Microbiology Exam 2 Book Questions

During DNA replication, which enzyme is involved in proofreading to prevent the incorrect matching of nucleotides?

DNA polymerase

RNA primers are removed from the leading and lagging strand by __________.

DNA polymerase I

What is important form removing RNA primers on the lagging strand

DNA polymerase I

In DNA replication, what is the main enzyme responsible for adding complementary nucleotides to the daughter strand while reading the parent strand?

DNA polymerase III

What is the primary enzyme that copies DNA

DNA polymerase III

Which enzyme is the main contributor to the development of spontaneous mutations?

DNA polymerase III

The term "redundancy" in molecular biology refers to __________.

Different codons that code for the same amino acid

In DNA replication, protein factors are more heavily required for replication in __________.

Eukaryotic cells

The process of removing incorrect nucleotides and replacing them with correct ones is referred to as __________.

Excision repair

True or False: RNA contains deoxyribonucleotides

False; DNA contains deoxyribonucleotides and RNA contains ribonucleotides

The genetic makeup of an organsim is its _____

Genotype

What relieves coiling tension in DNA as it unwinds

Gyrase

What unwinds DNA helix

Helicase

The Ames test is used to identify if a chemical will result in mutations. This test uses the microorganism S. typhimurium and the amino acid __________.

Histidine

The process of transferring of genetic information between cells in the same generation is referred to as __________.

Horizontal gene transfer

What would the likely consequence be if a gene's promoter was deleted or severly mutated?

If the promoter of a gene was deleated or severly mutated than most likely the gene would not be expressed

In eukaryotic mRNA, there are sequences of mRNA that do NOT encode for specific amino acids and do NOT contribute to the protein. These sequences are called __________.

Introns

Of the following statements, which does NOT apply to a microorganism that has a fertility plasmid? 1) It can undergo horizantal gene transfer 2) It can further develop into a Hfr cell 3) It can undergo vertical gene transfer 4) It has a pilus

It can undergo vertical gene transfer

Where is the chromosomal DNA found in prokaryotic cells?

Nucleoid

Which functional group is found at the 5' end of DNA?

Phosphate group

Label X-rays as a biological, chemical, or physical mutagen

Physical mutagen

Label UV radiation as a biological, chemical, or physical mutagen

Physical mutation

Which type of genetic material may be found in both prokaryotic and eukaryotic cells and may contain genes conferring antibiotic resistance?

Plasmids

Which of the following statements is NOT a characteristic of plasmids? 1) Plasmids are part of the cell's chromosomes 2) Plasmids are involved in horizontal gene transfer 3) Plasmids carry genes that may be involved in antibiotic resistance 4) Plasmids replicate independently of the cell's chromosomes

Plasmids are part of the cell's chromosomes

To start DNA replication, the origin of replication is recognized by a collection of factors called the __________.

Primosome

One major difference between prokaryotic and eukaryotic translation is __________.

Prokaryotic translation is polycistronic, and eukaryotic translation is almost always monocistronic

Primase lays down a short piece of __________ as a primer to start DNA replication.

RNA

What is the main enzyme required for transcription of a gene?

RNA polymerase

The role of transcription factors is to signal __________.

RNA polymerase to the promoter region of the intended gene to be transcribed

What serves as a jump-start platform for DNA polymerase I

RNA primer

The term used by molecular biologists to describe the flow of genetic information from DNA, to RNA, to protein is __________.

The central dogma of biology

In DNA replication, Okazaki fragments are required in synthesizing __________.

The lagging strand, because the DNA polymerase can move only in the 5' to 3' direction

Which of the following would be considered a FALSE statement about small noncoding RNAs? 1) They can be used to tag a ribosome to be destroyed. 2) They are used in post-transcription regulation. 3) They are found only in prokaryotic cells. 4) They reduce the amount of protein made from mRNA.

They are found only in prokaryotic cells.

Of the following statements, which one is NOT related to transposable elements? 1) They create a stable, non-changing genome 2) They recombine the genome 3) They can change the rate of gene expression 4) They require the transposase enzyme

They create a stable, non-changing genome

Assume you have the DNA sequence 3'-ACGTATCCAGCAGCTCCACCAA-5'. COuld the mRNA sequence you generated be translated? Why or why not?

This sequence does not have a start codon and therefore would not be translated

A codon consists of __________ nucleotides.

Three

Codons are _____ nucleotides long and are in _____, which is transcribed from DNA. During _____, tRNAs serve as adapter molecules to bring _____ to the ribosome to build a protein. Once the ribosome reaches a _____ on the mRNA, translation ends.

Three; mRNA; translation; amino acids; stop codon (or nonsense codon)

UV radiation can result in __________ in a cell's DNA.

Thymine dimers

Griffith's experiment proved that bacteria can take up naked DNA from the environment and use it as part of their genome. This process, which can occur in a laboratory or in a natural setting, is called __________.

