Lecture 6 CHO Classification & Function

Question 1

What are the main elements contained in CHO, proteins, lipids and vitamins?

Answer 1

• Hydrogen
• Carbon
• Nitrogen
• Oxygen
• Phosporus
• Sulphur

Question 2

Why is CHO considered hydrated carbon?

Answer 2

H to O ratio is 2:1 just like water

Question 3

Macronutrient DRIs of digestible CHO

Answer 3

~130 AI

Question 4

Macronutrient DRIs for fibre

Answer 4

Question 5

CHO AMDRs

Answer 5

45-65%

Question 6

Classification of CHO

Answer 6

Classified as either simple or complex
* simple: monosaccharides and disaccharies
* complex: oligosaccharides and polysaccharides

Question 7

Common monosaccharides

Answer 7

• glucose
• fructose
• galactose

Question 8

Common disaccharides

Answer 8

• lactose
• sucrose
• maltose

Question 9

Common oligosaccharides

Answer 9

• raffinose
• stachyose
• verbascose

Question 10

Common polysaccharides

Answer 10

• Starch
• glycogen
• dietary fibre

Question 11

Basic features of monosaccharides

Answer 11

• Aldose (-ose, 1 aldehyde, 1C) or ketose (-ulose, 1 ketone, 2C)
• Triose, tetrose, pentose, hexose, heptose, octose, nonose
• D or L- based on the chirality

Question 12

Identify

Answer 12

monosaccharide - glucose

Question 13

Identify

Answer 13

Galactose

Question 14

Identify

Answer 14

Fructose

Question 15

What is bond that links monosaccharides?

Answer 15

glycosidic bonds

Question 16

Formation of glycosidic bonds

Answer 16

Formed by condensation reaction of hydroxyl (-OH) of one molecule with a hydrogen atom (H) of another s and forming a molecule of water

Question 17

How are glycosidic bonds named?

Answer 17

The numbers in a glycosidic bond refer to the carbon atoms that form the bond.
* glycosidic bond facing down: 𝝰 glycosidic bond
* glycosidic bond facing up: β glycosidic bond

Question 18

What is the glycosidic bond of maltose?

Answer 18

a-1,4 glycosidic bond

Question 19

Basic features of disaccharides, oligosaccharides and polysaccharides?

Answer 19

• Consists of 2+ monosaccharides formed via glycosidic linkages
• Require specific enzymes for hydrolysis during digestion
• Reducing or non-reducing

Question 20

What are the branching structures of polysaccharides?

Answer 20

• Linear polysaccharides
• Alternating single sugar unit branches on linear polysaccharide
• Blocks of consecutive single sugar unit branches on linear polysaccharide
• Ramified structure, branches on branches

Question 21

What are reducing sugars?

Answer 21

Sugars that contain aldehyde groups & have an open chain form and can therefore react. The free anomeric -OH are free to react
* reduction
* oxidation
* isomerization

Question 22

Maillard reaction

Answer 22

Reaction between a CHO and an amine group to form glycosides

Louis Camille Maillard

Question 22

Maillard reaction

Answer 22

Shows how reducing sugars reacted whereby they reacted with glycoproteins to create a browning effect

Louis Camille Maillard

Question 23

Reactivity of amines with aldoses

Answer 23

Initiation of the Maillard reaction
* aminoketose formed can undergo a cascade of reactions

Question 24

What are advanced glycation end products?

Answer 24

proteins or lipids that become glycated after exposure to sugars which often occurs after prolonged exposure (diabetes) and can minimize original properties and functions * can collect in collagen rich tissue (joints, blood vessel walls, lens)

Question 25

What are the common reducing and non reducing sugars?

Answer 25

reducing * lactose * maltose nonreducing * sucrose * trehalose

Question 26

What is used as a proxy for the rate of progression of diabetes?

Answer 26

Glycosylation of HbA1C * glycation of Hb in the periphery is best indicator of whole body glycation as a result of excess glucose and is a marker of how poorly one is manageing diabetes

Question 27

Most abundant macronutrient

Answer 27

CHO

Question 28

What are the types of polysaccharides?

Answer 28

* digestible: starch (amylose & amylopectin), resistant starch, glycogen * non-digestible: dietary fibres