Download (b) Nucleotide deletion

Review: DNA RNA Protein
• In a cell, genetic information flows from DNA to RNA in the
nucleus and RNA to protein at the ribosome.
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Transcription
RNA polymerase
Nucleus
mRNA
DNA
Intron
Figure 10.20-1
Transcription
RNA polymerase
Nucleus
DNA
mRNA
Intron
RNA processing
Cap
Tail
mRNA
Intron
Amino acid
Ribosomal
subunits
tRNA
ATP
Enzyme
Amino acid
attachment
Initiation
of translation
Figure 10.20-4
Transcription
RNA polymerase
Polypeptide
Nucleus
DNA
mRNA
Stop
codon
Intron
RNA processing
Cap
Tail
Termination
mRNA
Intron
Anticodon
Ribosomal Codon
subunits
Amino acid
tRNA
ATP
Enzyme
Amino acid
attachment
Initiation
of translation
Elongation
Figure 10.20-6
• Transcription and translation are how genes control:
– The structures
– The activities of cells
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Mutations
• A mutation is any change in the nucleotide sequence of DNA.
• Mutations can change the amino acids in a protein.
• Mutations can involve:
– Large regions of a chromosome
– Just a single nucleotide pair, as occurs in sickle cell anemia
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 How can
Mutations be
BAD?
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 How can
Mutations be
GOOD?
• Although mutations are often harmful, they are the source of
genetic diversity, which is necessary for evolution by natural
selection.
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Mutagens
• Mutations may result from:
– Errors in DNA replication
– Physical or chemical agents called mutagens
– UV rays, X-rays, gamma rays, chemicals
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Types of Mutations
• Mutations within a gene can occur as a result of:
– Nucleotide substitution, the replacement of one nucleotide by another
– Nucleotide deletion, the loss of a nucleotide
– Nucleotide insertion, the addition of a nucleotide
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If a mutation
changed a codon
from GGU to GGA
then what would
happen?
If a mutation
changed a codon
from GGA to UGA
then what would
happen?
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Normal hemoglobin DNA
Mutant hemoglobin DNA
mRNA
mRNA
Normal hemoglobin
Sickle-cell hemoglobin
Figure 10.21
• Insertions and deletions can:
– Change the reading frame of the genetic message
– Lead to disastrous effects
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mRNA and protein from a normal gene
Base substitution
Figure 10.22a
mRNA and protein from a normal gene
Deleted
Nucleotide deletion
Figure 10.22b
mRNA and protein from a normal gene
Inserted
Nucleotide insertion
Figure 10.22c
mRNA and protein from a normal gene
(a) Base substitution
Deleted
(b) Nucleotide deletion
Inserted
(c) Nucleotide insertion
Figure 10.22
Mutation by Deletion:
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The Human Genome Project
• Begun in 1990, the Human Genome Project was a massive
scientific endeavor:
– To determine the nucleotide sequence of all the DNA in the human genome
and
– To identify the location and sequence of every gene
- Aims of the project:
- to identify the estimated 100,000 genes in the human DNA.
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• At the completion of the project in 2004:
– Over 99% of the genome had been determined to 99.999% accuracy
– 3.2 billion nucleotide pairs were identified
– About 24,000 genes were found
– About 98% of the human DNA was identified as noncoding
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• The Human Genome Project can help map the genes for specific
diseases such as:
– Alzheimer’s disease
– Parkinson’s disease
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Table 12.1
Benefits of Human Genome Project
research
- improvements in medicine.
- microbial genome research for
fuel and environmental
cleanup.
- DNA forensics.
- improved agriculture and
livestock.
- better understanding of
evolution and human
migration.
- more accurate risk assessment.
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Making Humulin
• In 1982, the world’s first genetically engineered pharmaceutical
product was sold.
• Humulin, human insulin:
– Was produced by genetically modified bacteria
– Was the first recombinant DNA drug approved by the FDA
– Is used today by more than 4 million people with diabetes
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• Today, humulin is continuously produced in gigantic fermentation
vats filled with a liquid culture of bacteria.
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If a strand of DNA has the sequence AAGCTC,
transcription will result in a(n) ______.
A) single RNA strand with the sequence TTCGAG
B) DNA double helix with the sequence AAGCTC for
one strand and TTCGAG for the complementary
strand
C) single DNA strand with the sequence TTCGAG
D) single RNA strand with the sequence UUCGAG
E) RNA double helix with the sequence UUCGAG for
one strand and AAGCUC for the complimentary
strand
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If a strand of DNA has the sequence AAGCTC,
transcription will result in a(n) ______.
A) single RNA strand with the sequence TTCGAG
B) DNA double helix with the sequence AAGCTC for
one strand and TTCGAG for the complementary
strand
C) single DNA strand with the sequence TTCGAG
D) single RNA strand with the sequence UUCGAG
E) RNA double helix with the sequence UUCGAG for
one strand and AAGCUC for the complimentary
strand
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Translation converts the information stored in ______
to ______.
A) DNA . . . RNA
B) RNA . . . a polypeptide
C) protein . . . DNA
D) DNA . . . a polypeptide
E) RNA . . . DNA
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Translation converts the information stored in ______
to ______.
