basic immunology Flashcards
characteristics of a SIGN
can be OBSERVED and MEASURED (cough, rashes)
characteristics of a SYMPTOM
can be FELT and DESCRIBED (headaches, nausea)
what are INFECTIOUS diseases?
1.caused by PATHOGENS (disease causing organisms)
2.can be SPREAD from ONE PERSON TO ANOTHER
(influenza, HIV, pneumococcal disease, malaria)
infectious diseases can be spread in what ways?
- AIRBRONE DROPLETS
- DIRECT CONTACT OF BODY FLUIDS
- CONTAMINATED FOOD/WATER
- DISEASE VECTORS
what is a DISEASE VECTOR?
an ORGANISM that acts as a CARRIER OF AN INFECTIOUS DISEASE between ORGANISMS OF A DIFFERENT SPECIES.
what are NON INFECTIOUS DISEASES caused by?
- ENVIRONMENTAL FACTORS
- MALNUTRITION
- LIFESTYLE CHANGES
bacterium are what kind of cell
PROKARYOTES
what is a PROKARYOTE
UNICELLUAR organism WITHOUT A NUCLEUS and LACKS MEMBRANE BOUND ORGANELLES
genetic material of bacterium?
SINGLE CIRCULAR DNA
CELL WALL of bacterium is made of?
PEPITDOGLYCAN
other special characteristics of bacterium cell?
- small circular DNA molecules (PLASMIDS)
- one or more FLAGELLA
how do bacterial cells reproduce?
BINARY FISSION
similarities between PROKARYOTES and EUKARYOTES?
both have:
1. CELL SURFACE MEMBRANE
2. CYTOPLASM
3. RIBOSOMES
4. DNA as their ONLY genetic material
differences between eukaryotes and prokaryotes
- size
- composition of cell wall
- presence of membrane bound organelles
- type of ribosomes
- location of ribosomes
- location of genetic material
- site of cellular respiration
- site of photosynthesis
size of cell?
prokaryotes smaller than eukaryotes
composition of cell wall
prokaryotes- peptidoglycan
eukaryotes-cellulose (plants) / chitin (fungi)
presence of membrane bound organelles
prokaryotes- absent
eukaryotes-present
type of ribosomes
prokaryotes- 70S
eukaryotes- 80S
location of ribosomes
prokaryotes- freely suspended in cytosol
eukaryotes- either found on rough ER or freely suspended in cytosol
location of genetic material
prokaryotes- DNA found in nucleoid region
eukaryotes- DNA found in nucleus
site of cellular respiration
prokaryote- cell surface membrane
eukaryote- mitochondria
site of photosynthesis
prokaryotes- photosynthetic cell surface membranes
eukaryotes- chloroplasts
what can pneumococcal disease cause?
- middle ear infection
- lung infection (pneumonia)
- inflammation of brain membranes
- inflammation of spinal cord membranes
- infection of blood
what bacteria is pneumococcal disease caused by?
Streptococcus pneumoniae
what are the MODES OF TRANSMISSION for pneumococcal disease?
-
airborne droplets
(person inhales droplets, reaches alveoli of lungs and you’re screwed) - contaminated surfaces
SIGNS AND SYMPTOMS of pneumococcal disease?
MILD : pain, fever, swelling of affected body part
PNEUMONIA : chest pain, cough, difficulty breathing, fever
how to DIAGNOSE pneumococcal disease?
- blood test
- urine test
- phlegm test
- chest x-ray
- spinal tap
TREATMENT for pneumococcal disease
- antibiotics
- vaccination
- avoid close contact with infected people
- wear a mask
- wash hands frequently
- avoid touching nose, eyes, mouth
what are viruses?
obligate intracellular parasites that can reproduce within a host cell
why cant viruses multiply outside a living host cell?
lack of cellular components and metabolic enzymes to carry out metabolism and synthesize proteins
can viruses be seen under a microscope
largest virus (500nm) can barely be seen under a light microscope
living characteristics of viruses
- acquire and use energy
- reproduce at a very fast rate
- evolve through time, adapt to environment
non-living characteristics of viruses
- no organelles
- cannot carry out own metabolism or synthesize proteins
- does not grow, move, respire, feed or excrete
why are viruses host specific
ability to interact with specific surface membrane proteins on the host cell surface membrane
structure of a virus
- contain genetic material (DNA/RNA) enclosed within a protein coat (capsid)
- some viruses have enzymes within the capsid
- some viruses have a membranous envelope
how does INFLUENZA infect a cell?
