digestive system Flashcards
what are carbohydrates broken down into
glucose
what are lipids broken down into
3 fatty acids and glycerol
what are proteins broken down into
amino acids
function of proteins
for growth and repair
function of lipids
-provides insulation
-long term energy store
-protection of organs
function carbohydrates
used in respiration
what are enzymes
a group of large porteins that act as biological catalysts
whats the digestive system
an organ system where several organs work together to digest and absorb food
lock and key theory
enzymes with uniquely shaped active sights bind with substrates which are complimentary to the active sight to form an enzyme substrate complex
what happens after an enzyme substrate complex is formed
products are released from the active sight and the enzyme remains unchanged
what factors can affect enzyme activity
temperature and PH
whats an enzyme which has been denatured
when the enzyme’s active sight loses its shape and is no longer complimentary to the substrate
how does high temperature affect the enzyme
shape of active sight becomes denatured and substrate no longer fits
how does increasing temperature change rate of reaction
particles gain more kinetic energy which increases collision frequency
how does PH affect enzymes
if PH is too high or low, enzymes denature and rate of reaction slows down
word equation for catalase experiment in potato tissue
hydrogen peroxide —> (catalase) makes water + oxygen
whats the role of hydrochloric acid in the stomach
to break down food and kill bacteria
function of epithelial tissue
covers outside and inside of stomach
function of glandular tissue
produces digestive juices
function of muscular tissue
allows food to be churned around stomach
order/process of digestion
mouth - oesophagus - stomach - small intestine (pancreas and liver) - large intestine
what happens in the mouth
food is chewed/broken down into smaller pieces
amylase from saliva breaks down starch
what happens in the oesophagus
peristalsis
what happens in the stomach
hydrochloric kills bacteria on food and provides optimum PH for proteases to break down proteins into amino acids
muscles churn food
what happens in the small intestine
where absorption of nutrients take place - molecules absorbed into bloodstream
what happens in the pancreas
pancreatic juice is made containing amylase, carbohydrase, lipase and protease
what happens in the liver
bile is produced which speeds up digestion of lipids
what happens in the gallbladder
stores bile then secretes it into small intestine
what happens in the large intestine
absorbs water leaving a mass of undigested food
what enzyme digests starch
amylase
where is fat digested
in the small intestine
what do lipases do
break down lipids into glycerol and 3 fatty acids
where does the breakdown of lipids happen
small intestine and pancreas
where does the breakdown of protein happen
stomach, pancreas, small int.
where does the breakdown of carbohydrates happen
pancreas, small intestine
what does carbohydrase do
breakdown carbohydrates into glucose or smaller sugars
what does amylase do
breakdown starch into maltose /simple sugars
where does the breakdown of starch happen
pancreas, mouth (salivary glands), small int.
what do proteases do
breakdown protein into amino acids
how is optimum PH maintained in the stomach
by the presence of hydrochloric acid
why is it important for bile to neutralise food from stomach
so PH doesn’t become acidic and fall in the small intestine. enzymes denature
what does bile do
neutralise food and emulsify lipids
how/why does bile emulsify lipids
bile emulsifies lipids to break them into smaller droplets which increase surface area to volume ration
equation to show digestion of fat
fat –> (lipase) makes fatty acids and glycerol
what happens to enzymes when temperature is too low
enzymes and substrates have less kinetic energy so they move around slower. meaning the collision frequency is much lower and fewer enzyme substrate complexes are formed
what do digestive enzymes do
convert food into small soluble molecules that can be absorbed into bloodstream
suggest why a person with coeliac disease might have symptoms of poor growth
coeliac disease damages the villi in the small intestine and causes it to flatten out. meaning that the surface area of it decreases and we absorb less nutrients, glucose for energy and amino acids in food which help build new proteins. all of these help us to grow so if there is a shortage of them, our growth would be very slow or even stunted.