A) DNA . . . RNA
B) RNA . . . a polypeptide
C) protein . . . DNA
D) DNA . . . a polypeptide
E) RNA . . . DNA
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Where is translation accomplished?
A) lysosomes
B) smooth endoplasmic reticulum
C) peroxisomes
D) ribosomes
E) nucleoli
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Where is translation accomplished?
A) lysosomes
B) smooth endoplasmic reticulum
C) peroxisomes
D) ribosomes
E) nucleoli
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A mutation within a gene that will insert a premature
stop codon in mRNA would ______.
A) result in a polypeptide that is one amino acid
shorter than the one produced prior to the mutation
B) result in a shortened polypeptide chain
C) result in a missense mutation
D) change the location at which transcription of the
next gene begins
E) have the same effect as deleting a single nucleotide
in the gene
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A mutation within a gene that will insert a premature
stop codon in mRNA would ______.
A) result in a polypeptide that is one amino acid
shorter than the one produced prior to the mutation
B) result in a shortened polypeptide chain
C) result in a missense mutation
D) change the location at which transcription of the
next gene begins
E) have the same effect as deleting a single nucleotide
in the gene
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What is the smallest number of nucleotides that must
be added or subtracted to change the triplet grouping
of the genetic message?
A) one
B) two
C) three
D) four
E) five
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What is the smallest number of nucleotides that must
be added or subtracted to change the triplet grouping
of the genetic message?
A) one
B) two
C) three
D) four
E) five
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Examine the genetic code table, shown below.
The codon AGC codes for
the amino acid ______.
A) serine
B) arginine
C) threonine
D) alanine
E) glycine
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Examine the genetic code table, shown below.
The codon AGC codes for
the amino acid ______.
A) serine
B) arginine
C) threonine
D) alanine
E) glycine
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A mutation would be most harmful to the cells if it
resulted in ______.
A) a single nucleotide insertion near the start of the
coding sequence
B) a single nucleotide deletion near the end of the
coding sequence
C) a single nucleotide in the middle of an intron
D) substitution of a base pair
E) deletion of a triplet near the middle of the gene
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A mutation would be most harmful to the cells if it
resulted in ______.
A) a single nucleotide insertion near the start of the
coding sequence
B) a single nucleotide deletion near the end of the
coding sequence
C) a single nucleotide in the middle of an intron
D) substitution of a base pair
E) deletion of a triplet near the middle of the gene
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In a DNA double helix, adenine pairs with ______
and guanine pairs with ______.
A) cytosine . . . thymine
B) guanine . . . adenine
C) uracil . . . cytosine
D) thymine . . . cytosine
E) cytosine . . . uracil
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In a DNA double helix, adenine pairs with ______
and guanine pairs with ______.
A) cytosine . . . thymine
B) guanine . . . adenine
C) uracil . . . cytosine
D) thymine . . . cytosine
E) cytosine . . . uracil
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RNA contains the nitrogenous base ______ instead of
______, which is only found in DNA.
A) a deoxyribose sugar . . . a ribose sugar
B) nucleotides . . . nucleic acids
C) uracil . . . thymine
D) cytosine . . . guanine
E) adenine . . . guanine
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RNA contains the nitrogenous base ______ instead of
______, which is only found in DNA.
A) a deoxyribose sugar . . . a ribose sugar
B) nucleotides . . . nucleic acids
C) uracil . . . thymine
D) cytosine . . . guanine
E) adenine . . . guanine
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If one strand of a DNA double helix has the sequence
GTCCAT, what is the sequence of the other strand?
A) ACTTGC
B) TGAACG
C) CAGGTA
D) CAGGUA
E) CUGGTU
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If one strand of a DNA double helix has the sequence
GTCCAT, what is the sequence of the other strand?
A) ACTTGC
B) TGAACG
C) CAGGTA
D) CAGGUA
E) CUGGTU
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What name is given to the collection of traits exhibited
by an organism?
A) holotype
B) genotype
C) typology
D) phenotype
E) morphology
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What name is given to the collection of traits exhibited
by an organism?
A) holotype
B) genotype
C) typology
D) phenotype
E) morphology
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How many nucleotides make up a codon?
A) one
B) two
C) three
D) four
E) five
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How many nucleotides make up a codon?
A) one
B) two
C) three
D) four
E) five
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Transcription is the ______.
A) manufacture of a strand of RNA complementary to
a strand of DNA
B) manufacture of two new DNA double helices that
are identical to an old DNA double helix
C) modification of a strand of RNA prior to the
manufacture of a protein
D) manufacture of a protein based on information
carried by RNA
E) manufacture of a new strand of DNA
complementary to an old strand of DNA
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Transcription is the ______.
A) manufacture of a strand of RNA complementary to
a strand of DNA
B) manufacture of two new DNA double helices that
are identical to an old DNA double helix
C) modification of a strand of RNA prior to the
manufacture of a protein
D) manufacture of a protein based on information
carried by RNA
E) manufacture of a new strand of DNA
complementary to an old strand of DNA
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