NUSCTX 10 Midterm 3 | 113 Actual Questions
And Correct Answers (Already Graded A+) | New
2025
overview of the digestion and absorption of vitamins - ANSWER 1. all vitamins:
digestive process in the stomach begin the release of vitamins from food
2. all vitamins: digestive enzymes produced by the pancreas and in the release of
vitamins and food (first put into form that is bioavailable)
3. fat soluble vitamins only: bile produced in the liver (and stored in the gall-
balder) aids in fat-soluble vitamin absorption
4. fat soluble vitamins only: fat-soluble vitamins are absorbed in the small
intestine, along with dietary fat and carried by chylomicrons into the lymphatic
circulation (piggy back on lipids packaged to get through aqueous environment)
5. waters-soluble vitamins only: water-soluble vitamins are absorbed in the small
intestine and released directly into the blood through hepatic portal circulation
(no special packaging needed)
5. vitamin K only: small amounts of K are made by bacteria in the ilium of the
small intestine and in the large intestine
lipid digestion and absorption - ANSWER -in the small intestine, the products
of fat digestion and bile acids form micelles, which move close enough to the
microvilli to allow lipids to diffuse into the mucosal cells
-inside the mucosal cells, fatty acids and monoglycerides are reassembled into
triglycerides and incorporated into lipid transport particles, which enter the lymph
lipoprotein - ANSWER -transport lipids and cholesterol in the blood
-contains triglycerides and free cholesterol, protein, phospholipids, cholesterol
bond to fatty acids
,-vitamin A: put together as a triglyceride (in the core)
-if you have disease like celiac that doesn't allow absorption of lipids --> Vitamin A
deficiency if its tied to absorption
lipoproteins (lipids in the blood circulation):
-VLDL: delivers fatty acids made by liver
-IDL: delivers fatty acids made by liver
-LDL: delivery of cholesterol
-HDL: picking up (scavenging) excess cholesterol from cells for delivery back to the
liver
-Chylomicrons: delivery of fatty acids
lipid transport from the small intestine - ANSWER 1. chylomicrons formed in
the mucosal cells pass first into the lymph, which drains into the blood. They
circulate in the blood, delivering triglycerides to body cells.
2. The enzyme lipoprotein lipase which is present on the surface of cells lining the
blood vessels, breaks down the triglycerides in chylomicrons into fatty acids and
glycerol. These can then enter the surrounding cells.
4. VLDLs are made in the liver and transport lipids away from the liver. They
function similarly to chylomicrons because both particles deliver triglycerides to
body cells with the help of the enzyme lipoprotein lipase
6. To deliver cholesterol, LDL particles bind to LDL receptors in the cell membrane.
This allows the LDL particle to enter the cell, where the cholesterol and other
components can be used.
7. HDL particles pick up cholesterol from other
lipoproteins and body cells and return it to the liver. Some of this cholesterol is
broken down and some is transferred to organs with high requirements for
cholesterol, such as those that synthesize steroid hormones.
,ketones - ANSWER -used for energy: converted back to acetyl CoA and enter
TCA cycle, brain can run on energy from ketones but can't run only on ketones
(still need glucose from diet or breaking down proteins), and ketones spare
protein
-ketones lost in urine and breath (fruity breath)
-inefficient use of energy
dietary factors that increase risk associated with fat intake - ANSWER -
cholesterol
-saturated fat
-trans fat
-sodium
-excess energy
-excess sugar
fat soluble vitamins (FSV) - ANSWER -vitamins A,D,E,K
-hydrophobic/lipophilic
-storage in cells associated with fat
-risk of toxicity is greater
1. FSV + fat + bile acids = micelles
2. Absorbed by enterocytes in SI and packaged into chylomicrons
3. chylomicrons are circulated through lymph, then blood before reaching the liver
4. stored in fat or attached to transport protein to circulate in blood
, Roles of Vitamin A in the body - ANSWER 1. vision (works at DNA level)
2. Skin, trachea, epithelial differentiation, immune function, thymus lymphoid
organs
3. reproduction spermato-genesis and reproduction embryonal development
Vitamin A: forms and precusors - ANSWER - 3 active retinoids: retinol, retinal,
retinoic acid: in liver, eggs, fortified milk or cereals
- Storage form in liver: retinyl ester
-VA precursor: B-carotene (most biologically active) found in
orange/red/yellow/dark green fruits and vegetables
-can choose b-carotene over retinoid to avoid toxicity
-cleavage in b-carotene can yield 2 VA molecules which occurs in gut
vitamin A conversion - ANSWER retinol binding protein = transport protein
necessary for transport of VA in the blood from the liver to target issues
the role of VA in protein synthesis and cell differentiation (retinoic acid) -
ANSWER -epithelial cells of skin and mucous membranes are the 1st line of
defense against infection
-supports differentiation and antibody production in T- and B-cells for specific
immune responses
-Vitamin A maintains healthy cells in the mucous membranes
-Without Vitamin A, the normal structure and function of the cells in the mucous
