Microbiology Chapter 7

The phrase "one gene-one enzyme" is associated with the work of Lederberg. Watson and Crick. Beadle and Tatum. Mendel.

The two strands of DNA are bonded to one another by covalent bonds. oxygen bonds. hydrogen bonds. carbon bonds.

What structure is indicated by: 10A, 15T, 3G, 7C? double-stranded RNA double-stranded DNA single-stranded RNA single-stranded DNA

GCCCAAAG is a molecule of RNA. DNA. protein. cannot tell as written.

RNA is characterized by which one of the following features? Deoxyribose. Thymine. Ribose. Double-stranded.

DNA is characterized by which of the following feature(s)? Ribose. Single-stranded. Deoxyribose. Thymine. Deoxyribose AND thymine.

Which is not true of RNA? It is usually single-stranded. It functions in the cytoplasm. It contains uracil. It contains ribose. There are 4 functional types.

The 3' end of DNA refers to the end that has a hydroxyl group attached to the number 3 carbon of deoxyribose. attaches to the 5' phosphate group of the incoming nucleotide. always has thymine attached to it. usually has guanine attached to it. refers to the end that has a hydroxyl group attached to the number 3 carbon of deoxyribose AND attaches to the 5' phosphate group of the incoming nucleotide.

Which of the following is/are true of DNA replication? It starts at the origin of replication. Nucleotides are added to the 3' end. It requires an RNA primer to get started. It utilizes polymerases. All of the choices are true.

DNA replication is conservative. interspersive. semiconservative. chain reference.

Which is true about DNA replication? It is semiconservative. It starts at an origin of replication. It is bi-directional. It requires RNA primers. All of the choices are correct.

The term antiparallel refers to the structure of single-stranded RNA. is synonymous with semiconservative. refers to the opposite orientation of the two strands in DNA. refers to a type of prokaryotic replication.

The lagging strand is the third type of RNA. is found during RNA replication. is necessary due to the properties of the enzymes and the antiparallel nature of DNA. is always the bottom strand.

Which is true about the RNA transcript? It is formed using the DNA minus strand as a template. It has the same 5'-3' orientation as the DNA positive strand. It is made in short fragments that are then stitched together. The template starts at the promoter region. It is formed using the DNA minus strand as a template, it has the same 5'-3' orientation as the DNA positive strand AND the template starts at the promoter region.

Which is true about prokaryotic (bacterial) RNA polymerase? It is used during transcription. It does not require a primer. It has a detachable subunit, sigma factor, which recognizes the promoter. It reads the template in the 3'-5' direction. All of the choices are true.

The specific sequence of nucleotides in the DNA to which the RNA polymerase binds is the regulatory region. promoter region. sigma region. core region.

The transcription terminator results in a hairpin loop structure in RNA. results in the polymerase falling off the DNA template. stops DNA polymerase. adds a terminator nucleotide to the RNA. results in a hairpin loop structure in RNA AND results in the polymerase falling off the DNA template.

How many nucleotides are in a codon? 1 2 3 4 5

There are _____ codons to code for the 20 possible amino acids. 20 30 64 61

The genetic code has more than one codon for some amino acids. This is an example of evolution. stringency. degeneracy. translation.

Which may be or is an RNA molecule? AGCCTAC GGGCCCA GCCCUUA AGCCTAC AND GGGCCCA GGGCCCA AND GCCCUUA

Which molecule carries an anticodon? DNA mRNA rRNA tRNA

AUG is only used as the start codon. codes for methionine. determines the reading frame. is one of the stop codons. codes for methionine AND determines the reading frame.

The amino acid that is placed first during translation in bacteria, mitochondria, and chloroplasts is glycine. methionine. N-formyl-methionine. serine.

The placement of the amino acid during translation is determined by the DNAse which transcribes both molecules. complementarity of the codon-anticodon. sequence of nucleotides at the 5' end of the tRNA. secondary structure of the newly forming protein.

What is the number of tRNA molecules that may be associated with translation? more than 100 75 64 less than 64

The P-site is found on the polymerase enzyme. is an allosteric site. is a promoter site. is the peptidyl site on the ribosome. is an allosteric site AND is a promoter site.

The A-site is found on the RNA polymerase enzyme. is found on the 30S ribosome. is found on the 70S ribosome. is the amino acid site. is found on the 70S ribosome AND is the amino acid site.

The E-site is found on the RNA polymerase enzyme. is responsible for the release of the tRNA. is found on the 35S polysome. is the eminoacyl site. is responsible for the release of the tRNA AND is the eminoacyl site.

A stop codon codes for the stop amino acid s-methyl-methionine. forms a hairpin loop forcing the ribosome to fall off. codes for no amino acid. enhances the binding of the e-polymerase. codes for the stop amino acid s-methyl-methionine AND forms a hairpin loop forcing the ribosome to fall off.

Post-translational modification may include formation of exons and introns. folding of the protein, often with the aid of chaperones. removal of the signal sequence. addition of glycine tags. folding of the protein, often with the aid of chaperones AND removal of the signal sequence.

