A Level Biology: Primary Non-Specific
Defences against Pathogens
Give four examples of primary non-specific defences against pathogens in animals -
correct answerskin, blood clotting, mucous, expulsive reflexes What is the outer layer of
skin called? - correct answerepidermis What are kertinocytes? - correct
answerepidermal cells that produce karatin What % of cells in the epidermis are
keratinocytes? - correct answer90% How and where are keratinocytes produced? -
correct answerby mitosis at the base of the epidermis True or false: keratinocytes
migrate out to the skins surface but die by the time they get there - correct answertrue
What is the process called where by the cytoplasm of keratinocytes dries out and
replaced by keratin-causing the cells to die? - correct answerkeratinisation What protein
is exposed when damage to a blood vessel occurs? - correct answercollagen What
does exposed collagen from the vessel wall cause platelets to do? - correct
answerattract to the collagen and become active platelets Give the equation that
produces thrombin enzymes - correct answerthromboplastin -> prothrombin -> thrombin
What two substances aid the production of prothrombin from thrombin? - correct
answervitamin k and calcium What reaction does the thrombin enzyme catalyse? -
correct answerthe formation of insoluble fibrin from soluble fibrinogen What is the
function of fibrin in a blood clot? - correct answerit creates fibres to hold a scab together
What three substances make up a scab? - correct answerfibrin, platelets, red blood
cells What are the four steps when repairing skin under a scab? - correct answera
deposition of fibrous collagen is created, stem cells divide by mitosis to form new cells
and migrate to the edges of the cut to differentiate, new blood vessels grow and the
tissue contracts to draw the edges of the cut together and the scab is released Give
three examples of exchange surfaces that are thinner and less protected from infection -
correct answerair ways, lungs, digestive system What physical non-specific defence
protects epithelial cells on exchange surfaces from pathogens? - correct answermucous
membranes What cells produce mucous? - correct answergoblet cells Where are
mucous producing glands found? - correct answerunder the epithelium What two things
does mucous contain that removes pathogens? - correct answerlysozymes and
phagocytes What is the role of lysozymes in mucous? - correct answerto break down
bacterial and fungal cell walls What is the role of cilia in the mucociliary escalator ? -
correct answerto waft mucous along the top of the trachea where it can be swallowed
How is the stomach involved in the mucociliary escalator? - correct answerpathogens
are killed by the acidity of the stomach as the low pH denatures pathogen's enzymes
Give 4 examples of when mucous membranes are found in the body other than the
trachea - correct answernose, ear, anus, genitals Give three examples of expulsive
Defences against Pathogens
Give four examples of primary non-specific defences against pathogens in animals -
correct answerskin, blood clotting, mucous, expulsive reflexes What is the outer layer of
skin called? - correct answerepidermis What are kertinocytes? - correct
answerepidermal cells that produce karatin What % of cells in the epidermis are
keratinocytes? - correct answer90% How and where are keratinocytes produced? -
correct answerby mitosis at the base of the epidermis True or false: keratinocytes
migrate out to the skins surface but die by the time they get there - correct answertrue
What is the process called where by the cytoplasm of keratinocytes dries out and
replaced by keratin-causing the cells to die? - correct answerkeratinisation What protein
is exposed when damage to a blood vessel occurs? - correct answercollagen What
does exposed collagen from the vessel wall cause platelets to do? - correct
answerattract to the collagen and become active platelets Give the equation that
produces thrombin enzymes - correct answerthromboplastin -> prothrombin -> thrombin
What two substances aid the production of prothrombin from thrombin? - correct
answervitamin k and calcium What reaction does the thrombin enzyme catalyse? -
correct answerthe formation of insoluble fibrin from soluble fibrinogen What is the
function of fibrin in a blood clot? - correct answerit creates fibres to hold a scab together
What three substances make up a scab? - correct answerfibrin, platelets, red blood
cells What are the four steps when repairing skin under a scab? - correct answera
deposition of fibrous collagen is created, stem cells divide by mitosis to form new cells
and migrate to the edges of the cut to differentiate, new blood vessels grow and the
tissue contracts to draw the edges of the cut together and the scab is released Give
three examples of exchange surfaces that are thinner and less protected from infection -
correct answerair ways, lungs, digestive system What physical non-specific defence
protects epithelial cells on exchange surfaces from pathogens? - correct answermucous
membranes What cells produce mucous? - correct answergoblet cells Where are
mucous producing glands found? - correct answerunder the epithelium What two things
does mucous contain that removes pathogens? - correct answerlysozymes and
phagocytes What is the role of lysozymes in mucous? - correct answerto break down
bacterial and fungal cell walls What is the role of cilia in the mucociliary escalator ? -
correct answerto waft mucous along the top of the trachea where it can be swallowed
How is the stomach involved in the mucociliary escalator? - correct answerpathogens
are killed by the acidity of the stomach as the low pH denatures pathogen's enzymes
Give 4 examples of when mucous membranes are found in the body other than the
trachea - correct answernose, ear, anus, genitals Give three examples of expulsive
