digestion and absorption 2

Question 1

what are lipids broken down by

Answer 1

lipase (with the help of bile salts)

Question 2

what aids in lipid break down

Answer 2

bile salts

Question 3

what do lipases do

Answer 3

lipase enzyme catalyse the breakdown of lipids into monoglycerides and fatty acids involving the hydrolysis of ester bonds in lipids

Question 4

where are lipases made and where do they work

Answer 4

lipases are made in the pancreas and work in the small intestine

Question 5

where are bile salts produced

Answer 5

the liver

Question 6

what do bile salts do

Answer 6

they emulsify lipids they cause the lipids to form small droplets

Question 7

why is it essential several lipid droplets are formed from lipids

Answer 7

as several lipid droplets greatly increases the surface area of lipid that’s available for lipase to work on

Question 8

what happens after the lipid has been broken down

Answer 8

monoglycerides and fatty acids stick with the bile salts to form tiny structures called micelles

Question 9

what are proteins broken down by

Answer 9

endo peptidases and exo peptidases

Question 10

what do endopeptidases do

Answer 10

they act to hydrolyse peptide bonds within a protein

Question 11

what are two examples of endopeptidases

Answer 11

trypsin and chromotrypisin

Question 12

where are endopeptidases synthesised

Answer 12

the pancreas and secreted into the small intestine

Question 13

where are endopeptidases secreted

Answer 13

the small intestines

Question 14

what is pepsin and where is it released into

Answer 14

it is another endopeptidase and is released into the stomach

Question 15

which cells release pepsin

Answer 15

cells in the stomach lining

Question 16

what type of conditions does pepsin work in

Answer 16

acidic condition

Question 17

what provides acidic conditions for pepsin

Answer 17

hydrochloric acid in the stomach

Question 18

what do exopeptidases do

Answer 18

they act to hydrolyse peptide bonds at the end of protein molecules

Question 19

what do exopeptidases remove from proteins

Answer 19

single amino acids

Question 20

what are dipeptidases

Answer 20

exopeptidases that work specifically on dipeptides. They act to separate the two amino acids that make up a dipeptide by hydrolysing the peptide bond between them

Question 21

where are dipeptides often located

Answer 21

in the cell surface membrane of epithelial cells in the small intestine

Question 22

where are the products of digestion absorbed

Answer 22

across the ileum epithelium into the bloodstream

Question 23

how is glucose absorbed

Answer 23

glucose is absorbed by active transport with sodium ions via a co transporter protein

Question 24

how is galactose absorbed

Answer 24

the same way as glucose using the same transporter proteins

Question 25

how is fructose absorbed

Answer 25

via facilitated diffusion through a different transporter protein

Question 26

what do micelles do

Answer 26

help to move monoglycerides and fatty acids towards the epithelium

Question 27

due to the micelles constantly breaking up and reforming what can they do

Answer 27

they can release monoglycerides and fatty acids allowing them to be reabsorbed, whole micelles are not taken up across the epithelium

Question 28

monoglycerides anf=d fatty acids are lipid soluble, what does this mean they can do

Answer 28

diffues directly across the epithelial cell membrane

Question 29

how are amino acids absorbed

Answer 29

via co transport a similar way to glucose and galactose

Question 30

because sodium ions are actively transported out of the ileum epithelial cells into the blood what does this result in

Answer 30

this creates a sodium ion concentration gradient

Question 31

how do sodium ions exit the ileum epithelial cells

Answer 31

active transport

Question 32

how do sodium ions diffuse from the lumen of the ileums int othe epithelial cells

Answer 32

through sodium-dependent transporter proteins, carrying the amino acids with them