
H
H
DNA Strands:
Anti-parallel
5 end
P
3 end
HO
5
4
2
3
2
1
A
T
G
P
P
G
C
P
P
T
Figure 10.5B
4
P
C
3 end
1
5
P
OH
3
A
P
5 end
Each strand of the
double helix is
oriented in the
opposite direction
Understanding How Cells Build
Essential Proteins
DNA Structure
Double helix
WC Base pair
Structure of a
Gene
Understanding how
genes are expressed
DNA RNAProtein
DNA nevers leaves the
nucleas but the
information does!
Strand to be transcribed
T
A
C
T
T
C
A
A
A
A
T
C
A
T
G
A
A
G
T
T
T
T
A
G
U
A
G
DNA
Transcription
A
U
G
A
A
G
U
U
U
RNA
Start
condon
Stop
condon
Translation
Polypeptide
Met
Lys
The information
constituting an
organism’s genotype
is carried in its
sequence of its
DNA bases.
“ATGACTAA”
A particular gene, a
linear sequence of
many nucleotides
Specifies a
polypeptide
Phe
“MET-LYS-LEU”
DNA
Transcription
RNA
Translation
Protein
Figure 10.6A
DNA  RNA Protein
Close up on DNARNA: Transcription
RNA nucleotides
RNA
polymerase
T C C A
A U
A
T
T
A
C C A
T A G G T
Direction of
transcription
Figure 10.9A
Newly made RNA
Template
Strand of DNA
DNA  RNA Protein
transcription
RNA nucleotides
• And RNA nucleotides
line up along one
strand of the DNA,
following the base
pairing rules
RNA
polymerase
T CCA A T
AUCCA
T A GGT T A
Figure 10.9A
Direction of
transcription
Newly made RNA
– In the nucleus, the
DNA helix unzips
Template
Strand of DNA
– As the single-stranded
messenger RNA
(mRNA) peels away
from the gene
• The DNA strands rejoin
RNA polymerase
DNA  RNA Protein
DNA of gene
Promoter
DNA
Terminator
DNA
Area shown
In Figure 10.9A
Growing
RNA
Completed RNA
RNA
polymerase
• RNA pol binds to
promoter
• Transcription of
strand to mRNA
• Instructions now in
mRNA
• RNA pol reaches
terminator
A
DNA  RNA Protein
DNA molecule
Second base
U
C
UUU
A
UCU
UAU
UCC
UAC
Phe
UUC
U
G
Tyr
Gene 1
U
Cys
C
UGA Stop
Ser
UUA
UGU
UGC
UCA
UAA Stop
UCG
UAG Stop
CCU
CAU
A
Gene 2
Leu
CUU
UGG Trp
G
U
CGU
His
CUC
C
CUA
First base
CAC
CCC
CCA
CUG
Gene 3
Arg
CAA
CAG
CCG
C
CGC
Pro
Leu
CGA
Gln
A
CGG
G
ACU
AUU
AUC
Ile
AAU
ACC
A
AAC
Ser
AGC
DNA strand
A A A C C G G C A A A A
C
Thr
AUA
ACA
Met or
AUG start
AGA
AAA
ACC
AAG
Lys
AGG
GUU
GCU
GAU
GUC
GCC
GAC
GGC
GAA
GGA
GUA
GUG
Val
A
Arg
Transcription
G
C
Gly
Ala
GCA
U
GGU
Asp
G
U
AGU
Asn
RNA
U U U G G C C G U U U U
Codon
Translation
A
Glu
GCG
GAG
GGG
G
Figure 10.7
Polypeptide
Amino acid