NTDT401 Exam #1

Essential nutrients

an element or organic compound required for normal body function

T/F: Essential nutrients can be synthesized by the body

False - Essential nutrients CANNOT be synthesized by the body

The 2 classfications of Vitamins:

1) Fat-soluble & Water-soluble

What was the first Vitamin discovered in history?

Thiamin (B1)

Vitamers

Multiple forms of 1 Vitamin

DRI comes from _______ individuals

Healthy

EAR covers ____% of individuals’ requirements

50%

_____ is needed to set RDA

EAR

T/F: All nutrients have UL

False

T/F: A nutrient cannot have both RDA and AI

True

Is recommendation or requirement larger?

Recommendation

T/F: If one takes vitamin C less than 40% of RDA for 2 days, he definitely will develop vitamin C deficiency

False, just 2 days will not lead to a deficiency

Vitamin name = form our body ______

absorbs

2 active coenzyme forms of Thiamin:

TDP & TPP

Thiamin food sources:

Pork, whole grains, enriched grains, watermelon

Thiamin exists in free form in ____ products, and TDP in ______ products

plant; animal

_______ are removed prior to absorption of Thiamin due to polarity and lack of absorption

Phosphates

Free Thiamin is absorbed from ______

intestines

_______ interferes with Thiamin absorption into the blood

Ethanol

Enzymes in Pyruvate Dehydrogenase:

E1, E2, E3

NADH competes with NAD+ for binding to which enzyme?

E3

Acetyl CoA competes with CoA for binding to which enzyme?

E2

PDH is an enzyme found in _______

Mitochondria

T/F: PDH can be reversed

False, cannot be reversed

PDH cuts off how many Carbons from what?

1 Carbon from 3 Carbon pyruvate

Thiamin diphosphate (TDP) has ____ Carbons

5

Thiamin deficiency is called ______

Beri-beri

Wernicke’s Encephalopathy is mostly associated with _______,__ and can cause ___________

alcoholism; memory loss

_______ vitamin can treat Maple Syrup Urine Disease (MSUD)

Thiamin

Thiamin (PDH) reactants & products:

Pyruvate + CoA + NAD → CO2 + Acetyl CoA + NADH

Is PDH reversible or irreversible?

Irreversible

______ Beriberi occurs more frequently in adults

Dry

Describe Thiamin structure

Two rings, connected by Methylene bridge, Sulfur-containing

_______ vitamin is light sensitive

Riboflavin

B1 vitamin is _____

Thiamin

B2 vitamin is ________

Riboflavin

2 coenzymes for Riboflavin:

FMN, FAD

Riboflavin binds to ____, but can also bind to ____

proteins; metals

Food sources of Vitamin B2

Dairy products, eggs, liver, oysters, and mushroom

Food sources of Vitamin B1

pork, watermelon, whole grains, enriched grains

Riboflavin is converted to coenzymes in _______

the liver

FMN and FAD function as coenzymes for a wide variety of ______ enzyme systems

oxidative

Riboflavin is typically in ______ form

free

Name of Riboflavin deficiency:

Ariboflavinosis

FAD role in PDH:

FAD serves as __**intermediate electron carrier**__ in the PDH complex

FAD role in Succinate Dehydrogenase

converts succinate to from fumarate; forms FADH2 from FAD

FAD plays a role in Vitamin __ metabolism, converting ______ to _______

A; retinal; retinoic acid

T/F: Riboflavin (B2) is abundant in our diet

True

T/F: FAD does not play a role in Fatty Acid Oxidation

False, acetyl CoA dehydrogenase requires FAD

Thiamin (B1)

TPP

TDP

Riboflavin (B2)

FMN

FAD

RDA Thiamin for adults

1\.1-1.2 mg/day

RDA Riboflavin for adults

1\.1 mg/day for women, 1.3 mg/day for men

What is Vitamin B3?

Niacin

Niacin

Which vitamin is a vitamer?

Niacin (B3)

What are the 3 vitamers of Vitamin B3?

Nicotinic acid, Nicotinamide, & Nicotinamide riboside

Coenzymes for Niacin:

NAD, NADP

NAD

NADP

Food sources for Niacin come from ______

Tryptophan

Food sources Niacin:

Tuna, enriched breads, cereal grains, and meats

T/F: Niacin is stored in the liver

False, Niacin is not stored in the body

Tryptophan content of mixed proteins (%):

1%

Tryptophan content of animal proteins (%):

1\.4%

Tryptophan content of plant proteins (%):

0\.7%

*__ mg Tryptophan =* __ mg niacin = 1 Niacin \n Equivalent (NE)

60 mg Trp = 1mg niacin = 1 Niacin \n Equivalent (NE)

RDA covers ___% of the population

97\.5%

EAR covers ___% of the population

50%

Form of Niacin found in NAD:

Nicotinamide

RDA for Niacin females and males:

Females 14 mg/day, Males 16 mg/day

Niacin deficiency

Pellagra

Describe Niacin toxicity:

Flushing of skin due to release of Histamine

What is Vitamin B5?

Pantothentic acid

Food sources for Pantothentic acid

All plant and animal foods (specifically egg yolks)

Vitamin B5 mostly occurs as a component of _______

CoA

CoA is hydrolyzed into Vitamin ___

B5 (Pantothenic acid)

Absorption of Pantothenic acid occurs in the _____ by _____ diffusion

jejunum; passive

T/F: Pantothenic acid contains Sulfur

False - it does NOT contain Sulfur

T/F: CoA contains Sulfur

True

Pantothenic acid (B5)

Vitamin ___ is found in plasma

B5

Reactions involving Pantothenic acid:

PDH, Alpha KG complex, Beta oxidation of fatty acids, synthesis of fatty acids (starters)

Coenzymes for Vitamin B5:

CoA, ACP

How is Pantothenic acid excreted from the body?

CoA is converted to pantothenate

AI of Vitamin B5:

5 mg/day

Deficiency of Vitamin B5

Burning Feet Syndrome

Pantothenic acid deficiency is reported in people with ________

malnutrition

In 1881, ____ fed mice on a diet \n with pure _____, pure CHO, fats and \n mineral salts in the proportion similar to \n those in milk

Lunin; casein

Weak muscles occurs from ______ Beriberi

Dry

Edema occurs from ______ Beriberi

Wet

_______ Beriberi is observed in infants

Acute

Thiamin food inhibitors:

Tea & coffee

____ mg Thiamin in the human body

30

T/F: Thiamin has low bioavailability

False - Thiamin has high bioavailability

Active coenzyme form for Thiamin

TDP