protein synthesis and structure

1. Protein Synthesis and
Structure
By AMER ALYAFEAI

2. INTRODUCTION
- protines are large biological
molecules, or macromolecules,
consisting of one or more long chains
of amino acid residues.
- Proteins perform a vast array
of functions within living
organisms

3. Two stages of protein synthesis:
1-Transcription.
2- Translation.

5. Transcription:
The first step is transcription.
The first step in transcription is the unwinding of the
DNA molecule so that some DNA that codes for the
needed protein can be transcribed.
After the DNA molecule unwinds, the enzyme, RNA
polymerase lines up nucleotides to create a strand of
mRNA.
After transcription, the new RNA strand is released and
the two unzipped DNA strands bind together again.
Since after this occurs the DNA strand is back to normal
this step can repeat.

6. Translation
- The next step is Translation.
- In this, mRNA is sent to the cytoplasm, where it
binds to the RNA.
- Once the mRNA is in place, tRNA molecules bind to
the ribosome defined by the mRNA code. At its tail
end, tRNA has a “stem” that attaches to a specific
amino acid. At its head, it has three nucleotides that
make up an anticodon.
- Translation begins with the binding of the mRNA
chain to the ribosome. The tRNA molecule forms a
base pair with the mRNA. A peptide bond is formed

9. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----

10. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----

11. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----

12. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG

13. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG AGA

14. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG AGA CCG

15. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG AGA CCG UAG

16. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG AGA CCG UAG UGA

17. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----
ACG AGA CCG UAG UGA
MRNA strand

18. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----

19. ---------------------TACTCTGGCATCACT------------------------
----
---------------------ATGAGACCGTAGTGA-----------------------
----

21. ACG AGA CCG UAG UGA

22. ACG AGA CCG UAG UGA

26. ACG AGA CCG UAG UGA

27. ACG AGA CCG UAG UGA

28. ACG AGA CCG UAG UGA

29. ACG AGA CCG UAG UGA

30. AUG AGA CCG UAG UGA
tRNA molecule
Anti codon

31. AUG AGA CCG UAG UGA

32. AUG AGA CCG UAG UGA

33. AUG AGA CCG UAG UGA

34. AUG AGA CCG UAG UGA

35. AUG AGA CCG UAG UGA

36. AUG AGA CCG UAG UGA

37. AUG AGA CCG UAG UGA

38. AUG AGA CCG UAG UGA

39. AUG AGA CCG UAG UGA

40. AUG AGA CCG UAG UGA

41. AUG AGA CCG UAG UGA

42. AUG AGA CCG UAG UGA
Amino acids
Peptide bond

45. Primary Structure Of Proteins
Linear sequence of amino acids which is held together
by covalent peptide bond.

46. Secondary Structure
The spatial arrangement of protein by
twisting of the poly peptide chain is referred
to as secondary structure.
Two different types of secondary structure
are exist Due to regular folding of the poly
peptide chain. α-helix and β-pleated
sheet.
Which happens due to hydrogen bonding.

47. 1) α-Helix-
It is tightly packed
coiled structure
with amino acid
side chains
extending outward
from the central
axis.

48. 2) β- sheets
These are
composed of
two or more
segments of
fully extended
peptide
chains.

49. Tertiary Structure
The three
dimensional
arrangement of
protein structure
is referred to as
tertiary
structure.

50. Quaternary Structure
Proteins composed of two
or more polypeptide chains
referred to as sub-units.
The spatial arrangement
of these sub units is known
as quaternary structure.