Nutrient Digestion (Fats, Vitamins and Minerals)

Question 1

Almost all ingested fat is a form of

Answer 1

Triacylglycerol

Question 2

All fat digestion takes place in ___ by ___ enzyme

Answer 2

The small intestine

Pancreatic lipase

Question 3

Triacylglycerols

Answer 3

Large droplets of lipid

Insoluble in water

Question 4

Lipase

Answer 4

Water soluble enzyme

Question 5

Lipase mechanism

Answer 5

Turns triacylglycerol into a monoglyceride and 2 fatty acids

Question 6

Where on the droplet can digestion take place

Answer 6

Surface (very slow for a large droplet)

Question 7

Emulsification

Answer 7

Divide large lipid droplets into smaller droplets which gives an increased surface area and accessibility to lipase action

Question 8

Emulsification requires

Answer 8

Mechanical disruption of droplets (by smooth muscle contraction which grinds and mixes lumenal contents)
Emulsifying agent (prevents the smaller droplets reforming into larger droplets

Question 9

Function of amphiphatic molecules

Answer 9

Coat droplets to keep them separate

Question 10

Micelles

Answer 10

Similar to emulsion droplets but much smaller

Bile salt + monoglyceride + fatty acids + phospholipids

Question 11

Micelle breakdown

Answer 11

Release of small amounts of free fatty acids and monoglycerides into solution which then diffuse across the plasma membrane of absorbing cells

Question 12

Dynamic equilibrium of ____ and ____ in solution and in micelles

Answer 12

Fatty acids and monoglycerides

Question 13

After entering epithelial cells, ____ and ____ enter ____ where they are reformed into ____ (by enzymes located within the sER)

Answer 13

Fatty acids
Monoglycerides
Smooth endoplasmic reticulum (sER)
Triacylglycerols

Question 14

Chylomicrons

Answer 14

Extracellular fat droplets

Question 15

Fat soluble vitamins

Answer 15

A, D, E, K

Follow same absorptive path as fat

Question 16

Water soluble vitamins

Answer 16

B group, C and folic acid

Either absorbed by passive diffusion or carrier mediated transport

Question 17

Vitamin B12

Answer 17

Large charged molecule

Binds to intrinsic factor in stomach to form complex which is absorbed via specific transport mechanism in distal ileum

Question 18

Vitamin B12 deficiency

Answer 18

Pernicious anaemia (failure of red blood cell maturation)

Question 19

Iron transported across brush border membrane into ____

Answer 19

Duodenal enterocytes via DMT1

Question 20

Iron ions incorporated into

Answer 20

Ferritin

Question 21

Unbound iron transported across ____ membrane to ____

Answer 21

Serosal

Blood

Question 22

Iron in blood binds to ____

Answer 22

Transferrin

Question 23

Ferritin expression regulated depending on body’s iron status
Hyperaemia  increased ferritin levels  more iron bound in enterocytes
Anaemia  decreased ferritin levels  more iron released to blood

Answer 23

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