bio ch 7

_________: an infecting virus would enter via the mouthparts of an herbivores insect

plant cell

tobacco mosaic virus (TMV) infects many species of

plants

a ________ is an infectious protein and is simpler than a virus

prion

______: structural component of the ribosome

rRNA

ribosomal RNA (rRNA) combines with proteins to form a protein-synthesizing structure Called a ___

ribosome

select all of the following that are true of HIV in a latent infection. -HIV responded more easily to HIV drug therapy -HIV genes are integrated into the host cell's DNA -HIV has entered the body by does not infect cells -Hiv's genetic information remains dominant

-HIV genes are integrated into the host cells DNA -HIV's genetic information remains dominant

select all of the following that are used during translation -mRNA -DNA -nucleosome -ribosome -rRNA

-mRNA -ribosome -tRNA

select all of the following that are true regarding mutation. -mutations can occur in a promoter region -all mutations are harmful -mutations are alterations in DNA sequence

-mutations can occur in a promoter region -mutations are alterations in DNA sequence

select the two plant defenses that must be overcome for a virus to infect a plant -deactivate the various plant defense chemicals and used them for DNA production -penetrate the thick plant cell wall -penetrate the chloroplasts to take over photosynthetic activities -penetrate waxy outer leaf layers

-penetrate the thick plant cell wall -penetrate waxy outer leaf layers

ribosomes consists of

a small and large subunit

_______: viral nucleic acid released inside host cell

penetration

some proteins are composed of multiple _______ that join together after translation

polypeptides

splicing of different exons together from the same mRNA molecule can result in

production of different proteins

true or false: insertions or deletions of large parts of chromosomes are considered mutations

true

select all of the following that are true about the human immunodeficiency virus (HIV). -can cause latent infections -its genetic material remains separate from the host cell genome -has an RNA genome -infects B cells of the immune system -is an enveloped virus -contains the enzyme reverse transcriptase

-can cause latent infections -has an RNA genome -is an enveloped virus -contains the enzyme reverse transcriptase

select all the conditions in a host cell that can cause bacteriophages to switch from the lysogenic pathway to the lytic pathway -cell starvation -DNA damage -prophage formation -cell division

-cell starvation -DNA damage

what disease results when HIV causes such an immense loss of T cells that the body's imbue system is defenseless against infections and cancer?

AIDS

epigenetic is he study of ________ that affect gene expression but do not change the DNA sequence

DNA modifications

________: includes many genes

DNA molecule

All viruses contain genetic material, which is either RNA or ________, and _______ coat that surrounds the genetic material

DNA; protein

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

RNA polymerase

_____: viral genes are expressed, new HIV particles are produced and released

active HIV infection

two strands of DNA within the double helix are said to be complementary to each other because ______ on one strand always pairs with thymine on the opposite strand, and cytosine on one strand always pairs with ______ on the opposite strand

adenine, guanine

a variant of a gene is referred to as an ______

allele

_________: an infecting virus would be engulfed by endocytosis into cytoplasm of cell

animal cell

in the _____ infection cycle, a bacteriophage causes the host cell the burst, thus killing it and releasing the new viral particles

lytic

_______: carries the information that specifies a protein

mRNA

a codon consists of three _______ that correspond to one _______

mRNA bases; amino acid

what method of gene expression regulation allows one gene to code for mutiple proteins due to different combinations of exons spliced togehter?

mRNA processing

___________: used xray diffraction to determine that DNA has a regular, repeating structure of building blocks

maurice Wilkins and Rosalind franklin

the first codon in initiation of translation corresponds to

methionine

___________: new viruses depart from the host cell

release

______: viral enzyme that synthesizes DNA from an RNA template

reverse transcriptase

a _____________ is composed of rRNA and proteins and is the site of protein synthesis

ribosome

select all the statements about nucleotides that are accurate. -they are composed of three fatty acids bonded to a three-carbon molecule of glycerol -they are composed of sugar, a nitrogen-containing group, and one or more phosphorus-containing groups -they are the building blocks of proteins -RNA contains the the sugar deoxyribose in its nucleotides -DNA always contains the same sugar in its nucleotides

-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

select all of the following that are true about the genetic code. -AUG is usually the last codon in a strand of mRNA -each amino acid is specified by only one codon -three codons are "stop" codons -AUG encodes methionine and "start"

-three codons are "stop codons" -AUG encodes methionine and "start"

select all of the following that can be components of RNA molecules. -deoxyribose -thymine -uracil -adenine -ribose -guanine

