Q: Which of the following equations correctly represents the relationship between genotype and phenotype?

$$\text{Phenotype} = \text{Genotype} + \text{Environment}$$

Question 1

Which of the following statements best describes the difference between lagging and leading strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 2

A patient is diagnosed with anthrax, caused by Bacillus anthracis. Which feature of this bacterium makes it particularly resistant to harsh environmental conditions?

Accepted Answer

It forms endospores, which are highly resistant to heat, radiation, and desiccation.

Question 3

Which of the following best describes the process of generalized transduction in bacteria?

Accepted Answer

A bacteriophage accidentally packages host bacterial DNA and transfers it to another bacterium.

Question 4

Which of the following equations correctly represents the relationship between genotype and phenotype?

Accepted Answer

$$	ext{Phenotype} = 	ext{Genotype} + 	ext{Environment}$$

Question 5

A hospital is deciding between using an autoclave and a chemical disinfectant to sterilize surgical instruments. Which method is most effective for complete sterilization, and why?

Accepted Answer

Autoclaving, because it uses pressurized steam to destroy all forms of microbial life, including endospores.

Question 6

Which of the following is a key difference between fungi and bacteria?

Accepted Answer

Fungi are eukaryotic, while bacteria are prokaryotic.

Question 7

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; it results in premature termination of translation.

Question 8

Which of the following best describes the function of DNA polymerase during DNA replication?

Accepted Answer

It synthesizes new DNA strands by adding nucleotides to a pre-existing chain in the 5' to 3' direction.

Question 9

A patient presents with a greenish wound infection. Laboratory analysis identifies the causative agent as Pseudomonas aeruginosa. Which characteristic makes this organism particularly difficult to treat?

Accepted Answer

It is highly resistant to many antibiotics and disinfectants.

Question 10

Which of the following best explains why mycoplasmas are unique among bacteria?

Accepted Answer

They lack a cell wall and have sterols in their plasma membrane.

Question 11

Which of the following is the correct sequence of events in the lytic cycle of a bacteriophage?

Accepted Answer

Attachment, penetration, biosynthesis, maturation, release

Question 12

Which of the following best describes the difference between sterilization and disinfection?

Accepted Answer

Sterilization destroys all forms of microbial life, including endospores; disinfection eliminates most pathogens but not necessarily endospores.

Question 13

A laboratory technician is using UV light to sterilize surfaces. What is the primary mechanism by which UV light kills microorganisms?

Accepted Answer

It causes the formation of thymine dimers in DNA, leading to mutations and cell death.

Question 14

Which of the following best describes the process of conjugation in bacteria?

Accepted Answer

A plasmid is transferred from one bacterium to another through a pilus.

Question 15

Which of the following is a key difference between transformation, transduction, and conjugation in bacteria?

Accepted Answer

Transformation involves uptake of naked DNA, transduction involves bacteriophages, and conjugation involves direct cell-to-cell contact.

Question 16

A Gram-negative coccus is isolated from a patient with meningitis. Which of the following organisms is most likely responsible?

Accepted Answer

Neisseria

Question 17

Which of the following best describes the function of RNA polymerase during transcription?

Accepted Answer

It synthesizes RNA from a DNA template in the 5' to 3' direction.

Question 18

Which of the following is a characteristic of cutaneous fungal infections (dermatophytoses)?

Accepted Answer

They are caused by fungi that infect keratinized tissues such as skin, hair, and nails.

Question 19

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics than Gram-positive bacteria?

Accepted Answer

They have an outer membrane that acts as a barrier to many antibiotics.

Question 20

Which of the following best describes the difference between vegetative mycelia and aerial mycelia in fungi?

Accepted Answer

Vegetative mycelia absorb nutrients, while aerial mycelia are involved in spore production.

BIO 246 Exam 2 Study Guide: Genetics, Growth Control, Bacterial Classification, and Fungi

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