Post on 23-Dec-2014
description
G
Leucine
Serine
Tyrosine
Stop
Cysteine
Stop
Tryptophan
Leucine
Proline
Histidine
GlutamineArginine
Phenylalanine
GlycineGlutamic acid
Aspartic acid
Alanine
Valine
Arginine
Serine
Lysine
Asparagine
Threonine
MethionineIsolucine
A
G U
A C
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
GU AC G
U AC
G
UA
C
G
U
AC
G
U
AC
G
C
C
A
G
C
C
A
G
A
AG
AG
C
CG A
G
C
CA
U
U
U
UU
U
U
U
What is the amino acid sequence for the codons: GCA UAC CCC GUA?alanine tyrosine proline valine
UUUUUCUUAUUG
UCUUCCUCAUCG UAU
UAC
Animated by Jeff Christopherson
Phenylalanine Leucine Serine Tyrosine Stop Cysteine Stop Tryptophan
Leucine Proline Histidine Glutamine Arginine
Isoleucine Methionine Threonine Asparagine Lysine Serine Arginine
Valine Alanine Aspartic Acid Glutamic Acid Glycine
Phenylalanine
UUUUUC
Leucine
UUAUUG
Serine
UCUUCCUCAUCG
Tyrosine
UAUUAC
Stop
UAAUAGUGA
Cysteine
UGUUGC
Stop
UGA
Tryptophan
UGG
Leucine
CUUCUCCUACUG
Proline
CCUCCCCCACCG
Histidine
CAUCAC
Glutamine
CAACAG
Arginine
CGUCGCCGACGG
Isoleucine
AUUAUCAUA
Methionine
AUG
Threonine
ACUACCACAACG
Asparagine
AAUAAC
Lysine
AAAAAG
Serine
AGUAGC
Arginine
AGGAGA
Valine
GUUGUCGUAGUG
Alanine
GCUGCCGCAGCG
Aspartic Acid
GAUGAC
Glutamic Acid
GAAGAG
Glycine
GGUGGCGGAGGG
A
G U
A C
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
G
U
AC
GU AC G
U AC
G
UA
C
G
U
AC
G
U
AC
G
C
C
A
G
C
C
A
G
AG
AG
AG
C
CG A
G
C
CA
U
U
U
UU
U
U
U
A. The Structure of RNA
B. Types of RNA
C. Transcription
D. RNA Editing
E. The Genetic Code
F. Translation
G. The Roles of RNA and DNA
H. Genes and Proteins
RNA and Protein Synthesis
from to to make up
Concept Map
also called which functions to also called also called which functions towhich functions to
can be
RNA
Messenger RNA Ribosomal RNA Transfer RNA
mRNA Carry instructions rRNACombine
with proteins tRNABring
amino acids toribosome
DNA Ribosome Ribosomes
RNADNA
RNApolymerase
Transcription
Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)
The Genetic Code
Messenger RNA
Messenger RNA is transcribed in the nucleus.
Transfer RNA
The mRNA then enters the cytoplasm and attaches to a ribosome. Translation begins at AUG, the start codon. Each transfer RNA has an anticodon whose bases are complementary to a codon on the mRNA strand. The ribosome positions the start codon to attract its anticodon, which is part of the tRNA that binds methionine. The ribosome also binds the next codon and its anticodon.
mRNA Start codon
Ribosome
Methionine
Phenylalanine tRNALysine
Nucleus
Translation
mRNA
The Polypeptide “Assembly Line”The ribosome joins the two amino acids—methionine and phenylalanine—and breaks the bond between methionine and its tRNA. The tRNA floats away, allowing the ribosome to bind to another tRNA. The ribosome moves along the mRNA, binding new tRNA molecules and amino acids.
mRNARibosome
Translation direction
Lysine tRNA
tRNA
Ribosome
Growing polypeptide chain
mRNA
Completing the PolypeptideThe process continues until the ribosome reaches one of the three stop codons. The result is a growing polypeptide chain.
Translation (continued)
Interest Grabber
• 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.
Interest Grabber continued
1. Copy the following information about Protein X: Methionine—Phenylalanine—Tryptophan—Asparagine—Isoleucine—STOP.
2. Use Figure 12–17 on page 303 in your textbook to determine one possible sequence of RNA to code for this information. Write this code below the description of Protein X. Below this, write the DNA code that would produce this RNA sequence.
3. Now, cause a mutation in the gene sequence that you just determined by deleting the fourth base in the DNA sequence. Write this new sequence.
4. Write the new RNA sequence that would be produced. Below that, write the amino acid sequence that would result from this mutation in your gene. Call this Protein Y.
5. Did this single deletion cause much change in your protein? Explain your answer.