7.

A C-G base pair in a DNA double helix is joined by ______ between the bases. Multiple choice question.

three hydrogen bonds

In his experiments with S. pneumoniae bacteria and mice, Frederich Griffith found that

something in heat-killed S bacteria could transform type R bacteria.

What role does DNA play in the cell?

store genetic information

In the central dogma, DNA is ______ into RNA, which is ______ into a sequence of amino acids.

transcribed; translated

True or false: During the early part of the twentieth century, some biologists believed that proteins were more likely than DNA to be the molecule of heredity.

t

True or false: Unlike DNA, RNA can catalyze chemical reactions.

t

During translation elongation, what molecule brings amino acids to the ribosome, as dictated by the sequence of codons on the mRNA?

tRNA

Select all of the following that are utilized in the process of translation.

tRNA ribosome mRNA amino acids

An anticodon is a sequence found on a(n) ______ molecule, whereas a codon is a sequence found on a(n) ______ molecule.

tRNA; mRNA

A specific sequence on the DNA called a(n) ______ sequence signals the end of a gene during transcription.

terminator

A specific sequence on the DNA called a(n) ______ sequence signals the end of a gene during transcription. Multiple choice question.

terminator

Complementary base pairing within a single RNA molecule determines

the three-dimensional shape.

Due to complementary base pairing rules, a sequence of AAGCTA on one strand of the DNA double helix means that the sequence on the opposite strand is

TTCGAT.

What represents Chargaff's discovery about the amounts of the nitrogenous bases A, G, C, and T in the DNA molecule?

amount of A = amount of T; amount of G = amount of C

What describes a ribosome?

an rRNA-protein structure that is the site of translation

What 3-base site of a tRNA molecule is complementary to an mRNA codon?

anticodon

Although the two chains of the DNA double helix are parallel to each other, they are oriented in opposite directions. This head-to-tail configuration is referred to as a(n) ______ arrangement.

antiparallel

As RNA is synthesized in transcription, it can curl into a three-dimensional shape that is dictated by ______ within the molecule.

complementary base pairing

as RNA is synthesized in transcription, it can curl into a three-dimensional shape that is dictated by ______ within the molecule

complementary base pairing

In the synthesis of RNA from DNA, the enzyme RNA polymerase adds ______ to the ______ end of the growing RNA molecule.

nucleotides; 3 prime

In a frameshift mutation, nucleotides are added or deleted in any number other than a multiple of

3

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 prokaryotic versus eukaryotic gene expression.

In eukaryotes, the nuclear membrane separates transcription from translation. In eukaryotes, mRNA is altered before it leaves the nucleus.

What is one major difference between eukaryotes and prokaryotes with respect to translation?

In prokaryotes, translation can take place even before transcription is complete.

What is one major difference between eukaryotes and prokaryotes with respect to translation? Multiple choice question.

In prokaryotes, translation can take place even before transcription is complete.

Select all of the correct statements regarding the results of Frederick Griffith's 1928 experiment involving Streptococcus pneumoniae. Multiple select question.

Live S strains caused pneumonia in mice. Heat-killed S strains mixed with live R strains caused pneumonia in mice.

Select all of the following that are true regarding mutations.

Mutations are alterations in DNA sequences. Some mutations have little to no effect on protein folding. Mutations can be the causes of diseases.

What occurs in a deletion mutation?

One or more nucleotides are removed from the DNA.

Gene expression is the production of a functional ______ or a ______.

RNA molecule; protein

The modern definition of gene is any stretch of DNA that is transcribed to

RNA or protein.

Select all the reasons why the polypeptide product of translation may be nonfunctional.

The amino acid sequence of the protein is altered. The DNA sequence is altered due to mutation. The polypeptide misfolds or clumps.

Select all of the effects on the lac operon when the repressor is bound to the operator.

The bacterial cell conserves energy by not producing lactose-degrading enzymes. RNA polymerase is unable to initiate transcription.

