2. Genetic Code → triplets in DNA → the amino acids in proteins
3. The Players
mRNA: messenger
RNA - carries
protein recipe from
the nucleus
tRNA: transfer RNA
-brings amino acids
to the ribosome
Ribosome: the site
of protein synthesis
- made of rRNA
(ribosomal RNA )and
Protein
4. Meet mRNA (ribonucleic acid)
mRNA (messenger RNA)
made in nucleus serves as
a template (pattern) of the
DNA molecule.
Triplet or codon:
grouping of 3 nitrogenous
bases in DNA or RNA
molecules (each codon will code
for a specific amino acid)
5. HOW DOES IT DIFFER FROM DNA?
1. The RNA molecule is a SINGLE
nucleotide strand, not a double
strand as in DNA.
2. The sugar molecule in RNA is
RIBOSE -- not deoxyribose as
in DNA.
3. The base URACIL (U) takes the
place of thymine. (T)
7. There are twenty different amino acids that
build proteins
There are 64 different triplets/codons
Each amino acid is coded for by more than
one triplet/codon
8. Meet tRNA
each molecule of tRNA carries
a specific type of amino acid
-each tRNA molecule can
only carry one type of
amino acid
The tRNA has a group of 3
nucleotides at the base called
the anticodon
12. DNA serves as a template
for the synthesis of
mRNA from RNA
nucleotides in the
nucleus.
transcription:
transfer of the genetic
message from DNA to mRNA
How are proteins synthesized from a
DNA template? (model)
13. The Process of Translation
mRNA takes recipe to the
ribosome in cytoplasm
ribosome attaches to the mRNA
14. How does tRNA know which
amino acid goes where?
The anticodon a sequence of 3
nucleotides
tRNA is complementary to a mRNA
codon
binds to matching codon
specifies the next amino acid to be
attached during protein synthesis.
Example:
mRNA codon = GAC = carries only
aspartic acid
tRNA anticodon = UAC carries only
methionine
16. Begin Translation
The ribosome moves along the mRNA until it
reaches the “Start” codon
Start codon = AUG signals the start of the
recipe
AUG also codes for the amino acid methionine
17. mRNA molecules
carrying a specific
code move from the
nucleus to the
cytoplasm and attach
to a ribosomes
(rRNA)
mRNA leaves through nuclear pores
19. A molecule of transfer RNA brings the amino
acid called for by the mRNA to the ribosome
transfer RNA = tRNA
20. A second tRNA
brings the second
amino acid to the
ribosome
The amino acids
are joined
together to begin
the protein
22. The ribosome moves over 1 codon (triplet) and
another tRNA molecule brings another amino acid
The process continues until the stop codon on the
mRNA is reached
The stop codon = the end of the protein recipe
23. These proteins are what directs the activity in
each cell!
Basically, RNA translates the DNA
information!
Translation: The genetic code carried by mRNA is decoded to produce
the specific sequence of amino acids in a protein
25. gene: the sequence of nucleotides in a DNA
molecule necessary to synthesize a protein
(polypeptide)
** One gene codes for one protein
Protein Synthesis Video
Protein Synthesis Rap
Protein Synthesis Interactive
26. DNA determines the sequence of amino acids in
specific proteins.
The specific shape of the protein (ex:enzymes and
hormones) determines the function of that protein
Offspring resemble their parents because they inherit:
similar genes…that code for
similar proteins… that have
similar structure and function
Major Understandings: