17 Practice Test Flashcards

Which of the following statements correctly describes Archibald Garrod's hypothesis for how "inborn errors of metabolism" such as alkaptonuria occur?

Enzymes are made of DNA, and affected individuals lack DNA polymerase.
Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
Certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors.
Metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.

According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

Which of the following characteristics is directly related to the coding of a single amino acid during the process of translation?

the amino acetyl tRNA synthase
the complementarity of DNA and RNA
the base sequence of the tRNA
the three-base sequence of mRNA

Which of the following processes occurs during transcription?

DNA is replicated
mRNA attaches to ribosomes
proteins are synthesized
RNA is synthesized

Which of the following molecular structures contain codons?

rRNA
mRNA
tRNA
a protein

Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer in eukaryotes that accomplishes this task?

DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis.

Histone proteins in the chromosomes transfer information from the nucleus to the ribosome, where protein synthesis takes place.

Transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place.

Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.

Which of the following processes occurs in prokaryotes but not in eukaryotes?

translation in the absence of a ribosome
transcription and translation occur simultaneously
post-transcriptional splicing
gene splicing

Transcription begins at a promoter. What is a promoter?

Part of the RNA molecule itself
The same as a start codon
A site in DNA that recruits the RNA Polymerase
A site found on the RNA polymerase

What is the function of RNA polymerase? See Concept 17.2 ( page 342)

It adds nucleotides to the 5' end of the growing mRNA molecule.
It relies on other enzymes to unwind the double helix.
It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule.
It unwinds the double helix and adds nucleotides to a growing strand of RNA.
All of the above.

Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase?

anticodons
ribosomes and tRNA
several transcription factors
aminoacyl-tRNA synthetase

Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes?

It is the recognition site for ribosomal binding during translation.
It sets the reading frame of the mRNA during translation.
It is the recognition site for ribosomal binding during transcription.
It is the recognition site for the binding of a specific transcription factor.

During RNA processing a(n) _____ is added to the 5' end of the RNA.

3' untranslated region
a long string of adenine nucleotides
5' untranslated region
coding segment
modified guanine nucleotide

During RNA processing a(n) _____ is added to the 3' end of the RNA.

3' untranslated region
a long string of adenine nucleotides
5' untranslated region
coding segment
modified guanine nucleotide

What is a ribozyme? See Concept 17.3

an enzyme that holds open the DNA double helix while RNA polymerase adds nucleotides
a biological catalyst consisting of DNA
a mutated ribosome
a DNA sequence near the promoter that assists in the binding of RNA polymerase
a biological catalyst made of RNA

Which of the following processes occurs in eukaryotic gene expression?

RNA polymerase requires tRNA to elongate the molecule.
mRNA, tRNA, and rRNA are translated.
A cap is added to the 5 end of the mRNA.
RNA polymerase binds to the terminator sequence.

Which of the following processes correctly describes alternative RNA splicing?

It is a mechanism for increasing the rate of translation.
It increases the rate of transcription.
It can allow the production of proteins of different sizes and functions from a single mRNA.
It can allow the production of similar proteins from different RNAs.

Where does translation take place?
Endoplasmic reticulum
Nucleus
Ribosome
Golgi apparatus

Which of the following steps occurs last in the initiation phase of translation?
The small subunit of the ribosome binds to the 5’ cap on the mRNA.
The large ribosomal subunit joins the complex.
An aminoacyl tRNA binds to the start codon.
A peptide bond is formed between two adjacent amino acids.

True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated.

The initiator tRNA attaches at the ribosome's _____ site.
A
translocation
E
P
Q

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the _____.
binding of the anticodon to small subunit of the ribosome
attachment of amino acids to rRNAs
binding of ribosomes to mRNA
binding of the anticodon to the codon and the attachment of amino acids to tRNAs

Which of the following processes is the first event to take place in translation in eukaryotes?
base pairing of activated methionine-tRNA to AUG of the messenger RNA
the ribosome reaches a stop codon
the small subunit of the ribosome recognizes and attaches to the 5 cap of mRNA
binding of the larger ribosomal subunit to smaller ribosomal subunits

What is the function of the release factor during translation in eukaryotes?

It supplies a source of energy for termination of translation.
It releases the amino acid from its tRNA to allow the amino acid to form a peptide bond.
It releases the ribosome from the ER to allow polypeptides into the cytosol.
It binds to the stop codon in the A site in place of a tRNA.

The tRNA shown in the figure has its 3 end projecting beyond its 5 end. Which of the following processes will occur at this 3 end?

The amino acid binds covalently.
The small and large subunits of the ribosome will attach to it.
The 5 cap of the mRNA will become covalently bound.
The excess nucleotides (ACCA) will be cleaved off at the ribosome.

Which of the following molecules are required for the process of translation?

mRNA, DNA, and rRNA
mRNA, tRNA, DNA, and rRNA
mRNA, tRNA, and DNA
mRNA, tRNA, and rRNA

True or false? A codon is a group of three bases that can specify more than one amino acid.