Part I Chiropractic Boards: Biochemistry -- Carbs, Lipids, Proteins, & Digestion

Which of the macronutrients is the primary source of the brain?

Carbohydrates

What are the 3 major functions of carbohydrates?

1) Energy

2) Storage as glycogen

3) Cell signaling

Where is the function of liver glycogen? About how many Calories does this contribute?

Blood glucose regulation

(400 Cal)

What is the function of muscle glycogen? About how many Calories does this contribute?

energy in muscles

(1400 Cal)

How many Calories are carbohydrates worth?

4 Cal/g

What is the RDA of Carbohydrates? Fiber RDA for males & females?

RDA = 130 g/day

Fiber RDA:

Females = 25g

Males = 38g

What is normal blood glucose?

70-99 mg/dL

What are structural isomers?

Same formula, different attachment

(Ex: glucose, galactose, fructose)

What are enantiomers?

Nonsuperimposable mirror images (D- vs L-glucose)

What are Diastereomers?

Not mirror images

What are epimers?

Type of diastereomer (not mirror image), with rotation different around 1 Carbon

What are the C4 epimers for carbohydrates?

Glucose & Galactose

What are the C2 epimers for carbohydrates?

Glucose & Mannose

What is an anomer?

Type of epimer specific for anomeric C (alpha or beta)

What is the chemical formula for a carobhydrate?

Cn(H2O)n

(think carbon water)

- Hydrated carbons

- SAME number of Carbons and Oxygen, 2x as many H as O and C

What is a single sugar called

Monosaccharide

What type of monosaccharide is glucose and galactose? What is their anomeric C?

Aldohexose

C1 Anomeric

What type of monosaccharide is ribose? What is its anomeric C?

Aldopentose

C1 Anomeric

What type of monosaccharide is fructose? What is its anomeric C?

Ketohexose

C2 Anomeric

What are two sugars bound together? What is the bond used to bind the sugars and what reaction does it undergo to accomplish this bond?

Disaccharide

Glycosidic bonds

- Dehydration rxn

What is sucrose made up of?

Glucose (a1-B2) Fructose

What is lactose made up of?

Galactose (B 1-4) Glucose

What is Maltose made up of?

Glucose (a 1-4) glucose

What is Isomaltose made up of?

Glucose (a 1-6) glucose

NOTE Maltose & Isomaltose both are 2 glucoses, just the bond that changes

Which disaccharide is the non-reducing sugar?

Sucrose

(Glucose (a1-B2) Fructose)

Which disaccharide is in milk?

Lactose

(Galactose B1-4 Glucose)

How are the disaccharides digested (sucrose, lactase, maltose, isomaltase)?

Brush border enzymes

What are 3-10 sugars in a chain called? Greater than 10 sugars?

Oligosaccharides

Polysaccharides

What is a single repeating sugar?

Homopolysaccharide

What is Starch a homopolysaccharide of? What are it's two forms?

100% Glucose!

(storage form of glucose in plants)

15% Amylose

85% Amylopectin

What is Amylose made up of? Amylopectin?

Amylose = Glu a(1-4) glu

Amylopectin = Glu a(1-4) glu & BRANCHED Glu a(1-6) Glu

What are the 3 major sources of starch?

1) Rice

2) Pasta

3) Potato

Amylopectin is branched every ______ glucoses

24-30 glu

(Glu a1-6 Glu) remember = branching point!

What is Glycogen a homopolysaccharide of? Where is it stored?

100% glucose

Stored in liver & muscles (storage form of glucose in animals)

What is the structure of Glycogen and its bonds?

Glu a(1-4) Glu & BRANCHED Glu a(1-6) Glu

Glycogen is branched every ________ glucose

Every 8-12 glucose

(Glu alpha(1-6) Glu)

What is a mixture of >1 type of sugar, such as pectin or gums?

Heteropolysaccharide

What is non-digestible plant material? What are the 2 types?

Fiber

Soluble (Fermented) & Insoluble (Not fermented)

What are the 3 functions of Soluble (Fermented) fiber?

