bio chapter 7

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- Occurs after transcription but before translation. Protein degradation- Occurs after translation. Transcription factors- Occurs at initiation of transcription.

Epigenetics is the study of ______ that affect gene expression but do not change the DNA sequence.

DNA modifications

Select the true statement about viral infection of a host cell.

Viral penetration into a host cell may not cause immediate death of the host cell.

Select the two characteristics that all viruses share.

a protein coat that surrounds the genetic material genetic material, either RNA or DNA

A variant of a gene is referred to as a(n)___________

allele

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

anticodon

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

anticodon

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

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

After a virus attaches to and penetrates a host cell, a virus can enter a phase where symptoms of the infection are delayed or it can

cause immediate cell death.

During transcription, a gene's DNA sequence is transcribed into a

complementary RNA molecule.

The instructions in ______ encode the information that a cell needs to produce proteins, which are vital to living things.

DNA

What symptom of influenza infection is due to dead and damaged host cells in the airway?

cough and sore throat

During the elongation stage of translation, a _______ bond is formed between the incoming _______ acid and the growing polypeptide chain, and empty tRNAs are released from the ribosome.

covalent; 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

A(n) _________is any external agent, such as X-rays or chemicals, that induces mutations.

mutagen

UV rays, X-rays, some chemicals found in tobacco, and radioactive fallout are all examples of _____, agents that can damage DNA and cause mutations.

mutagens

A change in a gene sequence or a regulatory DNA sequence is called a(n) ______.

mutation

A(n) ___________is a change in a cell's DNA sequence.

mutation

Subunits called ______ are the building blocks of DNA.

nucleotide

The DNA double helix is made up of two strands of ______ monomers oriented in opposite directions.

nucleotide

What describes a substitution mutation?

one DNA base is replaced with another

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.

operon

Tobacco mosaic virus (TMV) infects many species of

plants

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

polymerase

A(n) ______ is an infectious protein and is simpler than a virus.

prion

At the beginning of transcription, RNA polymerase binds to the ______ on the DNA.

promoter

The ______ is a sequence of DNA that signals the start of a gene and also which of the two strands of DNA is the template for transcription.

promoter

What role does DNA play in the cell?

store instructions for making proteins

The replacement of one DNA base with another is called a(n)

subsitution mutation

During_________ , the information that is encoded in the DNA base sequence is copied into the complementary language of mRNA. Then, once the mRNA is produced and modified, a process called ___________uses that information to assemble a sequence of amino acids.

transcription, translation

True or false: Gene regulation allows cells to produce only the proteins that they need.

true

Preventative treatments for viruses called ______ cause the immune system to recognize molecular components of a virus without exposing the person to the disease, conferring future immunity to the target virus.

vaccines

Attachment, penetration, synthesis, assembly, and release are the stages of

viral replication

A small, infectious agent that is composed of genetic information inside of a protein coat is a called a

virus

A(n)_______ is a noncellular, small, infectious agent that is simply genetic information enclosed in a protein coat.

virus

Rank the five steps of viral replication in the order in which they occur during an infection, beginning with the first step at the top.

1. attachment to host cell 2. penetration 3. synthesis of viral components 4.assembly of new viruses 5. release of new viruses from host cell

Put the following events of translational elongation (the stage in translation that occurs after initiation) in the order that they occur, beginning with the first step at the top.

1.) After the first amino acid has been brought to the ribosome, a tRNA carrying the second amino acid of a protein binds to the second codon. 2.) A covalent bond forms between the first and second amino acids. 3.)The ribosome releases the first tRNA. 4.) The ribosome moves down the mRNA by one codon, and a tRNA carrying the third amino acid comes into place. 5.) A covalent bond forms between the second and third amino acids. 6.) The ribosome releases the second tRNA.

All viruses contain genetic material, which is either RNA or ______, and a(n) ______ coat that surrounds the genetic material.

DNA; protein

________ provides the raw material for evolution because it can create new alleles, which are alternative forms of the same ______.

Mutation; gene

Select all of the reasons that gene regulation is advantageous in multicellular eukaryotic organisms.

Not all cells need all proteins encoded in the genome. It saves energy.

During transcription, what reads the template strand within a gene and adds complementary bases?

RNA polymerase

Select all of the bases that can be present in DNA nucleotides.

cytosine guanine adenine thymine

A DNA molecule consists of two intertwining strands of nucleotides that form a

double helix

A DNA molecule consists of two intertwining strands of nucleotides that form a _________

double helix

Transcription, translation, nucleotide synthesis, and modification of mRNA are all processes that require

energy

Modifications to the DNA, such as methylation, that do not change the nucleotide sequence but do affect gene expression are called ______ modifications.

epigenetic

What are coding regions of eukaryotic mRNA that are translated?

exons

_____ are portions of mRNA that get spliced together to form mature mRNA before translation occurs in eukaryotes.

exons

After translation is complete, the newly synthesized protein must ______, as determined by some regions of the amino acid chain.

fold into its functional shape

A(n) ________is a portion of mRNA that is about 1,000 nucleotides long and that is removed before translation.

intron

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

intron

An animal virus can cause a(n) ______ viral infection, in which disease symptoms are not produced immediately, but the viral information remains inside the cell.

latent

In the ______ infection cycle, a bacteriophage replicates and then causes the host cell to burst, thus killing it and releasing the new viral particles.

lytic

In what type of bacteriophage infection does the host cell burst open, releasing the new viral particles?

lytic

Enzymes and chaperone proteins assist in ______ that takes place after translation is complete.

protein folding

The term prion is an abbreviation that stands for

proteinaceous infectious particle

The term prion is an abbreviation that stands for

proteinaceous infectious particle.

In the "central dogma," information flows from DNA to RNA to ______.

proteins

Only producing proteins that are needed allows a cell to______

save energy

How does a fever help fight a viral infection?

speeds immune responses

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

tag DNA with methyl groups wind or fold DNA in a way that makes it unavailable

Vaccines work by causing_______

the immune system to recognize molecular components of the virus without the person having the disease.

A latent viral infection is one in which

the viral genetic information remains inside the cell but does not cause disease symptoms.

The first virus ever discovered was ______, a virus that infects over 120 plant species.

tobacco mosaic virus

The first virus ever discovered was ______, a virus that infects over 120 plant species..

tobacco mosaic virus

In the "central dogma" describing the flow of genetic information from DNA to protein, DNA is copied to RNA in a process called_________ , and the information in RNA is used to direct the synthesis of a protein in a process called ____________

transciption,translation

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

transcription

In a process called ______, an RNA copy of a gene sequence on the DNA molecule is made.

transcription

In eukaryotic cells, proteins called ______ factors bind at specific DNA sequences and form a pocket that allows RNA polymerase to initiate transcription.

transcription

In eukaryotes, RNA polymerase cannot bind to the promoter and initiate transcription without the presence of regulatory proteins called

transcription factors.