Ch. 24.2 Viruses Flashcards
Are viruses living things?
No, they only possess portion of properties of living organisms
Do viruses have cell membrane or cellular organelles?
No, viruses don’t have cell membrane or cellular organelles
What are viruses’ hereditary material?
DNA or RNA
Do viruses replicate outside of host cell?
No, they don’t
What do viruses infect?
Viruses infect specific cell types that hs the receptors viruses can bind to
What does hepatitis of viruse infect?
Hepatitis only infect liver cells
What are zoonotic viruses?
Viruses that can bind to similar receptors in more than one species
What is the example of zoonotic viruses?
Influenza that bind to birds, humans, or pigs
What is the mutation rate of virus?
Viruses have high mutation rate therefore they are likely to cause pandemics
What are bacteriophages?
Bacteriophages are viruses that infect bacteria
What is lytic cycle?
Viruses kill the infected host and replicating (spreading)
What is lysogenic cycle?
virus integrates itself into the host genome but does not replicate
What is prophage?
Virus residing in the host
What cycles does virus that infect humans have?
It can either be lytic cycle or both lytic and lysogenic cycles
What is Attachment for lytic and lysogenic Cycles?
The proteins on the virus capsid bind to a specific receptor
What is Infiltration for lytic and lysogenic Cycles?
The host cell takes up the virus
What is Replication for lytic and lysogenic Cycles?
The virus uses host cell organelles, nutrients, and ATP to make new virus particles
What is Assembly for lytic and lysogenic Cycles?
New virus particles form and are released from the host cell, causing lysis and death of the host cell
How does virus with RNA replicate within host cell?
Viruses that contain RNA must convert to DNA before they replicate within the host cell
What is the enzyme reverse transcriptase?
Process of viruses that contain RNA converting into DNA
Is it viruses with RNA or DNA that mutate more rapidly? and what is the reason behind that?
It is VIruses with RNA that mutate more rapidly because reverse transcriptase make mistakes during replication due to the lack of proofreading ability
What are the examples of viruses with RNA?
Examples of RNA viruses include HIV, influenza, SARS, hepatitis,
measles, and polio
What does HIV infect?
HIV infects only certain white blood cells within the human bloodstream (immune cells)
What are specific cells that HIV infect?
CD4+ T cells but also macrophages and dendritic cells
What does HIV infection lead to?
HIV infection leads to a low level of properly functioning immune cells
What happens if level of functioning immune cells decrease?
When immune cell numbers decline below a critical level, the body becomes progressively more susceptible to opportunistic infections
What happens if HIV infection is untreated?
If untreated, eventually most HIV-infected individuals develop AIDS (acquired immunodeficiency syndrome)
Explain Rhinovirus, adeno-virus, and respiratory syncytal virus of viruses
Infected on sinuses and upper airways: Over 100 viruses cause common cold and killed by immune system; Symptoms include stuffed or runny nose, sneezing, sore throat, and coughing usually don’t last longer than 7 days to 10 days
Explain influenza of viruses
Infected on sinuses and upper airways: There are A, B, and C type influenza A and B being most common that is similar to common cold, influenza is RNA virus which spread and mutates faster may leading to second opportunistic infection
Explain Herpes of viruses
Infected on Lips or genitals, and sensory neurons: DNA virus causing cold sores or genital herpes transmittied by skin to skin contact having a period and re-appears when it’s infected during lytic cycle; easily treated by antiviral medication
Explain Human papilloma viruses (HPV) of viruses
Infected on keratinocytes of skin:100 strains of HPV viruses that cause warts but mostly cause no symptom; some strains cause wart from 30-40% of sexual contaction and two strains cause female cervical cancer
Explain hepatitis of viruses
Infected on liver: Inflammation of liver caused by 5 types of hepatitis which are A, B, C, D, and E; A and E are cause through contaminated food or water causing no major disease while B, C, D are transmitted through body fluid especially B and C cause chronic disease in millions of people
Explain Rotavirus of viruses
Infected on gastrointestinal tract: common intestinal infection in children, almost all children will have the infection by 5 giving them antibodies that will protect them against future disease; adults barely has it
Explain Epstein-Barr virus (EBV), mononucleosis of viruses
Infected on B cells and epithelial cells: Herpes virus transmitted through saliva; 90 % of adults has this infection by 40, common viral infection which cause asymptomatic in young ones to severe fatigue that last months and fever, sore throat,swollen lymph nodes