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.

On one half of a DNA double helix, a single strand of nucleotides has

a 3' end on one side, and a 5' end at the opposite end.

Question Mode Multiple Choice Question Most of the epigenetic markers present in a multicellular organism are placed onto its DNA

after the sperm and egg cell unite in fertilization.

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.

Select all the types of protein modification that can occur after translation to produce a functional protein.

altering or cutting by enzymes joining with other polypeptides

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 enhacer

Select all the roles that microRNAs play in regulating gene expression.

bind to mRNA and prevent translation cause mRNA to be degraded

Select all of the following that are ways to control gene expression after translation.

blocking addition of a necessary sugar to a newly synthesized protein degrading the protein preventing the protein from reaching its correct destination

Select all of the following that are methods of gene regulation found in eukaryotes but not prokaryotes.

blocking mRNA exit from the nucleus adding methyl groups to silence genes splicing exons in alternative ways

Select all of the following that are true about frameshift mutations.

can be caused by the addition of one nucleotide likely to change the amino acid sequence disrupts the codon reading frame can be caused by the deletion of two nucleotides

What type of illness is characterized by unregulated cell division and can be caused by defective transcription factors?

cancer

Select all of the following that are affected by epigenetic modifications in eukaryotes.

cell division developmental patterns gene expression

The regulation of gene expression in eukaryotic cells allows for

cell specialization in multicellular eukaryotes.

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.

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.

covalent; amino

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.

DNA has a ______ helical structure consisting of two intertwining strands of ______.

double; 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.

By the early 1900s, biologists had observed that abnormal or missing ______ were often associated with heritable traits or conditions. Multiple choice question.

enzymes

Select all of the following agents or processes that can cause mutations.

errors in DNA replication some forms of radiation chemical mutagens

What are coding regions of eukaryotic mRNA that are translated?

exons

An underlying cause of Huntington Disease is a(n) ______ mutation, in which the copies of GTC increase over several generations and cause extra glutamines in the protein product of the gene. Multiple choice question.

expanding repeat

True or false: A mutation that occurred in a brain cell due to radiation exposure would be passed to the next generation.

f

Whereas _____ wipes away most epigenetic markers on the genome, _____ does not; therefore, identical twins may accumulate epigenetic differences throughout life.

fertilization; cell division

In the Hershey and Chase experiment, radioactively-labeled sulfur was found in the ______ within one test tube, while radioactively-labeled phosphorus was found in the ______ within the other test tube, indicating that ______ was the genetic material.

fluid; bacterial cells; DNA

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 true about the frequency of mutations that arise during DNA replication.

generally higher in bacteria averages about 1 in 100,000 bases for most genes varies among organisms and among genes

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 sperm or egg. Multiple choice question.

germline

Which of the following mutations can be passed from one generation to the next?

germline

In an average mRNA molecule that has just been transcribed, the amount of genetic material devoted to introns is _____ the amount devoted to exons.

greater than

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.

What mechanism allows eukaryotic cells to control gene expression by preventing translation?

mRNA degradation

What RNA modification in eukaryotes decreases the chances that the mRNA will be degraded before translation?

poly A tail

RNA ______ is the enzyme that builds the RNA chain during transcription.

polymerase

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

Some proteins are composed of multiple ______ that join together after translation. Multiple choice question.

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.

The ______ is a sequence of DNA that signals the start of a gene and is the site where RNA polymerase binds to begin transcription. Multiple choice question.

promoter

Select all of the following that are involved in transcription initiation in eukaryotes.

promoter RNA polymerase enhancers TATA box transcription factors

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. Multiple choice question.

protein folding

Having multiple ribosomes bound to an mRNA is one way a cell increases the rate of

protein synthesis.

The DNA strand that is "read" during transcription is called the ______ strand.

template

At the beginning of transcription, RNA polymerase binds to

the promoter.

