Digestion Flashcards
(30 cards)
what is the definition of a tissue?
a group of cells with a similar structure and function
what is the definition of an organ?
a group of tissues working together for a specific function
what are the 3 main nutrients that food contains?
carbohydrates, proteins and lipids
what happens during digestion?
large food molecules are broken down into smaller molecules by enzyme, which can then be absorbed into the bloodstream
what is the first stage of digestion?
MOUTH
-food is chewed
-enzymes in the saliva digest starch into smaller sugar molecules
SALIVARY GLANDS
-releases saliva
-contains the enzyme amylase
what is the second stage of digestion?
OESOPHAGUS
-food passes down it into the stomach
STOMACH
-enzymes begin the digestion of proteins
-containing hydrochloric acid, helping the break down
-contracts muscular walls
-produces pepsin (protease - proteins into amino acids)
what does the pancreas produce?
all three types of digestive enzyme - amylase, protease, lipase
what does the churning action within the stomach do?
turns the food into fluids increasing the surface areas for enzymes to digest
where is bile made?
liver - emulsifying fats (mechanical digestion)
what happens in the small intestine?
where most digestion takes place, releasing digestive enzymes
what are they important features of villi?
-huge surface area
-single layer of surface cells
-really good blood supply
-micro villi which increases surface area even more
what is the role of the large intestine?
to absorb excess water
what is stored in the rectum?
waste product before being released out of the anus
what is the function of the gall bladder?
stores bile to release into the duodenum
define a catalyst
a substance that increases the speed of a reaction, without being changed or used up in the process
what type of catalyst is an enzyme and what are they made up of?
biological catalysts - amino acids
how do enzymes work?
substrates turning into products
what are features of the active site?
complementary to the substrates
what happens if a substrate doesn’t fit the active site?
reaction won’t be catalysed
what is the optimum temperature for enzymes to work in the human body?
37
what happens to the enzyme when the active site is lost completely?
they become denatured
what happens to this process when temperature is increased?
-active site has been distorted
-more successful collisions
what is the effect of pH with enzymes?
-if too high or too low bonds can be destroyed, changing the state of the active site
what are carbohydrases?
-break down carbohydrates into simple sugars
-amylase breaks down starch into maltose, then into glucose by the enzyme maltase
-amylase is made in the salivary glands, small intestine and pancreas
