Download Purpose of DNA

Quiz (take out a sheet of paper
1.
2.
3.
4.
T/F DNA can exit the nucleus
Name the bases found in RNA
Name the enzyme used to construct RNA
during transcription
BONUS
► Create the matching RNA sequence for this
DNA
► ATTGGTACA
Presentation outline
► Review
of Central Dogma of Molecular
Biology
► Codons and anticodons
► Overview of Translation
 RNA  protein
► Mistakes
in DNA
Purpose of DNA
► DNA
holds the genetic information.
 A blueprint for the cell
 It tells the cell what to build
► The
purpose of DNA
 DNA codes for the proteins that make up an organism
► The
past two days we talked about DNA
replication and transcription (DNA to RNA)
► Today, we talk about translation (RNA to protein)
Central Dogma of Molecular Biology
1.
2.
3.
DNA
RNA
Protein
Figure 12–14 Transcription
Section 12-3
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
DNA
RNA
Go to
Section:
Purpose of translation
► Now
that the mRNA is created from the
DNA during transcription, translation may
begin.
► In translation, the appropriate amino acid is
matched with the codons (3 bases) in the
mRNA sequence to form a protein
 Amino acids are the monomers of a protein
Figure 12–17 The Genetic Code
Section 12-3
Go to
Section:
The players in translation
► mRNA
 Holds the genetic code in the sequence of bases
► Codon
 3 consecutive bases in the mRNA sequence
► tRNA
 Carries the amino acid
► Anticodon
 3 consecutive bases on the tRNA sequence
► Ribosome
(made of rRNA and proteins)
 Has two spaces for mRNA and tRNA to meet and join
amino acids
Translation (slide 1 of 2)
Messenger RNA
Messenger RNA is transcribed in
the nucleus.
Phenylalanine
tRNA
Methionine
Lysine
mRNA
Transfer RNA
Translation begins at the start
codon AUG. The codons match
with the complimentary
anticodon on the tRNA. Each
tRNA has a specific amino acid
attached to it. The ribosome
moves over one codon
Ribosome
mRNA
Nucleus
Start codon
Translation (slide 2 of 2)
The Polypeptide “Assembly Line”
As the ribosome moves along the
mRNA, the amino acid chain is built.
tRNAs bring in more amino acids.
The ribosome (2 car garage)
continues to move and read the
codons on the mRNA.
Lysine
Growing polypeptide chain
Ribosome
tRNA
tRNA
mRNA
mRNA
Ribosome
Translation direction
Completing the Polypeptide
The process ends when it
reaches a stop codon. The
amino acid chain (protein) is
released.
mRNA to protein (amino acid)
Determining the Sequence of a
Gene
► DNA
contains the code of instructions for
cells. Sometimes, an error occurs when the
code is copied. Such errors are called
mutations.
Go to
Section:
Gene Mutations:
Substitution, Insertion, and Deletion
Section 12-4
Substitution
Go to
Section:
Insertion
Deletion
Overview of translation
► mRNA
is created from the DNA during
transcription and exits the nucleus
► The AUG codon is the starting point for translation
► Ribosome binds to the mRNA and a tRNA matches
its anticodon with the codon
► The tRNA has the amino acid attached to it which
becomes part of the protein chain
► Translation will occur until a stop codon is reached
Review
1.
DNA to DNA - Purpose of DNA replication

2.
DNA to RNA – Purpose of transcription

3.
To make copies of the DNA for cell division
To make a copy of the blueprint that codes for
the amino acids (proteins)
RNA to protein – Purpose of translation
► Match codons from mRNA to anticodons on
tRNA which has the amino acid to form a
protein
Homework
► Create
an 8 panel cartoon describing the
steps of TRANSLATION
► Lab on Monday
Finish 2 day classwork (40 points)
► Create
an informational and creative poster
showing the process and importance of
TRANSLATION
► In color
► 4 or less
► You can use analogies to help illustrate