Microbiology Chapter 8: Microbial Genetics and Genetic Engineering

The letters of an mRNA codon are based on the ______ in the nucleotides of the transcript.

nitrogenous bases

The lac operon is usually in the _____ position and is activated by a/an _______ molecule.

off; inducer

If lactose is present, the operator of the lac operon is switched ____; therefore, this is an example of a(n) ______ operon.

on; inducible

The lac repressor is an allosteric molecule, meaning that is has two binding sites,

one for the operator sequence and one for lactose.

The antiparallel arrangement within DNA molecules refers to ____.

one helix strand that runs from the 5' to 3' direction and the other strand runs from the 3' to 5' direction.

The ____ is the site where the repressor binds to turn transcription of the structural genes off.

operator

An operator, promoter, and regulator are components of a(n) ____ in bacteria.

operon

In bacteria, a regulatory gene, a control region, and structural genes collectively are referred to as a(n) ____.

operon

Bacterial and archaeal genes are arranged into?

operons

Donor and recipient bacterial cells are connected by the sex ____ during conjugation.

pilus

What is a mutation?

A permanent inheritable alteration in the DNA sequence or content of a cell.

____ is the pentose sugar in DNA.

Deoxyribose

Which is true regarding DNA semiconservative replication?

Each new DNA helix contains one parent strand and one newly synthesized strand.

True or False: Bacterial conjugation is sexual reproduction.

False

A mutation resulting from an insertion or deletion of bases that causes a change in the reading frame of the mRNA.

Frameshift mutaiton

Select the statement that best describes the purpose of gel electrophoresis.

Gel electrophoresis separates DNA fragments based on size.

Which organic molecule is formed from chains of amino acids that are produced in translation?

Preotein

The spliceosome is comprised of?

RNA & protein

Which is the main event of transcription elongation?

RNA polymerase joins nucleotides

During transcription, RNA polymerase synthesizes ____ from a(n) ____ template.

RNA; DNA

____ ____ technology, also known as genetic engineering, deliberately modifies the genetic structure of an organism to create novel products or organism.

Recombinant DNA

Which term refers to the transfer of genes from donor to recipient microorganisms?

Recombination

A mutation that changes one codon to a different codon that specifies the same amino acid, such that there is no change in the resulting polypeptide.

Silent mutation

Which type of mutation alters the DNA sequence of a gene, but does not change the amino acid sequence of the protein that is encoded by the gene?

Silent mutation

____ mutations occur when errors are made in DNA replication whereas ____ mutations are caused by exposure to radiation or chemical agents.

Spontaneous; Induced

Which part(s) of an operon will eventually be translated to protein?

Structural genes

If RNA polymerase was reading a segment of template DNA with the sequence AGGCGTA, what order of nucleotides would be added to the mRNA transcript?

UCCGCAU

Which nitrogenous base is found in RNA but not found in DNA?

Uracil

tRNA carries __________ ___________ to the ribosome to build peptide chains during protein synthesis.

amino acids

In DNA, the two strands of the helix are arranged in a(n) _____ arrangement?

antiparallel

Part of the cleanup efforts for the Deepwater Horizon oil spill in 2010 involved ____. (Tutorial Assignment)

bioremediation

A ____ is a discrete cellular structure composed of a neatly packaged DNA molecule.

chromosome

A(n) ____ is the specific sequence of 3 mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid.

codon

In conjugation, a copy of the DNA being transferred is retained by the donor, and this is termed a ____ process.

conservative

The current disease that might prove curable by gene therapy are those like

cystic fibrosis, which is the result of a mutation in a single gene.

According to the rules of complementary base pairing, the nitrogenous base ____ forms hydrogen bonds with guanine.

cytosine

In eukaryotic genes, introns are interspersed between ____, which are coding regions that will be translated into protein.

exons

In eukaryotic genes, introns are interspersed between coding regions called ____, that will be translated into protein.

exons

A ____ mutation results from an insertion or deletion of nucleotides in multiples of 1 or 2, and always leads to a change in the "reading" of the codons in mRNA.

frameshift

The science of heredity is ____.

genetics

The complete set of chromosomes and genes in a organism is referred to at the ____.

genome

The term ____ refers to all the genes constituting an organism's distinctive genetic makeup, the expression of which results in the organism's phenotype.

genome

Which of the following describes the systematic study of an organism's genes and their functions?

genomics

Changes to the genome of an individual that are passed on to offspring are termed ____ therapy.

germline

In CRISPR, the gene sequence to be altered is specified by a ____ RNA.

guide

A sequence of DNA in a eukaryotic gene that does not code for protein is called a(n) ____.

intron

Which term identifies a sequence of DNA in a eukaryotic gene that does not code for protein?

intron

The ____ strand is synthesized continuously, while the ____ strand is synthesized in a series of short fragments termed Okazaki fragments.

leading; lagging

Which type of RNA is a copy of the DNA template corresponding to a protein-encoding gene?

mRNA

Which of the following describes the study of all of the genomes in an ecological niche?