1) Decrease motility of GI tract

2) Swell in stomach, increasing satiety

3) Bind bile (cholesterol), TG, Glucose, and decrease absorption

Where is Soluble fiber fermented? Into what?

Fermented in LI

Gas & SCFA

What are 3 major types of Soluble fibers? Where is each found?

1) Pectin (inside fruit)

2) Gums (seed/trees)

3) B-glucans (oats/barley)

What is the major function of insoluble (not fermented) fiber?

Increase motility of GI tract

What are the 2 major examples of insoluble (not fermented) fiber? Where is each found?

1) Cellulose (peels of plants/bran of whole grains)

2) Lignin (inside vegetables)

What specific fiber can humans not digest because we lack the enzyme?

Cellulose

-- Humans lack Cellulase

What is a protein + oligosaccharide?

Glycoprotein

What is a repeating disaccharide of sugar acid & sugar amine?

Glycosaminoglycans (GAG; mucopolysaccharide)

What are the 2 major examples of GAGs? What is their precursor?

1) Chondroitin sulfate

2) Hyaluronic acid

Precursor = Glucosamine

What is a protein + Glycosaminoglycan (GAG)?

Proteoglycan

Proteoglycans form __________ or ____________, which attach to __________ chain in synovial fluid.

Monomers (bottle brush) or Aggregates

Attached to Hyaluronic acid chain

What is a sugar + AA polymer, and makes up the cell wall of microorganisms?

Peptidoglycan

What are the 2 forms of secondary active transport for glucose?

1) Sodium glucose transporters (SGLT)

2) Na/K ATPase pump

Where is SGLT-1 glucose transport found? SGLT-2?

SGLT-1 = Small intestine

SGLT-2 = kidney

What are the transporters used in facilitated diffusion of glucose transport?

Glucose Transporters (GLUTs)

What are the 3 insulin-insensitive GLUTs? Where is each located?

GLUT 1 & GLUT 3 --> Most tissues

GLUT 5 --> SI

What is significant about the GLUT5 transporter that differentiates it form the other 4?

Absorbs FRUCTOSE

What are the 2 Insulin sensitive GLUTs? Where is each located?

GLUT2 --> Liver, kidney, pancreas, intestine

GLUT4 --> Muscle & Adipose

What are the 5 major functions of Lipids?

1) Energy during rest

2) Insulation & protection around organs

3) Lipid bilayer in cell membrane (phospholipids)

4) Steroid hormones (made from cholesterol)

5) Fat-soluble vitamin absorption

How many Calories are Lipids worth? Why?

9 Cal

-- fatty acids are highly reduced

What is the AMDR for lipids?

20-35% Calories

What are the 3 degrees of saturation for lipids?

Saturated (0 db)

Monounsaturated (1 db)

Polyunsaturated (>1 db)

What is the carbon chain length for short chain fatty acids? Medium chain fatty acids? Long chain fatty acids?

SCFA = 2-6C

MCFA = 8-12C

LCFA = 14-24C

Long chain fatty acids are very _______________________, so they require _______ to enter the mitochondria.

HYDROPHOBIC

Require Carnitine

The more the double bonds for fatty acids, the ______ the melting point, the ______ likely to go rancid (lipid peroxidation)?

Lower melting point

More likely to go rancid

What type of fatty acid is the most likely to go rancid (lipid peroxidation)?

PUFA

What is the most common lipid in the diet & body? What is its structure?

Triacylglycerols (TGs)

-- 3 FA esterified to glycerol backbone

What type of bond joins the FA to the glycerol backbone in TGs?

Ester bonds

Are fatty acids polar or nonpolar?

Both?

Polar head (carboxylic acid) & nonpolar tail (hydrocarbon)

How do you convert delta to omega fatty acids?

Total # of carbons minus the last bond #

Ex:

Delta: 18 : 2 d 9, 12

18 - 12 = 6

Omega: 18 : 2 w 6

How do you convert omega to delta fatty acids/

Total # of Cs minus bond # = last bond #

Ex:

Omega: 18 : 2 w 6

18 - 6 = 12

12 - 3 = 9

Delta: 18 : 2 d 9, 12

What is the common name for 3:0 SCFA? What is the source?

