Basic Immunology

Question 1

how can infectious diseases be spread?

Answer 1

• by droplet nuclei
• direct contact
• contaminated food and water
• disease vectors; organism that acts as a carrier of an infectious disease between organisms of a different species

Question 2

what are non-infectious diseases?

Answer 2

• not caused by pathogens
• cannot be spread
• inherited from malnutrition, lifestyle changes and environment factors

Question 3

what is a host?

Answer 3

an organism infected by a pathogen

Question 4

structure of a bacterium?

Answer 4

• prokaryotes; no nucleus and membrane-bound organelles
• single circular DNA plasmids
• peptidoglycan cell wall
• one or more flagella

Question 5

similarities between eukaryotes and prokaryotes?

Answer 5

• presence of cell surface membrane
• presence of ribosomes
• presence of cytoplasm
• DNA only as genetic material

Question 6

differences between eukaryotes and prokaryotes?

Answer 6

• eukaryotes are larger than prokaryotes
• cell wall composition
• membrane-bound organelles
• location of genetic material
• site of cellular respiration
• site of photosynthesis

Question 7

what is pneumococcal disease caused by?

Answer 7

Streptococcus pneumoniae

Question 8

how is S. pneumoniae transmitted?

Answer 8

• respiratory droplets
• contaminated surfaces and objects

Question 9

what are some signs and symptoms of S. pneumoniae?

Answer 9

• pain fever and swelling of infected sites
• leads to pneumonia
• chest pain
• cough
• difficulty breathing
• fever

Question 10

how to treat and prevent S. pneumoniae?

Answer 10

• take antibiotics
• wash hands
• wear a mask
• get a pneumococcal vaccination
• avoid touching eyes, nose and mouth

Question 11

what are viruses?

Answer 11

obligate intracellular parasites that can reproduce only in a host cell

Question 12

why are viruses unable to reproduce outside a host cell?

Answer 12

• no essential cellular components
• no essential metabolic enzymes
• cannot carry out metabolism and synthesize proteins

Question 13

living characteristics of viruses?

Answer 13

• able to acquire and use energy
• reproduce at a fast rate in host cells
• evolve and adapt to environment through time

Question 14

non-living characteristics of viruses?

Answer 14

• no organelles and cellular components
• cannot carry out metabolism
• cannot synthesize proteins
• cannot grow, move, feed and excrete

Question 15

characteristics of a virus?

Answer 15

• very small
• host specific
• genetic material (DNA or RNA) enclosed within protein coat capsid
• some viruses contain membranous envelope

Question 16

how is influenza transmitted?

Answer 16

• droplet infection
• contact with contaminated surfaces

Question 17

signs and symptoms of influenza?

Answer 17

• incubation period of a day
• high fever
• sore throat
• no excessive mucus

Question 18

how to treat and prevent influenza?

Answer 18

• take vaccinations
• antiviral drugs that block virions release from infected cells
  (pretty much the same actions as with Streptococcus pneumoniae)

Question 19

properties of lymphocytes and their functions?

Answer 19

• few or no granules
• round nucleus
• little cytoplasm
  1. mature into plasma B cells that secrete antibodies
  2. mature into memory B cells that differentiate into plasma B cells for subsequent infections

Question 20

properties of neutrophils and their functions?

Answer 20

• large, pale granules containing hydrolytic enzymes
• multi-lobed nucleus
• short-lived
  1. engulfs and destroys foreign bodies through phagocytosis
  2. circulates the blood

Question 21

properties of macrophages and their functions?

Answer 21

• few or no granules
• kidney bean-shaped nucleus
• long lifespan
  1. engulfs and destroys foreign bodies through phagocytosis
  2. moves freely in organs and tissues

Question 22

what is a vaccine?

Answer 22

an agent that resembles a pathogen by stimulating lymphocytes to quickly produce antibodies when a pathogen invades

Question 23

what is the mode of action of vaccines?

Answer 23

1. agent that resembles a pathogen enters the body
2. antigen binds to the receptor of a lymphocyte complementary to its shape
3. lymphocyte differentiates to plasma B and memory B cells
4. plasma B cells secrete large amounts of antibodies into the bloodstream
5. antibodies bind to antigens on pathogen to kill or mark for phagocytosis
6. memory B cells remain in the body to divide rapidly into plasma B cells for subsequent infections to provide immunity

Question 24

mode of action of antibiotics?

Answer 24

1. inhibits the synthesis of bacterial cell wall
2. inhibits function of cell surface membrane
3. inhibits ribosome function
4. inhibits enzyme activity in cytoplasm
5. inhibits DNA replication

Question 25

mode of action for bacteria to become antibiotic-resistant?

Answer 25

1. exposed to mutagenic agents 2. changes to genetic material 3. produce proteins that resist antibiotics 4. resistant bacteria survive 5. bacteria multiplies and passes down antibiotic-resistant genes to the next generation