Digestion Flashcards

Question

how is villi in gut wall adapted for digestion

Answer 1

surface of wall is folded and has villi - large surface area - epithelial cells that cover each villus have projections called microvilli - network of blood capilleries - easy absorbtion, maintains concentraion gradient - digested food passes through epithelial cells of gut wall and carried by blood to liver

Answer 2

biological catalysts that are proteins with a complex shape. Has a region called the active site which is specific to the substrate that fits to it

Answer 3

molecule taking part in reaction

Answer 4

- substrate collides with active site and attaches - active site has complementary shape to substrate - enzyme catalyses breakdown of substrate - enzyme molecule is unchanged and can be used again

Answer 5

low temp - molecular movement decreases high temp - at optimum temp 37 degrees hight temp - also disrupts shape of active site which reduces its activiity as it no longer fits with substrate and so the enzyme is denatured.

Answer 6

enzymes made of folding chains of amino acids which is held together by weak forces between amino acid molecules in the chain. If temp is too high, rate of reaction will be affected because the shape has changed.

Answer 7

amino acids carry a charge in an enzyme molecule - negative and positive attract changing ph will affect the shape of the chains of folding amino acids can become denatured

Answer 8

secretion of hydrochloric acid

Answer 9

by secreting sodium hydrogen carbonate

Answer 10

breaks carbohydartes into simple sugars

Answer 11

breaks starch into glucose

Answer 12

breaks proteins down into amino acids

Answer 13

breaks lipids down into fatty acids and glycerol

Answer 14

starch - maltose ( amylase catalyst )

Answer 15

amylase produced in pancreas | starch - maltose ( pancreatic amylase )

Answer 16

pepsin produced in gastric glands | proteins - amino acids (pepsin catalysts)

Answer 17

protease ( trypsin ) produced in pancreas | protein - amino acids

Answer 18

lipids - fatty acids + glycerol ( lipase produced in pancreas )

Answer 19

buffer solutions remain at the same ph even when acids and alkalis are added 1. place one drop of iodine solution into each well of spotting tile 2. 3 test tubes 3. 1st test tube - add 3cm cubed of starch solution 4. 2nd test tube - 2cm cubed of amylase solution 5 3rd test tube - 2cm cubed of ph 5 buffer solution - controls ph 6. place all 3 test tubes in water bath at 30 degrees for 10 mins 7. combine all three test tubes into one solution - mix with a stirring rod 8. return to the water bath and start timer 9. after 30 secs, transfer one drop of solution to a spotting tile iodine should turn blue black if starch is present 10. take a sample every thirty seconds until the iodine remains orange - starch is no longer present in solution 11. record time to see the rate of amylase at ph 5 12. repeat experiment with different ph buffers 6, 7 , 8

Answer 20

taking samples every 30 seconds - only an approximate time for reaction to complete, just an indication of rate. it is the INVERSE of the rate so we can do ONE / TIME TAKEN to work out a more accurate answer take it every 10 seconds instead colour change tends to be gradual ask several people to look at spotting tile to decide if the reaction has completed

Answer 21

wear goggles amylase may cause allergic reactions iodine solution is an irritant

Answer 22

use a water bath to maintain temps with different test tubes breakdown of lipids by lipase - monitor ph change - as reaction proceeds, release of fatty acids would mean ph decreases

Answer 23

liver produces bile - emulsifies lipids into tiny droplets which have a bigger surface area for the lipds to work on. contains - sodium hydrocarbonate - alkali - neutralises stomach acid - optimum ph bile produced in liver - stored in gal bladder