smartbook chapter 15
Each aminoacyl-tRNA synthetase present in a cell recognizes __________ of the 20 common amino acids. For credit, please answer with a number.
1
How many codons are possible with four types of bases in mRNA, and a genetic code containing three bases in a codon?
64
With four types of bases in mRNA, and a genetic code containing three bases in a codon ________different codons can be specified.
64
What term refers to a point mutation that results in the replacement of one base pair for another in DNA?
A base substitution mutation
Which of the following statements accurately describes a frameshift mutation?
A mutation that changes the reading frame of a sequence
Alternative splicing allows...
A single transcript can produce different mRNAs.
The enzymes that catalyze the attachment of amino acids to tRNA molecules are known as which of the following?
Aminoacyl-tRNA synthetases
Which of the following describes mRNA?
An RNA transcript that contains information for making a polypeptide
For proteins that are targeted to the ER, where is the signal sequence usually located?
At the beginning of the protein (first several amino acids added during translation)
The universality of the genetic code is evidence for which of the following?
Common evolutionary heritage
micro-RNA
Control of gene expression
The transcript of eukaryotes is protected from degradation by the addition of which of the following?
GTP to the 5' PO4 group
Which of the following best describes a major difference between prokaryotic and eukaryotic mRNA transcription?
In eukaryotes, a primary transcript is first synthesized which is modified to become the mature mRNA.
mRNA
Intermediate form of information of DNA that can be transported out of nucleus
what are the two functions of the AUG codon
It encodes the amino acid methionine, it acts as a start codon
What are the two main roles of the 5' cap of a eukaryotic mRNA?
It participates in translation, it protects the mRNA from degradation.
What is the function of the poly-A tail of a eukaryotic mRNA?
It protects the mRNA from degradation.
rRNA
Part of the ribosome
What type of mutation happens when a single base in DNA is substituted with another base, for example, an A becomes a G?
Point
Which of the following statements accurately describes the level of alternative splicing in mammalian genomes?
The average estimated number of transcripts per gene can vary widely from as high as 10 to as low as 1.5 per gene.
Scientists have successfully transferred and expressed genes from jellyfish into mammals. What makes that possible?
The genetic code is the same in almost all living things.
Which of the following describes how proteins are targeted for translation to the rough ER?
The initial amino acid sequence of these proteins serves as a signal sequence that targets them to the rough ER.
tRNA
The intermediary adapter between mRNA and amino acids
Which of the following are differences in the way mitochondria interpret the genetic code?
The stop codon UGA codes for an amino acid in mitochondria, mitochondria use some atypical stop codons such as AGA.
How do eukaryotic transcription factors help form the initiation complex?
They recruit RNA polymerase to the promoter
What is the main function of the promoter in a bacterial transcription unit?
To form a recognition and binding site for RNA polymerase
Identify the three stop codons of the genetic code.
UAG,UGA,UAA
Each of the three eukaryotic polymerases is able to begin transcription by recognizing ______
a different promoter sequence
Prokaryotes have
a single RNA polymerase
Most mature eukaryotic mRNAs have a string of nucleotides referred to as a poly- ______ tail
adenylated or adenine
The proteome of a cell consists of ______
all of the proteins produced by it
The phenomenon called_________ __________ enables a single primary transcript to be modified to encode two or more proteins.
alternative splicing
The enzymes that catalyze the attachment of ________ _______ to tRNA molecules are known as aminoacyl-tRNA synthetases or activating enzymes.
amino acids
Peptidyl transferase catalyzes the formation of a peptide bond between an amino group in the _________ site and the carboxyl group of the growing chain.
aminoacyl
The enzyme activity responsible for making peptide bonds between amino acids is found on
an rRNA located in the large subunit of the ribosome
The enzyme activity responsible for making peptide bonds between amino acids is found on ______.
an rRNA located in the large subunit of the ribosome
The template strand of DNA during transcription is also known as the ______
antisense strand
RNA polymerase I promoters _____
are specific for each species
The poly-A tail of most mature eukaryotic mRNAs is found ______
at the 3' end of the transcript
Which of the following can exhibit deviations from the universal genetic code?
chloroplasts and mitochondria
The sequence TATA (known as the TATA box) has been found upstream of the start site in some eukaryotic genes. That sequence is part of eukaryotic ______
core promoters
The current view of RNA polymerase II promoters in eukaryotes is that they contain a __________promoter and other controlling elements that could act in tissue or developmental ___________-specific manner.
core, time
In 1958, who first proposed the central dogma of transcription and translation?
crick
The central dogma of gene expression at the molecular level was first proposed by Francis ______
crick
n eukaryotes, translation can be carried out by ribosomes located (1) in the _______, or (2) on the rough endoplasmic reticulum (RER).
