Transcript From DNA to Proteins

Compare and contrast the DNA molecule on
the left with the RNA molecule on the right
Include 3 similarities and 3 differences
between the two molecules
We have looked at DNA. But how is this
gentic code actually used for anything?
Lets
See!
The genetic
code is used
as a blueprint
to make
proteins.
To manufacture proteins, cells
follow a very systematic 2 step
procedure that first transcribes
DNA in the nucleus into mRNA
and then translates
the mRNA into chains
of amino acids
in the cells
ribosomes.
RNA is very similar to DNA except that it:
contains a different sugar (ribose
instead of deoxyribose)
has only a single strand of
nucleotides instead of two strands
contains the nitrogen base uracil
(U) instead of thymine (T)
• Ribosomal RNA (rRNA), along
with protein, makes up the
ribosomes
• Messenger RNA (mRNA) copies
DNA’s code & carries the
genetic information to the
ribosomes
• Transfer RNA (tRNA) transfers
amino acids to the ribosomes
where proteins are synthesized
The “m” in “mRNA”
stands for “messenger,”
because mRNA copies
genetic information from
DNA (which is found in
the nucleus) and carries
it to another part of
the cell (the ribosomes).
Transcribe the DNA sequence below into
a strand of mRNA
G T T C C G A T C
?
? ? ? ? ?
?
? ?
Where in a cell does the process
below take place?
A A A G G C T A G
T T T C C G A T C
U U U C C G A U C
What product is produced as a
result of this process?
A A A G G C T A G
T T T C C G A T C
U U U C C G A U C
Think of the genetic
code the mRNA is
carrying as a series
of three-letter
“words.” Each of
these three-letter
words is called a
codon.
Codon
Codon
Codon
Codon
Codon
Codon
Different codons code
for different amino
acids. For example, the
codon for the amino
acid methionine is AUG
(adenine, uracil,
guanine). The codon
for the amino acid
serine is UCA (uracil,
cytosine, adenine).
Another type of RNA,
called tRNA (“t” stands for
“transfer”) matches the
codons in mRNA to the
correct amino acids.
As the mRNA strand moves along the
ribosome, the amino
acids are joined in the
correct sequence to
form a protein. This
process is called
translation.
U C G A C C G G A
G
Codon
Codon
Codon
Codon
Codon
Codon