BIO 210 Test 4 | Questions with 100% Verified Answers | Latest Update 2026/2027

BIO 210 Test 4 | Questions with 100% Verified Answers |
Latest Update 2026/2027
Question: What are nutritional mutants in bacterial genetics?
Answer: Auxotrophs that indicate one gene utilizes a particular nutrient.




Question: What is a 'replicon' in bacterial genomes?
Answer: A single chromosome and plasmid.

Question: What is plasmid incompatibility?
Answer: When one plasmid 'loses out' and is not replicated due to identical copy number
control
mechanisms.

Question: What is the genotype in microbial genetics?
Answer: The collection of alleles of a given set of genes.

Question: How are genes designated in bacterial genetics?
Answer: With a three-letter abbreviation in italics followed by a capital letter (e.g., lacY vs.
lacZ).

Question: How are proteins designated in bacterial genetics?
Answer: With a three-letter designation, the first letter capitalized, and no italics (e.g., LacZ).

Question: What is phenotypic selection in the detection of mutants?
Answer: Using growth mediums that restrict the growth of microbes lacking the desired genes.
Antibiotic selection is commonly used.




Question: What is the purpose of creating duplicate plates in phenotypic
selection?
Answer: To identify mutations by comparing growth on fully supported versus partially
supported
media.

,Question: In a phenotypic selection, duplicate plates are created by the
process of ______ _______ .
Answer: replica plating

Question: Created by transferring colonies to a gridded plate(patching).
Answer: Duplicate plates method

Question: What did Lenski's experiment illustrate about E. coli?
Answer: The evolution of E. coli over 75 days, showing increased fitness in fresh nutrient
conditions.




Question: What did Esther Lederberg's experiments demonstrate about
mutations?
Answer: That streptomycin-resistant mutations arise spontaneously in the absence of selective
pressure.

Question: T/F: Cells that were exposed to streptomycin developed
resistance, showing that mutations can arise in the absence of
the selective agent.
Answer: True

Question: What did Luria & Delbruck's experiments show about bacterial
resistance?
Answer: That variable resistance to phage infection arises without selective pressure.




Question: What are restriction enzymes (REs)?
Answer: Proteins that recognize specific DNA sequences and cut DNA asymmetrically.

, Question: What is the significance of paired ends in restriction enzyme
activity?
Answer: They can be ligated together by DNA ligase after being cut.




Question: Recombinant DNA
Answer: 1. DNA produced by combining DNA from different sources
2. Can be used to clone or make many copies of a bacterial gene of interest

Question: Used to insert a recombinant DNA molecule into a recipient
hot bacterial cell
Answer: Vectors

Question: Name 3 vectors.
Answer: 1. Plasmids
2. Phages
3. Cosmids

Question: What is the role of plasmids in bacterial genetics?
Answer: Plasmids can carry genes and replicate independently of chromosomal DNA.

Question: What is the effect of auxotrophic mutants on growth patterns?
Answer: They may show visible phenotype changes, such as no growth on defined media.

Question: What is the purpose of the 'patching' method in phenotypic
screening?
Answer: To transfer colonies to a gridded plate for easier identification of mutants.

Question: What does a white colony indicate in sugar hydrolysis tests?
Answer: A mutant strain that cannot hydrolyze the chromogenic substrate.

Question: What is the significance of the defined growth medium in
bacterial genetics?
Answer: It allows for the identification of auxotrophic mutants based on their nutrient
requirements.

Question: What is the primary method for detecting mutations in
bacteria?
Answer: Phenotypic selection through growth media.

Question: What are cloning vectors used for?
Answer: To insert recombinant DNA molecules into recipient host bacterial cells.