- has a membranous envelope containing projections made out of protein, which attaches onto host cell, gaining entry
- cells take in virus though endocytosis
mode of transmission of INFLUENZA
- airborne droplets
- contact with contaminated surfaces
signs and symptoms of INFLUENZA
- high fever
- sore throat
- congestion
- dry cough (no excessive mucus)
- headache
how to diagnose INFLUENZA
- signs and symptoms are present
- laboratory tests
treament for influenza
- antiviral drugs (blocking the release of virions from infected cells)
- pain relievers to alleviate symptoms of flu
- vaccines
- same preventive measures mentioned for pneumococcal disease
what are ANTIGENS?
- surface membrane proteins found on pathogens that are recognised by leukocytes
- bind to specific receptors on leukocyte’s cell surface membrane
how does a white blood cell respond to recognising an ANTIGEN?
-
secretes antibodies
OR - kills pathogen by phagocytosis
what is an immune response
a mechanism used by a host to defend itself against foreign pathogens
another term for red and white blood cells
red blood cell - erythrocyte
white blood cell- leukocyte
where do blood cells arise from
hematopoietic stem cells found in the bone marrow
what process gives rise to blood cells
hematopoiesis
types of leukocytes (white blood cells)
- lymphocyte
- neutrophil
- macrophage
details of a LYMPHOCYTE
2nd most common
cytoplasm: few or no granules
little cytoplasm
nucleus: round
functions of a LYMPHOCYTE
- B lymphocytes mature into plasma B cells that produce and secrete antibodies OR memory B cells that provide long term immunity.
- some memory B cells will diffrentiate into plasma B cells
details of a NEUTROPHIL
most common
cytoplasm: large, pale granules containing hydrolytic enzymes
nucleus: multi-lobed
functions of a neutrophil
- engulf and destroy foreign bodies via phagocytosis
- short lived
- circulates the blood
details of MACROPHAGE
least comon
cytoplasm: few to no granules
nucleus: kidney bean shaped
functions of a MACROPHAGE
- engulf and destroy foreign bodies via phagocytosis
- long lifespan
- move freely, found in almost all organs and tissues
what is a vaccine?
contains an agent resembling a pathogen and prevents infectious diseases by stimulating lymphocytes to quickly produce antibodies when the pathogen invades
what is an antibody?
- proteins secreted by lymphocytes that bind to specific antigens on pathogen
- they can kill pathogen directly or mark pathogen for further destruction by macrophages and neutrophils
mode of action of vaccines
- a vaccine, containing an antigen, enters the body
- antigen binds to the receptor of lymphocyte that is complementary to shape of antigen, causes lymphocyte to divide rapidly and differentiate into memory B cells and plasma B cells
- plasma b cells secrete large amount of antibodies into bloodstream
- antibodies bind onto antigen on the pathogen, either killing them or marking them for destruction by macrophages or neutrophils
- memory B cells remain in body and can rapidly divide or differentiate into plasma B cells during future infections of the same pathogen (immunity)
what is an antibiotic
drug used to treat bacteria by interfering with the growth and metabolic activities of bacteria
mode of action of ANTIBIOTICS
inhibition of:
-
SYNTHESIS OF BACTERIAL CELL WALL
prevents synthesis of peptidolycan cell wall, causes bacteria to expand, burst and die by osmosis -
BACTERIAL CELL MEMBRANE FUNCTION
breaks up cell surface membrane -
RIBOSOME FUNCTION IN PROTEIN SYNTHESIS
binds to bacterial 70s ribosome, prevents them fromsynthesizing proteins -
ENZYME ACTIVITY
inhibits the enzymeneeded for synthesis of folic acid (needed for growth) -
DNA REPLICATION
inhibits enzyme needed for DNA replication, preventing bacteria from dividing via binary fission
how antibiotic resistant bacteria arise
- colony of bacteria is exposed to mutagenic agents, causing changes to genetic material, allows some bacterial cells to produce proteins that confer antibiotic resistance
- if amount of antibiotic is inadequate to kill the bacteria, resistant bacteria will multiply, passing down their genes for antibiotic resistance to the next generation, resulting in more resistant bacteria
- different or more powerful antibiotic must be used to kill these resistant bacteria.
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how can antibiotic resistance be reduced?
- course of antibiotics should be completed
- do not misuse or overuse antibiotics
- use antibiotics only when neccessary