Ch 14-1 Flashcards
What is one gene-one enzyme hypothesis
The function of a gene is dictated by the production of a specific enzyme.
How was the one gene-one enzyme hypothesis revised?
It was later identified that some gene products were proteins but not enzymes, leading to the revision: one gene = one protein.
The discovery of genes whose final products are RNA molecules led to the final revision: one gene = one product.
What is the central dogma of molecular biology?
genetic information flows directionally from DNA to RNA to protein.
What are the two main steps in gene expression?
Transcription: The process of creating an RNA copy from a DNA template.
Translation: The process of using the information in mRNA to synthesize a polypeptide.
What is the difference between transcription and translation?
Transcription uses DNA as a template to create an RNA molecule.
Translation uses mRNA as a template to create a polypeptide chain.
Genetic code meaning
The genetic code is a set of rules that defines how the sequence of nucleotides in mRNA is translated into the sequence of amino acids in a protein.
How many nucleotides code for one amino acid?
Three nucleotides, called a codon, code for one amino acid.
What are the three types of point mutations?
Silent mutations: Do not change the amino acid sequence.
Missense mutations: Result in a different amino acid being coded.
Nonsense mutations: Result in a premature stop codon, leading to a truncated protein.
Frameshift mutation meaning
A frameshift mutation is an insertion or deletion of nucleotides that is not a multiple of three,
- altering the reading frame of the gene and often leading to a non-functional protein.
How does the genetic code allow for genetic engineering?
The genetic code is nearly universal across all species, meaning that the same codons code for the same amino acids in different organisms. This allows genes from one species to be expressed in another.
Which of the following is NOT a type of point mutation?
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(a) Silent mutation
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(b) Missense mutation
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(c) Nonsense mutation
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(d) Frameshift mutation
D
What is the function of a ribosome?
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(a) To translate mRNA into protein
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(b) To transcribe DNA into RNA
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(c) To replicate DNA
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(d) To repair damaged DNA
A
Which molecule carries genetic information from the nucleus to the cytoplasm?
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(a) DNA
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(b) tRNA
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(c) mRNA
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(d) rRNA
C
What is the start codon for protein synthesis?
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(a) UAA
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(b) UAG
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(c) UGA
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(d) AUG
D
Which of the following statements about the genetic code is TRUE?
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(a) Each codon codes for multiple amino acids.
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(b) The genetic code is nearly universal.
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(c) The genetic code is different in prokaryotes and eukaryotes.
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(d) The genetic code is constantly evolving.
B
What is the term for a mutation that results in a premature stop codon?
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(a) Silent mutation
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(b) Missense mutation
○
(c) Nonsense mutation
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(d) Frameshift mutation
C
What is the main difference between gene expression in prokaryotes and eukaryotes?
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(a) In prokaryotes, transcription and translation occur simultaneously. In eukaryotes, they are separated.
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(b) Prokaryotes use a different genetic code than eukaryotes.
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(c) Eukaryotes do not have ribosomes.
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(d) Prokaryotes do not have mRNA.
A
Which of the following is an example of a gene product that is not a protein?
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(a) Enzyme
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(b) Hormone
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(c) rRNA
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(d) Antibody
C
What is the template strand in transcription?
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(a) The mRNA molecule
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(b) The DNA strand that is used to synthesize RNA
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(c) The tRNA molecule
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(d) The ribosome
B
Which enzyme is responsible for unwinding the DNA double helix during transcription?
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(a) DNA polymerase
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(b) RNA polymerase [Information from outside sources: RNA polymerase is responsible for unwinding the DNA double helix during transcription.]
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(c) Helicase
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(d) Primase
B
The process by which DNA is copied into RNA is called
Transcription
The process by which RNA is used to synthesize a protein is called
Translation
A sequence of three nucleotides that codes for an amino acid is called a
Codon
The enzyme responsible for synthesizing RNA is called
RNA polymerase
The molecule that carries amino acids to the ribosome during translation is called
tRNA
A mutation that changes a single nucleotide in a gene is called
Point mutation
A mutation that results in the insertion or deletion of a nucleotide is called a ___ if it is not a multiple of three.
Frameshift mutation
The central dogma of molecular biology states that genetic information flows from __ to ___ to ___.
Dna
Rna
Protein
The one gene-one enzyme hypothesis was later revised to the ___ hypothesis.
One gene-one polypeptide
___ was the first to hypothesize that genes determine phenotype through enzyme production.
Archibald garrod
T/f
A silent mutation always results in a change in the amino acid sequence
F
A silent mutation does not change the amino acid sequence.
T/f
The genetic code is redundant, meaning that multiple codons can code for the same amino acid.
T
T/f
Transcription occurs in the cytoplasm of eukaryotic cells.
False
It occurs in nucleus
T/ f
Translation occurs in the cytoplasm of both prokaryotic and eukaryotic cells.
T
T / f
A missense mutation always results in a non-functional protein
F
A missense mutation may or may not result in a non-functional protein.
T/f
A nonsense mutation results in a truncated protein
T
T/f
All mutations are harmful
F
Some mutations can be beneficial or neutral.
T/f
The genetic code is nearly universal, meaning that the same codons code for the same amino acids in different organisms
T
T/f
A frameshift mutation can alter the reading frame of a gene, leading to a non-functional protein
T
T/f
DNA polymerase is responsible for transcribing DNA into RNA
F
RNA polymerase is responsible for transcribing DNA into RNA.
