Bio chapter 10

A gene is usually______.

the information for making a polypeptide

What is the source of the membranous envelope in viruses such as the mumps virus?

the plasma membrane, which covers the virus as it leaves the host cell.

Why do we usually recover completely from a cold, but rarely recover completely from polio?

The cells of the respiratory tract undergo mitosis, whereas mature nerve cells do not divide.

Translation of mRNA begins when which of the following occurs? a) An initiator tRNA that carries methionine base-pairs with the mRNA start codon on a small ribosomal subunit b) mRNA and tRNA move together along the ribosome as new amino acids are added to the growing polypeptide chain c) New peptide bonds are formed as amino acids are added to the growing chain d) An initiator mRNA that carries methionine base-pairs with the tRNA start codon on a large ribosomal subunit e) An initiator tRNA that carries the codon for methionine base-pairs with its complementary mRNA anticodon

a) An initiator tRNA that carries methionine base-pairs with the mRNA start codon on a small ribosomal subunit.

Each molecule of DNA or RNA has a backbone consisting of two molecules, ________. The third component is ______.

a sugar and a phosphate group: a nitrogenous base

The frequency with which we need a vaccination against Disease X depends partly on ________.

how quickly the virus mutates

Retroviruses use an enzyme called _______ to synthesize _____.

reverse transcriptase: DNA

In translation, four nucleotides specify ____ amino acids, but there are _____ possible codons. What is the consequence of this?

20: 64: Some amino acids can be specified by more than one codon.

________ marks the end of a gene and causes transcription to stop

A terminator

The base sequence of the anticodon on tRNA that corresponds to the sequence AGT on DNA is ______.

AGU

What was the most important result of the studies of heritability using bacteriophages that were conducted by Hershey and Chase in the 1950s?

DNA, not protein, is the molecule of heredity

Why is the replication of DNA called "semiconservative"?

Each new DNA molecule has one newly synthesized strand and one parental strand.

Uses each strand of a DNA molecule as a template for the creation of a new strand

DNA replication

The three RNA codons UAA, UGA, and UAG have a special function. What is it?

They are stop codons that end translation of a gene

During translation, the start codon on mRNA is AUG. The anticodon is _____ on _____.

UAC: tRNA

A virus emerged recently that is transmitted by mosquitoes from one victim to the next, causing brain inflammation. It is the _____ virus.

West Nile

Which of the following statements about eukaryotic RNA is true? a) Exons are spliced together b) Introns are not transcribed from DNA to RNA c) The modified RNA molecule is transported into the nucleus d) A small cap of extra nucleotides is added to both ends of the RNA

a) Exons are spliced together

All of the following events EXCEPT ONE occur in the interval between mRNA transcription and the exit of mRNA from the nucleus for translation. Which event occurs outside of this interval? a) Start and stop codons on mRNA are read b) Introns are removed from the mRNA transcript c) Exons are spliced together d) RNA splicing occurs to produce continuous coding regions e) A cap and tail are added to the mRNA molecule

a) Start and stop codons on mRNA are read

Which of the following is an INCORRECT statement about genetic mutations? a) Substitution mutations usually result in dysfunctional proteins b) Missense mutations result in one amino acid changing to another c) A mutation is any change in the genetic information of a cell or virus d) Nonsense mutations change an amino acid codon into a stop codon e) Frameshift mutations result from the insertion or deletion of a nucleotide

a) Substitution mutations usually result in dysfunctional proteins

Which of the following is an INCORRECT match between a disease that affects humans and the genetic material in the virus that causes it? a) mumps: DNA b) cold sores: DNA c) measles: RNA d) AIDS: RNA e) hepatitis: DNA

a) mumps: DNA

Considering only the steps that take place during translation, which of the following is not needed in order for translation to occur? a) sources of energy, including ATP b) DNA template c) tRNA d) ribosomes

b) DNA termplate

If words were amino acids... which of the following choices would illustrate a silent mutation of the "wild-type" sentence: "Please drive Priscilla home after her ballet lesson"? a) Please drive Ellen home after her ballet lesson b) Please take Priscilla home in the car after her dance class c) Please bring Priscilla... d) Bricks red dogs hunger carries Priscilla bike e) Please take Fred to New York after breakfast