-uracil -adenine -ribose -guanine

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

anticodon

________: new viruses are put together from newly produced protein coats and nucleic acids

assembly

_________: virus binds to cell surface

attachment

antibiotics are targeted to the cell walls and enzymes of _______, and they are not effective against _______

bacteria, viruses

viruses that infect bacteria are called _______

bacteriophages

_______: an infecting virus would inject genetic material directly into cell through a hole in the cell wall

bacterium

in a lytic infection of bacteriophage, the host cell ____, whereas in a lysogenic infection of a bacteriophage, the host cell _______.

bursts when new viruses leave the cell; is not destroyed immediately

_________: discrete package of DNA copied around proteins

chromosome

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

double helix

____________: determined that DNA contains equal amounts of adenine and thymine and of guanine and cytosine

erwin chargaff

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

exons

what are coding regions of eukaryotic mRNA that are translated?

exons

_____: a sequence of nucleotides that codes for a specific protein or RNA molecule

gene

the human genome contains 20,000-25,000 ______ scattered on its 23 pairs of _______-

genes; chromosomes

all of the genetic material that is within a cell is called its ______

genome

________: interacts with envelope protein on HIV during viral attachment

host cell receptor

_________: 10 microns _________: 1 micron (1,000 nanometers) _________: 80 nanometers

human cell bacterium virus

steps of the process of translation

initiation elongation termination

an _________ is a portion of mRNA that is about 1,000 nucleotides long and this is removed before translation

intron

in eukaryotic cells, the mRNA is altered before it leaves the nucleus. after transcription, the _____ are removed from mRNA, and _____ are spliced together to form the mature mRNA

introns; exons

_________: used the known ratios of nucleotides along with the X-ray diffraction data to build a ball-and-stink model of the DNA double helix

james Watson and Francis crick

______: viral genome is integrated into host genome but no new virus particles are produced

latent HIV infection

what features do some viruses have

lipid-rich envelope enzymes

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

mutagen

the DNA double helix resembles a twisted ladder, where the rails of the ladder (also called the backbones) are composed of alternating deoxyribose sugars and _______ groups joined by covalent bonds, while the rungs of the ladder are composed of A-T and G-C base pairs joined by ________ bonds

phosphate; hydrogen

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

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

transcription

in a process called _______, an RNA copy of a gene sequence on the DNA molecule is made

transcription

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

transfer (t)

in a process called ________, an RNA molecule is uses to produce a protein

translation

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

a ________ is a small, infectious agent that is genetic information enclosed in only a protein coat

virus

select all of the reasons that gene regulation is advantageous in multicellular organisms. -it allows cells to delete unneeded genes and recycle the nucleotides for other processes -it saves energy -not all cells need all proteins encoded in the genome

-it saves energy -not all cells need all proteins encoded in the genome

select all the types of protein modification that can occur after translation to produce a functional protein. -addition of poly A tails -joining with other polypeptides -cutting of the protein by enzymes -removal of introns

-joining with other polypeptides -cutting of the protein by enzymes

select all of the following that can be a direct product of transcription -lipid -glucose -tRNA -mRNA -rRNA -DNA

-rRNA -mRNA -rRNA

select all of the symptoms of viral infection in plants -early flowering -streaked flower petals -blotchy, mottled leaves -bent stems

-streaked flower petals -blotchy, mottled leaves

select all the reasons why the protein product of translation may be nonfunctional -only one ribosome binds to an mRNA during translation -the DNA sequence is altered due to mutation -the amino acid sequence of the protein is altered -the polypeptide misfiles or clumps

-the DNA sequence is altered due to mutation -the amino acid sequence of the protein is altered -the polypeptide misfiles or clumps

select all of the ways that a cell can maximize the efficiency of protein synthesis -proteins may initiate their own replication at ribosomes -the cell may produce multiple copies of each mRNA -RNA polymerase may read amino acid sequences and transcribe new proteins directly -many ribosomes may simultaneously translate the same mRNA molecule

-the cell may produce multiple copies of each mRNA -many ribosomes may simultaneously translate the same mRNA molecule

select all the ways that newly made viruses can exit host cells. -budding out of the cell by exocytosis -forming prophages -moving through transmembrane channels -making holes in the cell wall and killing the cell

-budding out of the cell by exocytosis -making holes in the cell wall and killing the cell

select all of the following that are true about the Epstein-barr virus -can cause a latent infection of B cells. -can lead to cancer -can lead to mononucleosis -carried by more than 80% of the human population -carried by only 10% of the human population -infects helper T cells

-can cause a latent infection of B cells. -can lead to cancer -can lead to mononucleosis -carried by more than 80% of the human population

select the two characteristics that all viruses share. -ribosomes -several cell organelles, such as a cell membrane and a nucleus -genetic material, either RNA or DNA -a protein coat that surrounds the genetic material -outer envelope composed of lipids

