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
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
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
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