BIO 111:
Put the steps in the order that they occur during initiation of translation, beginning with the first step at the top.
1. 5' end of mRNA binds to the small ribosomal subunit. 2. tRNA with UAC anticodon binds to AUG start codon 3. Methionine is in place at the beginning of the polypeptide, and large ribosomal subunit attaches to the small subunit.
Put the following steps in the order that they occur during transcription initiation in eukaryotes, beginning with the first step at the top.
1. a transcription factors binds to the TATA box of the promoter 2. The TATA binding protein attracts other transcription factors, including transcription factors bound at enhancers 3. RNA polymerase is able to bind to the promoter at the start of the gene and begin transcription
Given that there are 20 common amino acids in living things, researchers determined that the length of each codon in RNA is
3 nucleotides
If a DNA sequence underwent a missense mutation, what would be the result?
A codon would code for a different amino acid.
Select all of the following that are true about the genetic code.
AUG encodes methionine and "start." There are three codons that act as "stop" codons. The same genetic code is used by nearly all species.
During translation initiation, the first codon to specify a particular amino acid is usually ______, which encodes the amino acid ______.
AUG; methionine
The mRNA sequence ______ codes for the amino acid sequence Met-Trp-Arg.
AUGUGGAGG
Select all of the following that occur during the elongation stage of translation.
Bonds between amino acids are formed. Proteins called elongation factors assist in translation elongation. Amino acids are transferred from tRNAs to a polypeptide chain. Anticodons bind to their complementary codons.
Match each mRNA codon to the amino acid it corresponds to, per the genetic code.
CCA: proline UAC: tryosine GAG: glutamic acid AGC: serine UUC: phenylalanine CUU: leucine
Match each eukaryotic regulatory mechanism with where it would act within the "central dogma."
DNA availability: occurs before transcription mRNA processing, mRNA exit from the nucleus
Select all of the following that are true regarding mutations.
Mutations are alterations in DNA sequences. Mutations can be the causes of diseases. Some mutations have little to no effect on protein folding.
What occurs in a deletion mutation?
One or more nucleotides are removed from the DNA.
A(n) ______ mutation is caused by the replacement of one nucleotide with another.
Substitution
Select all the reasons why the polypeptide product of translation may be nonfunctional.
The DNA sequence is altered due to mutation. The amino acid sequence of the protein is altered. The polypeptide misfolds or clumps.
If an mRNA was blocked from exiting the nucleus, what would happen to expression of the gene from which the RNA transcript was made?
The gene would be silenced
If an mRNA was blocked from exiting the nucleus, what would happen to expression of the gene from which the RNA transcript was made?
The gene would be silenced.
Select all of the following that are true about the termination stage of translation.
The large and small ribosomal subunits separate. A release factor protein prompts the release of the last tRNA from the ribosome. The polypeptide is released.
What is an example of an expanding repeat mutation?
The number of copies of the sequence CCG increases every time the DNA is copied.
True or false: Although mutations often cause changes that are harmful, they are also the source of genetic variation for evolution. True false question.
True
Select all of the following that are "stop" codons, which signal the end of translation.
UGA UAG UAA
Protein processing and degradation is a method of regulating gene expression that occurs
after translation.
A variant of a gene is referred to as a(n)
allele
What gene regulation mechanism allows for the production of different proteins from the same mRNA?
alternative splicing of exons
In adult humans that can digest milk, ______ is modified so that the lactase gene is able to be transcribed.
an enhancer
What 3-base site of a tRNA molecule is complementary to an mRNA codon?
anticodon
A(n) _____ is a three-base sequence on the tRNA that binds to a(n) _____ on the mRNA.
anticodon; codon
On a tRNA molecule, the _____ is a three-base sequence that is complementary to and binds to an mRNA codon during translation.
anticondon
Select all of the following that are true about the frequency of mutations that arise during DNA replication.
averages about 1 in 100,000 bases for most genes generally higher in bacteria varies among organisms and among genes
Select all the roles that microRNAs play in regulating gene expression.
bind to mRNA and prevent translation cause mRNA to be degraded
What type of illness is characterized by unregulated cell division and can be caused by defective transcription factors?
cancer
Regulating gene expression allows cells to produce
certain proteins only when they are needed.
