FORM & FUNCTION (Micronutrients)

Question 1

Vitamins and minerals:

Answer 1

-organic compounds that are NOT synthesized by animals
-MUST be supplied in DIET
-function as essential compounds in many biochemical functions

Question 2

Deficiencies in micronutrients:

Answer 2

-can be associated with various metabolic conditions

Question 3

B-complex vitamins:

Answer 3

-Thiamin
-Riboflavin
-Niacin
-Biotin

Question 4

Thiamin:

Answer 4

-vitamin B1
-produced by microbes, found in plant and animal tissues
-not stored in the body (only when attached to enzymes)
*coenzyme

Question 5

Coenzyme:

Answer 5

-assist in activation of an enzyme
-does NOT have activity on its own

Question 6

Thiamin in metabolism:

Answer 6

-required for enzymes involved in glycolysis and TCA cycle
*critical for energy metabolism
>pyruvate to acetyl-CoA
>alpha-KG to succinyl-CoA

Question 7

Thiamin deficiency: caused by

Answer 7

-imbalanced home made diets (supplemented in commercial food)
-raw fist diets in cats
>contain high levels of thiaminase=inactivates thiamin

Question 8

Severe thiamin deficiencies:

Answer 8

-can lead to various central and peripheral neurological disorders (ex. seizures and paralysis)
*impairs aerobic metabolism ->switch to anaerobic metabolism in the brain ->excess lactic acid production (ex. metabolic acidosis)
**can be fatal if left untreated

Question 9

Riboflavin:

Answer 9

-B2
-core component of FMN and FAD
-made by plants and microbes

Question 10

Dietary source of riboflavin:

Answer 10

-vegetable
-yeast
-animal liver

Question 11

FMN and FAD:

Answer 11

-riboflavin 5’-monophosphate (FMN)
-flavin adenine dinucleotide (FAD)
*synthesized in liver

Question 12

FAD:

Answer 12

-electron carrier molecules
-is reduced to FADH2 during TCA cycle and beta-oxidation
*passes through ETC to produce 2 ATP molecule

Question 13

Riboflavin deficiency:

Answer 13

-not life threatening
-associated with various non-specific symptoms
>mucus membrane inflammation
>dermatitis
>anemia
>cataracts

Question 14

Niacin:

Answer 14

-B3
-forms nicotinate mononucleotide (NMN)=precursor for NAD+ and NADP+
-supplemented in animal foods
-can be made from nicotinamide which is present in most plants

Question 15

Nicotinamide adenine dinucleotides (NAD+)

Answer 15

-electron carrier in nearly all pathways of energy metabolism
>glycolysis
>TCA cycle
>beta-oxidation
-reduced to NADH

Question 16

Niacin deficiencies:

Answer 16

-NADH generates ATP (3 protons=3ATP)
-can lead to pellagra
-more commonly in poultry
>skin and digestive organ disorder
>weight loss, reduced egg production, decrease in hatching

Question 17

Pellagra:

Answer 17

-dermatitis
-diarrhea
-dementia

Question 18

Biotin:

Answer 18

-produced by plants
-found in animal tissues
-involved in carboxylation reactions

Question 19

Carboxylation reactions:

Answer 19

-fatty acid synthesis
-gluconeogenesis (pyruvate to oxaloacetate)
-ketogenesis (from Leu)

Question 20

Common elements in the body:

Answer 20

-macrominerals
-trace elements
-ultra trace elements

Question 21

Macrominerals:

Answer 21

-large amount required in diet

Question 22

Trace elements:

Answer 22

-required in smaller amounts
-serve as cofactors

Question 23

Trace elements: cofactors

Answer 23

-enzymes
-electrolytes
-oxygen binding
-structural components

Question 24

Ultra trace elements:

Answer 24

-almost undetectable
>high levels lead to toxicity

Question 25

Role of iron:

Answer 25

-easily gain or lose electrons=important element for various biological processes
-Fe-sulfur cluster regulate ETC
-Heme molecules to transfer electron or coordinate oxygen binding

Question 26

Ferrous iron:

Answer 26

-Fe2+
-reduced form
- oxidized (lose electron) to Fe3+

Question 27

Ferric iron:

Answer 27

-Fe3+
-oxidized form
-reduction (gain electron) to Fe2+

Question 28

Iron: oxygen transport

Answer 28

-heme group contains a ferrous (Fe2+) iron that binds to:
>proximal end of hemoglobin polypeptide chain
>oxygen molecule

Question 29

Oxygen molecule:

Answer 29

-when heme group binds:
>it binds to the distal end of hemoglobin peptide chain

Question 30

Oxygen binding:

Answer 30

-oxidizes Fe2+ to Fe3+
>electron is donated to O2- that facilitates distal binding

Question 31

Iron-sulfur cluster: Fe-S

Answer 31

-core component of ETC
-electron binds to iron in heme of cytochrome c (Fe3+ to Fe2+)
-similar heme group is found in complex IV
>transfers electron to oxygen to form water (cyanide inhibits this process)

Question 32

Iron deficiency:

Answer 32

-anemia
-important syndrome leading to weakness and lethargy
>due to decreased O2 transport and affects ETC
-young, fast growing animals are particularly vulnerable (younger=metabolism is higher)

Question 33

Iron overload (excessive absorption):

Answer 33

-toxic leading to hemochromatosis characterized by:
>pigmentation of skin
>pancreatic damaged leading to diabetes
>liver damage leading to cirrhosis

Question 34

Iodine:

Answer 34

-essential for mammalian thyroid hormone biosynthesis
-iodine to iodide (digestive track): 95% absorption efficiency

Question 35

Thyroid hormones deficiency:

Answer 35

-leads to goiter formation
-usually stimulates lipid mobilization (lipolysis) and gluconeogenesis
-also stimulate diverse metabolic activities in most tissues influencing basal metabolic rate