The document explains the process of protein synthesis, which involves transcription (copying genetic information from DNA to mRNA) and translation (decoding mRNA to form proteins using tRNA). It discusses the structure and functions of proteins, including their roles in fighting disease, building tissues, and acting as enzymes. Additionally, the document outlines the genetic code and how amino acids are assembled to form proteins based on that code.

1. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Ryan A.Bersamin
Genetic Coding and
Protein Synthesis

2. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
• Proteins make up all living materials

3. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Proteins
• Proteins are composed of
amino acids – there are
20 different amino acids
• Different proteins are
made by combining these
20 amino acids in different
combinations

4. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
• Proteins are manufactured (made) by the ribosomes

5. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Function of Proteins
1. Help fight disease
2. Build new body tissue
3. Enzymes used for
digestion and other
chemical reactions
are proteins
(Enzymes speed up
the rate of a reaction)
4. Component of all cell
membranes

6. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Making Proteins
Step 1:
Transcription

7. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Making a Protein—Transcription
• First Step: Copying of genetic information from DNA to RNA
called Transcription
Why? DNA has the genetic code for the protein that needs to be
made, but proteins are made by the ribosomes
—ribosomes are outside the nucleus
in the cytoplasm.
DNA is too large to leave
the nucleus
(double stranded),
but RNA can leave
the nucleus
(single stranded).

8. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Unzipping of the DNA
• Part of DNA temporarily unzips
and is used as a template to
assemble complementary
nucleotides into messenger RNA
(mRNA).

9. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
mRNA leaves the Nucleus
• mRNA then goes
through the
pores of the
nucleus with the
DNA code and
attaches to the
ribosome.

10. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Making Proteins
Step 2:
Translation

11. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
How to Translate mRNA to Amino Acids
(DECODING THE GENETIC CODE)

12. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Making Protein—Translation
• Second Step: Decoding
of mRNA into a protein
is called Translation.
• Transfer RNA (tRNA)
carries amino acids
from the cytoplasm to
the ribosome.

13. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Function of Proteins
These amino acids come
from the food we eat.
Proteins we eat are broken
down into individual
amino acids and then
simply rearranged into
new proteins according to
the needs and directions
of our DNA.

14. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The Transfer-RNA
• A series of three adjacent bases
in an mRNA molecule codes for a
specific amino acid—called a
codon.
• Each tRNA has 3 nucleotides
that are complementary to the
codon in mRNA.
• Each tRNA codes for a different
amino acid.
Amino acid
Anticodon

15. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The Messenger-RNA
• mRNA carrying the DNA instructions and
tRNA carrying amino acids meet in the
ribosomes.

16. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
• Amino acids are joined together to make a protein.
Polypeptide = Protein

17. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Codons and Amino Acids
To determine the amino acid sequence coded in the following
section of an mRNA,
5′ CCU AGC GGA CUU 3′
1. refer to the genetic code for the identity of the amino acids
CCU = Proline AGC = Serine
GGA = Glycine CUU = Leucine
2. mRNA section codes for the amino acid sequence are
written in the following order:
Pro—Ser—Gly—Leu

18. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Codons and Amino Acids
To determine the amino acid sequence coded in the following
section of an mRNA,
5′ CCU AGC GGA CUU 3′
1. refer to the genetic code for the identity of the amino acids
CCU = Proline AGC = Serine
GGA = Glycine CUU = Leucine
2. mRNA section codes for the amino acid sequence are
written in the following order:
Pro—Ser—Gly—Leu

19. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The Genetic Code: mRNA Codons

20. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Codon Wheel

21. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Protein Synthesis, Activation
3. Molecules of tRNA pick up specific amino acids according to their
anticodons. tRNA activation occurs when the correct amino acid is
attached to each tRNA.

22. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Protein Synthesis

23. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Study Check
Write the amino acids coded for by a section of mRNA with
the following base sequence:
5 GCC GUA GAC 3
ʹ ʹ
Some possible codons to use are the following:
GGC = Glycine GAC = Aspartic acid
CUC = Leucine GUA = Valine
GCC = Alanine CGC = Arginine

24. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Solution
Write the amino acids coded for by a section of mRNA with
the following base sequence:
5 GCC GUA GAC 3
ʹ ʹ
Ala—Val—Asp

25. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Study Check
• A short oligopeptide is encoded in this sequence of RNA
5' GAC-UAU-GCU-CAU-AUU-GGU-CCU-UUG-ACA
a) Where does it start and stop, and how many amino
acids are encoded?

26. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Solution
Write the amino acids coded for by a section of mRNA with
the following base sequence:
5 GAC-UAU-GCU-CAU-AUU-GGU-CCU-UUG-ACA
ʹ
Asp - Tyr - Ala - His - Tyr - Iso - Pro - Leu - Thr

27. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
DNA vs RNA

28. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
The Shape of the Molecule
• DNA is a very long
polymer.
• The basic shape is
like a twisted ladder
or zipper.
• This is called a
double helix.

29. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
The Double Helix Molecule
• The DNA
double helix
has two
strands
twisted
together.

30. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
30
One Strand of DNA
• The backbone of
the molecule is
alternating
phosphates and
deoxyribose
sugar
• The teeth are
nitrogenous
bases.
phosphate
deoxyribose
bases

31. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
31
Nucleotides
C C
C
O
Phosphate
O
C
C
O -P O
O
O
O -P O
O
O
O -P O
O
O
• One deoxyribose together
with its phosphate and base
make a nucleotide.
Nitrogenous
base
Deoxyribose

32. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
32
One Strand of DNA
• One strand of DNA
is a polymer of
nucleotides.
• One strand of DNA
has many millions
of nucleotides.
nucleotide

33. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
33
Two Stranded DNA
• Remember, DNA
has two strands
that fit together
something like a
zipper.
• The teeth are the
nitrogenous
bases but why
do they stick
together?

34. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
34
34
Four nitrogenous bases
• Cytosine C
• Thymine T
• Adenine A
• Guanine G
DNA has four different bases:

35. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
The DNA Strand
35
35
Chargraff’s Rule:
• Adenine and Thymine
always join together
A T
• Cytosine and Guanine
always join together
C G

36. General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake
© 2016 Pearson Education, Inc.
Have a
great day
ahead!!!
Have a
great day
ahead!!!