Biochem Lecture: Carbohydrates

Is converted into glucose for your body to function

Carbohydrates

Simple carbohydrates

Monosaccharides (single sugar), Disaccharides (dual/double sugar)

Complex carbohydrates

Polysaccharides (many sugar)

Monosaccharides chemical formula

C6H12O6

Dextrose or blood sugar

1\. Primary fuel for the body

2\. Found in all disaccharides & polysaccharides.

Glucose

Fruit sugar (sweetest)

1\. Found in fruit, honey, syrup

2\. Converts to glucose in the body

Fructose

Part of lactose

1\. Found in milk.

2\. Converts to glucose in the body

Galactose

Maltose – malt sugar

1\. Glucose + Glucose

2\. Found in germinating seeds & used in fermentation to produce malted beverages (beer, whiskey)

Maltose

Table sugar

1\. Glucose + Fructose

2\. Refined from sugar beets & cane

Sucrose

Milk sugar

1\. Glucose + Galactose

2\. Lactose intolerance – missing digestive enzyme needed to split into two monosaccharide parts to absorb it

Lactose

Bonding of 2 monosaccharide

Condensation

Separation of 2 monosaccharide

Hydrolysis

Long chains of glucose are found in animals.

1\. Stored in liver & muscles.

2\. Helps maintain blood glucose and important source of “quick energy”, esp. during exercise (lasts only about 12 hrs)

Glycogen

Long chains of glucose found in plants.

Cereal grains (wheat, rice, corn, etc.), legumes (beans & peas), and root vegetables (potatoes, yams)

Starch

Mostly indigestible CHO; gums, mucilages, lignin

• Component of plant cell walls

• Classified according to solubility in water.

• Abundant in whole grains, legumes, fruits and vegetables

Fibers

nonviscous;cellulose, lignins

Insoluble Fibers

viscous & fermentable ; pectins, gums, mucilages

Soluble Fibers

Process of Digestion

Mouth

Stomach

Small Intestines

Pancreas

Large Intestines

Produced by Mouth

Salivary Amylase

Produced by Pancreas

Pancreatic Amylase

Produced by Large Intestines

Mainly gas (flatulence)

Stored as glycogen-(_) in the liver (_) in the muscle

1/3 and 2/3

Gluconeogenesis

Glucose made from protein

What happens when carbohydrates are in excess?

Converted to fat

Glucose Pyruvate + ATP are produced

Glycolysis

Conversion of excess glucose into glycogen in the liver for storage

Glycogenesis

Breakdown of glycogen to glucose

Glycogenolysis

Conversion of non-carbohydrate source (amino acids) to glucose

Gluconeogenesis

Conversion of carbohydrates to fatty acids

Lipogenesis

Breakdown of fats to glucose for energy

Lipolysis

These maintain glucose homeostasis.

Regulating hormones

Primary hypoglycemic agent; uptake of glucose by cells

From beta cells

Insulin

Primary hyperglycemic agent

From Alpha cells

Glucagon

Autoimmune diabetes

Type 1 Mellitus Diabetes

Acquired diabetes

Types 2 Mellitus Diabetes

Complex carbohydrates & fibre may reduce the risk of:

\-Heart disease

\-Diabetes

\-GI issues

\-Cancer

\-Obesity

• Lower blood cholesterol by binding dietary cholesterol so less absorbed.

• Slow glucose absorption

• Slow transit of food through upper GI tract

• Holds moisture in stools, softening them.

• Lower risk of heart disease

• Lower risk of diabetes

Soluble Fibers

• Increase fecal weight - helps form soft, bulky stools which improves G.I. motility & reduces risk of constipation, hemorrhoids, diverticulosis & colon cancer.

• Speed fecal passage through colon

• Provide bulk and feelings of fullness (satiety)

Insoluble Fibers

Alternative sweeteners (Sugar Alcohol)

Mannitol, Sorbitol, Xylitol

Alternative sweeteners (Artificial Sweeteners)

Aspartame, Sucralose

Hyperglycemia

Increase in blood glucose concentration

160-180mg/dL

Glucosuria

Glucose in the urine

Hypoglycemia

Decrease in blood glucose concentration

50-55mg/dL

A. low blood glucose

B. Symptoms of hypoglycemia

C. Relief of symptoms after glucose administration

Whipple’s triad

DIABETIC COMA

Hyperglycemia above 400 mg/dL

Hypoglycemia below 60 mg/dL

Sorbitol, Mannitol, Xylitol

0\.5

0\.7

1

(Relative Sweetness)

Aspartame

Sucralose

200

600

(Avg Amount to replace 1 tsp Sugar)

Aspartame

Sucralose

18 mg

6 mg