Select all of the reasons why eukaryotic cells regulate gene expression.

to coordinate early development to express different subsets of genes in different types of cells to activate different genes at different times in the life of an organism

Select all the reasons a cell regulates gene expression.

to respond to changing conditions to have a specialized function

In eukaryotic cells, proteins called ______ factors bind at specific DNA sequences, which allows RNA polymerase to initiate transcription. Multiple choice question.

transcription

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.

Eukaryotic cells can compact their DNA or add methyl groups to make their DNA unavailable for

transcription.

In eukaryotes, mRNA degradation regulates gene expression by preventing

translation.

What is a DNA sequence that can cause mutation by randomly inserting into a gene and disrupting its function?

transposon

Mutations can be harmful, but they also provide the ______ that makes evolution possible.

variation

In the Hershey-Chase experiment in 1950, ______ were labeled with two types of radioactive markers, one that marked protein and one that marked ______, and then allowed to infect E. coli bacteria.

viruses; DNA

Select all the ways that cells can make DNA less available for transcription.

wind DNA more tightly tag DNA with methyl groups

______________mutations do not pass from generation to generation because they occur in non-sex cells.

Blank 1: Somatic, somatic cell, or somatic

in a(n) ___________________ repeat mutation, the number of copies of a three- or four-nucleotide sequence increases over several generations

Blank 1: expanding or expanding repeat mutation

In eukaryotic cells, the mRNA is altered before it leaves the nucleus. After transcription_________________are removed from mRNA, and_________________are spliced together to form the mature mRNA.

Blank 1: introns, intron, or intragenic regions Blank 2: exons or exon

a _______________ is any external agent, such as X-rays or chemicals, that induces mutations.

Blank 1: mutagen

In bacterial operons, a DNA sequence that exists between the promoter and the protein coding region is called the __________and is where a repressor protein can bind.

Blank 1: operator

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. Anticodons bind to their complementary codons. Amino acids are transferred from tRNAs to a polypeptide chain.

What is an example of an expanding repeat mutation?

The number of copies of the sequence CCG increases every time the DNA is copied.

Select all of the following that are true about the termination stage of translation.

The polypeptide is released. The large and small ribosomal subunits separate. A release factor protein prompts the release of the last tRNA from the ribosome.

What would result if a mutation caused the addition of the three-base codon GUG?

The protein product would contain one extra amino acid.

Select all of the following that are true about E. coli bacteria in an environment lacking lactose.

The repressor binds to the operator of the lac operon. The three genes of the lac operon are not transcribed

Select all the statements about nucleotides that are accurate.

They are composed of a sugar, a nitrogen-containing group, and one or more phosphorus-containing groups. DNA always contains the same sugar in its nucleotides.

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

If a substitution mutation changes a codon such that it specifies a different amino acid, it is called a ______ mutation.

missense

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 change in a protein-encoding DNA sequence or a regulatory DNA sequence, such as an enhancer, is called a(n)

mutation

a ___________is a change in a cell's DNA sequence.

mutation

in DNA may arise spontaneously as errors in replication, or they can be induced by external agents, like chemicals and radiation.

mutation

Inversions, duplications, or deletions of parts of chromosomes are types of ______ that affect extensive regions of DNA.

mutations

Select all of the following that are components of nucleotides.

nitrogen-containing base phosphorus-containing groups sugar

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 bacterial operons, if a repressor protein binds to a sequence on the DNA called a(n) ______, transcription is inhibited. Multiple choice question.

operator

Select all of the following that are present in a bacterial operon.

operator promoter group of genes

In bacteria, a(n) ______ is a group of genes under control of a single promoter. Multiple choice question.

operon

Ribosomes are composed of rRNA and ______.

proteins

A ribosome is 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.

A protein that binds to the operator sequence in bacterial DNA and prevents transcription of genes is called the

repressor.