metageonomics

A change in the genetic code that leads to the insertion of a different amino acid in a protein is called a ____ mutation.

missense

An agent that induces changes in DNA is a(n) ____.

mutagen

An operon is a group of genes in a linear arrangement that will be transcribed together and require only one ____ to initiate transcription and one ____ to act as an on/off switch.

promoter; operator

The primary intent of ____ DNA technology is to combine the genetic material from two organism.

recombinant

DNA ____ must occur prior to cell division to ensure that each new cell has a complete genome.

replication

The duplication of a cell's DNA is called _______.

replication

Two subunits of the ____ comprise the site of protein synthesis.

ribosome

Two subunits of the ___________ comprise the site of protein synthesis.

ribosome

rRNA composes _____ subunits together with protein.

ribosomes

The pyrimidine nitrogenous bases found in RNA are cytosine and ____.

uracil

Which are events of translation elongation?

- A tRNA delivers the next amino acid in the sequence. - Amino acids are joined by peptide bonds. - The ribosome shifts from one codon on the mRNA to the next.

Which are events of translation elongation?

- Amino acids are joined by peptide bonds. - The ribosome shifts from one codon on the mRNA to the next. - A tRNA delivers the next amino acid in the sequence.

What of the following are true for repressible operons?

- Code for anabolic enzymes - Usually turned on unless product is in excess

Which two components of a nucleotide are bound to form the backbone of a DNA strand?

- Deoxyribose sugar - Phosphate

In which of the following ways do the chromosomes of bacteria and eukaryotes differ?

- Eukaryotic chromosomes are located in the nucleus and bacterial chromosomes are not in a membrane-bound organelle. - Eukaryotes have histones but bacteria have histone-like proteins that are not true histones.

What is commonly shared between bacteria through the process of conjugation?

- Genes for virulence factors - Resistance plasmids

Match the definition of horizontal and vertical gene transfer.

- Horizontal gene transfer: Transfer of DNA from a source other than the parent organism. - Vertical gene transfer: Transfer of DNA from parent organisms during reproduction.

How does RNA differ from DNA in bacteria and eukaryotes?

- In RNA, uracil replaces thymine. - RNA is usually single-stranded.

Which three of the following are correct regarding CRISPR technology?

- It can be used in most organisms. - The procedure is easy to perform. - Materials to perform the procedure are cheap.

Which two of the following are ethical concerns that have been raised about the use of CRISPR?

- It can be used to accelerate mutagenesis in an organism's offspring. - Changes affecting regions of the genome besides the target have occurred.

Which of the following make good cloning vectors?

- Plasmids - Bacteriophages

How does RNA differ from DNA in bacteria and eukaryotes?

- RNA is usually single-stranded. - In RNA, uracil replaces thymine.

Match these other types of RNA with their roles.

- Regulatory RNAs: determine gene expressions in prokaryotes and eukaryotes. - Primer RNA: laid down in replication as a template for dna sequence. - Ribozymes: remove introns in eukaryotes.

Which of the following are differences between eukaryotic and bacterial protein synthesis?

- Transcription and translation are simultaneous in bacteria but not eukaryotes. - The first amino acid is slightly different.

Which two types of horizontal gene transfer do NOT require direct contact between the donor and recipient cells?

- Transduction - Transformation

Synthetic biology may be used to

- create an antibody with defined specificity - create an operon using genes from different microbes - create a cell whose entire chromosome was synthesized in vitro.

A change in the gene that encodes the Iac repressor was detected such that the amino acid alanine was inserted into the polypeptide instead of the amino acid glycine. This mutation can be described by which two of the following?

- missense mutation - point mutation

What are the three components of a DNA nucleotide?

- phosphate - deoxyribose sugar - nitrogenous base

A CRISPR region of a bacteria chromosome is compromised of:

- spacer DNA with pieces of bacteriophage or plasmid - short sequences repeated many times

Which three are basic categories of genes?

- structure genes - genes that encode ribosome components - regulatory genes

Which of the following are true for inducible operons?

- usually turned off unless substrate is present - code for catabolic enzymes - example is lac operon

What events initiate translation?

-Ribosome scans to find AUG on the mRNA transcript -Assembly of the ribosomal subunits

What is the complementary DNA sequence to the DNA template 3'-ATACTAAAATTT-5'

5'-TATGATTTTAAA-3'

____ are formed from long chains of amino acids produced in translation.

Proteins

____ refers to the transfer of genes between donor and recipient microorganisms, forming a new strain different from donor and recipient.

Recombination

A(n) ____ is a sequence of DNA nucleotide that codes for a group of related proteins.

gene

A mutation that does not lead to adverse or helpful changes is termed a ____ mutation.

neutral

Match each enzyme with its role in DNA replication.

- helicase: unzips the DNA helix. - primase: synthesizes an RNA primer. - DNA polymerase I: removes the primer, closes gaps, and repairs mismatches. - DNA polymerase III: adds bases to the growing DNA chain, proofreads. - topoisomerase: untangles new replicated strands. - ligase: seals nicks in DNA.