membranes are impaired
And Correct Answers (Already Graded A+) | New
2025
overview of the digestion and absorption of vitamins - ANSWER 1. all vitamins:
digestive process in the stomach begin the release of vitamins from food
2. all vitamins: digestive enzymes produced by the pancreas and in the release of
vitamins and food (first put into form that is bioavailable)
3. fat soluble vitamins only: bile produced in the liver (and stored in the gall-
balder) aids in fat-soluble vitamin absorption
4. fat soluble vitamins only: fat-soluble vitamins are absorbed in the small
intestine, along with dietary fat and carried by chylomicrons into the lymphatic
circulation (piggy back on lipids packaged to get through aqueous environment)
5. waters-soluble vitamins only: water-soluble vitamins are absorbed in the small
intestine and released directly into the blood through hepatic portal circulation
(no special packaging needed)
5. vitamin K only: small amounts of K are made by bacteria in the ilium of the
small intestine and in the large intestine
lipid digestion and absorption - ANSWER -in the small intestine, the products
of fat digestion and bile acids form micelles, which move close enough to the
microvilli to allow lipids to diffuse into the mucosal cells
-inside the mucosal cells, fatty acids and monoglycerides are reassembled into
triglycerides and incorporated into lipid transport particles, which enter the lymph
lipoprotein - ANSWER -transport lipids and cholesterol in the blood
-contains triglycerides and free cholesterol, protein, phospholipids, cholesterol
bond to fatty acids
,-vitamin A: put together as a triglyceride (in the core)
-if you have disease like celiac that doesn't allow absorption of lipids --> Vitamin A
deficiency if its tied to absorption
lipoproteins (lipids in the blood circulation):
-VLDL: delivers fatty acids made by liver
-IDL: delivers fatty acids made by liver
-LDL: delivery of cholesterol
-HDL: picking up (scavenging) excess cholesterol from cells for delivery back to the
liver
-Chylomicrons: delivery of fatty acids
lipid transport from the small intestine - ANSWER 1. chylomicrons formed in
the mucosal cells pass first into the lymph, which drains into the blood. They
circulate in the blood, delivering triglycerides to body cells.
2. The enzyme lipoprotein lipase which is present on the surface of cells lining the
blood vessels, breaks down the triglycerides in chylomicrons into fatty acids and
glycerol. These can then enter the surrounding cells.
4. VLDLs are made in the liver and transport lipids away from the liver. They
function similarly to chylomicrons because both particles deliver triglycerides to
body cells with the help of the enzyme lipoprotein lipase
6. To deliver cholesterol, LDL particles bind to LDL receptors in the cell membrane.
This allows the LDL particle to enter the cell, where the cholesterol and other
components can be used.
7. HDL particles pick up cholesterol from other
lipoproteins and body cells and return it to the liver. Some of this cholesterol is
broken down and some is transferred to organs with high requirements for
cholesterol, such as those that synthesize steroid hormones.
,ketones - ANSWER -used for energy: converted back to acetyl CoA and enter
TCA cycle, brain can run on energy from ketones but can't run only on ketones
(still need glucose from diet or breaking down proteins), and ketones spare
protein
-ketones lost in urine and breath (fruity breath)
-inefficient use of energy
dietary factors that increase risk associated with fat intake - ANSWER -
cholesterol
-saturated fat
-trans fat
-sodium
-excess energy
-excess sugar
fat soluble vitamins (FSV) - ANSWER -vitamins A,D,E,K
-hydrophobic/lipophilic
-storage in cells associated with fat
-risk of toxicity is greater
1. FSV + fat + bile acids = micelles
2. Absorbed by enterocytes in SI and packaged into chylomicrons
3. chylomicrons are circulated through lymph, then blood before reaching the liver
4. stored in fat or attached to transport protein to circulate in blood
, Roles of Vitamin A in the body - ANSWER 1. vision (works at DNA level)
2. Skin, trachea, epithelial differentiation, immune function, thymus lymphoid
organs
3. reproduction spermato-genesis and reproduction embryonal development
Vitamin A: forms and precusors - ANSWER - 3 active retinoids: retinol, retinal,
retinoic acid: in liver, eggs, fortified milk or cereals
- Storage form in liver: retinyl ester
-VA precursor: B-carotene (most biologically active) found in
orange/red/yellow/dark green fruits and vegetables
-can choose b-carotene over retinoid to avoid toxicity
-cleavage in b-carotene can yield 2 VA molecules which occurs in gut
vitamin A conversion - ANSWER retinol binding protein = transport protein
necessary for transport of VA in the blood from the liver to target issues
the role of VA in protein synthesis and cell differentiation (retinoic acid) -
ANSWER -epithelial cells of skin and mucous membranes are the 1st line of
defense against infection
-supports differentiation and antibody production in T- and B-cells for specific
immune responses
-Vitamin A maintains healthy cells in the mucous membranes
-Without Vitamin A, the normal structure and function of the cells in the mucous
membranes are impaired
