CH 10 Mastering Biology

How can bacteriophage DNA be spread from cell to cell without causing cell death?

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Early geneticists wondered how only four nucleotides can specify the sequence of 20 amino acids in proteins. They hypothesized that there must be a code that linked the nucleotide sequence in a gene to the amino acid sequence in a protein. Each nucleotide code is called a codon. Today we know that there is a genetic code in which __________nucleotide(s) code(s) for each amino acid. 3 4 1 2

3. The number of possible 3-letter codes is 43 or 64. This is more than the number of amino acids. Thus, the code can be redundant. In some cases, there is more than one codon that codes for the same amino acid.

Which one of the following choices is true of tRNA? tRNAs carry special sequences known as codons. Each tRNA binds a specific amino acid. There are four types of tRNA. tRNAs are extremely small molecules.

Each tRNA binds a specific amino acid. A tRNA with a particular codon will bind to a specific amino acid and transfer it to the ribosome for insertion into the new polypeptide.

How would you test to see whether a particular influenza vaccine protects elderly people from influenza ?

Follow tens of thousands of people over the age of 65 during flu seasons and record illnesses and vaccination status. This would be the "experimental" part of the scientific method.

Which of the following processes occurs in the cytoplasm of a eukaryotic cell? translation RNA processing, including adding a cap and a tail DNA replication transcription

Translation. Translation takes place at ribosomes, which are found in the cytoplasm.

Viruses are lifelike structures that have characteristics of living cells with the exception of __________. nucleic acid transcription nucleic acid to transmit viral characteristics a requirement for a host cell for replication structural proteins

a requirement for a host cell for replication. Viruses are unable to reproduce unless they can get their nucleic acid into a host cell.

*The characteristic of the human immunodeficiency virus (HIV) that makes it different from other RNA viruses is that it __________. inserts into the DNA of the host can synthesize DNA from an RNA template can synthesize mRNA from a double-stranded DNA template. causes hepatitis

can synthesize DNA from an RNA template. HIV produces an enzyme called reverse transcriptase, which catalyzes reverse transcription.

Which of the following is an animal virus? T4 virus tobacco mosaic virus chicken pox virus lambda virus

chicken pox virus. Chicken pox is a human virus that causes a childhood disease.

Beadle and Tatum discovered that each mutant mold they observed lacked a specific enzyme. As a result, they concluded that __________. genes carry information for making proteins cells need specific enzymes to function genes are made of DNA mutations are changes in genetic information

genes carry information for making proteins, From their experiments with Neurospora crassa, they developed the one gene-one enzyme hypothesis.

The most important aspect of Watson and Crick's discovery of the structure of DNA was that it __________.

helped explain how cells divide to form identical daughter cells (It explained a copying mechanism for our genetic material.)

*The influenza virus, a deadly infectious agent found around the world, is composed of _____ and _____. RNA ... protein nucleic acid ... RNA DNA ... protein DNA ... RNA

RNA ... protein (The influenza virus contains RNA surrounded by a protein coat.)

*How does RNA polymerase know where to start transcribing a gene into mRNA? The ribosome directs it to the correct portion of the DNA molecule. Transfer RNA acts to translate the message to RNA polymerase. RNA polymerase starts when the enzyme attaches to a certain nucleotide sequence called a promoter at the beginning of a gene. It starts at one end of the chromosome.

RNA polymerase starts when the enzyme attaches to a certain nucleotide sequence called a promoter at the beginning of a gene. RNA polymerase binds to a gene's promoter to initiate mRNA synthesis.

Most plant viruses have _____ as their genetic material.

RNA. RNA is the genetic material of most of the plant viruses discovered to date.

Which of the following is an accurate statement about the T4 bacteriophage that infects E. coli? The T4 bacteriophage reproduces through a cycle called the lytic cycle. Both the T4 and lambda bacteriophages contain RNA and are called RNA viruses. The T4 bacteriophage injects its DNA into an E. coli cell, where the DNA becomes known as a prophage. In the lytic cycle of bacteriophage replication, the bacteriophage inserts its DNA into the bacterial chromosome.

The T4 bacteriophage reproduces through a cycle called the lytic cycle. After producing many copies of the bacteriophage, the bacterium lyses, releasing mature bacteriophages.

What name is given to the collection of traits exhibited by an organism? morphology genotype holotype phenotype

phenotype

The modern phrasing of Beadle and Tatum's hypothesis about relationships between genes and their products is "one gene-one ______." RNA polypeptide enzyme protein

polypeptide

*The anticodon of an incoming _____ molecule, carrying its amino acid, pairs with the mRNA _____ at the ribosome. tRNA ... phosphates ribosome ... protein amino acid ... structure tRNA ... codon

tRNA ... codon. The codon-anticodon interaction positions an amino acid in the correct location in the growing polypeptide.

Mad cow disease is caused by

infectious proteins called prions.

The deadliest infectious disease outbreak of all time happened over an 18-month period in 1918-1919. What disease caused this outbreak?

influenza

*Which of the following are the three phases of translation? addition of cap and tail, removal of exons, and RNA splicing activation, chain growth, and completion initiation, elongation, and completion initiation, elongation, and termination

initiation, elongation, and termination. These terms apply to both transcription and translation.

After an RNA molecule is transcribed from a eukaryotic gene, portions called _____ are removed and the remaining _____ are spliced together to produce an mRNA molecule with a continuous coding sequence. introns ... exons caps ... tails codons ... anticodons promoters ... terminators

introns ... exons. Introns, intervening or noncoding sequences, are removed, and the exons, the expressed sequences, are spliced together.

DNA and RNA are polymers composed of ______ monomers. nucleotide carbohydrate amino acid fatty acid

nucleotide

One strand of DNA serves as a template for the synthesis of another so that __________. the helical shape of DNA is conserved there are two copies of each gene on a single DNA molecule DNA can serve as a template for the synthesis of other polymers the progeny of each cellular replication gets the same genetic information

the progeny of each cellular replication gets the same genetic information. After the double-stranded DNA molecule splits into two strands, each serves as a template for the synthesis of a complementary strand.

What do DNA and RNA have in common? Both are composed of nucleotides. They are composed of the same nucleotides. Both contain deoxyribose. Both form double helices.

Both are composed of nucleotides. Both molecules are polymers built from nucleotide monomers.

The information carried by a DNA molecule is in __________. the sugars and phosphates forming its backbone its amino acid sequence the total number of nucleotides it contains the order of the nucleotides in the molecule

the order of the nucleotides in the molecule. Genetic information resides in the order of the nucleotides on a DNA molecule.