Topic 2: Digestion and Enzymes

Flashcards by Cameron.g, updated more than 1 year ago
Created by Cameron.g almost 6 years ago


Flashcards on Topic 2: Digestion and Enzymes, created by Cameron.g on 01/05/2015.

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Topic 2 Digestion and Enzymes
when food has been digested the products must be absorbed into the ileum (small intestine) and transported in the blood the ileum is adapted for absorption because it has a large surface area as it is highly folded and very long with lots of villi. it also has a good blood supply that maintains the concentration gradient.
the epithelium is thin for a short diffusion distance. the lacteal absorbs glycerol and fatty acids. the blood capillary absorbs glucose and amino acids and carries them to the hepatic portal vein which goes to the liver..
th villi have a large surface are and have a finger like shape to aid their function.
part 2... enzymes
enzymes are proteins that speed up chemical reactions- biological Catalyists enzymes have an active site that is complimentary to a specific substrate...
the lock and key model is where the substrate fits into the enzyme. enzyme specificity is where each enzyme only has one type of substrate that fits into the active site, for example protease will only break down protein.
part 3... effects of temperature, pH and enzyme concentration on enzyme action
*as the temperature rises, the rate of reation increases. there is more kinetic energy and therefore more collisions between enzymes. *the highest part= optimum temperature which is the max rate of activity. *at high temperatures the enzyme is denatured (destroyed). this means the substrate no longer fits into it.
*at the optimim pH the enzyme works best. at either side of the optimum pH the enzyme is denatured
*as enzyme concentration increases, the rate of reaction increases as there are more active sited available for substrates. *it levels off because there are too many active sited and not enough substrates to fill them
part 4... digestive enzymes
digestive enzymes break down large insoluble molecules into small soluble molecules so they can be absorbed into the blood there are three different types of enzyme...
1. amylase *breaks down starch *produces glucose *it is released in the mouth and small intestine amylase breaks down starch over time, at the start of the experiment the solution will turn blue/black in iodine becuase starch is present but when the amylase wll eventually break down that starch into glucose meaning the iodine wil turn back to brown.
2. protease *breaks down protein *produces amino acids *released in the stomach and small intestine protease works best in acidic conditions so its optimum pH is pH2
3. lipase *breaks down fat *produces fatty acids and glycerol *released in the small intestine when lipase breaks down fat, fatty acids are release which will turn the solution acidic. if a solution containing fat started at pH7 and was tested at different temperatures the following would happen:
temp= 20 pH= 5 low temperatures mean low amount of kinetic energy and therefore fewer reactions. less fat is be broken down we know this as it is only slightly acidic
temp= 35 pH= 2 this is the optimum temperature as ther is lots of kinetic energy therefore lots of reations and lots of fat broken down into fatty acids and we know this as it is very acidic.
temp= 60 pH= 7 high temperature so the enzyme is denatured. the active site has changed shape so the fat substrate doesnt fit. this means no fat is broken down as the pH is neutral.
enzymes are also used commercially in things like biological washing powders... different enzymes are needed to break down different stains suchas lipase to break down fat, protease to break down protein ect.
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