Which two factors are possible applications of single nucleotide polymorphisms to personalized medicine?

- identification of disease - determining the best drug to treat a disease

Which of the following describe the origin of replication?

- located on the chromosome - AT-rich

Which of the following are the three major types of RNA?

- messenger - ribosomal - transfer

All DNA nucleotides contain:

- the same sugar and phosphate, but different nitrogenous bases.

Order the following steps in excision repair.

1. Enzymes recognize a mismatch in the two DNA strands. 2. Enzymes remove the nitrogenous case on one strand. 3. DNA polymerase I synthesizes new DNA as needed. 4. Ligase seals the phosphate backbone of the DNA.

Put these general steps in order for the recombinant DNA procedure.

1. Remove and isolate a selected gene from a donor organism. 2. Insert the gene of interest into a vector. 3. Use vector to deliver selected gene into cloning host.

Order these organisms by the size of their genomes, from smallest at the top to largest at the bottom.

1. Viruses 2. Bacteria 3. Fungi 4. Humans

Order the following events in the processing of eukaryotic transcripts.

1. the gene is transcribed to mRNA. 2. a series of adenosines is added to the mRNA 3. a spliceosome exises introns from the mRNA 4. The mRNA leaves the nucleus 5. the mRNA is translated into protein.

Which sequence of DNA nucleotides is complementary to the DNA triplet 5'-ATG-3'?

3'-TAC-5'

Which of the following nitrogenous bases is found in both DNA and RNA?

Adenine

Select all of following that represent advancements due to genetic engineering. (Tutorial Assignment) Growth of organic produce Enhanced nutrition Mass production of industrial enzymes Medicine and vaccine production Resistant crop production

All options are correct Growth of organic produce Enhanced nutrition Mass production of industrial enzymes Medicine and vaccine production Resistant crop production

What does it mean to refer to an organism as a "recombinant" in the biotechnology field? (Tutorial Assignment)

An organism with DNA from multiple sources

Which of the following is a household example of biotechnology? (Tutorial Assignment)

Bread making

The anticodon of the tRNA carrying the codon GUU is ____.

CAA

What type of bacterial cell can be transformed by DNA in the environment?

Competent cell

What is the function of rRNA?

Comprises ribosomal submits

DNA transfer from a donor bacterium to a recipient via sex pili

Conjugation

Which of the following are methods of gene transfer in bacteria?

Conjugation Transformation Transduction

In the bacterium Escherichia coli, where is the chromosome located?

Cytoplasm

Transcription occurs in the___ of bacteria and the ___ of yeast cells.

Cytoplasm; nucleus

An operon is composed of _____.

DNA

Genomes of cells are composed of

DNA

Genomes of cells are composed of ____.

DNA

What is the central theme of molecular biology?

DNA encodes RNA which encodes proteins.

Cellular genomes are composed of ____ whereas viral genomes may be either DNA or ____.

DNA; RNA

____ breaks the hydrogen bonds holding the two strands of DNA together, resulting in two separate strands.

Helicase

A mutation that results in a change in a codon such that a different amino acid is specified.

Missense mutation

A nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a(n) ____.

Nitrogenous base

A mutation that changes a codon that specifies an amino acid to a stop codon, resulting in premature termination of polypeptide synthesis.

Nonsense mutation

In a protozoal or fungal cell, chromosomes are located in the ____.

Nucleus

The characteristics resulting from the interaction of the particular genetic makeup of an organism and the environment is the ____ of that organism.

Phenotype

What is a cloning host?

The organism that receives and replicates a foreign piece of DNA inserted during a genetic engineering experiment.

What is the role of the promoter in operon?

The site of RNA polymerase binding

Which nitrogenous base is found in DNA but not found in RNA.

Thymine

DNA transfer from one bacterial cell to another cell via bacteriophage

Transduction

Which method of genetic transfer involves bacteriophages?

Transduction

The transfer of naked DNA from one cell to another

Transformation

_____ involves the uptake of free DNA by competent bacterial cells.

Transformation

_____ is a type of horizontal gene transfer often used in recombinant DNA technology.

Transformation

____ is the process of decoding the messenger RNA into a polypeptide.

Translation

TRUE of FALSE: Only viruses can have an RNA genome.

True

True of False: The use of recombinant DNA for gene cloning is shown in this image. (Figure 8.10; page 240 in textbook)

True

True or False: All structural genes in an operon code for proteins related to the same function.

True

True or False: Several codons can be translated into the same amino acid, but one particular codon cannot be translated into different amino acids.

True

The property of wobble means that ______ mutations result if changes occur in _____ position of some codons.

silent; the third

In the CRISPR technique, a guide RNA

targets the gene sequence to be modified.

DNA replication is semiconservative because the ___ strand will become half of the __ molecule.

template, finished

The pyrimidine nitrogenous bases found in RNA are cytosine and ____.

uracil (There are four nitrogenous bases found in RNA: adenine, guanine, cytosine, or uracil. Adenine and guanine are known as purine bases while cytosine and uracil are known as pyrimidine bases.0