Chapter 8 - Multiple Choice Questions

what are the three binding sites of the functional ribosomal unit

1. E site "EXIT site", where empty tRNA are released 2. P site -PEPTIDYL site, where peptide chain elongates; tRNA amino acids can bind here as well-only the tRNA with fMET amino acid 3. A site- "acceptor" site, where tRNA amino acids with correct anitcodon bind to mRNA

What are 2 types of Transposable Elements?

1. Insertion Sequence 2. Transposon-can carry antibiotic resistant genes.

What repair methods are there for mutations?

1. mismatch repair 2. Excision repair

What are categories and results of POINT MUTATIONS?

Base Pair Substition, Base pair deletion & addition

ONLY one codon specifies a specific amino acid TRUE OR FALSE

False MORE THAN ONE CODON specifies for a specific amino acid

Central dogma

Identifies the genetic flow of information DNA-->RNA-->PROTEIN

What Plating technique helps identify auxotrophs that fail to grow on a medium lacking histidine?

Negative selection-detect mutant cells that DO NOT grow

SPONTANEOUS MUTATIONS

OCCURS IN ABSENCE OF MUTAGEN

Bacterial conjugation involves:

a donor cell with a plasmid and a pilus

Where does DNA replication begin?

at the sequence of nucleotides called the ORIGIN OF REPLICATION

Which of the two mutation happens more often: a. Spontaneous Mutation b. Mutations caused by Mutagens

b. Mutagen mutations

Translation-Chain initiation begins with : a. 30s ribosomal unit b.50s ribosomal unit c. mRNA with start code of AUG d. tRNA with anti code (UAC)-fMET e. ONLY A, C, D initiate the translation

E. only a, c, & d initiate the translation. 30s ribosomal unit, mRNA with AUG start code, and initiator tRNA at the AUG start codon to initiate translation the 50s ribosomal subunit then attaches to form functional 70S ribosomal unit with 3 binding sites

What essential protein is needed to form the cross septum at the center of the cell and not at the ends during binary fission?

FtsZ Protein

What is the "start codon" and "stop" codon in Translation phase

Start codon: AUG (think of school starting in august) which normally specifies the amino acid MET-methionine, in prokaryotes AUG codes for fMET STOP codon: UGA, UAG, UAA- three codons that do not code for amino acids

Genetics

Study of Genes, what they are, how they carry info, how info is expressed and how they are replicated

Genomics

Study of genetic make up of a cell, species or organism

DNA Polymerase III can only add a nucleotide to the 3' prime end of a pre-existing chain of nucleotides and CANNOT initiate a nucleotide chain TRUE OR FALSE?

TRUE

Transposable Elements can also cause mutations where segments of one DNA can move from one DNA site and integrate into another site in the same DNA molecule. They ARE ALSO REFERRED TO AS "jumping genes" TRUE OR FALSE?

TRUE

Length of DNA containing genes. The cells intracellular source of genetic information

chromosome

DNA compaction involves ________. a. a twisting and packing of the DNA b. Supercoiling c. The formation of looped domains d. All of the above

d. all of the above

Spontaneous mutations could arise from ______. a. DNA replication errors b. atmospheric radiation c. addition of insertion sequences d. All of the above

d. all of the above

Which of the following are examples of repair mechanisms in cells? a. mismatch repair b. excision repair c. DNA polymerase d. DNA ligase e. all are important in fixing mutations

e. all are important in fixing mutations

What results in the following base pair substitution in 1. Silent Mutation 2. Missense Mutation 3. Nonsense Mutation

1. Silent Mutation-nucleotide changes, but no change in resulting amino acid 2. Missense Mutation-Nucleotide base change, resulting amino acid changes thereby changing the protein that's needed 3. Nonsense Mutation-Nucleotide base change, resulting in a "stop" codon early and protein synthesis cannot occur.

MUTAGEN

AGENT CAUSING MUTATION

Genome

ALL DNA found in an organism In a Cell:DNA In virus: DNA or RNA

F PLASMIDS

Allow for the transfer of genetic material from donor to recipient through RECOMBINANT PROCESS

If the DNA sequence is ATTCCGGA, the mRNA Transcript would be: a. TAAGGCCT b. UAAGGCCU c. attccgga d. GUUAATTG

B. UAAGGCCU

The RNA molecules that carry amino acids to the ribosomes during protein synthesis are called: a. Ribosomal RNA b. Messanger RNA c. transfer RNA d. primer RNA

C. tRNA or Transfer RNA

MUTATION

CHANGE IN GENETIC MATERIAL in DNA the result would be the production of a miscoded mRNA-ALTER PROTEINS or amino acids

TRANSCRIPTION

COPIES GENETIC INFO FROM DNA Gene DNA serves as a template for new mRNA molecules

In all cells genes are composed of

DNA

The duplication of a cell's DNA is called

Replication

Genes

Segments of DNA, which code for proteins. DNA Segment that is a unit of heredity

How can protein synthesis be regulated?