Epigenetics is the study of changes in gene expression due to
chemical modifications of histones or DNA bases.
The genetic code specifies what amino acid is matched to each three-nucleotide ______ in the mRNA.
codon
In the 1960s, researchers did not know how many RNA nucleotides specified each amino acid. Match each codon length with the number of amino acids it could specify.
condon is 1 nucleotide long: could specify 4 amino acids 2: 16 3: 64
During the elongation phase of translation, a _______ bond is formed between the incoming _______ acid and the growing polypeptide chain, and empty tRNAs are released from the ribosome to be reused. Multiple choice question.
covalent; amino
Select all of the following that are ways to control gene expression after translation.
degrading the protein blocking addition of a necessary sugar to a newly synthesized protein preventing the protein from reaching its correct destination
A mutation that causes a single codon to be removed such that a protein lacks one amino acid is a ______ mutation.
deletion
In humans, the production of the protein keratin in hair follicle cells and the protein hemoglobin in red blood cells is made possible by expressing
different subsets of genes in different cells.
Select all of the following that are true about frameshift mutations.
disrupts the codon reading frame can be caused by the addition of one nucleotide likely to change the amino acid sequence can be caused by the deletion of two nucleotides
Transcription, translation, nucleotide synthesis, and modifying mRNA are all processes that require
energy
A eukaryotic transcription factor may bind to a promoter or to a(n) _____, a regulatory region on the DNA that lies outside the promoter and regulates transcription.
enhancer
In eukaryotes, transcription factors can bind at near or distant regulatory DNA sequences called
enhancers.
Select all of the following agents or processes that can cause mutations.
errors in DNA replication some forms of radiation chemical mutagens
In a(n) _____ repeat mutation, the number of copies of a three- or four-nucleotide sequence increases over several generations.
expanding
After translation is complete, the newly synthesized polypeptide must ______, as determined by some regions of the amino acid chain.
fold into its functional shape
Select all of the following that are examples of mutations that cause changes in chromosome structure.
fusion of chromosomes or parts of chromosomes inversion of a long DNA sequence deletion or duplication of part of a chromosome
Select all of the following that are affected by epigenetic modifications in eukaryotes.
gene expression developmental patterns cell division
The ______ describes the correspondence of three-nucleotide codons to specific amino acids or directions for starting and stopping translation.
genetic code
Using synthetic mRNA molecules in test tubes with all the translation machinery, researchers in the 1960s deciphered the ______, which determines what amino acid is specified by each three-nucleotide ______.
genetic code; mRNA codon
A(n) _____ mutation is one that occurs in the cells that give rise to the sperm or egg.
germline
A(n) _____ mutation occurs in cells that give rise to sperm and egg cells, whereas a(n) _____ mutation occurs in non-sex cells.
germline; somatic
Select all the types of protein modification that can occur after translation to produce a functional protein.
joining with other polypeptides altering or cutting by enzymes
As described by Jacob and Monod, what E. coli genes and regulatory sequences are only produced when the bacteria need to break down lactose in the immediate environment?
lac operon
Transcription of the three genes in the lac operon occurs when
lactose is present in the environment and binds to the repressor.
The lac operon in E. coli bacteria includes three genes that produce
lactose-degrading proteins.
Each ribosome has one _____ subunit and one ______ subunit that join at the initiation of protein synthesis.
large;small
What mechanism allows eukaryotic cells to control gene expression by preventing translation?
mRNA degradation
To determine which codons correspond to which amino acids, scientists synthesized _____ and put them in a test tube containing the ingredients for translation. They then analyzed the resulting _____.
mRNA molecules; proteins
Match each type of RNA with its correct description.
mRNA: carries the information that specifies a protein tRNA: connector molecule that binds to an mRNA codon and to an amino acid rRNA: structural component of the ribosome
Match each type of RNA with its correct role in translation.
mRNA: contains codons specifying the order of amino acids tRNA: contains an anticodon on one end that determines what amino acid binds to the other end rRNA: major component that makes up the structure of a ribosome
During production of a protein, the information encoded in a DNA base sequence is transcribed to produce a molecule of ______ , which is then processed and translated to produce the sequence of ______ acids in a protein.
