a pathogen must; gain
entry, colonise the
tissue, resist defences
and cause damage to the
tissues
eg
bacteria,
viruses
am fungi
the enter though gass
exchange eg flue and food
thought the digestive system
e.g cholera
defence mechanisms so that pathogeens
do not enter are like thick mucus in the
nose to trap air pathogens, stomach acid
that kills pathogens and skin thats
impermeable and also enzymes that break down pathogens
pathogens cause damage in two ways 1,
they release toxins like cholera's pathogen
which causes toxins which leads to
diarhea and 2, they damage the hosts
tissue eg flu stops DNA and RNA synthesis
main roles in digestion
the mouth, once food enters
the the mouth amilyase is
added (present in the saliva)
which helps break down the
large carbohydrates into
maltose
the stomach
contains
enzymes that
digest
proteins into
amino acids, it
also
produceses a
lot of mucus
to protect the
stomach from
all the acidity
small intestines where digestion
happens, lots of enzymes present in
and on wall
pancreas, pancreatic juice
which contains protease which
digests lipids, starch and
proteins
two types of digestion
physical
where the food is broken down a
churned in the stomach which
increases the surface area
making it easier for the enzymes
to act
chemical
large insoluble
molecules are broken
down in to smaller
soluble molecules by a
process called hydrolysis
done by enzymes
sucrose= glucose and fructose
lactose=glucose and galactose
and maltose = glucose and
maltase
a reducing sugar is one that
donates one electron to a
chemical
test for a reducing sugar, benedict tesr
1, make sure its liquid or solid disolved in liquid
2, add an equal volume of benedict solution
3, heat in a water bath
if there are reducing
sugars present the
solution will turn a
orange-brown colour
glycosidic bond
this happens when 2 alpha
glucous' bond by removing
a H2O molecile
non- reducing sugars test
first you must add
hydrochloric acid and
heat the solution, then
add sodium charbonate
an dmake sure its
neutralised the acid and
then preform the
benedict test
starch test
add iodine to the solution if it
turns blue black then starch is
present
lactose intolerence
found in milk and other dairy products
due to the lack of
enzyme lactase
(faulty gene) which
breaks down lactose
which is found in
dairy producta causes
indigestion and gas
build up