Quiz 4

Question 1

Dormant Vs Active Tuberculosis (TB)

Answer 1

Dormant: bacteria is present in the body but are inactive and cause no symptoms. people with latent TB are not contagious

Active: The bacteria are active and multiply, causing symptoms and can be spread to others.

Question 2

Primary vs. Secondary vs. Disseminated TB

Answer 2

Primary: initial infection, usually occurring in the lungs. May resolve or progress to active disease

Secondary: Reactivation of dormant bacteria, often due to weakened immune system

Disseminated: infection spreads beyond the lungs to other parts of the body through bloodstream

Question 3

Testing for TB presence

Answer 3

Tuberculin Skin Test : A small amount of tuberculin is injected under the skin

Interferon Gamma release: blood tests that measure the immune response to TB bacteria.

Sputum Test: Microscopy and culture of sputum samples to detect TB bacteria.

Question 4

Vaccine for TB?

Answer 4

BCG vaccine: used to prevent severe forms of TB in children. Not widely used in the US but is common in countries with high TB prevalence.

Question 5

Pertussis Cough?

Answer 5

Characterized by severe coughing fits followed by a whooping sound during inhalation

Question 6

Vaccine for Pertussis?

Answer 6

DTaP Vaccine: For children, protecting against diphtheria, tetanus, and pertussis

Tdap Vaccine : for older children, adults, as a booster

Question 7

Latent infection?

Chronic Infection?

Acute Infection?

Answer 7

Latent: virus remains dormant within the host cell and can reactivate later ex) Herpes

Chronic: continuous, low-level production of the virus over a long period ex) Hepatitis B (HBV)

Acute : Rapid onset of disease, short duration ex) Influenza (flu)

Question 8

General Structure of SARS-CoV-2

Answer 8

RNA or DNA: RNA virus
Enveloped or Not: Enveloped

Question 9

SARS-CoV-2 host cell receptor and Host Range

Answer 9

Host Cell Receptor: ACE2
Host Range: primarily humans, but also other mammals

Question 10

Type of Influenza Virus That is the main human pathogen

Answer 10

Influenza A: the primary cause of seasonal flu epidemics and pandemics in humans.

Question 11

Main Spikes for the Flu virus and their roles

Answer 11

Hemagglutinin (HA): helps the virus bind to and enter host cells

Neuraminidase (NA) : helps the new viral particles release from the host cell

Question 12

Methods of infection and Flu viral multiplication

Answer 12

Method of Infection: HA binds to sialic acid receptors on the host cell, allowing entry

Viral Multiplication: Involves entry, replication, assembly, and release from the host cell.

Question 13

Antigenic Drift:

Answer 13

Definition: small, gradual changes in the genes of influenza viruses that happen over time

Mechanism: Mutations accumulate in the virus’s RNA

Impact: causes seasonal flu variations, requiring annal vaccine updates.

Question 14

HIV: CCR5 Coreceptor Function

Answer 14

Function: a protein on the surface of certain cells that HIV uses to enter the cells.

Question 15

Antigenic Shift:

Answer 15

Definition: Abrupt, major changes in influenza A viruses, resulting in new hemagglutinin and or proteins

Mechanism: Reassortment of genes from different virus strains infecting the small cell

Impact: can lead to pandemics since the population has little to no pre existing immunity

Question 16

Cells with HIV receptors

Answer 16

Types: CD4+ T cells, macrophages, dendritic cells
Receptors: CD4 and either CCR5 or CCXR4

Question 17

HIV mechanism of Replication

Answer 17

Entry: HIV binds to CD4 and a coreceptor (CCR5/CXCR4) on the host cell.
Reverse Transcription: HIV’s RNA is reverse-transcribed into DNA by reverse transcriptase (RT).
Integration: Viral DNA integrates into the host cell genome, forming a provirus.
Transcription & Translation: Host cell machinery transcribes and translates viral genes.
Assembly & Release: New viral particles are assembled and released from the host cell.

Question 18

Reverse Transcriptase?

Answer 18

Enzyme that converts viral RNA into DNA

Question 19

Provirus definition

Answer 19

integrated viral DNA in the host genome, capable of producing new viruses

Question 20

Difference between HIV & AIDS

Answer 20

HIV: virus that causes AIDS. attacks and weakens immune system

AIDS: the most advanced stage of HIV infection. diagnosed when CD4+ T cell count falls below 200 cells/mm3 or the presence of certain opportunistic infections

Question 21

Steps of Replication mode of HIV

Answer 21

Attachment and Fusion: HIV binds to CD4 receptor and coreceptor, fuses with the host cell membrane.
Reverse Transcription: RNA genome is reverse-transcribed into DNA.
Integration: Viral DNA integrates into the host cell DNA.
Transcription: Host cell machinery transcribes viral DNA into RNA.
Translation: RNA is translated into viral proteins.
Assembly and Release: New viruses are assembled and bud off from the host cell.

Question 22

Bacteriophages and Their mode of Multiplication

Answer 22

Phages: Definition: viruses that infect bacteria

Modes of multiplication: Lytic cycle and Lysogenic Cycle

Question 23

Temperate Phages

Answer 23

Definition: Bacteriophages that can choose between the lytic and lysogenic pathways
Can either cause immediate lysis of the host or integrate their genome into the hosts genome as a prophage

Question 24

Prophage

Answer 24

Definition: the phage that is integrated into the bacterial hosts genome

Remains dormant and replicates along with the hosts DNA until induced to enter the lytic cycle

Question 25

Lysogenic Conversion

Answer 25

A change in the phenotype of a bacterium due to the presence of a prophage . ex) the prophage can carry genes that confer new properties to the host bacterium

Question 26

Lysogenic Conversion

Answer 26

Definition: a change in the phenotype of a bacterium due to the presence of a prophage

Question 27

HBV is DNA or RNA?

Answer 27

DNA. only HAV and HCV is RNA

Question 28

how is HCV, HBV, HAV transmitted?

Answer 28

HCV: blood
HBV: secual contact, blood, perinatal
HAV: fecal-oral

Question 29

Lymph Node Fuctions

Answer 29

filtration: trap and destroy foregin particles: bacteria, viruses

Question 30

Lymphatic Vessesl?

Answer 30

structure: thin walled vessels with valves to prevent back flow

function: transport lymp from peripheral tissue to the central venous system