Propionic Acid

Fermented foods

What is the common name for 4:0 SCFA? What is the source?

Butyric Acid

Butter, Goat milk

What is the common name for SCFA 6:0? What is the source?

Caproic Acid

Goat milk

What is the main chain length we synthesize? The main chain length we digest?

Synthesize = 16C

Ingest = 18 C

What is the common name for MCFA 8:0? What is its source?

Caprylic Acid

Goat milk

What is the common name for MCFA 10:0? What is its source?

Capric Acid

Goat milk

What is the common name for MCFA/saturated fatty acid 12:0? What is its source?

Lauric acid

Coconut oil

What is the common name for saturated fatty acid 14:0? What is its source?

Myristic acid

Coconut & palm oil

What is the common name for saturated fatty acid 16:0? What is its source?

Palmitic acid

Palm oil

What is the common name for saturated fatty acid 18:0? What is its source?

Stearic acid

Animal fat, some plants

What is the common name for unsaturated fatty acid 18:1 d9 (n-9)? What is its source?

Oleic acid

Olive oil

What is the common name for unsaturated fatty acid 18:2 d9,12 (n-6)? What is its source?

Linoleic acid

Corn, sunflower, safflower

What is the common name for unsaturated fatty acid 18:3 d9,12,15 (n-3)? What is its source?

alpha-linolenic acid (ALA)

Flax, soy

What is the common name for unsaturated fatty acid 20:4 d5,8,11,14 (n-6)? What is its source?

Arachidonic acid (ARA)

Animal, Eggs

What is the common name for unsaturated fatty acid 20:5 d5,8,11,14,17 (n-3)? What is its source?

Eicosatetraenoic acid (EPA)

Fish, algae

What is the common name for unsaturated fatty acid 22:6 d4,7,10,13,16,19 (n-6)? What is its source?

Docosahexaenoic acid (DHA)

fish, breast milk

What are the 5 essential FA? Why are they essential?

Linoleic acid, ALA, ARA, EPA, DHA

(18:2, 18:3; 20:4; 20:5; 22:6)

Humans lack the desaturases to make

What are the 3 benefits of hydrogenation for fatty acids?

1) Increases melting point

2) Increases shelf-life

3) Produces trans fat (partial hydrogenation)

Linoleic acid (18:2 n-6) is converted to ________________ using elongase & desaturase?

Arachidonic acid (20:4 n-6)

What 3 molecules does Arachidonic acid make? Which use the COX (cyclooxygenase) enzyme? Which use the LOX (lipoxygenase) enzyme?

COX:

2-series Prostaglandins (PGE2)

2-series Thrombaxanes (TXA2)

LOX:

4 - series Leukotrienes (LTB4)

NOTE: PT's are COX -- match the L's so Leukotrienes & LOX

Omega 6 FA are even numbered

Alpha-linoleic acid (18:3 n-3) is converted to ____________ using elongase & desaturase?

EPA (20:5 n-3)

What 3 molecules does EPA make? Which use the COX (cyclooxygenase) enzyme? Which use the LOX (lipoxygenase) enzyme?

COX:

3-series Prostaglandins (PGE2)

3-series Thrombaxanes (TXA2)

LOX:

5 - series Leukotrienes (LTB4)

NOTE: PT's are COX -- match the L's so Leukotrienes & LOX

Omega 3 FA are odd numbered

Lipid metabolism starts where? What is the other location of digestion?

Mouth (lingual lipase)

SI

Lipids = Mouth & SI

What phospholipid is a DAG + a phosphate (glycerol backbone)?

Glycerophosphates

What is the MC phospholipid in the body?

phosphatidyl choline

What is the phospholipid involved in cell signaling & membrane anchoring, and can have its polar head released via phospholipase C?

Phosphatidyl inositol

What is the phospholipid involved in apoptosis signaling?

Phosphatidyl serine

What type of phospholipid has a sphingosine backbone?

Spingophosphatides

What type of spingophosphatide is involved in the myelin sheath?

Sphingomyelin

What type of glycolipid is a ceramide (sphingosine + FA) + Monosaccharide?

Cerebroside

What is a sphingosine + FA?

Ceramide