Microbiology Ch. 9 Review

Mutations are the primary source of genetic variation that makes evolution possible

True

Mutations are the primary source of genetic variation that makes evolution possible.

True

Recombinant organisms often exhibit new traits, such as antibiotic resistance or novel metabolic capabilities

True

A specific segment of DNA that contains the necessary code to make a protein or RNA molecule is a _____

gene

The sum total of the genetic material of a cell is its ____

genome

The genetic makeup of an organism is referred to as its _______. whereas the observable traits due to gene expression are referred to as its _________

genotype; phenotype

DNA polymerase adds new nucleotides ____

in the direction toward the replication fork on the leading strand

DNA polymerase adds new nucleotides ______

in the direction toward the replication fork on the leading strand

During DNA replication, the ______ strand is synthesized continuously while the _________ strand is synthesized in a series of short fragments called Okazaki fragments.

leading: lagging

A permanent change in the DNA base sequence is a _____

mutation

DNA replication is described as _____

semiconservative

Select the type of RNA molecule that is associated with an amino acid, which is used to build a polypeptide chain during translation.

tRNA

DNA is semiconservative because the ______ strand will become half of the ______ molecule.

template; finished

Bacteriophages serve as a mechanism for genetic transfer in the process called _____

transduction

Bacteriophages serve as a mechanism for genetic transfer in the process called ______

transduction

A/An ________ is a group of bacterial genes in a linear arrangement that will be transcribed together.

орeгon

Which of the following processes does not directly involve DNA?

Translation

Select all of the differences between DNA and RNA to test your understanding of these nucleic acids.

- DNA is double-stranded, whereas RNA is single-stranded - DNA nucleotides contain deoxyribose, whereas RNA nucleotides contain ribose

Select all of the features that you would include if you drew a short segment of DNA

- Double-stranded - Helical shape - Chains of nucleotide - Nucleotides are base-paired with T bonded to A and C bonded to G through hydrogen bonds - Backbone comprised of sugar and phosphate groups

Select all statements that describe features of transcription and translation found in eukaryotes but not in bacteria

- Genes are interrupted by intervening sequences - A tail of multiple adenine ribonucleotides is added to the mRNA transcript - The mRNA transcript must pass through pores to get out of the nucleus - RNA transcript is processed to remove introns and splice together exons

Select the statements that are true of repressible operons to test your understanding of the differences between inducible and repressible operons

- Repressible operons are usually the "turned on" state and are "turned off" when their product is in adequate supply - The product of the enzymes in the operon functions as a compressor - Enzymes necessary for the synthesis of amino acids are often encoded by genes in repressible operons

Match the term with its description to test your understanding of mechanisms of horizontal gene transfer in bacteria.

1 Transformation - The transfer of naked DNA from one cell to another 2 Conjugation - DNA transfer from a donor bacterium to a recipient via sex pili 3 Transduction - DNA transfer from one bacterial cell to another cell via bacteriophage

Select the statements that accurately reflect codons and their use in translation. Check all that apply.

AUG is a start codon. UGA, UAA, and UAG are stop codons.

Evaluate the statements below, and select those that correctly apply to the mechanisms of conjugation, transformation, and transduction.

Certain cells, called F+ cells, contain a plasmid that codes for a sex pilus to connect to a recipient F- cell and donate a copy of the plasmid. When bacteriophage progeny are being assembled, occasionally a fragment of host DNA is packaged in error and transferred to a new cell by the process of transduction. During transformation, DNA that has been released from a dead cell passes through the cell wall of a competent cell.

Move the terms to their correct description to review a variety of enzymes involved in DNA replication

DNA polymerase III - Responsible for adding bases to the new DNA chain and proofreading the newly laid down bases Topoisomerases I and II - Responsible for supercoiling and untangling of DNA DNA polymerase I - Responsible for removing the primer, closing gaps in the DNA and repairing mismatched bases Ligase - Responsible for the final binding of nicks in DNA during replication Primase - Responsible for synthesizing an RNA primer Helicase - Responsible for unzipping the DNA helix

RNA molecules are circular and double-stranded, as compared to the linear single-stranded structure of DNA molecules.

False

Select the statements that are true of inducible operons to test your understanding of the differences between inducible and repressible operons.

Inducible operons often contain genes for enzymes that function in catabolic processes. Inductible operons will be "turned on" in the presence of the substrate and turned off in its absence. The lac operon is an example of an inducible operon.

Match the term with the molecule on which it is found.

Promoter - DNA A and P sites - rRNA Start codon - mRNA

Select which of the following represents a proper pairing of a nucleic acid and one of its components.

RNA, uracil

Select the term that best describes any organism that contains and expresses genes that originated in another organism.

Recombinant

Select the type of antibiotic that is used to treat cases of tuberculosis, due to its ability to more specifically target bacterial RNA polymerase than the eukaryotic form of the enzyme.

Rifamycin

Which of the following is not a mechanism of horizontal gene transfer?

Spontaneous mutations

Consider the following wild-type DNA sequence on the template strand: TACGACACCTTA Four different mutations of this sequence are indicated. Match the mutated sequence with the type of mutation it represents. Use the genetic code to help you.

TACGTCACCTTA - missense mutation ТАCGATACCTТА - silence mutation ТАСTGACACCТТА - frameshift mutation TACGACACTTTA - nonsense mutation

Select the accurate statement reflecting the genotype or phenotype of an organism.

The alleles contained within the cells of an organism comprise its genotype.

Select the most accurate statement reflecting the process of transcription.

Transcription relies upon the action of RNA polymerase.

Select the mechanisms below which enable the horizontal transfer of antibiotic resistance genes.

Transformation Transduction Conjugation

Select the statement that explains the newer version of the "central dogma."

While information primarily flows from DNA to RNA to protein, some information from RNA flows back to DNA in a regulatory role.

The tRNA bound to the growing polypeptide chain during translation can be found in what area of the ribosome complex?

Within the A or P site, but not the E site