1. The blueprint of life; from DNA to Protein
Biology 261
Medgar Evers College
Prof. Santos

3. DNA, the substance of inheritance Hereditary information
Is the most celebrated molecule of our time
Hereditary information
Is encoded in the chemical language of DNA and reproduced in all the cells of your body
It is the DNA program
That directs the development of many different types of traits

4. (a) Key features of DNA structure (c) Space-filling model
Figure 16.7a, c C T A G
0.34 nm
3.4 nm
(a) Key features of DNA structure
1 nm
(c) Space-filling model

5. DNA The Components and Structure of DNA DNA is made up of nucleotides.
A nucleotide is a monomer of nucleic acids made up of:
Deoxyribose – 5-carbon Sugar
Phosphate Group
Nitrogenous Base

6. There are four kinds of bases in in DNA:
adenine
guanine
cytosine
thymine

7. Chargaff’s rule Chargaff's Rules Erwin Chargaff discovered that:
The percentages of guanine [G] and cytosine [C] bases are almost equal in any sample of DNA.
The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA.

8. There are 2 hydrogen bonds between adenine and thymine and three hydrogen bonds between cytosine and guanine.

9. DNA to RNA to Protein connection

10. Protein synthesis 3 steps 1- transcription 2- RNA processing
3- translation

11. Transcription Copying the genetic code directly from DNA.
We make a single strand of messenger RNA.
We begin initiation by unwinding the double stranded DNA and copying only one of the strands. The strand that is copied is called the nonsense strand. It serves as a template for the production of messenger RNA.

13. RNA processing
The pre messenger RNA made must be modified before it can leave the nucleus and direct the production of proteins.
3 steps
1- removal of introns
2- addition of cap at 5 end
3- poly A tail at 3 end

14. The coding regions are called exons and the non-coding regions are called introns.
The introns are removed by an enzyme-RNA complex known as the spliceosome.
A tail of adenine bases is added to the 3 prime end and a modified guanine nucleotide is added to the 5 prime end.

16. Once the messenger RNA has been processed, it is ready to leave the nucleus and bind to a ribosome.
The mature messenger RNA carries the message from DNA in the forms of codons.
A codon is a group of 3 bases that correspond to one of the 20 amino acids.

17. There are 64 possible codons and only 20 amino acids
There are 64 possible codons and only 20 amino acids. There is redundancy with some of the amino acids!
The initial codon is AUG or methionine and there are three stop codons, UAA, UGA and UAG.

18. Figure 17.5 Second mRNA base U C A G UUU UUC UUA UUG CUU CUC CUA CUG
AUC
AUA
AUG
GUU
GUC
GUA
GUG
Met or
start
Phe
Leu
lle
Val
UCU
UCC
UCA
UCG
CCU
CCC
CCA
CCG
ACU
ACC
ACA
ACG
GCU
GCC
GCA
GCG
Ser
Pro
Thr
Ala
UAU
UAC
UGU
UGC
Tyr
Cys
CAU
CAC
CAA
CAG
CGU
CGC
CGA
CGG
AAU
AAC
AAA
AAG
AGU
AGC
AGA
AGG
GAU
GAC
GAA
GAG
GGU
GGC
GGA
GGG
UGG
UAA
UAG
Stop
UGA
Trp
His
Gln
Asn
Lys
Asp
Arg
Gly
First mRNA base (5 end)
Third mRNA base (3 end)
Glu

19. Translation
The messenger RNA attaches to the ribosome and the message in the form of codons is “translated” and the appropriate amino acid is put in place.
A molecule of RNA called transfer RNA brings along the amino acid. It resembles a four leaf clover.
On the top is the amino acid and on the bottom is a sequence known as the anti codon.

20. 3 C A G U * 5
Amino acid
attachment site
Hydrogen
bonds
Anticodon

21. The anticodon pairs up with the codon
The anticodon pairs up with the codon. This allows the amino acids to put placed in the correct sequence or order.