AP Biology
RNA polymerase moves in which direction along the DNA?
3' → 5' along the template strand
A codon consists of ______ bases and specifies which ______ will be inserted into the polypeptide chain. (Concept 17.1)
3; amino acid
What is a ribozyme? (Concept 17.3)
A biological catalyst consisting of RNA
What is currently considered the best definition of a gene? (Concept 17.6)
A gene codes for either a polypeptide or an RNA molecule.
The nitrogenous base adenine is found in all members of which group?
ATP, RNA, and DNA
How is translation initiated? (Concept 17.4)
All of the above
A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which might this illustrate?
Any mutation in the sequence is selected against.
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Where does tRNA #2 move to after this bonding of lysine to the polypeptide?
E site
Which one of the following is true of tRNAs? (Concept 17.4)
Each tRNA binds a particular amino acid.
The "universal" genetic code is now known to have exceptions. Evidence for this could be found if which of the following is true?
If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only).
Where does RNA polymerase begin transcribing a gene into mRNA? (Concept 17.2)
It starts at a certain nucleotide sequence called a promoter.
In which of the following actions does RNA polymerase differ from DNA polymerase?
RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.
Which of the following statements best describes the termination of transcription in prokaryotes?
RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall off the DNA and release the transcript.
Each of the following options is a modification of the sentence THECATATETHERAT. Which of the following is analogous to a frameshift mutation?
THECATATTHERAT
As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs?
The tRNA that was in the A site moves into the P site.
Which of the following statements are true about protein synthesis in prokaryotes?
Translation can begin while transcription is still in progress.
RNA polymerase ______ (Concept 17.2)
Unwinds the double helix and adds nucleotides
In the 1920s Muller discovered that X-rays caused mutation in Drosophila. In a related series of experiments, in the 1940s, Charlotte Auerbach discovered that chemicals - she used nitrogen mustards - have a similar effect. A new chemical food additive is developed by a cereal manufacturer. Why do we test for its ability to induce mutation?
We want to prevent any increase in mutation frequency.
A mutagen causes _____. (Concept 17.5)
a change in the base sequence of DNA
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a deletion of 2 nucleotides
When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by
a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane.
Which of the following nucleotide triplets best represents a codon?
a triplet in the same reading frame as an upstream AUG
What is a ribozyme?
an RNA with enzymatic activity
Gene expression in Archaea differs from that in other prokaryotes. It shares features with which of the following?
bacteria and eukaryotes
Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes
excision of introns.
A mutation in which of the following parts of a gene is likely to be most damaging to a cell?
exon
The flow of information in a cell proceeds _____. (Concept 17.1)
from DNA to RNA to protein
Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because
genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
What are polyribosomes?
groups of ribosomes reading a single mRNA simultaneously
After an RNA molecule is transcribed from a eukaryotic gene, portions called _____ are removed and the remaining _____ are spliced together to produce an mRNA molecule with a continuous coding sequence. (Concept 17.3)
introns ... exons
A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that
many noncoding stretches of nucleotides are present in mRNA.
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Which component of the complex described enters the exit tunnel through the large subunit of the ribosome?
newly formed polypeptide
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. Which enzyme causes a covalent bond to attach lysine to the polypeptide?
peptidyl transferase
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?
polypeptide factors plus GTP
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form. The dipeptide that will form will be
proline-threonine.
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
several transcription factors (TFs)
The TATA sequence is found only several nucleotides away from the start site of transcription. This most probably relates to which of the following?
the number of hydrogen bonds between A and T in DNA
Each eukaryotic mRNA, even after post-transcriptional modification, includes 5' and 3' UTRs. Which are these?
the untranslated regions at either end of the coding sequence
Which of the following is a function of a signal peptide?
to translocate polypeptides across the ER membrane