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

select all of the following that can be components of RNA nucleotides -deoxyribose -guanine -ribose -adenine -uracil -thymine

-guanine -ribose -adenine -uracil

select all of the following that are true about the termination stage of translation. -the polypeptide is released -a release factor protein prompts the release of the last tRNA from the ribosome -the stop codon attracts a stop tRNA molecule -the large and small ribosomal subunits separate

-the polypeptide is released -a release factor protein prompts the release of the last tRNA from the ribosome -the large and small ribosomal subunits separate

latent viruses, such as human papilloma virus and Epstein-barr virus, can induce a cell division disorder called ______ because they are signaling the host cell to continue to divide

cancer

after transcription in eukaryotes, a short sequence of modified nucleotides called the _________ is added to one end of the mRNA molecule, and a string of 100 to 200 adenines called the ____ is added to the opposite end of the mRNA molecule

cap; poly A tail

after a virus attached 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

select the viruses that contain DNA as their genetic material -chickenpox virus -smallpox virus -rabies virus -polio virus -papilloomavirus -hepatitus B virus

chickenpox virus small pox virus papillomavirus hepatitis b virus

in an RNA molecule, a ______ is a genetic "code word" that corresponds to one amino acid

codon

how does an abnormal prion protein (PrP) form?

contact with an abnormal PrP

HIV infects ____ cells, and the Epstein Barr virus infects _____ cells

T B

sickle cell disease results from a _______ mutation

substitution

the DNA strand that is read during transcription is called the _____ strand

template

a specific sequence on the DNA called a _____ sequence signals the end of a gene during transcription

terminator

when is a substitution mutation "Silent"

when the replaced DNA base does not change the protein encoded by the gene

select all of the following that occur during the synthesis and assembly stages of a viral infection. -the viral genetic material is used by the host cell to synthesize viral proteins -the genetic material of the virus enters the host cell -proteins needed to form the viral capsid diffuse into the cell through special channels -capsid subunits join and surrounded viral genetic material -multiple copies of the viral genetic material are sydnthazised by the host cell

-the viral genetic material is used by the host cell to synthesize viral proteins -capsid subunits join and surrounded viral genetic material -multiple copies of the viral genetic material are synthesized by the host cell

select the two ways that viral infections can spread through plant tissue. -water uptake through the roots -windblown pollen -vascular tissue that distribute sap -bridges of cytoplasm between cells

-vascular tissue that distribute sap -bridges of cytoplasm between cells

the modern definition of gene is any sequence of DNA that is transcribed into

RNA

_______ viruses -rhinovirus -measles virus -hepatitis a virus -Ebola virus -influenza virus

RNA viruses

genes that control the formation of an organism's body parts and therefore profoundly influence animal evolution are called _______ genes

homeotic

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

in prokaryotes, both transcription and translation occur in the cytoplasm

the genetic variability of viruses complicates the development of ________ drugs

antiviral

________ into a host cell may not cause immediate death of the host cell

viral penetration

what type of infectious agent is a naked RNA molecule that can prevent plants from producing one or more essential proteins

viroid

in ________, mRNA is altered before it is translated

eukaryotic cells

epigenetic modifications to the DNA are removed at

fertilization

whereas ___ wipes away most epigenetic markers on the genome, _______ does not; therefore, identical twins may accumulate epigenetic differences throughout life

fertilization; cell division

after translation is complete, the newly synthesized protein must _____ as determined by some regions of the amino acid chain

fold into its functional shape

what type of mutation if most likely to alter many amino acids in a protein

frameshift mutation

the development of antiviral drugs is difficult due to the _________ of many viruses

genetic variability

the outer envelope present in some viruses, such as the influenza virus and HIV, is composed of ____, which maybe derived from the host cell's membrane

lipids and proteins

An ______ molecule may persist long enough to be translated many time and may be degraded before it is translated

mRNA

in eukaryotes, gene expression can be blocked by preventing ______ from leaving the nucleus

mRNA

what mechanism of regulating gene expression acts after RNA processing but before translation

mRNA degradation

what method of gene expression regulation allows one gene to code for multiple proteins due to different combinations of exons spliced together?