cytoplasm
The genetic code is said to be ________ because more than one codon can specify the same amino acid.
degenerate
Similar to the 5' cap, the poly-A tail of a eukaryotic mRNA protects it from ______
degradation
The central dogma describes information flow in cells as ____ to ____ to ____
dna, rna, protein
The three stages of translation are initiation, _____, and termination.
elongation
Which have three different RNA polymerases?
eukaryotes
In RNA splicing, the noncoding DNA is removed, and the coding DNA sequences, called ______, are expressed.
exons
The coding DNA sequences of a eukaryotic gene are called ______
exons
The ribosome uses the ________ AUG (methionine) codon it encounters in an mRNA as a start codon.
first
Functions of the ribosome.
forming peptide bonds, decoding the transcribed message
The association of transcription factors and RNA polymerase II at the eukaryotic promoter is called the _____ complex
initiation
Eukaryotic genes may contain non-coding regions known as _________ because they interrupt the sequence of a gene.
introns
The noncoding DNA sequences in a gene are termed which of the following?
introns
What are the two main roles of the 5' cap of a eukaryotic mRNA?
it participates in translation, it protects the mRNA from degradation
The two subunits that make up any ribosome are called the _______ subunit and the _________ subunit.
large, small
An RNA transcript that contains information that can be used by the ribosome to make a polypeptide is called a _________ RNA
messenger
How many aminoacyl-tRNA synthetases are present for each of the 20 common amino acids?
one
The enzyme peptidyl transferase is required in the formation of _______ bonds by the ribosome.
peptide
__________ __________ catalyzes the formation of a peptide bond between the amino group of the amino acid in the A site of the ribosome and the carboxyl group of the growing chain
peptidyl transferase
The transcription bubble contains the RNA ______, the DNA template, and the growing RNA transcript.
polymerase
Which of these is not one of the three sites where RNA binds to the ribosome?
polypeptide site
The RNA synthesized by RNA polymerase II is known as the ________ transcript
primary
Each of the three RNA polymerases in eukaryotic cells recognizes a different ______structure
promoter
In a bacterial transcription unit, the role of the ________ is to form a recognition and binding site for the RNA polymerase.
promoter
Which RNA is the structural component of the ribosome?
rRNA
The peptidyl transferase activity of the ribosome is carried out by a(n) _________ molecule located in the _________ ribosomal subunit.
rRNA, large
What class of viruses can convert their RNA genome into a DNA copy using reverse transcriptase?
retrovirus
Retroviruses can convert their RNA genome into a DNA copy using the enzyme _________
reverse transcriptase
The promoters for which RNA polymerase appear to be species-specific?
rna polymerase I
Identify the RNA polymerase responsible for transcribing the mRNA from eukaryotic structural genes.
rna polymerase II
Select the components of the eukaryotic initiation complex.
rna polymerase II, promoter, and transcription factors
Which of the eukaryotic RNA polymerases requires promoters that are internal to the gene itself?
rna polymerase III
Before it can bind to the promoter, a eukaryotic RNA polymerase II has to be recruited by ______
several transcription factors
When a base substitution mutation does not result in a change in the amino acid sequence of a protein (due to the degeneracy of the genetic code), we say that this mutation is:
silent
The decoding function of the ribosome is performed by the______ ribosomal subunit.
small
A large complex called a(n) ________ removes noncoding sequences from a eukaryotic pre-mRNA.
spliceosome
The AUG codon has a dual function. It serves as the ______ codon and it encodes the amino acid ______
start, methionine
Which RNA functions as a mediator molecule that interacts both with RNA and amino acids during translation?
tRNA
What sequence signals the location on a gene where transcription should stop?
terminator sequence
In transcription, the DNA strand that is not copied is called which of the following?
the coding strand
Choose the three sites where RNAs bind to the ribosome.
the exit site, the peptidyl site, and the aminoacyl site
What defines the reading frame of an mRNA?
the first codon that is read
Which ribosomal subunit contains the enzyme activity required to build peptide bonds?
the large subunit
The first codon defines _____
the reading frame of an mRNA.
How many nucleotide bases are in one codon?
three
rna polymerase II
transcribes mRNA
rna polymerase I
transcribes rRNA
rna polymerase III
transcribes tRNA
What is the name of the process that makes an RNA copy of DNA?
transcription
_______ is the process during which an RNA copy of DNA is made
transcription
The region containing the RNA polymerase, the DNA template, and the growing RNA transcript is called the _______ _______
transcription bubble
The sum of all the RNAs produced from a genome is known as the _________
transcriptome
In the central dogma, the RNA-to-protein step is termed ______
translation
Like transcription, the process of _______ in ribosomes occurs in three stages called initiation, elongation, and termination.
translation
What is the function of transfer RNA in the synthesis of polypeptides from information contained in mRNA?
translator
