BIOD 171 Module 6 Exam Review Virus Composition: Size And Shape.

BIOD 171 Module 6 Exam Review Virus Composition: Size And Shape. Question 1 0 / 0 pts Your Answer: Can viruses be classified as either prokaryotic or eukaryotic microorganisms? No. They are neither. No. Viruses are neither prokaryotic nor eukaryotic. Question 2 0 / 0 pts Your Answer: What is an obligate intracellular parasite? 9/6/2020 M6: Module 6 Review: Essential Microbiology with Lab- Zangus It's an organism that can't replicate by itself - a virus is an example of one. As an obligate intracellular parasite, viruses cannot (obligate) replicate unless inside (intracellular) a living host cell. As a parasite, a virus depends on its living host to provide the framework (proteins, etc) to replicate—to make additional copies of itself. Question 3 0 / 0 pts Your Answer: What is a viral capsid? It's the viruses protective membrane that holds the genetic material. The capsid is a membrane-like protective structure that contains the genetic material, similar to the nucleus of a eukaryotic cell. Question 4 0 / 0 pts Your Answer: What is the viral envelope, and what does the presence (or absence) of it tell you about the type of virus? It's an added membrane that envelopes the capsid of a virus. Most viruses with envelopes are animal viruses. Most plant and bacteria-infecting viruses are not enveloped. 9/6/2020 M6: Module 6 Review: Essential Microbiology with Lab- Zangus The envelope surrounds the viral capsid, is derived from the host cell membrane and serves as an additional barrier to the external environment. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not. Question 5 0 / 0 pts Your Answer: What type of microscope would be used to study the shape of a viral capsid? Electron microscope. Due to its size (~30-150 nm) most viral capsids must be visualized via electron microscopy. Question 6 0 / 0 pts Your Answer: How does the viral envelope both aid in cell entry as well as hide it from being detected by the immune system? The envelope has proteins on it which allows it to interact with cell proteins to gain entry. The envelope also hides from its host's immune system as it derives it from the host -- which helps it go undetected by the immune system since it isn't considered a foreign body.