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
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(c) Nonsense mutation
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(d) Frameshift mutation
C