The regulatory gene can encode a repressor protein that binds to the "operator" thereby preventing the transcription of the structural genes by the RNA Polymerase (bound to Promoter)-NEGATIVE CONTROL if an inducer is used to change SHAPE of repressor, RNA Polymerase is no longer blocked and protein synthesis continues antibiotics can be used to inhibit protein synthesis

What type of mutagen is UV Light categorized under and what type of mutation does it cause?

UV Light is a physical mutagen It causes THYMINE bases in the DNA to covalently link together forming DIMERS

What plating technique can be used to identify antibiotic resistant mutants? a. Positive (Direct) selection b. Negative (indirect) selection c. both a & b

a. Positive selection-detects mutant cells that grow or appear different tested with two plates, one with antibiotics and the without. All colonies should grow in a complete medium where only mutants will grow in a medium with antibiotics

Which of the following codons would terminate translation? a. AUG b. UUU c. UAA d. UGG

a. UAA

Ribosomes match up the ______ of the mRNA and the ______ of the tRNAs. a. codons; anticodons b. introns; exons c. anticodons; codons d. genes; anticodons

a. codons; anticodons

Which of the following is NOT part of an operon? a. regulatory gene b. operator c. promoter d. structural genes

a. regulatory gene

Nucleotide excision repair would correct DNA damage caused by _______. a. antibiotics b. UV light c. transcription d. a DNA replication error

b. UV light

Which of the following are examples of mutagens? a. detergent b. UV light c. fertilizer d. none of the above are correct

b. UV light

In all cells a gene is a segment of DNA that specifies : A. rRNA B. A PROTEIN C. A tRNA D. A LIPID

b. a protein

Plasmids are _______. a. another name for transposons b. accessory genetic information c. domains within a chromosome d. daughter chromosomes

b. accessory genetic information

A heritable change in DNA is called a ______. a. mistake b. mutation c. gene d. pathogen

b. mutation

In the semiconservative method of replication a. both parent strands are degraded. b. one parent strand is conserved in each of the the new DNA. c. both parent strands reform with one another. d. Okazaki fragments form both of the new molecules of DNA.

b. one parent strand is conserved in each of the the new DNA.

In bacteria a group of genes located together and functioning together on a chromosome are called _____. a. polysome b. operon c. polymerase d. exons

b. operon

Nutritional mutants are referred to as _______. a. phototrophs b. wild type c. revertants d. auxotrophs

d. auxotrophs

What happens at the ribosome in the production of a protein? a. mRNA brings the codon b. tRNA brings the anticodon c. the amino acids are linked by polypeptide bonds d. translation e. all the above

e. all the above

PLASMIDS

most are double stranded DNA, though a few are not

TRANSLATION

process of making the polypeptide at the ribosome 1. Chain initiation 2. Chain Elongation 3. Chain Termination/release

What results in Base pair deletion/insertion?

resulting in an inappropriate number of bases which can cause a "frame shift". This can result in producing an abnormal protein (nonsense) unable to carry out its role in metabolism

What repair method can be used for thymine dimer-thymine to thymine link?

Light repair Excision repair an enzyme cuts (excise) out and removes damaged dna, DNA Polymerase fills gap by synthesizing new DNA using the other undamaged strand as a template. DNA Ligase then seals or splices old and new DNA

POINT MUTATIONS

Most common type of mutation where one base pair is affected in a gene and CHANGES THE GENETIC EXPRESSION OR PROTEIN PRODUCTION 1. base pair substitution: produces silent, missense or nonsense mutation 2. Base pair Deletion/Insertion: causes a FRAME SHIFT in the ribosome

What enzyme initiates and carries out Transcription? Where does it start?