mRNA; amino
In transcription, the genetic information in DNA is copied into a(n) ______ molecule, and in translation, the "message" in an mRNA molecule is translated into a(n) ______ sequence.
mRNA; amino acid
During the elongation stage of translation, the ribosome exposes codons on the ______ one at a time; each codon determines what ______ will bring its attached amino acid to the ribosome to be added to the polypeptide chain.
mRNA; tRNA
This figure shows the genetic difference between two versions of the hemoglobin gene, one that produces normal red blood cells and one that results in sickled red blood cells. What class of mutation does the sickle cell mutation represent?
missense substitution mutation
A transposable element is a short DNA sequence that can cause mutations because it
moves and inserts randomly within the genome
Select ways that cells increase the speed of protein synthesis.
multiple ribosomes simultaneously translate an mRNA produce multiple copies of each mRNA
A(n) _____ is a change in a cell's DNA sequence.
mutation
A change in a protein-encoding DNA sequence or a regulatory DNA sequence, such as an enhancer, is called a(n)
mutation.
Homeotic genes control the formation of body parts in many animals, and ______ in homeotic genes have led to limb modifications that profoundly influenced animal evolution.
mutations
Inversions, duplications, or deletions of parts of chromosomes are types of ______ that affect extensive regions of DNA.
mutations
_____ in DNA may arise spontaneously as errors in replication, or they can be induced by external agents, like chemicals and radiation.
mutations
A substitution mutation that changes an amino acid into a "stop" codon is called a(n) ______ mutation and shortens the protein product.
nonsense
What describes a substitution mutation?
one DNA base is replaced with another
In bacterial operons, if a repressor protein binds to a sequence on the DNA called a(n) ______, transcription is inhibited.
operator
In bacteria, a(n) ______ is a group of genes under control of a single promoter.
operon
Enzymes and chaperone proteins assist in ______ that takes place after translation is complete.
polypeptide folding
Some proteins are composed of multiple ______ that join together after translation.
polypeptides
What mechanism of regulating gene expression acts after RNA processing but before translation?
preventing mRNA exit from the nucleus
Splicing of different exons together from the same mRNA molecules can result in
production of different proteins
A change in the amino acid sequence of a protein can cause the protein to be nonfunctional because ______ is affected by the amino acid sequence.
protein folding
Having multiple ribosomes bound to an mRNA is one way a cell increases the rate of
protein synthesis
Ribosomes are composed of rRNA and ______.
proteins
Bacterial cells and skin cells are more likely to accumulate mutations than other types of cells because they
replicate their DNA and divide frequently.
Select all of the following that are true of a nonsense mutation.
results in a shortened protein product could be caused by a codon change from UGG to UGA polypeptide synthesis terminates prematurely
Only producing proteins that are needed allows a cell to
save energy.
A mutation that causes an mRNA nucleotide to change from GGC to GGA is a ______ mutation.
silent
A substitution mutation is said to be ______ if the mutated gene encodes the same protein as the original gene version.
silent
_____ mutations do not pass from generation to generation because they occur in non-sex cells.
somatic
When the ribosome exposes a UGA, UAG, or UAA codon on the mRNA during translation, release factors rather than tRNAs bind to these codons, which is why these three sequences are called _____ codons.
stop
Select all of the following that are utilized in the process of translation.
tRNA mRNA amino acids ribosome
An anticodon is a sequence found on a(n) ______ molecule, whereas a codon is a sequence found on a(n) ______ molecule.
tRNA; mRNA
In a frameshift mutation, nucleotides are added or deleted in any number other than a multiple of
three
Select all the reasons a cell regulates gene expression.
to respond to changing conditions to have a specialized function
A signal molecule binding to a target cell can turn on eukaryotic gene transcription by activating a
transcription factor.
Defects in ______ can affect the production of proteins that regulate cell division and can lead to cancer.
transcription factors
Transcription factors are eukaryotic proteins that are required for RNA polymerase to bind to a promoter and initiate
transcription of genes.
What is a DNA sequence that can cause mutation by randomly inserting into a gene and disrupting its function?
transposon
Select all of the following that are mutagens
ultraviolet radiation chemicals in tobacco radioactive fallout harmful chemicals
Mutations can be harmful, but they also provide the ______ that makes evolution possible
variation