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

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

A(n) ______ mutation is caused by the replacement of one nucleotide with another.

substitution

True or false: A mutation that occurs in a sperm cell has the potential of being passed on to the next generation.

t

True or false: Although mutations often cause changes that are harmful, they are also the source of genetic variation for evolution.

t

The genetic code specifies what amino acid is matched to each three-nucleotide ______ in the mRNA.

codon

The average size of an exon is about

100-300 nucleotides.

Given that there are 20 common amino acids in living things, researchers determined that the length of each codon in RNA is

3 nucleotides.

During transcription, RNA polymerase moves along the DNA template strand, adding RNA nucleotides to the growing ______ end of the RNA molecule.

3'

During translation initiation, the first codon to specify a particular amino acid is usually ______, which encodes the amino acid ______.

AUG; methionine

Using the table (which is shown larger in the text), select all of the following mRNA sequences that would code for the polypeptide Met-Ser-His-Arg-Gln.

AUGUCCCAUCGUCAA AUGUCUCACCGUCAA AUGUCUCAUCGUCAA AUGUCUCAUCGUCAG

The mRNA sequence ______ codes for the amino acid sequence Met-Trp-Arg.

AUGUGGAGG

Shortly after transcription in eukaryotic cells, a string of 100-200 adenines is added to the 3' end of the mRNA molecule, producing what is known as a poly______________tail, and a short sequence of nucleotides called the 5'_______________is added to the 5' end of the mRNA molecule.

Blank 1: A, -A, or a Blank 2: cap, mRNA cap, or 5' cap

Early in the twentieth century, scientists were at first hesitant to accept that_________________as the genetic information molecule because______________________, with its 20 common amino acid building blocks, could code for many more traits.

Blank 1: DNA Blank 2: protein, RNA, or proteins

On a tRNA molecule, the_______________is a three-base sequence that is complementary to and binds to an mRNA codon during translation.

Blank 1: anticodon

A(n) __________________ is a three-base sequence on the tRNA that binds to a(n)__________________on the mRNA.

Blank 1: anticodon Blank 2: codon

Messenger RNA contains______________which are triplets of bases that act as "code-words" corresponding to the______________acid monomers that make up a polypeptide.

Blank 1: codons or codon Blank 2: amino

A(n) _________________ is a portion of RNA that averages about 1,000 nucleotides long and that is removed before translation. Listen to the complete question

Blank 1: intron or Introns

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

Blank 1: mRNA, RNA, or messenger rna Blank 2: amino

_________________is a type of RNA that serves as a "connector" between the mRNA codon and a particular amino acid.

Blank 1: tRNA, Transfer RNA, or Transfer

DNA contains the nitrogenous base_____________, whereas RNA does not contain this base but instead uses________________

Blank 1: thymine or T Blank 2: uracil, Uracil, or U

In the DNA molecule, why does A pair with T and not C?

Both A and T can only form two hydrogen bonds.

Avery, MacLeod, and McCarty concluded that ______ from lethal type S bacteria had transformed harmless R bacteria into S bacteria because DNA-destroying enzymes disrupted the transforming ability, while protein-destroying enzymes did not.

DNA

During transcription, RNA nucleotide bases bind with the exposed complementary bases on the template strand of

DNA.

______ are portions of mRNA that get spliced together to form mature mRNA prior to translation.

Exons

True or false: In the 1940s, Avery, McCarty, and MacLeod figured out that the "transformation principle" from Griffith's experiments was actually protein.

False

All of the genetic material that is within a cell is called its

GENOME

During transcription, what enzyme attaches to the promoter, unzips the DNA double helix, and adds complementary RNA nucleotides?

RNA polymerase

Select all of the following that are true about Hershey and Chase's experimental design in 1950.

They used bacteriophages to infect bacteria in order to determine whether DNA or protein was the genetic information. They used radioactive labels to mark proteins in one set of viruses and to mark DNA in another set of viruses. After infection of the bacteria, they agitated the mixture to separate the viral coats from the bacterial cells.