Transformation

True or False: DNA ligase forms phosphodiester bonds between Okazaki fragments on the lagging strand

True

True or False: In DNA, C bonds with G

True

True or False: In RNA, A bonds to U

True

True or False: RNA primase is required on the leading and the lagging strand

True

Which of the following nucleotides is found only in RNA and not in DNA?

Uracil

Proteins provide cells with the necessary equipment to perform normal cellular activity. Without gene expression the cell __________.

Would die

Riboswitches are best defined as _____.

parts of mRNA that are not translated and act as post-transcription regulators

An anticodon is found on __________.

tRNA

Assume you have the DNA sequence 3'-ACGTATCCAGCAGCTCCACCAA-5'. What would the complementary DNA sequence be?

5'-TGCATAGGTCGTCGAGGTGGTT-3'

Assume you have the DNA sequence 3'-ACGTATCCAGCAGCTCCACCAA-5'. What would the corresponding mRNA sequence be?

5'-UGCAUAGGUCGUCGAGGUGGUU- 3'

True or False: DNA has a parallel arrangement

False; DNA has an antiparallel arrangement

True or False: DNA is replicated in a 3' to 5' direction

False; DNA is replicated in a 5' to 3' direction

True or False: Prokaryotic mRNA requires processing before it is translated

False; Eukaryotic mRNA requires processing before it is translated

Which of the following mutations is the most detrimental to the cell? 1) Missense mutation 2) Nonsense mutation 3) Silent mutation 4) Frameshift mutation

Frameshift mutation

Why are the terms gene expression and protein sythesis often used interchangeably?

Gene expression requires transcription and translation, which is protein synthesis

In order for the lactose operon to be "on" and actively transcribe, _____ must be present and _____ must be absent

Lactose; glucose

Which of the following are involved in pre-transcriptional regulation? Choose all that apply 1) Methylation 2) Riboswitches 3) Operons 4) Short inferfering RNAs (siRNAs) 5) Transcription factors

Methulation, operons, transcription factors

What lays RNA primers to start DNA replication

Primase

List three features of the genetic code

Redundancy, triplet code, 64 different codons that encode 20 different amino acids, 2 stop signals, and one start signal

cDNA is a product of the action of __________.

Reverse transcriptase

How is a ribonucleotide different from a deoxyribonucleotide?

Ribonuleotides contain ribose instead of deoxyribose, which is found in deoxyribonucleotides. Ribonucleotides are used to build DNA. RIbonucleotides will not incorprate thymine as a nitrogen base and instead use uracil

RNA nucleotides are made of a sugar, a phosphate, and a nitrogen base. Which sugar is unique to RNA nucleotides and NOT found in DNA nucleotides?

Ribose

Select the false statement: 1) DNA is made of deoxyribonucleotides 2) RNA is made of ribonucleotises 3) RNA is built in a 5' to 3' direction 4) DNA is built in a 5' to 3' direction 5) Rna primase builds RNA in transcription

Rna primase builds RNA in transcription

There are two nonstandard encoding amino acids: __________.

Selenocysteine and pyrrolysine

What keeps DNA strands separated during replication

Single-strand DNA-binding protein

Transduction that involves a temperate phage integrating into the host cell genome is called __________.

Specialized transduction

Which type of RNA carries in amino acids and adds the amino acids to the "A" site in the ribosome?

tRNA

Which of the following is considered a pre-transcriptional regulation and NOT a post-transcriptional regulation?

A repressed operon

In an inducible operon, what protein is used to turn off transcription by binding to the operator sequence?

A repressor protein

A transposon that relies on an RNA intermediate is called __________.

A retrotransposon

After translation, protein modifications are necessary for a final functioning product. Which of the following is NOT part of protein modification?

Addition of a methionine

Quorum sensing allows bacteria within communities to communicate with chemical messages, which may help regulate gene expression. The chemical messages are called __________.

Autoinducers

Label plasmids as a biological, chemical, or physical mutagen

Biological mutagen

Label transposons as a biological, chemical, or physical mutagen

Biological mutagen

Label viruses as a biological, chemical, or physical mutagen

Biological mutagen

Genes can be silenced by a process called DNA methylation. Which of the following compounds is a methyl group?

CH3

Label alcohol as a biological, chemical, or physical mutagen

Chemical mutagen

Label cigarette smoke as a biological, chemical, or physical mutagen

Chemical mutagen

If a cell is to be transformed in a lab, the cell must be __________ to uptake the available genetic information.

Competent

The exchange of genetic information by use of a pilus and cell-to-cell interaction is called __________.

Conjugation

During _____ a pilus forms between an F+ and an F- cell and alloows for the exchange of genetic material. By the end of the process, the previously F- cell is converted to a(n) _____ cell

Conjugation; F+

During optimum conditions, E. coli will replicate every 20 minutes. Because the genes required for replication are needed as part of a routine function, these genes are considered __________.

Constitutive genes