BIO 169 ACTUAL 2026/2027 EXAM QUESTIONS AND
SOLUTIONS RATED A+
✔✔Compare the locations of MALT and Peyer patches. - ✔✔MALT located in lamina
propria of the mucosa of the gastrointestinal, respiratory, urinary, and reproductive
tracts
Peyer patches in gastrointestinal tract lumen, small intestine
✔✔Compare and contrast the 5 major classes of infectious agents - ✔✔Bacteria:
microscopic, single-celled organisms composed of prokaryotic cells, lack of nuclear
envelope, lack membrane-bound organelles, enclosed by cell wall
Viruses: not cells, much smaller than bacteria, composed of DNA or RNA within a
protein capsid or shell
Fungi: composed of eukaryotic cells that have a cell wall external to the plasma
membrane, includes molds, yeast, and multicellular fungi that produce spores
Protozoans: microscopic, unicellular eukaryotic organisms that lack a cell wall, ones that
cause disease are considered to be unicellular parasites
Parasitic worms: nonmicroscopic multicellular parasites that reside within a host, which
provides nourishment to the parasite
✔✔Describe prions and name the disease they cause - ✔✔small fragments of infectious
proteins that cause disease in nervous tissue
cause Variant Creutzfeldt-Jakob disease (cow to human)
✔✔Types of leukocytes of the immune system and describe how they may be found -
✔✔-Granulocytes : neutrophils (most abundant, multi-lobed, phagocytize bacteria and
debris), eosinophils (fight parasitic infections, large red/orange), and basophils (least
common, release histamine and heparin, dark purple) ; found in blood
-Monocytes (largest, become macrophages in tissues)
-T-lymphocytes (T-cells)(attack infected cells), B-lymphocytes (b-cells)(-produce
antibodies), and NK cells (natural killers)(destroy virus-infected or cancer cells)
✔✔Define cytokines, describe their similarities to hormones and list general categories -
✔✔small, soluble proteins produced and released by various types of cells to regulate
and facilitate immune system activities, communication between cells, control
development and behavior of immune cells and regulate the inflammatory response
Like hormone: binds to specific receptor
✔✔Interleukin (IL) - ✔✔regulates immune cells
source : T lymphocytes, macrophages, endothelial cells
✔✔Tumor necrosis factor (TNF) - ✔✔destroys tumor cells
source: t-lymphocytes, macrophages, mast cells, dendritic cells
, ✔✔Colony-stimulating factor (CSF) - ✔✔stimulates leukopoiesis in bone marrow to
increase synthesis of a specific type of colony of leukocytes
source: t-lymphocytes and monocytes
✔✔Interferon (IFN) - ✔✔"interferes with" replication of pathogens that enter cells
(intracellular pathogens)
source: infected cells, NK cells, T-lymphocytes
✔✔Compare and contrast the primary features of innate and adaptive immunity -
✔✔Innate immunity : provided by multiple components that protect against a wide array
of substances; immediate response , skin and mucosal membranes (prevent entry) ,
nonspecific internal defenses, most immune cells
Adaptive immunity: provided by lymphocytes that are activated to replicate and respond
when stimulated by a specific antigen, response takes days , T-lymphocytes, B-
lymphocytes->plasma cells synthesize and release antibodies
✔✔describe the physical, chemical and biological barriers to entry of harmful agents
into the body - ✔✔Physical barriers : block pathogens from entering body ex: skin,
mucous membranes, cilia (tiny hairs), flushing actions (tears, saliva, urine, and
coughing)
Chemical: lysozyme (enzyme in tears, saliva, and mucus), stomach acid (HCl), sebum
(oily secretion on skin), sweat, antimicrobial peptides
Biological: normal microbiota on skin and mucous membranes, compete with pathogens
for space and nutrients
✔✔List the 4 main components of the nonspecific internal defenses - ✔✔-selected
immune cells
-antimicrobial proteins
-inflammation
-fever
✔✔Describe the cells that function as part of the nonspecific internal defenses un
providing innate immunity - ✔✔Phagocytic cells: "pac man cells" eat microbses ex
neutrophils, macrophages, dendritic cells
Proinflammatory cells: "alarm cells" release histamine and start inflammation ex mast
cells and basophils
Apoptosis-initiating cells "assassin cells" kill infected cells by triggering apoptosis ex NK
cells
Eosinophils "parasite fighters" release toxic granules to attack parasites
✔✔Explain the general function of interferons - ✔✔target intracellular pathogens,
interfere with the process of pathogen replication in our cells
