When eukaryotic cells are stained with DNA specific dyes and viewed under the light microscrope, DNA molecules are revealed in
D. All of the above
Charles Yanofsky helped decipher the genetic code working with the ___ biosynthesis genes in ___.
B. tryptophan; Escherichia coli
A codon is a three base sequence of
D. mRNA that codes for an amino acid
Researchers purified the lac repressor and showed that it actually has two sites for binding. These two distinct binding sites are
D. lactose binding, DNA binding
The molecules used in a chloroplast to carry our photosynthesis
a. are all encoded by chloroplast to carry our photosynthesis
a. are all encoded by chloroplast DNA
b. some are encoded by chloroplast DNA
c. are all encoded by nuclear DNA
d. some are encoded in nucear DNA and some in mitochondrial DNA
a. some are encoded by chloroplast DNA
Nonsense codons are
D. some are encoded by chloropast DNA
Which of these is NOT a step in transcription?
C. replication
Molecules responsible for stimulating the synthesis of a specific protein are called
D. inducers
Which of the following statements is correct with respect to mitochondrial genes?
A. They are transmitted, largely intact, from parent to offspring.
The pattern or sequence in which a molecule of mRNA is deciphered by a ribosome is called the
A. reading frame
Splicing of transcripts normally occurs only in
A. eukaryotes
In the operon model of gene regulation, transcription is shut off by the binding of repressor to the promoter.
a. True
b. False
b. False
Which of the following has been associated with Alzheimer's Disease?
C. mutations in cytochrome oxidase c genes in brain cells
There are ______ usually found in the genetic code.
B. 1 start codon and 3 stop codons
The sequences within mRNA that are spliced out are called
A. introns
The occurence of constitutive mutations of all three of the lactose utilizing enzymes indicates that their synthesis is regulated together, probably by another gene.
a. True
b. False
a. True
Inhibitors of bacterial translation, such as chloramphenicol and erythromycin, generally
B. are inhibitors of mitochondrial protein synthesis
The expressed sequences within mRNA that code for gene products are called
A. exons
A(n) _______ consists of proteins and small nuclear RNAs forming discrete particles that mediate splicing.
A. splicesome
The transition from transcriptional initiation to elongation involves
D. release of sigma factor
Molecular evidence suggests that DNA sequences may have been transferred between
D. All of the above
Which of these is NOT a character of the genetic code?
C. There are the same number of codons as there are amino acids
RNA molecules that can act as enzymes and catalyze specific biochemical reactions are known as ______
A. ribozymes
The actual site of binding RNA polymerase in order to initiate transcription is
C. promoter
Mitochondria and chloroplasts are considered to be semiautonomous.
a. True
b. False
a. True
Aminoacyl-tRNA synthetase is the enzyme that
A. adds the appropriate amino acid to an uncharged tRNA
rRNA carried an anticodon, which is the complmentary sequence to the mRNA codon that specifies a particular amino acid
a. True
b. False
b. False
What would be the phenotype of a mutation that altered lac repressor function?
A. constitutive
What type of DNA sequences might be studied to help reunite displace children with their families?
C. mtDNA
Transcription occurs in the ____ and translation occurs in the ____ of prokaryotic cells.
D. cytoplasm. cytoplasm
which of the following statements is true under ordinary conditions?
B. DNA lasts forever within a cell while RNA lasts only for a short time.
RNA polymerase binds to a sequence called a/an _____ before beginning transcription
D. promoter
The scientists who proposed the operon theory are
B. Monod and Jacob
Ribosomes are composed of
B. rRNA and protein
In the modification of eukaryotic mRNA, a "cap" consisting of a/an ___ and a tail consisting of ___ are usually added to the transcript.
D. methyl group; multiple adenines
A single DNA unit that enables the simultaneous regulation of more than one gene in response to environmental changes is called
D. operon
Mitocondrial DNA has an approximately 10-fold higher rate of mutation compared to nuclear DNA.
a. True
b. False
a. True
A single DNA unit that enables the simultaneous regulation of more than one gene in response to environmental changes is called
C. operon
Mitochondrial DNA has an approximately 10-fold higher rate of mutation compared to nuclear DNA
a. True
b. False
a. True
A tRNA that recognizes a nonsense codon and inserts an amino acid where protein synthesis should have stopped is called a
D. suppressor tRNA
A mutation that occurs when a base is inserted into or deleted from a DNA sequence, completely altering the subsequent amino acid sequence, is called a
D. frameshift mutation
The universal code of DNA is the same for mtDNA as for chromosomal DNA.
a. True
b. False
b. False
An 60S eukaryotic ribosomal subunit does NOT consist of which of the following rRNAs?
B. 18S
Except in reverse transcription, RNA is synthesized in a 3' to 5' fashion.
a. True
b. False
b. False
The template and RNA-like DNA strand are equivalent.
a. True
b. False
