Protein Synthesis

By Donna Jean Roberts

Cytoplasm

Nucleolus

Ribosomes

Nuclear Membrane

Cell Membrane

Nucleolus

Ribosomes

Nuclear Membrane

Nucleus

Ribosomes

Nuclear Membrane

Nucleus

Nuclear Membrane

Nucleus

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

T =Thymine

A =Adenine

C =Cytosine

G =Guanine

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

RNA Polymerase

A

T

C

G

T

A

G

C

A

T

T

A

G

C

A

T

C

G

C

G

G

C

T

A A

T

C

G

T

A

RNA Polymerase

A

TC

GT

AG

C

A

T

T

A

G

C

A

TC

GC

G

G

C

T

A A

T

C

G

T

A

A

TC

GT

AG

C

A

T

T

A

G

C

A

TC

GC

G

G

C

T

A A

T

C

G

T

A

UA

G

A

T

C

GT

AG

C

A

T

T

A

G

C

A

TC

G

C

G

G

C

T

A A

T

C

G

T

A

U

A

G

A

T

C

GT

AG

C

A

T

T

A

G

C

A

TC

G

C

G

G

C

T

A A

T

C

G

T

A

UAG

G A G

A

TC

GT

A G

C

A

T

T

A

G

C

A

TC

G

C

G

G

C

T

A A

T

C

G

T

A

UA

GG

AG

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G

C

G

G

C

T

A A

T

C

G

T

A

UAG

G A G

CU A

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

UA

GG

AG

CU

A

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

AA

T

C

G

T

A

UAG

G A GC

U AGC

U

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

UAG

G A G

CU

A

GCU

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

UA G G A G CU AGC U U G A

A

T C

GT

A G

C

A

T

T

A

G

C

A

TC

G C

G

G

C

T

A A

T

C

G

T

A

UA G G A G CU A GC U U G A

mRNA

RNA Polymerase

Nucleus

UA G G A G CU A GC U U G A

Nucleus

Nuclear Membrane

UA G G A G CU A GC U U G A

Nucleus

Ribosomes

Nuclear Membrane

Cytoplasm

Nuclear Pore

UA G G A G CU A GC U U G A

AU C

Start Codon

End Codon

tRNA

Amino Acid

Anticodon

Large Subunit

Small Subunit

Ribosome

UA G G A G CU A GC U U G A

UA G G A G CU A GC U U G A

AU C

UC C

AU C UC C

UA G G A G CU A GC U U G A

AU C UC C

Peptide Bond

UA G G A G CU A GC U U G A

UC C

UA G G A G CU A GC U U G A

UC C

A GU

UA G G A G CU A GC U U G A

UC C A GU

UA G G A G CU A GC U U G A

UC C A GU

UA G G A G CU A GC U U G A

A GU

UA G G A G CU A GC U U G A

A GU AG C

UA G G A G CU A GC U U G A

A GU AG C

UA G G A G CU A GC U U G A

AG C

UA G G A G CU A GC U U G A

AG C

UA G G A G CU A GC U U G A

AG C STOP

UA G G A G CU A GC U U G A

STOP

UA G G A G CU A GC U U G A

Peptide chain

UA G G A G CU A GC U U G A

1o = Primary Structure

2O = Secondary Structure

3O = TERTIARY STRUCTURE

Protein

Protein Synthesis Essay• Protein synthesis is the process of which proteins are made in the cell. The first

step in protein synthesis is Transcription. Transcription occurs in the nucleus of the cell. The reason for this step is that the double stranded DNA is to big to fit through the nuclear pore so a single stranded mRNA needs to be made to be sent to the cytoplasm. DNA holds the code to make the proteins. First, RNA Polymerase binds onto the DNA strand at the promoter region. RNA Polymerase unravels the DNA strand. As it unravels RNA polymerase adds the complementary nucleotides on to the mRNA strand, being made. The difference between an RNA strand and DNA strand is the base pairing rules, which on the RNA strand are A=U and G=C. RNA polymerase reads 3I to 5I and synthesizes 5I to 3I and adds nucleotides in codons, a group of three base pairs. The mRNA strand being made is built off to the side of the DNA strand. On every mRNA strand the first codon, start codon, is AUG and the last, stop codon, is UAA, UAG, or UGA. After the whole mRNA strand is made the DNA strand connects together again and forms the double helix. The single mRNA strand leaves the nucleus through the nuclear pore and into the cytoplasm where the next step occurs.

Protein Synthesis Essay• The second step in protein synthesis is Translation. In Translation the mRNA

strand is read by a ribosome. A ribosome has two parts a large subunit and a small subunit. The mRNA strand goes in between the two units to be read. The ribosome reads in codons and starts at the start codon. Then a tRNA molecule comes. The structure of the tRNA is at the top is an amino acid, which is determined by the codon on the mRNA strand, and at the bottom is an anticodon, which is the three complementary nucleotides of the codon. The tRNA temporally connects to the mRNA strand. Once the ribosome reads the next codon and another tRNA molecule comes and connects the to the mRNA strand a peptide bond is made with both of the amino acids at the top of the tRNA molecules. After the peptide bond is made the first tRNA molecule leaves the amino acid connected to the other amino acid. This process repeats itself until the stop codon is reached. At the stop codon no tRNA molecule comes with an amino acid the last tRNA molecule just leaves it’s amino acid behind and the ribosome unbinds from the mRNA strand.

Protein Synthesis Essay

• Now, with all of the amino acids connected with a peptide bond that forms a peptide chain. When the amino acids are unfolded they are in the primary structure. Then the amino acids start to fold and from a crimped type shape, which is the secondary structure. Finally, the amino acids fold up into a ball and are in the last structure the tertiary structure. The amino acids are now a protein. The protein gets its function from its unique shape