Select all of the following that are "stop" codons, which signal the end of translation. Multiple select question.

UAG UGA UAA

What scientists worked out the double helical structure of DNA using a ball-and-stick model?

Watson and Crick

Select all of the following organisms that have introns in their primary mRNA transcripts. Multiple select question.

archaea eukaryotes animals

Select all of the following that are actions of the enzyme RNA polymerase.

attach to the promoter on DNA build an mRNA chain unzip the DNA to expose the template strand

In eukaryotic cells, the mRNA is altered before it leaves the nucleus. A short sequence of modified nucleotides, known as a ______ is added to the 5' end and a string of adenines called a ______ is added to the 3' end.

cap; poly-A tail

What is a discrete package of DNA and its associated proteins?

chromosome

In 1962, James Watson,________________and Maurice Wilkins won the Nobel Prize in physiology or medicine for their discovery of the DNA double helix. Rosalind Franklin had also contributed important work, but she had died by the time the prize was awarded.

crick

Within the DNA double helix, the so-called backbone is composed of ______ sugars alternating with phosphate groups.

deoxyribose

The terms 3' and 5' refer to numbered carbon atoms within the ______ of DNA, and at one end of the DNA double helix, there is a free ______ on one backbone and a free ______ on the other backbone.

deoxyribose sugar; 3' carbon; 5' carbon

The information that each cell needs to produce proteins is stored in a molecule called

dna

Select all of the following that are functions of the 5' cap and 3' poly A tail added to mRNA after transcription in eukaryotes.

help ribosomes attach to 5' end of mRNA protect RNA from degradation

Within the DNA double helix, the nitrogenous bases in base pairs are joined by ______ bonds, which are collectively strong but can also be pulled apart if the cell needs access to the DNA.

hydrogen

What process describes the removal of spacer portions of mRNA to produce mRNA consisting of regions to be translated?

intron removal and splicing together of exons

In eukaryotes, a part of an mRNA molecule that is removed before translation is called a(n)

intron.

When Griffith mixed together live strain R bacteria and heat-killed S bacteria and injected them into mice, the mice died, and ______ bacteria were isolated from the mice, indicating that something could pass between cells and transform them.

live S strain

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

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

Select all of the following that are true about the genetic material of eukaryotes.

mature mRNA molecules can contain 70 or more exons exons alternate with introns in DNA and immature mRNA transcripts removing introns and splicing exons plays a role in gene regulation

Where would you find a transcriptional terminator sequence?

on a DNA sequence

The antiparallel configuration of the DNA double helix means that the two strands of nucleotides are oriented in ______ directions with respect to each other.

opposite

During the Hershey-Chase experiment, radioactive ______ was used to label the DNA, and radioactive ______ was used to label the protein.

phosphorus; sulfur

During the Hershey-Chase experiment, radioactive ______ was used to label the DNA, and radioactive ______ was used to label the protein. Multiple choice question.

phosphorus; sulfur

When Avery, McCarty, and MacLeod treated a solution from the S strain bacteria with a ______-destroying enzyme, it retained its ability to transform R strain bacteria into the lethal S strain. However, when they treated the same solution with a ______-destroying enzyme, it lost its ability to transform the R strain into a killer.

protein; DNA

In the Hershey and Chase experiment, ______ was found inside the infected bacteria, indicating that the labeled viral ______ had entered the bacterial cells to direct new virus production.

radioactive phosphorus; DNA

he sugar in RNA nucleotides is called ______, whereas the sugar in DNA nucleotides is called ______.

ribose; deoxyribose

RNA differs from DNA chemically because RNA nucleotides contain the sugar ______, and in RNA, the nitrogenous base ______ is substituted for thymine. Multiple choice question.

ribose; uracil

What type of RNA binds to an mRNA codon at one end and a specific amino acid at the other end?

transfer RNA (tRNA)

In what process does the cell use the information in an RNA molecule to assemble a protein?

translation