Download Ch10 CentralDogma_andMutations20142015

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 10
Protein Synthesis
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The flow of genetic information in the cell is
DNARNAprotein
The Central Dogma: Transcription and Translation
Bozeman Science
https://www.youtube.com/watch?v=yLQe138HY3s
• The sequence of codons in DNA spells out the
primary structure of a polypeptide
– Polypeptides form proteins that cells and
organisms use
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Gene 1
Gene 3
DNA molecule
Review/Previewcontrol of Gene
expression in
Eukaryotes
http://highered.mcgrawhill.com/sites/9834092339
/student_view0/chapter16/
control_of_gene_expressio
n_in_eukaryotes.html
Gene 2
DNA strand
TRANSCRIPTION
RNA
Codon
TRANSLATION
Polypeptide
Figure 10.7
Amino acid
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Summary of
transcription
and
translation
TRANSCRIPTION
DNA
mRNA
RNA
polymerase
Stage 1 mRNA is
transcribed from a
DNA template.
Amino acid
TRANSLATION
Enzyme
Stage 2 Each amino
acid attaches to its
proper tRNA with the
help of a specific
enzyme and ATP.
tRNA
Initiator
tRNA
mRNA
Figure 10.15
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Anticodon
Large
ribosomal
subunit
Start
Codon
Small
ribosomal
subunit
Stage 3 Initiation of
polypeptide synthesis
The mRNA, the first
tRNA, and the
ribosomal subunits
come together.
Modification of the polypeptide
Endoplasmic reticulum
• Collects proteins made by the ribosomes
• Packages them into vesicles which move
to the Golgi apparatus
Golgi apparatus
• Proteins are altered, packaged into
vesicles, and transported to different
parts of the cell or exported out of the cell
http://vcell.ndsu.edu/animations/proteinmo
dification/movie-flash.htm
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mutations can change the meaning of genes
• Mutations are changes in the DNA base
sequence
– These are caused by errors in DNA replication
or by mutagens
– The change of a single DNA nucleotide causes
sickle-cell disease
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Normal hemoglobin DNA
mRNA
Mutant hemoglobin DNA
mRNA
Normal hemoglobin
Sickle-cell hemoglobin
Glu
Val
http://www.cleanvideosearch.com/media/action/yt/watch?videoId=1fN7rOwDyMQ&name=Evolution+of+sickle+cell+malaria&uploadUsername=acorvettes&hitCount=36284
Figure 10.16A
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The genetic code is the Rosetta stone of life
• Virtually all
organisms
share the same
genetic code
Figure 10.8A
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Types of mutations
NORMAL GENE
mRNA
Protein
Met
Lys
Phe
Gly
Ala
Lys
Phe
Ser
Ala
BASE SUBSTITUTION
Met
Missing
BASE DELETION
Met
Lys
Leu
Ala
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
His
Figure 10.16B
Types of Mutations
There are 2 general categories of mutations:
1. Base substitution
•
The replacement of one nucleotide with
another
•
Can result in no change in the protein
•
An insignificant change
– The altered amino acid has no effect on the
function of the protein
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Types of Mutations
•
A change that is crucial to life of the organism
– The altered amino acid has an effect on the
function of the protein
2. Base insertions or deletions
•
One or more bases are added or deleted from
the DNA
•
Often have disastrous effects
– The nucleotide sequence following the change
alters the genetic message (reading frame)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mutations are Useful
Mutations are useful because they
1. Provide diversity that allows evolution by
natural selection to occur
2. Essential tool for geneticists
•
Create different alleles needed for genetic
research
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings