Ch. 10 Study guide
b
During the replication of DNA molecules, __________. a)errors never occur b)both strands of the DNA molecule serve as templates c)the cell undergoes mitosis d)RNA polymerases catalyze the reaction e)only one strand of the molecule acts as a template
genome, DNA, Chromosome
Which is bigger gene or genome? DNA or Polynucleotide, Chromosome or Gene
d
In eukaryotic cells, transcription occurs in the _________ while translation occurs in the __________. a)endoplasmic reticulum; nucleus b)cytoplasm; cytoplasm c)nucleus; nucleus nucleus; cell membrane d)nucleus; cytoplasm
DNA polymerases
What enzymes connect nucleotides together during DNA replication?
a
Which of the following features of DNA molecules contains the actual code for building proteins? a)Sequence of bases b)Deoxyribose bonds c)Phosphate alignment d)Order of deoxyriboses
lagging strand
formed in separate pieces
b
Ribosomes are made up of __________. a)protein b)protein and RNA c)lipids d)RNA e_protein, RNA, and lipids
polynucleotides; nucleotides
A molecule of DNA contains two polymer strands called , made by bonding together many monomers called .
mRNA
This molecule takes information from DNA out to the cytoplasm.
mRNA; DNA
Transcription is the synthesis of ________, using ________ as a template.
protein; codon
Translation is the synthesis of ________, with one ________ determining each amino acid in the sequence.
bacteriophage
A ___________ is a virus that specifically infects bacteria.
prophage
A ______is a viral genome that has inserted itself into the genome of its host.
d
A cell biologist found that two different proteins with different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same gene in the cell nucleus. Which mechanism below could best account for this? a)The gene could be transcribed in different directions to produce two different proteins. b)The two proteins have different functions in the cell. c)Different systems of DNA unpacking could result in two different mRNAs. d)Exons from the same gene could be spliced in different ways to make different mRNAs. e)A mutation might have altered the gene.
d
A gene is __________. a)made by a ribosome b)made of protein c)the same thing as a chromosome d)the information for making a specific amino acid sequence e)made of a long chain of amino acids
d
A geneticist finds that a particular mutation has no effect on the polypeptide encoded by the gene. This mutation probably involves a)deletion of one nucleotide. b)alteration of the start codon. c)insertion of one nucleotide. d)substitution of one nucleotide.
a
A mutation in a DNA sequence is likely to have no effect on phenotype if the mutation __________. a)occurs in an intron b)changes a stop codon to a codon specifying an amino acid c)forms a new stop codon d)prevents the initiation of transcription of the DNA sequence that codes for ATP synthase e)substantially changes the structure of an enzyme
d
A particular __________ contains the information for making only one specific polypeptide, but __________ can be used to make any polypeptide. a)mRNA ... a gene b)RNA transcript ... a ribosome c)tRNA ... mRNA d)mRNA ... a ribosome e)mRNA ... an intron
c
A sequence in DNA specifies __________. a)the sequence of fatty acids in a phospholipid b)the sequence of sugars in a polysaccaharide c)the amino acid sequence of a protein
virus
Although generally not considered to be alive, a ______is studied alongside other microbes such as bacteria.
b
Assume a specific virus infects a cell and randomly inserts many short segments of DNA, each containing a stop codon, throughout the organism's chromosomes. This will probably cause __________. a)slower polypeptide assembly b)manufactured proteins to be short and defective c)incorrect pairing between mRNA codons and tRNA anticodons d)no bad effects, as long as the stop codons are not also inserted into tRNA e)the DNA to break up into thousands of short segments
a
Assume that a cell is carrying out its day-to-day activities. At one point, the nucleotides GAT are paired with the nucleotides CUA. This pairing occurred __________. a)during transcription b)during translation c)It is impossible to say, given this information. d)when an mRNA codon paired with a tRNA anticodon e)during replication of DNA
a
During the transcription of a given portion of a DNA molecule, __________. a)mRNA is synthesized on only one of the strands b)mRNA is synthesized from both strands of the DNA molecule, but in different directions c)mRNA is synthesized back and forth across the two strands of a DNA molecule. d)amino acids are assembled into mRNA e)mRNA is synthesized from only one of the DNA strands, which is selected at random
b
During translation, the start codon ___________. a)is UAA, UAG, or UGA, each of which encodes different amino acids b)codes for "start" and the amino acid methionine c)is AUG and does not code for an amino acid d)codes for "start" but not for an amino acid
Deoxyribose sugar
DNA
double stranded
DNA
thymine base
DNA
Nucleotides
DNA and RNA
phosphate
DNA and RNA
4
Extra adenine nucleotides are added to the end of the RNA strand, forming a tail
reverse transcriptase; The process of reverse transcription occurs only in infections by RNA-containing retroviruses like HIV. Cells do not require reverse transcriptase (their RNA molecules do not undergo reverse transcription), so reverse transcriptase can be knocked out without harming the human ho
HIV requires an enzyme called to convert its RNA genome to a DNA version. Why is this enzyme a particularly good target for anti-AIDS drugs?
c
Homeostasis is a living organism's a)ability to pump blood through the body. b)ability to hibernate during cold times of the year. c)ability to maintain constant internal conditions even when environmental conditions change. d)attempt to carry out photosynthesis even when there is no sunlight present. e)attempt to cool off, even when it is cold outside.
a
How do retroviruses, such as HIV, differ from other viruses? a)They contain the enzyme reverse transcriptase. b)They can reproduce only inside living cells. c)They contain DNA that is used as a template to make RNA. d)They have much simpler reproductive cycles than other RNA viruses. e)They contain nucleic acids that code for proteins.
The genetic material of these viruses is RNA, which is replicated inside the infected cell by special enzymes encoded by the virus. The viral genome (or its complement) serves as mRNA for the synthesis of viral proteins.
How do some viruses reproduce without ever having DNA?
c
How do transfer RNAs (tRNAs) bring the correct amino acid to the growing polypeptide? a)By complementary base pairing with the gene in the nucleus b)By base-pairing with the ribosomal RNA (rRNA) c)By complementary base pairing between the tRNA anticodon and the messenger (mRNA) codon d)None of the listed responses is correct.
It recognizes the gene's promoter
How does RNA polymerase "know" where to start transcribing a gene?
by infecting a living cell and directing the cell's molecular machinery to make more viruses.
How does a virus multiply?
When the two strands of the double helix separate, each serves as a template on which nucleotides can be arranged by specific base pairing into new complementary strands.
How does complementary base pairing make DNA replication possible?
e
How many messenger RNA (mRNA) bases make up a codon? a)One b)20 c)This varies, depending on the species. d)Six e)Three
d
Imagine an error occurring during DNA replication, so that where there is supposed to be a T in one of the genes, there is instead a G. What effect might this have on the cell? a)The entire amino acid sequence of this protein will be completely changed. b)An amino acid will be missing from the protein product of this gene. c)Many different proteins will contain an incorrect amino acid. d)There could be an amino acid substitution in the protein product of the affected gene. e)An amino acid will be missing from a variety of different proteins.
d
In DNA, the "backbone" of the double helix is formed by bonds between __________. a)None of the listed responses accurately describes the DNA backbone. b)the nitrogenous base of one nucleotide and the phosphate group of the next c)the nitrogenous base of one nucleotide and the deoxyribose sugar of the next d)the deoxyribose sugar of one nucleotide and the phosphate group of the next
chromosome, gene, codon, nucleotide
List these terms in order of size from largest to smallest: chromosome, codon, gene, nucleotide.
e
Mutations are changes in the sequence of __________. a)mRNA b)None of the listed responses are correct. c)DNA, mRNA, and protein d)protein e)DNA
sugar (deoxyribose), phosphate, nitrogenous base
Name the three parts of every nucleotide.
b
On official documents, you are asked to give your first and last names. Which name is analogous to a genus and which to a species name? a)There is no analogous structure between them. b)First name is analogous to species, last name to genus. c)Both first and last names are analogous to species. d)Both first and last names are analogous to genus. e)First name is analogous to genus, last name to species.
Uracil base
RNA
ribose sugar
RNA
single stranded
RNA
d
RNA polymerase __________. a)synthesizes new DNA strands b)forms part of the ribosome c)brings amino acids to the mRNA d)synthesizes messenger RNAs (mRNAs)
b
Reginald Pisum was exposed to high doses of mutagenic compounds because of a bizarre industrial accident. Should he be concerned about having mutant children? a)No, mutations have never been expressed in humans. b)Yes, if the mutation occurs in gamete-producing cells. c)No, mutations affect only adults. d)Yes, if the mutation affects his liver cells, the children will have mutant livers, too. e)Yes, if the mutation affects the somatic cells.
d
Scientists have discovered how to put together a bacteriophage with the protein coat of phage A and the DNA of phage B. If this composite phage were allowed to infect a bacterium, the phages produced in the cell would have a)the protein of A and the DNA of B. b)the protein of B and the DNA of A. c)the protein and DNA of A. d)the protein and DNA of B.
2
Segments of the RNA strand that do not actually code for the protein are removed
3
Segments of the RNA that do code for the protein are reconnected
a
Successful DNA replication results in __________. a)two double helix molecules, each half parental DNA and half newly synthesized DNA b)two double helix molecules, one all parental DNA and one all newly synthesized DNA c)one double helix molecule that is all newly synthesized DNA d)one double helix molecule that is half parental DNA and half newly synthesized DNA
mRNA
The RNA is then processed--splicing together exons and removing introns--and becomes _____
separates the DNA double helix
The RNA polymerase then ________, and one strand is used to generate a molecule of RNA.
lytic cycle
The ______ is a viral life cycle that results in bursting of the host cell.
lysogenic cycle
The _______ is a viral life cycle in which the virus inserts its genome into the genome of its host, where it may remain dormant for long periods.
step 5
The completed mRNA leaves the nucleus
c
The end of translation occurs when __________. a)RNA polymerase reaches the end of the gene b)the final codon encoding an amino acid is reached c)a stop codon in the mRNA is reached d)a tRNA anticodon attaches to the ribosome
a
The genetic information in DNA is contained in __________. a)the sequence of nucleotides along the length of one strand of the DNA molecule b)the types of sugars used in making the DNA molecule c)the three-dimensional, double-helix structure of the DNA d)the variation in phosphate groups e)the sequence of amino acids that make up the DNA molecule
CAU, GUA
The nucleotide sequence of a DNA codon is GTA. What would be the nucleotide sequence of an mRNA molecule transcribed from this DNA? In the process of protein synthesis, a tRNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodon that corresponds to this mRNA codon?
Phosphate
The sugar of one nucleotide joins with another nucleotide to form a polynucleotide binds with the
RNA polymerase
The transcription process begins with ______ binding to the promoter of a gene.
codon
This 3-base subunit on mRNA enables tRNA to deliver the correct amino acid to the growing polypeptide chain.
RNA polymerase
This enzyme helps to create mRNA using the information in DNA.
Ribosome
This is the "workbench" where the polypeptide chain is made.
tRNA
This molecule has an anticodon that specifies a particular amino acid, which it delivers to the growing polypeptide chain.
b
Viruses are a)alive because they often contain DNA. b)not alive because they are not made of cells and require a host cell for reproduction. c)not alive because they can only carry out photosynthesis and not cellular respiration. d)alive because they mutate and change over time through evolution.
c
Viruses is part of the __________. a)Domain Bacteria b)Kingdom Viridia c)None of the listed responses are correct. d)Domain Archaea e)Kingdom Protista
through lesions caused by injuries, transfer by insects that feed on the plant, and contaminated farming or gardening tools
What are three ways that viruses can get into a plant?
In the mRNA, the reading of the triplets downstream from the deletion is shifted, leading to a long string of incorrect amino acids in the polypeptide.
What happens when one nucleotide is lost from the middle of a gene?
DNA consists of a double helix of polynucleotides.
What is the structure of DNA?
mRNA transcribed from the mutated gene would be nonfunctional because ribosomes would not initiate translation.
What would happen if a mutation changed a start codon to some other codon?
b
Which of the following can be found in bacteria, but not viruses? a)nucleic acids b)a cell membrane c)genetic material d)proteins
a
Which of the following pairs of terms represents an incorrect match? a)rRNA—anticodon b)mRNA—codon c)DNA—code d)rRNA—ribosome e)tRNA—anticodon
e
Which one of the following is uniquely associated with RNA? a)existence of a double-stranded molecule b)deoxyribose c)hydrogen bonding between the two nucleotide strands d)existence of two different types of RNA with two different functions e)uracil
e
Which one of the following statements about double-stranded DNA is true? a)It contains disulfide bonds. b)It is a nonhelical, linear molecule. c)The strands are parallel and are synthesized in the same direction. d)Adenine and uracil are present in equal amounts. e)The two strands are complementary.
a
Which one of the following statements correctly describes mRNA processing in eukaryotes? a)Introns are cut out, and the resulting exons are spliced together. b)Introns are cut out and transported to the ribosomes. c)Exons are cut out, and the introns are spliced together. d)Exons are cut out and transported to smooth endoplasmic reticulum. e)Introns are cut out and spliced together at the end of the mRNA.
c
Which role do ribosomes play in protein synthesis? a)Ribosomes function in transcription. b)Ribosomes provide a source of amino acids. c)Ribosomes provide a site for tRNA to bind to mRNA. d)Ribosomes translate DNA code to RNA code.
It is the only molecule that produces more DNA (that keeps one copy and passes the other along) and it can direct the production of proteins.
Why is DNA so important?
because introns are removed from the RNA
Why is a final mRNA often shorter than the DNA gene that coded for it?
because herpesvirus leaves viral DNA in the nuclei of nerve cells
Why is infection by herpesvirus permanent?
c
You discover a mutation in the protein-coding sequence of a gene that does not change the amino acid sequence. This makes sense because __________. a)mutations affect DNA only, not proteins b)it could be a frameshift mutation c)there is redundancy in the genetic code d)every amino acid is encoded by a single, unique codon
1
a modified guanine nucleotide is added to the beginning of the RNA strand as a cap.
sugar and phosphate
are the same for all DNA nucleotides.
leading strand
formed in one piece
cytoplasm
mRNA exits the nucleus via a nuclear pore. In the _____, the mRNA is used as instructions for generating a protein.
b
which one of the following statements is true? a)It takes three genes to code for one protein. b)Each amino acid in a protein is coded for by three bases in the DNA. c)Each gene codes for three proteins. d)Each DNA base codes for three amino acids. e)Each triplet of bases can mean different things.
