Do Now...
Suppose you start with
two DNA strands:
ACCGTCAC and
TCGCACGT. Use the
“rules” of base pairing
to replicate the DNA
strands.
RNA and Protein
Synthesis
Chapter 14
RIBONUCLEIC ACID
RNA is SINGLE STRANDED
Does not have to stay in the nucleus!
Does not carry the genetic code
Can read DNA and take
the information out of the nucleus.
RNA’s main job is to build proteins!
RNA Structure
• The building blocks of
RNA are Nucleotides
• 4 nitrogen bases (A,G,C,U)
A—U C-G
• A Nucleotide in RNA is still made of
3 important things:
• 1. 6-Carbon Sugar - Ribose (instead
of Deoxyribose)
• 2. Phosphate
• 3. Nitrogen base
Types of RNA
• Messenger RNA (mRNA)
Carries copies of instructions for
the assembly of amino acids
into proteins (serve as
“messenger”)
Types of RNA
• Ribsomomal RNA (rRNA)
Site of protein synthesis
Types of RNA
Transfer RNA (tRNA) Transfers amino acids to
ribosomes during protein
synthesis
Proteins
Proteins are made up of a chain of
amino acids into long chains
called polypeptides.
The properties of a protein are
determined by the order in which
different amino acids are
joined together
Proteins are enzymes, which catalyze
and regulate chemical reactions.
2 Steps to Make a Protein
1. Transcription
• DNA → RNA
2. Translation
• RNA → Protein
(Chain of amino
acids)
Transcription
• mRNA
• Use DNA as a template to produce a complimentary RNA molecule
• A-U G-C
• Practice:
1. DNA strand: AAT TGC CCA GAT
mRNA:
2. DNA strand: CGT GCA GAT
mRNA:
Genetic Code
•
•
•
•
The genetic code is read 3 base pairs at a time
Codon-3 nucleotides in mRNA
Anticodon- 3 bases in tRNA
64 possible three base codons
Genetic Code Chart
Translation
• Ribosomes use the sequence
of codons in mRNA to
assemble amino acids into
polypeptide chains
• RNA used = tRNA
Click to add text
Practice
• Using the DNA template strand:
• mRNA• Protein-
Practice

5’
Consider the following RNA
sequence:
3’
UCGCACGGU

This sequence will be read
three bases at a time as:
UCG – CAC – GGU

Read the codons to find the
amino acids.
Practice
Consider the following RNA
sequence and identify the amino
acids it will code for.
5’
AUGCGCUUCUAA
Consider the following DNA
sequence and identify the
amino acids it will code for.
3’
CTTGGAATG
5’
3’