The ribosomes move along the tRNA in a 3'-5' direction. move along the mRNA in a 5'-3' direction. move along the DNA in a 5'-3' direction. provide a platform which brings the amino acids into a favorable position for joining. move along the mRNA in a 5'-3' direction AND provide a platform which brings the amino acids into a favorable position for joining.

Some segments of the precursor mRNA in eukaryotes are non-coding and are called exons. introns. integrans. uselessans.

"Junk DNA" are also called introns. are also called exons. may have regulatory roles. have no known function. are also called exons AND have no known function. are also called introns AND may have regulatory roles.

Ribozymes are complexes of ribosomes and RNA. are self-catalytic RNA. suggest that nucleic acids evolved before proteins. are enzymes that degrade RNA and therefore have potential for clinical applications. are self-catalytic RNA AND suggest that nucleic acids evolved before proteins.

The scientists responsible for the idea that RNA can act as a catalyst were Watson and Crick. Beadle and Tatum. Altman and Cech. Lederberg and Stanley.

Gene regulation may entail turning on genes only when needed. turning off genes when not needed. turning on or off entire groups of genes. All of the choices are correct.

The regulatory protein binds to the promoter region of DNA. may inhibit or enhance transcription. may control translation of the operon. affects the activity of the DNA polymerase. binds to the promoter region of DNA AND affects the activity of the DNA polymerase.

Operon(s) in bacteria refers to a group of genes that are coordinately controlled. involve polycistronic mRNA. involve monocistronic mRNA. are also known as Wagnerons. refers to a group of genes that are coordinately controlled AND involve polycistronic mRNA.

The set of genes in bacteria that are linked together and transcribed as a single unit is referred to as a(n) operon. regulon. operator. repressor.

The DNA site to which the repressor protein binds is the operon. regulon. operator. repressor.

The molecules that bind to a repressor and cause it to no longer bind to the operator are called activators. repressors. introns. inducers.

Repressors are involved in negative control. are involved in positive control. always bind to the promoter. bind or do not bind to the operator depending on their shape (conformation). are involved in negative control AND bind or do not bind to the operator depending on their shape (conformation).

Activators are involved in negative control. are involved in positive control. always bind to the promoter. are allosteric proteins. are involved in positive control AND are allosteric proteins.

Negative control means a regulator molecule is bound and transcription starts. removed and transcription is inhibited. bound and transcription is inhibited. removed and transcription starts. bound and transcription is inhibited AND removed and transcription starts.

Glucose is preferentially used over lactose in E. coli as a result of catabolite repression. levels are directly sensed via catabolite repression. levels are the inverse of cAMP levels. levels directly affect the production of lactose dehydrogenase. is preferentially used over lactose in E. coli as a result of catabolite repression AND levels are the inverse of cAMP levels.

The lac operon is an example of negative control. is affected by catabolite repression. produces lactose. is an example of a regulon. is an example of negative control AND is affected by catabolite repression.

CAP is involved in positive control. stands for cyclic amp protein. works in conjunction with cAMP. is involved in negative control. is involved in positive control AND works in conjunction with cAMP.

RNAi is the form of mRNA that initiates translation. uses short pieces of single stranded RNA to direct the degradation of specific RNA transcripts. is a mechanism of genetic regulation found in eukaryotes. is any chemical that inhibits transcription. uses short pieces of single stranded RNA to direct the degradation of specific RNA transcripts AND is a mechanism of genetic regulation found in eukaryotes.

Signal transduction is the relay of information about conditions outside a cell to inside the cell. often relies on a two component system. may involve phosphorylation of various molecules. is used by certain pathogens to sense low magnesium conditions. All of the choices are correct.

Quorum sensing is used by bacteria to sense the density of cells. involves the production and monitoring of the amount of homoserine lactone present. is used by bacteria to limit the density of bacteria. is used by eukaryotes to sense the presence of bacteria. is used by bacteria to sense the density of cells AND involves the production and monitoring of the amount of homoserine lactone present.

In DNA sequence analysis the + strand of DNA is used. the start codon is ATG. ORFs are searched for. codon usage is a helpful indicator for protein coding areas. All of the choices are correct.

Adenine binds to thymine via 3 hydrogen bonds. True False

One end of a strand of DNA is different from the other end. True False

DNA replication is usually unidirectional. True False

There are 4 functional types of RNA. True False

The minus strand of DNA serves as the template for RNA production. True False

Antisense RNA is the complement of the plus strand and may be useful in inhibiting translation. True False

The genetic code is universal. True False

A codon consists of 2 nucleotides. True False

The anticodon determines which amino acid is linked to its tRNA. True False

Ribozymes are non-protein molecules with catalytic activity. True False

Bacteria use ______ attached TO the polymerase to direct RNA polymerase to promoters; eukaryotic cells use ______ that attach directly to the DNA first instead. sigma factors; transcription factors transcription factors; sigma factors ribosomes; sigma factors tRNA; rRNA