Chapter 17 & 24

What structural components make up a virus, and how do they relate to its classification?

Viruses are made of nucleic acid and a protein coat, sometimes with a membranous envelope; they are classified by their type of genetic material

Compare the lytic and lysogenic cycles of bacteriophages. Which statement is true?

In the lytic cycle, the host cell is destroyed; in the lysogenic cycle, the viral DNA integrates into the host genome as a prophage

What is a key feature of a virulent phage?

It reproduces through the lytic cycle, leading to host cell lysis

Describe how a retrovirus replicates within a host. What enzymes are involved?

Retroviruses use reverse transcriptase in the cytoplasm to convert RNA into DNA, which integrates into the host genome with integrase

What are prions, and why are they unique compared to viruses?

They are infectious proteins that cause brain disease and lack nucleic acids

What is the difference between a prophage and a provirus?

A prophage is viral DNA integrated in bacterial DNA; a provirus is viral DNA integrated in eukaryotic DNA

Compare and contrast prokaryotic and eukaryotic cells. Which statement is correct?

Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes have both

How do Gram-positive and Gram-negative bacteria differ structurally and functionally

Gram-positive bacteria have thick peptidoglycan walls; Gram-negative bacteria have thinner walls and an outer membrane that may be toxic

What processes contribute to genetic variation in prokaryotes?

Rapid reproduction, mutations, and genetic recombination

Describe the three mechanisms of genetic recombination in prokaryotes. Which set correctly identifies them?

Transformation, transduction, and conjugation

What roles do fimbriae, pili, and flagella play in bacterial life?

Fimbriae allow attachment, pili transfer DNA, and flagella provide motility

What are extremophiles?

Organisms that live in extreme environments such as high salinity or temperature

What is an endospore, and why is it important for bacterial survival?

A dormant, tough cell that allows bacteria to survive harsh conditions