MICROBIO 4000 EXAM 3 CH12 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

MICROBIO 4000 EXAM 3 CH12 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 After the T4 lytic phage attaches to an E. coli cell, what occurs? - Answers Phage-encoded lysozyme degrades a hole in the bacteria cell wall so the genome can enter Generalized transduction often involves bacteriophages that are doing what? - Answers Actively making more viral particles (productive) Which type of HGT would need to involve a temperate phage? - Answers Specialized transduction Filamentous phage ____________ a. DNA does not enter the host b. do not lyse a host cell c. do not form a prophage d. do not target bacteria - Answers b. do not lyse a host cell Which of the following viruses is least likely to encode a replicase enzyme in its genome? a. DNA virus b. dsRNA virus c. (+) RNA virus d. enveloped virus - Answers a. DNA virus True or False - Animal viruses always need to be in the host nucleus to replicate - Answers False Retroviridae (Retroviruses) are reverse transcribing viruses, therefore ___________. a. infect the human immune system b. use RNA as a template for DNA synthesis c. cause latent infections d. evolved in the 1960s - Answers b. use RNA as a template for DNA synthesis A virus that is latent is _____________. a. deadly b. non-infectious c. non-productive d. non-enveloped - Answers c. non-productive A provirus is _______. a. always latent b. part of the host cell's genome c. extremely infectious d. a bacteriophage that can infect human cells - Answers b. part of the host cell's genome What is a genome? - Answers The primary characteristics used to classify viruses What is the Baltimore classification? - Answers The way scientists classify viruses based on genome What are the viral attachment proteins? - Answers Spike proteins, tail fibers, and fiber proteins What are the five viral replication steps? - Answers 1. Host cell recognition & attachment 2. Genome entry 3. Biosynthesis 4. Assembly/Maturation 5. Release What happens during host cell recognition? - Answers viral surface protein - host receptor bindings What happens during genome entry? - Answers -nucleic acid needs to be in the host for replication -genome alone or whole virus particle - depends of the virus What happens during biosynthesis? - Answers -mechanisms depends on the viral genome What happens during assembly/maturation? - Answers -build new virions -often prior to release. some enveloped viruses continue to mature during or after release What happens during release? - Answers -get out of the host, find new host cells, repeat -may or may not kill the host cell What is a virus? - Answers A noncellular particle containing a genome that can only replicate inside a host cell What is a viron? - Answers A complete, individual virus particle What is bacteriophage? - Answers a type of virus that specifically infects bacteria What is obligate intracellular parasite? - Answers an agent that must hijack a host cell's machinery to generate energy (atp) and synthesize proteins, as it lacks its own ribosomes and plasma membrane What is a nucleocapsid? - Answers the combination of the nucleic acid (genome) and its protein coat (capsid) What is a capsomeres? - Answers the repeating identical protein subunits that make up the capsid and determine the viruses shape What is the difference between an enveloped vs naked virus? - Answers An enveloped virus has an extra outer lipid layer and a naked virus does not have an outer lipid envelope what do spike proteins do? - Answers on the viral surface that determine host range and tissue tropism (which cells can be infected) what is DNA polymerase? - Answers used by DNA viruses to replicate their genome; often utilizes host enzymes in the nucleus what is RNA-dependent RNA polymerase (replicase)? - Answers used by RNA viruses to replicate RNA from an RNA template; these are viral-encoded and typically act in the cytoplasm what does reverse transcript do? - Answers an RNA-dependent DNA polymerase used by retroviruses to turn an RNA genome into a DNA copy what is antigenic drift? - Answers SMALL, SLOW changes caused by mutations during replication what is a antigenic shift? - Answers LARGE, RAPID changes caused by recombination or reassortment of segmented genomes What does bacteriophage cycle consist of? - Answers The lytic cycle, lysogenic cycle, induction, and lysogenic conversation What happens in the Lytic Cycle? - Answers a productive infection where the phage replicates and eventually lyses the host cell to release new virions What happens in the Lysogenic Cycle? - Answers a latent state where the viral genome integrates into the bacterial chromosome, becoming a prophage What happens in Induction? - Answers The process where a prophage is excised from the host genome and switches to the lytic pathway? What happens in Lysogenic Conversation? - Answers when a prophage gives the host bacterium new properties, such as the ability to produce toxins what is a viroid? - Answers an infectious particle consisting only of RNA with no protein coat; primarily infects plants what is a prion? - Answers an infectious age agent made only of proteins that is an abnormal form of a normal neural protein what happens during restriction-modification systems? - Answers bacteria use restrictive enzymes to cut foreign DNA at specific sequences, while using METHYLATION to protect their own "self" DNA what is CRISPR? - Answers a bacterial "immune memory" system that integrates phage sequences into the genome to recognize and cleave invading phage DNA in the future What is the difference between DNA polymerase vs RNA polymerase? - Answers DNA replicates viral genomes while RNA transcribes viral genomes Phage conversion does what? - Answers changes genotype What are viral oncogenes? - Answers genes on the provirus that increase cell division and lead to host tumor formation Proviruses are typically what kind of virus? - Answers DNA virus