NUTR 3330 MIDTERM 2 EXAM WITH 100% CORRECT
ANSWERS
What type of vitamin k has a phytal side chain? - ANSWER Vitamin K1 (phylloquinone)
What type of vitamin k has a isoprene side chain? - ANSWER vitamin K2 (menaquinone)
What type of vitamin k has no side chain? - ANSWER vitamin K3 (menadione)
what are the 2 things GLA is important for? - ANSWER 1) blood clotting
2) bone proteins
For what reaction is vitamin k required as a coenzyme - ANSWER carboxylation of
glutamic acid (GLU) to gamma carboxyglutamic acid (GLA)
what is GLAs sole purpose? - ANSWER to interact with calcium
how is vitamin k dependent carboxylation done? - ANSWER glutamic acid residue of
vitamin k dependent proteins
Blood clotting depends on what? - ANSWER - vitamin k
- >12 proteins and calcium
* 7 are vit k dependent proteins
- clotting cascade
How are clotting inactive factors converted to active factors? - ANSWER calcium
,why are clotting factors left inactive till activated? - ANSWER Only want blood to clot at
certain times, could cause infarction through body and cause problems
where are vitamin k dependent blood coagulation proteins synthesized? - ANSWER liver
What do vitamin k dependent blood coagulation proteins have and why? - ANSWER -
multiple GLA residues
- allows for binding of multiple calcium ions which chelates calcium and forms bridge on
membrane of injury site, allows clot to form (FIBRIN)
clotting cascade steps? - ANSWER - prothrombin to thrombin
- fibrinogen to fibrin
- cross linked CLOT
what is the prothrombin time test? - ANSWER - measures how long it tastes for blood to
clot
- measures presence of 5 clotting factors
what would high (long) prothrombin time tell us about vitamin k status? - ANSWER low
vitamin k status
steps of the vitamin k cycle? - ANSWER - vit KH2 participates in carboxylation of GLU to
GLA and is converted to vit k epoxide
- vit k epoxide converted to vit k
- vitamin k reduced back to vit KH2
what kind of form is the process of vitamin k cycle - ANSWER cyclical
, what are the 2 enzymes important to take vit k epoxide back to vit KH2? - ANSWER - vit k
epoxide reductase
- vit k (quinone) reductase
what is warfarin? - ANSWER - drug prescribed for people at risk for thrombotic events
- also used as a rodenticide
What does warfarin do? - ANSWER - blocks regeneration of vit KH2
- inhibits vit k cycle enzymes: vit k (quinone) reductase, vit k epoxide reductase
- decreases blood clotting
should patients taking warfarin decrease their vit k intake - ANSWER Don't want too
much vitamin k, consume less leafy greens, as its going against what warfarin is doing
what is bone GLA protein (BGP) OR osteocalcin synthesized by and what does it do? -
ANSWER - by osteoBLASTS
- promotes bone mineralization (^ in bone especially growing bone)
where is matrix GLA protein (MGP) found and what does it do? - ANSWER - found in bone
& blood vessels
- reduces calcification of blood vessels (CVD implications)
how many GLA residues does BGP and MGP have? - ANSWER - BPG: 3
- GLA: 5
vitamin k food sources? - ANSWER - phylloquinone: green leafy vegs (collards, spinach,
kale, broccoli), soybean & canola oil
- menaquinone: fermented foods (natto japanese fermented soy)
ANSWERS
What type of vitamin k has a phytal side chain? - ANSWER Vitamin K1 (phylloquinone)
What type of vitamin k has a isoprene side chain? - ANSWER vitamin K2 (menaquinone)
What type of vitamin k has no side chain? - ANSWER vitamin K3 (menadione)
what are the 2 things GLA is important for? - ANSWER 1) blood clotting
2) bone proteins
For what reaction is vitamin k required as a coenzyme - ANSWER carboxylation of
glutamic acid (GLU) to gamma carboxyglutamic acid (GLA)
what is GLAs sole purpose? - ANSWER to interact with calcium
how is vitamin k dependent carboxylation done? - ANSWER glutamic acid residue of
vitamin k dependent proteins
Blood clotting depends on what? - ANSWER - vitamin k
- >12 proteins and calcium
* 7 are vit k dependent proteins
- clotting cascade
How are clotting inactive factors converted to active factors? - ANSWER calcium
,why are clotting factors left inactive till activated? - ANSWER Only want blood to clot at
certain times, could cause infarction through body and cause problems
where are vitamin k dependent blood coagulation proteins synthesized? - ANSWER liver
What do vitamin k dependent blood coagulation proteins have and why? - ANSWER -
multiple GLA residues
- allows for binding of multiple calcium ions which chelates calcium and forms bridge on
membrane of injury site, allows clot to form (FIBRIN)
clotting cascade steps? - ANSWER - prothrombin to thrombin
- fibrinogen to fibrin
- cross linked CLOT
what is the prothrombin time test? - ANSWER - measures how long it tastes for blood to
clot
- measures presence of 5 clotting factors
what would high (long) prothrombin time tell us about vitamin k status? - ANSWER low
vitamin k status
steps of the vitamin k cycle? - ANSWER - vit KH2 participates in carboxylation of GLU to
GLA and is converted to vit k epoxide
- vit k epoxide converted to vit k
- vitamin k reduced back to vit KH2
what kind of form is the process of vitamin k cycle - ANSWER cyclical
, what are the 2 enzymes important to take vit k epoxide back to vit KH2? - ANSWER - vit k
epoxide reductase
- vit k (quinone) reductase
what is warfarin? - ANSWER - drug prescribed for people at risk for thrombotic events
- also used as a rodenticide
What does warfarin do? - ANSWER - blocks regeneration of vit KH2
- inhibits vit k cycle enzymes: vit k (quinone) reductase, vit k epoxide reductase
- decreases blood clotting
should patients taking warfarin decrease their vit k intake - ANSWER Don't want too
much vitamin k, consume less leafy greens, as its going against what warfarin is doing
what is bone GLA protein (BGP) OR osteocalcin synthesized by and what does it do? -
ANSWER - by osteoBLASTS
- promotes bone mineralization (^ in bone especially growing bone)
where is matrix GLA protein (MGP) found and what does it do? - ANSWER - found in bone
& blood vessels
- reduces calcification of blood vessels (CVD implications)
how many GLA residues does BGP and MGP have? - ANSWER - BPG: 3
- GLA: 5
vitamin k food sources? - ANSWER - phylloquinone: green leafy vegs (collards, spinach,
kale, broccoli), soybean & canola oil
- menaquinone: fermented foods (natto japanese fermented soy)
