43. 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.
44. 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.
45. 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