SOLUTIONS RATED A+
✔✔Compare the locations of MALT and Peyer patches. - ✔✔MALT located in lamina
propria of the mucosa of the gastrointestinal, respiratory, urinary, and reproductive
tracts
Peyer patches in gastrointestinal tract lumen, small intestine
✔✔Compare and contrast the 5 major classes of infectious agents - ✔✔Bacteria:
microscopic, single-celled organisms composed of prokaryotic cells, lack of nuclear
envelope, lack membrane-bound organelles, enclosed by cell wall
Viruses: not cells, much smaller than bacteria, composed of DNA or RNA within a
protein capsid or shell
Fungi: composed of eukaryotic cells that have a cell wall external to the plasma
membrane, includes molds, yeast, and multicellular fungi that produce spores
Protozoans: microscopic, unicellular eukaryotic organisms that lack a cell wall, ones that
cause disease are considered to be unicellular parasites
Parasitic worms: nonmicroscopic multicellular parasites that reside within a host, which
provides nourishment to the parasite
✔✔Describe prions and name the disease they cause - ✔✔small fragments of infectious
proteins that cause disease in nervous tissue
cause Variant Creutzfeldt-Jakob disease (cow to human)
✔✔Types of leukocytes of the immune system and describe how they may be found -
✔✔-Granulocytes : neutrophils (most abundant, multi-lobed, phagocytize bacteria and
debris), eosinophils (fight parasitic infections, large red/orange), and basophils (least
common, release histamine and heparin, dark purple) ; found in blood
-Monocytes (largest, become macrophages in tissues)
-T-lymphocytes (T-cells)(attack infected cells), B-lymphocytes (b-cells)(-produce
antibodies), and NK cells (natural killers)(destroy virus-infected or cancer cells)
✔✔Define cytokines, describe their similarities to hormones and list general categories -
✔✔small, soluble proteins produced and released by various types of cells to regulate
and facilitate immune system activities, communication between cells, control
development and behavior of immune cells and regulate the inflammatory response
Like hormone: binds to specific receptor
✔✔Interleukin (IL) - ✔✔regulates immune cells
source : T lymphocytes, macrophages, endothelial cells
✔✔Tumor necrosis factor (TNF) - ✔✔destroys tumor cells
source: t-lymphocytes, macrophages, mast cells, dendritic cells
, ✔✔Colony-stimulating factor (CSF) - ✔✔stimulates leukopoiesis in bone marrow to
increase synthesis of a specific type of colony of leukocytes
source: t-lymphocytes and monocytes
✔✔Interferon (IFN) - ✔✔"interferes with" replication of pathogens that enter cells
(intracellular pathogens)
source: infected cells, NK cells, T-lymphocytes
✔✔Compare and contrast the primary features of innate and adaptive immunity -
✔✔Innate immunity : provided by multiple components that protect against a wide array
of substances; immediate response , skin and mucosal membranes (prevent entry) ,
nonspecific internal defenses, most immune cells
Adaptive immunity: provided by lymphocytes that are activated to replicate and respond
when stimulated by a specific antigen, response takes days , T-lymphocytes, B-
lymphocytes->plasma cells synthesize and release antibodies
✔✔describe the physical, chemical and biological barriers to entry of harmful agents
into the body - ✔✔Physical barriers : block pathogens from entering body ex: skin,
mucous membranes, cilia (tiny hairs), flushing actions (tears, saliva, urine, and
coughing)
Chemical: lysozyme (enzyme in tears, saliva, and mucus), stomach acid (HCl), sebum
(oily secretion on skin), sweat, antimicrobial peptides
Biological: normal microbiota on skin and mucous membranes, compete with pathogens
for space and nutrients
✔✔List the 4 main components of the nonspecific internal defenses - ✔✔-selected
immune cells
-antimicrobial proteins
-inflammation
-fever
✔✔Describe the cells that function as part of the nonspecific internal defenses un
providing innate immunity - ✔✔Phagocytic cells: "pac man cells" eat microbses ex
neutrophils, macrophages, dendritic cells
Proinflammatory cells: "alarm cells" release histamine and start inflammation ex mast
cells and basophils
Apoptosis-initiating cells "assassin cells" kill infected cells by triggering apoptosis ex NK
cells
Eosinophils "parasite fighters" release toxic granules to attack parasites
✔✔Explain the general function of interferons - ✔✔target intracellular pathogens,
interfere with the process of pathogen replication in our cells