b) Please take Priscilla home in the car after her dance class

Which of the following is the correct sequence of bases on the mRNA molecule that is transcribed from this DNA strand: TAC TTC AAA ATC? a) UAC UUC AAA AUC b) TAC TTC AAA ATC c) AUG AAG UUU UAG d) ATG AAG TTT TAG e) TAC TTC AAA ATC

c) AUG AAG UUU UAG

Which of the following is an INCORRECT match between a disease and the pathogen that causes the disease? a) scrapie: prion b) AIDS: human immunodeficiency virus c) kuru: herpesvirus d) hemorrhagic fever: Ebola virus e) mumps: RNA virus

c) kuru: herpesvirus

Which of the following does not fit into the "one gene-one enzyme" hypothesis of Beadle and Tatum? This work won them the Nobel Prize in Chemistry in 1958. a) Each mutation in the bread mold Neurospora crassa was traceable to a single gene b) Genes are made of double-stranded DNA c) Enzymes catalyze specific chemical reactions d) Genes produce proteins such as keratin and insulin e)Each step in a metabolic pathway is catalyzed by a specific enzyme

d) Genes produce proteins such as keratin and insulin

All of the following statements about the structure of the DNA molecule are correct except one. Which one? a) The same bases cannot bond with each other b) C-G forms three hydrogen bonds, while A-T forms two hydrogen bonds c) Each gene has a unique order of nucleotides d) Purines bond with purines, and pyrimidines bond with pyrimidines e) The phosphate-sugar "backbones" are oriented in opposite directions

d) Purines bond with purines, and pyrimidines bond with pyrimidines.

Which of the following are implicated in the development of antibiotic resistance? a) F plasmids b) phages c) retroviruses d) R plasmids e) prophages

d) R plasmids

Which of the following statements regarding a DNA double helix is true? a) The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine b) The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine c) The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine d) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine

d) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine

Which of the following characterizes a lysogenic, but not a lytic, viral reproductive cycle? a) Once the phage has entered the cell, most of its genes become active b) The host cell soon releases new viruses when it lyses c) Once the phage has entered the cell, its DNA assumes a circular form d) The prophage can remain in the bacterial chromosome indefinitely e) Phage DNA is injected into a bacterial cell

d) The prophage can remain in the bacterial chromosome indefinitely

Which of the following statements is false? a) During polypeptide initiation, an mRNA molecule, the first amino acid attached to its tRNA, and the two subunits of a ribosome are brought together b) Translation consists of initiation, elongation, and termination c) During the first step of initiation, an mRNA molecule binds to a small ribosomal subunit d) The start codon can be different depending on what kind of protein is to be translated

d) The start codon can be different depending on what kind of protein is to be translated

Which of the following is a function of a tRNA molecule? a) recognizing the appropriate anticodons in mRNA b) transferring nucleotides to rRNA c) helping to translate codons into nucleic acids d) joining to only one specific type of amino acid

d) joining to only one specific type of amino acid

Which of the following best describes transduction between bacteria? a) DNA from the environment is taken up by a bacterium b) One bacterium engulfs another, adding new DNA to its own genome c) One bacterium engulfs another, adding new DNA to its own genome d) A bacterium infects a virus and incorporates the viral DNA into its own DNA e) A phage injects a piece of bacterial DNA into another bacterium

e) A phage injects a piece of bacterial DNA into another bacterium

Which of the following statements about tRNA is incorrect? a) tRNA moves from the ribosome's A site to its P site during translation b) tRNA contains uracil (U) instead of thymine (T) c) tRNA has attachment sites for an anticodon and an amino acid d) Initiator tRNA carries the amino acid methionine e) The enzyme transferase joins each amino acid to its correct tRNA

e) The enzyme transferase joins each amino acid to its correct tRNA

In DNA replication, one strand is synthesized in a single continuous piece by an enzyme that works _____ the replication fork. The other strand is composed of Okazaki fragments that are linked into a single strand by an enzyme called ______.

toward: DNA ligase

HIV does the greatest damage to

white blood cells