Question 1

Which of the following organelles provides the strongest evidence for the endosymbiotic theory of eukaryotic cell evolution?

Accepted Answer

Mitochondria

Question 2

A scientist observes a eukaryotic cell with a thick, rigid cell wall composed primarily of chitin. Which organism is the cell most likely from?

Accepted Answer

A fungus

Question 3

Which of the following best describes the function of the nucleolus within the eukaryotic nucleus?

Accepted Answer

It is the site of rRNA synthesis and ribosome subunit assembly.

Question 4

A patient is diagnosed with a systemic fungal infection after inhaling spores. Which of the following fungi is most likely responsible?

Accepted Answer

Histoplasma capsulatum

Question 5

Which of the following statements about the structure and function of eukaryotic flagella is CORRECT?

Accepted Answer

They are covered by an extension of the cell membrane and move with a lashing motion.

Question 6

A mutation changes a DNA codon from AAA to TAA. What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 7

Which process allows a bacterium to acquire new genetic material from a lysed cell in its environment?

Accepted Answer

Transformation

Question 8

A virus with a single-stranded RNA genome that can be directly translated by host ribosomes is classified as which Baltimore class?

Accepted Answer

Class IV (+ssRNA)

Question 9

Which of the following is a key difference between the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

The lysogenic cycle allows the viral genome to be replicated with the host cell without causing immediate lysis.

Question 10

A protozoan parasite is transmitted via contaminated water and forms highly resistant cysts. Which organism fits this description?

Accepted Answer

Giardia lamblia

Question 11

Which of the following equations correctly calculates the final number of bacterial cells ($$N_f) $$after $$n$$ generations, starting from $$N_i$$ initial cells?

Accepted Answer

$$N_f = N_i 	imes 2^n$$

Question 12

Which of the following best explains why prions are unique among infectious agents?

Accepted Answer

They are misfolded proteins with no nucleic acid.

Question 13

A fungal species produces ascospores within a sac-like structure. To which phylum does it belong?

Accepted Answer

Ascomycota

Question 14

Which of the following statements about DNA replication is CORRECT?

Accepted Answer

The lagging strand is synthesized in short fragments called Okazaki fragments.

Question 15

Which of the following is a function of the eukaryotic smooth endoplasmic reticulum (SER)?

Accepted Answer

Synthesis and storage of lipids

Question 16

A patient presents with symptoms of ergot poisoning after eating contaminated rye bread. Which organism is responsible for this intoxication?

Accepted Answer

Claviceps purpurea

Question 17

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on its anticodon.

Question 18

Which of the following is TRUE regarding the difference between inducible and repressible operons in prokaryotes?

Accepted Answer

Repressible operons are normally ON and turned OFF by the product synthesized.

Question 19

A patient is infected with a roundworm that has a complete digestive tract and separate sexes. Which group does this organism belong to?

Accepted Answer

Nematodes (roundworms)

Question 20

Which of the following best explains why viruses are considered obligate intracellular parasites?

Accepted Answer

They require host cell machinery to replicate their genome and produce new virions.

BIO-55 Exam 2 Study Guide: Eukaryotes, Fungi, Protists, Helminths, Viruses, Microbial Genetics, and Bacterial Growth

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