mRNA processing

________: lead to anitbiotic resistance in bacteria, allow scientists to learn the normal functions of genes, and agricultural scientists use them to create new varieties of crops

mutations

in ______, translation of an mRNA can begin before transcription of the mRNA is complete

prokaryotic cells

the DNA of a lysogenic bacteriophage that is inserted into a host's chromosome is called a

prophage

what is produced during translation

protein

enzymes and chaperone proteins assist in _____ that takes place after translation is complete

protein folding

in eukaryotes, the car and poly A tail on the mature mRNA ensures that

ribosomes attach to the correct end of the mRNA for translation

only producing proteins that are needed allows a cell to

save energy

how does a fever help fight a viral infection

speeds immune responses

when the ribosome reaches a UGA, UAG, or UAA codon on the mRNA, it halts because none of these codons has a corresponding tRNA. these three sequences are called ______ codons

stop

defects in _______ can effect the production of proteins that regulate cell division and can lead to cancer

transcription factors

select all of the following that occur during lysogenic infection of a bacterial cell. -new viruses are produced -genetic material of virus is replicated -host cell is killed -prophage may be formed

-genetic material of virus is replicated -prophage may be formed

select all of the following that are true with respect to genomes. -in eukaryotic cells, the genome usually consists of just one circular DNA molecule -in prokaryotic cells, the genome is usually divided up into multiple chromosomes -in eukaryotic cells, the genome is usually divided up into multiple chromosomes -in prokaryotic cells, the genome usually consists oj just one circular DNA molecule

-in eukaryotic cells, the genome is usually divided up into multiple chromosomes -in prokaryotic cells, the genome usually consists of just one circular DNA molecule

select all of the following that are ways to control gene expression after translation. -preventing a protein from reaching its correct destination -degrading proteins -blocking the exit of mRNA from the nucleus -degrading mRNA -block modifications or alterations to proteins

-preventing a protein from reaching its correct destination -degrading proteins -block modifications or alterations to proteins

select all of the following that are present in a bacterial operon. -enhancer -promoter -operator -group of genes -TATA box

-promoter -operator -group of genes

which of the following are true with respect to mutations? -some mutations can increase an organism's reproductive success -some mutations produce detrimental alleles -all mutations that are passed from parent to offspring are harmful -mutations can cause drug resistance in bacteria -mutations provide the raw material for evolution

-some mutations can increase an organism's reproductive success -some mutations produce detrimental alleles -mutations can cause drug resistance in bacteria -mutations provide the raw material for evolution

select all of the following that are components of chromosomes -specialized proteins -DNA -RNA -ribosomes

-specialized proteins -DNA

select all the ways that cells can make DNA less available for transcription -tag DNA with methyl groups -wind of fold DNA in a way that makes in unavailable -unwind DN -remove introns and split exons together

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

select all of the following that describe RNA. -the nitrogenous base trail is used instead of thymine -nucleotides contain the sugar ribose -can catalyze chemical reactions -always occur as a double stranded helix -nucleotides contain the sugar deoxyribose -can be single stranded -the nitrogenous base thymine is used instead of guanine

-the nitrogenous base uracil is used instead of thymine -nucleotides contain the sugar ribose -can catalyze chemical reactions -can be single stranded

select all of the following that are true about E. coli bacteria in an environment lacking lactose -the three genes of the lac operon are not transcribed -the repressor is bound to lactose -the lac operon makes lactose-degrading enzymes -the repressor binds to the operator of the lac operon

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

select all the ways that plants can fight off viral infections. -viral mRNA is destroyed before it is translated -infected cells commit suicide -lysosomes ingest infected cells -pollen incompatibility mechanisms are activated

-viral mRNA is destroyed before it is translated -infected cells commit suicide

list from smallest at top to largest on bottom -bacterium -virus -human cell

-virus -bacterium -human cell

what describes a substitution mutation

one DNA base if replaced with another

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

operator

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

operator

in bacteria, an ______ is a group of genes under control of a single promoter

operon

messenger RNA contains ______, which are triplets of bases that act as "code-words" corresponding to the ______ acid monomers that make up a polypeptide

codons, amino

during transcription, a gene's DNA sequence is transcribed into a -sequence of amino acids -complementary RNA molecule -complementary DNA molecule -protein

complementary RNA molecule

during a __________ infection, a bacteriophage's genetic material is replicated along with the host cell's DNA, but the host cell is not immediately destroyed

lysogenic

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 chemicals called mutagens

mutations

_________: building block of nucleic acids

nucleotide

a single strand of DNA consists of a polymer of _________ monomers

nucleotide

where would you find a transcriptional terminator sequence

on a DNA sequence

_____: host cell produces viral nucleic acids and proteins

synthesis

_______: connector molecule that binds to an mRNA codon and to an amino acid

tRNA

during transcription, RNA nucleotide bases are added to the growing mRNA strand as dictated by the complementary bases on the ___ strand of the DNA

template

a homeotic gene encodes a

transcription factor that affects embryo development

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

transcription factors

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

in the "central dogma" describing the glow 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_______.

transcription, translation