Blake_BIochem_23_Fundamentals of nutrition

Question 1

Define amino acids in chemistry speak:

Answer 1

Nitrogen-containing carboxylic acids

Question 2

What kind of amino acids are the basic building blocks of peptides and proteins? how many of these A.A.s are there?

Answer 2

proteinogenic amino acids

20

Question 3

Besides protiens, how else can amino acids be used? (3)

Answer 3

• Acetyl-CoA is produced from pyruvate which can be generated from AAs; TCA cycle intermediates can also be generated from amino acids
• Precursors of Nitrogen-containing molecules (heme, biogenic amines, melanin, and genetic materials)
• Hormones, such as insulin and Glucagon

Question 4

What is the general formula for carbohydrates?

Answer 4

C_n(H₂O)_n; (n=3-9)

Question 5

Why can’t the body produce the essential fatty acids?

Answer 5

No mechanism for double bonds or long chains

Question 6

name the essential fatty acids, their C-numbers, omega-numbers, and double bonds:

Answer 6

• Linoleic acid, C18:2, w6(delta 9, 12)
• Linolenic acid, C18:3, w3(delta 9, 12,15)
• Arachidonic acid, C20:4, w6(delta, 8, 11, 14)

Question 7

Lipid Digesting enzymes of the GI system (5)

Answer 7

• Lingual lipase: short to medium chain F.A.s (mouth)
• Gastric Lipase: short to medium chain F.A.s (stomach)
• Pancreatic lipase with colipase: phospholipids (small intestine)
• Phospholipase: phospholipids (small intestine)
• Cholesterolase: cholesterol esters (small intestine)

Question 8

What ar the 4 fatty acid derived vitamins?

Answer 8

A,D,E,K

Question 9

What are the steps in the activation of vitamin D?

• Substrate to Products/Enzyme/loccation

Answer 9

• D₃ production
  
  • 7-Dehydrocholesterol to Cholecalciferol (D₃)/UV/Skin
  • Ergocalciferol (D₂) to Cholecalciferol (D₃)//Intestine
• Cholecalciferol (D₃) to 25-hydroxycholecalciferol/ 25-hydroxylase/ Liver
• 25-hydroxycholecalciferol to 1,25-Dihydroxycholecalciferol/ 1-a-Hydroxylase/Kidney
  
  • +PTH, Low[PO₄^3-]
  • • Calcitriol

Question 10

What are the effects of Calcitriol on Ca²⁺ and PO₄^3- in varios tissues?

What Net physiological effect does this cause?

Answer 10

• Intestinal cells
  
  • absorbtion of Ca²⁺ and PO₄^3-
• Kidneys
  
  • Ca²⁺ resorbtion
• Bone
  
  • Ca²⁺ resorbtion
• The net physiological effect is increased [Ca²⁺ and PO₄^3-] in blood

Question 11

What are the + and - regulators of calcitriol?

Answer 11

+ PTH

• Calcitonin

Question 12

List the steps of the Vitamin K cycle:

Answer 12

• Vit. K phylloquinone to Vit. K Hydroquinone/ Vitamin K reductase
  
  • (-) Warfarin
• Vit. K Hydroquinone to Vit.K epoxide/ gamma-carboxylase​
  
  • Glu residue on Factor (II, VII, IX, & X) to Mature clotting factor with exposed carboxylate group on Glu residue from CO₂ + O₂ coffactors
• Vit.K epoxide to Vit.K Phylloquinone/ Vit.K epoxide reductase
  
  • (-) Warfarin

Question 13

List the steps of Iron absorption, storage, and transport for nonheme irons

Answer 13

• Nonheme irons reduced by ferric reductase to Fe^2+​
  
  • ^​(-)antacids, polyphenols, certain fibers; (+) vitamin C
• transported through enterocyte by ferroportin
  
  • (+) low dietary iron; (-) Hepcidin, High dietary iron
  • OR oxidised in enterocyte for Feritin Storage
• Oxidised by in blood ferrooxidase (requires Cu)
• Transported to liver, spleen, and bone marrow by Transferrin
  
  • ​(+) low stored iron
  • (-) high stored iron

Question 14

What mechanism helps compartmentalize Iron within the enterocyte?

Answer 14

Only the oxidized form Fe³⁺ is stored in the enterocyte. to cross the basolateral membrane by ferroportin, it must be reduced to Fe²⁺.

Question 15

Serum levels of K⁺

Answer 15

3.5-5.0 mEq/L

Question 16

Serum levels of Na⁺

Answer 16

136 - 145 mEq/L

Question 17

Serum levels of Cl^-

Answer 17

95-105 mEq/L

Question 18

Serum Levels of Ca²⁺

Answer 18

8.4 - 10.2 mg/dL

Question 19

Serum levels of PO₄^3-

Answer 19

3.0-4.5 mg/dL

Question 20

Serum levels of Mg²⁺

Answer 20

1.7 - 2.2 mg/dL

Question 21

why are microelments found in such small ammounts in the body?

Answer 21

there is no storage mechanism for the micro/trace elements

Question 22

what are the seminal differences between fed and fasting states reguarding metabolism?

Answer 22

• Fed
  
  • High Glucose, High insulin, Low Glucagon
  • Dietary glucose is primary energy source
  • Dietary fat is stored in adipose tissue
  • AAs can be used for Protein synthesis
  • Brain and RBCs use Blood Glucose
• Fasting
  
  • Low Glucose, Low Insulin, High Glucagon
  • Adipose TGs are converted to Glycerol and FAs
  • Proteins are degrated into AAs for energy
  • Glycerol, AAs, Lactate, and Glycogen are converted to Glucose for use by brain and RBCs