Carbs

Question 1

Source of carbs

Answer 1

• Plants convert sunlight into carbohydrates through photosynthesis (process in which green
  plants use sunlight to make their own food)

Question 2

What are simple carbs?

Answer 2

Monosaccharides
-Single-sugar units

1. glucose
2. fructose
3. galactose

Question 3

What is glucose?

Answer 3

Most important carb
- Focuses on CHO metabolism

-Most cells rely on glucose -> Brain and nervous system

Question 4

What is fructose?

Answer 4

• Fruit sugar
  -naturally in fruits, veggies, honey and part of table sugar

Question 5

What is galactose?

Answer 5

• Mostly occurs as part of lactose
  -Byproduct of digestion

Question 6

What are disaccharides?

Answer 6

-Pairs of sugar units bonded together
-Combination of pairs of monosaccharides
1. Maltose
2. Sucrose
3.Lactose

Question 7

How to link two monosaccharides?

Answer 7

Condensation

Question 8

How to break up into two monosaccharides?

Answer 8

Hydrolysis

Question 9

What is condensation?

Answer 9

Form a bond between two compounds
-Water is released

Question 10

What is hydrolysis?

Answer 10

Bond is broken
-Water is required for this reaction

Question 11

What is maltose

Answer 11

-Plant sugar
-Composed of two glucose units
-Occurs in plants during break down of stored starch and in humans during carb digestion

Question 12

What is sucrose?

Answer 12

Composed of glucose and fructose
-Table sugar

Question 13

What is lactose?

Answer 13

Glucose and galactose

Question 14

What ars complex carbs?

Answer 14

Oligosaccharides & polysaccharides

-More than two monosaccharides (starch, glycogen, fibre)

Question 15

What are major polysaccharides?

Answer 15

1. Starch
2. Glycogen
3. Fibre

Question 16

What is starch?

Answer 16

Multiple glucose units
(occasionally branched or
unbranched)

Storage form in plants (grains
e.g. rice, legumes e.g. beans,
tubers e.g. potatoes)

Question 17

What is glycogen?

Answer 17

Multiple glucose units

Not a significant food source of carbs

Important role in carb storage in the body

Question 18

What os fibre?

Answer 18

Non-starch polysaccharides

• Indigestible

Question 19

What are the three types of fibre?

Answer 19

1. Dietary fibre: non-digestible of plants (grains, rice, seed, legumes, fruits)
2. Functional fibre: non-digestible carbs extracted from plants and added to food (cellulose, pectin)

Question 20

How to calculate total fibre?

Answer 20

dietary + functional

Question 21

What is soluble fibre?

Answer 21

absorbed water to form a gel

Fermented and broken down by bacteria in colon producing gasses and short chain fatty acids

Slow GI motility

Question 22

What are non-soluble fibres?

Answer 22

-Do not dissolve in water and do not form a gel

• Non-fermentable

-Provide bulk and feeling of fullness
-Help with weight management
-Help with constipation

Question 23

Digestion of carbs in mouth

Answer 23

– salivary amylase
– breaks down starch into small polysaccharides and maltose

Question 24

Digestion of carbs in stomach

Answer 24

– acid inactivates salivary
amylase, halting starch
digestion

Question 25

Digestion of carbs in pancrease

Answer 25

– pancreas secretes pancreatic amylase into small intestine to digest starch into small polysaccharides and maltose

Question 26

Digestion of carbs in small int.

Answer 26

– Enzymes (maltase, sucrase, lactase) hydrolyze disaccharides (maltose, sucrose, lactose) into monosaccharides (glucose, fructose and galactose) – Monosaccharides are absorbed across the microvillus membrane of the small intestine into the portal blood system for transport to the liver.

Question 27

What is glycemic response?

Answer 27

glucose absorption after a meal

Question 28

What is glycemic index?

Answer 28

-Potential to raise Blood glucose -Measures how quick carbs absorb

Question 29

Factors that influence GI

Answer 29

-starch structure, -fiber content, -presence of fat and protein, -food processing, -mixture of foods in a meal, -individual glucose tolerance

Question 30

What are excess carbs stored as?

Answer 30

glycogen

Question 31

What is insulin?

Answer 31

– produced by beta cells of the pancreas – helps cells take in glucose from the blood – facilitates glucose uptake by muscles and adipose tissue – stimulates the liver and muscle to take up glucose and convert it to glycogen

Question 32

What is glucagon?

Answer 32

– produced by alpha cells of the pancreas – stimulates the breakdown of glycogen to glucose (glucose is exported from liver but not muscle) – more glucose is available to cells of the body

Question 33

What is glucogenesis?

Answer 33

the production of glucose from amino acids in liver

Question 34

RDA for carbs is?

Answer 34

130g of digestible carbs per day for adults - Adequate for normal brain function

Question 35

Carb recommendations

Answer 35

Total carbohydrates: 45-65% caloric input (Health Canada’s recommendation) – 200-330 g/day men – 180-230 g/day women

Question 36

What happens when carb intake is low?

Answer 36

Proteins are used for gluconeogenesis

Question 37

Recommended total fibre?

Answer 37

About 14 g of dietary + functional fibre/1000 kcal/day

Question 38

What are non-nutritive sweeteners?

Answer 38

1. Aspartame 2. Saccharin 3. Sucralose 4. Stevia