RNA Polymerase initiates transcription and starts at a promoter

The deliberate removal of genetic material from one organism and combining it with the genetic material of another organism is a specific technique called: a. genetic engineering b. biotechnology c. recombinant DNA d. gel electrophoresis

a. genetic engineering

The Ames test is used to _______. a. identify potential human carcinogens b. discover auxotrophic mutants c. find pathogenic bacterial species d. identify antibiotic resistant mutants

a. identify potential human carcinogens

In a eukaryotic microbe, those sections of a primary RNA transcript that will NOT be translated are called _____. a. introns b. anticodons c. "jumping genes" d. exons

a. introns

Transposons are of particular significance because they a. often contain genes for antibiotic resistance. b. inhibit the effects of overlapping genes. c. come in pairs and often are associated with viruses. d. regulate gene transcription in bacterial cells.

a. often contain genes for antibiotic resistance.

Multiple ribosomes working together on one mRNA are called ______. a. polysomes b. multisomes c. polymerases d. A-C are correct

a. polysomes

The translation of a mRNA by multiple ribosomes is called _______ formation. a. Okazaki b. polysome c. plasmid d. transposon

b. polysome

What is the process called of making a mRNA copy of DNA? a. translation. b. transcription. c. transposon d. transformation

b. transcription

Which one of the following could NOT cause a change in the mRNA "reading frame"? a. Insertion sequence b. base-pair substitution c. base addition d. base deletion

c & d

The enzyme ______ adds complementary bases to the DNA template strand during replication. a. ligase b. helicase c. DNA polymerase III d. RNA polymerase

c. DNA polymerase III It is the major enzyme involved in DNA Replication

Which one of the following statements is true? a. Plasmids are circular molecules of RNA. b. RNA replicates by a conservative method of replication. c. Deletions or insertions of a nucleotide in a gene will cause a reading frameshift during translation. d. Okazaki fragments are removed from a RNA before translation occurs.

c. Deletions or insertions of a nucleotide in a gene will cause a reading frameshift during translation.

what enzyme unwinds the DNA strand during DNA Replication a. DNA Polymerase III b. DNA Polymerase I c. Helicase

c. Helicase

Which one of the following statement is NOT true of the bacterial chromosome? a. It is located in the nucleoid b. It usually is a singular circular molecule c. Some genes are dominant to others d. It usually is haploid

c. Some genes are dominant to others

Being compartmentalized, bacterial RNA polymerases are localized in the ______ and ribosomes are found ______. a. nucleoid; at the nucleoid periphery b. cytosol; in the cytosol c. cytosol; at the cell poles d. nucleoid, in the nucleoid

c. cytosol; at the cell poles

Why is DNA replication considered semiconservative? a. none of the materials are wasted b. it is a very efficient process c. half of the new DNA molecule is half of the original molecule d. none of the above are correct

c. half of the new DNA molecule is half of the original molecule

If an antibiotic binds to a 50S subunit, which cellular process will be inhibited? a. DNA replication b. intron excision c. translation d. transcription

c. translation

A ______ can move a part of DNA to another place on the chromosome. a. translation. b. transferon c. transposon d. transition e. transcription

c. transposon

What is a difference between prokaryotic and eukaryotic cells in making protein. a. Eukayotes have introns that stay inside the nucleus b. Prokaryotes can transcribe and translate at the same time c. the process is faster in prokaryotes d. A-C are correct

d. A-C are correct

Which one of the following is common between prokaryotic and eukaryotic chromosomes? a. Presence or absence of introns. b. Loop or linear chromosomes. c. Genetic recombination occurrence in RNA. d. Mutations occur in the DNA.

d. Mutations occur in the DNA.

At a chromosome replication fork, the lagging strand consists of _____ that are joined by _____. a. RNA sequences; DNA ligase b. Okazaki fragments; RNA polymerase c. RNA sequences; robosomes d. Okazaki fragments; DNA ligase

d. Okazaki fragments; DNA ligase

Which one of the following statements is not true of RNA? a. RNA contains the monosaccharide ribose. b. RNA is primarily a single-stranded molecule. c. RNA has a sugar-phosphate backbone. d. RNA contains five different nucleotides.

d. RNA contains five different nucleotides.

Transposons ______. a. were first discovered by Warson and Crick b. are smaller than insertion sequences c. are examples of plasmids d. may have information for antibiotic resistance

d. may have information for antibiotic resistance

The development of virulent, toxin-producing bacterial strains due to the presence of a temperate phage can occur in : a. bacterial conjugation b. transformation c. translation d. transduction

d. transduction