The genetic message of DNA is transcribed into mRNA and then translated into proteins. During transcription, the DNA unwinds and mRNA is produced that carries the protein code out of the nucleus. There are three types of RNA: mRNA, rRNA and tRNA. Translation occurs in the cytoplasm where ribosomes read the mRNA codons and join amino acids specified by each codon into proteins via peptide bonds. tRNA molecules match amino acids to codons to enable protein assembly according to the DNA's genetic instructions.

1. From Gene to Protein
Transcription & Translation

2. I. PROTEINS:
 The NUCLEUS controls the ACTIVITIES in the
cell and the DNA inside is composed of genes
that code for certain proteins
 _PROTEIN codes for a particular trait or helps
perform various activities within the cell or
body
 The processes explained here will show how
the genetic message of DNA is able to leave
the nucleus and reach ribosomes which
assemble all the proteins

3. All in all, how you look and the activities of your body is largely
determined by the proteins that are made!!

4. II. STRUCTURE OF RNA
Nuclear
Pores
 DNA is too big to exit
the nucleus, so its
code must be read
by RNA
 RNA is the molecule
that will be
assembled to help
make proteins and
the ribosomes

5. A. RNA: RIBONUCLEIC ACID
1. _SINGLE strand
2. Nucleotide:
–5 carbon sugar
–Phosphate group
–Nitrogen base
Pairs: A-U (not T!)
C-G

6. B. 3 Types of RNA:
1. Messenger RNA (mRNA)
• Reads DNA code and carries the MESSAGE for
making proteins out of the nucleus to the
ribosome

7. B. 3 Types of RNA: (cont.)
2. Ribosomal RNA (rRNA)
• Makes the structure of the RIBOSOME
(remember from bio-a that ribosomes are the
“workers” of the cell!!)

8. B. 3 Types of RNA: (cont.)
3. Transfer RNA (tRNA)
• Transfers AMINO ACIDS to the ribosome for
protein assembly

9. III. DIRECTIONS FOR MAKING PROTEINS
A. Transcription
happens in the
Nucleus
• _MESSAGE of DNA is
copied or
TRANSCRIBED into
mRNA, which can
leave the nucleus

10. III. DIRECTIONS FOR MAKING PROTEINS (cont.)
A. Transcription
happens in the
Nucleus
• _MESSAGE of DNA is
copied or
TRANSCRIBED into
mRNA, which can
leave the nucleus

11. III. DIRECTIONS FOR MAKING PROTEINS (cont.)
 Process of Transcription:
1. DNA UNZIPS
animation

12. III. DIRECTIONS FOR MAKING PROTEINS (cont.)
2. mRNA is TRANSCRIBED from the DNA
message
 mRNA bases are grouped into sets of 3
nucleotides called a CODON or triplet code
Codon: triplet code
that represents an
amino acid that will
build a protein

13. III. DIRECTIONS FOR MAKING PROTEINS (cont.)
3. mRNA BREAKS AWAY from the DNA strand

14. III. DIRECTIONS FOR MAKING PROTEINS (cont.)
4. mRNA LEAVES the
NUCLEUS and enters the
cytoplasm to await
attachment of the
ribosome.

15. B. Translation:
Happens in the cytoplasm, proteins built at ribosomes
 Process of READING the mRNA codons and
translating them into PROTEINS (by attaching
amino acids together)

16. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
 Process of translation: mRNA leaves the nucleus
to the cytoplasm
1. A RIBOSOME (rRNA) ATTACHES to the mRNA,
which is the site for constructing proteins
mRNA ribosome

17. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
2. mRNA CODONS will be READ by the ribosome

18. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
3. A tRNA carrying an AMINO ACID in the cell will
base pair its ANTICODON with the complimentary
(matching) codon on the mRNA strand

19. ANTICODON: a
codon’s
COMPLEMENT that
will help bring the
correct amino acid
to the ribosome

20. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
4. Translation begins with a START codon, which
is AUG
 AUG – Methionine…starts the process
but does not make the protein

21. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
4. Translation ends when a STOP codon is read

22. B. Translation (cont.):
Happens in the cytoplasm, proteins built at ribosomes
6. When each amino acid joins together at the
ribosome, they are LINKED by a PEPTIDE bond
which forms the PROTEIN