Carbohydrates Flashcards
1
Q
What are carbohydrates?
A
- organic compounds (saccharides- starches and sugars) composed of carbon, hydrogen, and oxygen
- hydrogen and oxygen usually in 2:1 ratio or H2O
2
Q
What are the three classifications of carbohydrates?
A
- monosaccharides
- disaccharides
- polysaccharides
3
Q
What are monosaccharides?
A
- simplest form, simple sugar
- sweet and requires no digestion, absorbed directly into the bloodstream from the small intestine
4
Q
What is glucose (dextrose) or blood sugar?
A
- monosaccharide
- principal form in which carbohydrate is used by the body
- abundant in fruits, sweet corn, and corn syrup
- moderately sweet
5
Q
What is fructose (levulose)?
A
- monosaccharide
- sweetest of the simple sugars
- found in honey, most fruits and some vegetables
- converted into glucose in the body
6
Q
What is galactose?
A
- monosaccharide
- not found free in foods
- produced from lactose (milk sugar) by digestion
- converted into glucose in the body
7
Q
What is galactosemia?
A
a condition where infants are born with an inability to metabolize glucose
8
Q
What are disaccharides?
A
- made up of monosaccharides
- sweet and changed to simple sugar by hydrolysis before they can be absorbed
9
Q
What is sucrose?
A
- disaccharide
- ordinary table sugar - granulated, powdered, or brown
- processed from cane and beet sugar
- found in fruits, vegetables, syrup, and sweet food production
- converted into glucose and fructose upon digestion
10
Q
What is lactose?
A
- disaccharide
- milk sugar
- found in milk and milk products except cheese
- converted into glucose and galactose upon digestion
- less soluble and less sweet than sucrose
11
Q
What is maltose?
A
- disaccharide
- not found free in foods
- produced by hydrolysis of starch
- converted into glucose in digestion
- occurs in malt products and germinating cereals
- found in infant formulas, beer, and malt beverage products
- less sweet compared to glucose and sucrose
12
Q
What are polysaccharides?
A
complex sugars
13
Q
The most significant polysaccharide in human nutrition
A
starch
14
Q
What are the major food sources of starch?
A
- cereal grains
- potatoes and other root vegetables
- legumes
15
Q
What happens to starch upon digestion?
A
- converted entirely into glucose
- requires longer time to digest
- supplies energy over a longer period of time
16
Q
What are dextrins?
A
- not found free in food
- formed as an intermediate product in the break down of starch
17
Q
What is cellulose?
A
- non digestible by humans
- forms the frame work of plants found in unrefined grains, vegetables, and fruits
- lowers blood glucose level of DM pxs.
18
Q
What are the classifications of cellulose?
A
- soluble
- insoluble
- pectins
- glycogen
19
Q
What is soluble cellulose?
A
- delays gastrointestinal transit and glucose absorption
- lowers blood cholesterol
20
Q
What is soluble cellulose?
A
- delays gastrointestinal transit and glucose absorption
- lowers blood cholesterol
21
Q
What is insoluble cellulose?
A
- accelerate gastrointestinal transit
- increase fecal weight
- slow down starch hydrolysis
- delay glucose absorption
22
Q
What are pectins?
A
- used to treat diarrhea as they absorb toxins and bacteria in the intestine
- binds with cholesterol, reducing the amount the blood can absorb
23
Q
What is glycogen cellulose?
A
- formed from glucose and stored in liver and muscle tissue
- glucagons help the liver convert glycogen every time the body needs energy
24
Q
How are carbohydrates digested in the mouth?
A
amylase, an enzyme, breaks down starch into dextrin and maltose
25
How are carbohydrates digested in the small intestine?
1. pancreatin and amylopsin converts starch into dextrin and maltose
2. intestinal juice contains three disaccharides (sucrose, lactose and maltose) which act on their respective disaccharides
26
What are the functions of carbohydrates?
- serves as a major source of energy
- exert a protein sparing-action in which the body will convert protein into glucose if there is insufficient carbohydrates
- necessary for normal fat metabolism in the same case of protein
27
Indigestible carbohydrates ____________
aid in normal elimination, they stimulate peristaltic movement and absorb water to the intestinal contents
28
Carbohydrates supply significant quantities of _______________
proteins, minerals, and B vitamins
29
Lactose remains in the intestine longer than other disaccharides and encourages _________________
growth of beneficial bacteria resulting in a laxative action
30
Lactose remains in the intestine longer than other disaccharides and encourages _________________
growth of beneficial bacteria resulting in a laxative action
31
How does glucose benefit the nervous system?
- maintenance of the functional integrity of nerve tissue
- sole energy source for the brain
32
What are the sources of carbohydrates?
1. whole grains
2. sweet and white potatoes
3. milk
4. sugars and sweets
5. empty calories
33
What are whole grains?
- important source
- rich in iron, thiamin, niacin, and other nutrients
34
What are sweet and white potatoes?
- important contributors to carbohydrate intake from vegetable and fruit groups
35
What is milk?
- only source of lactose (1 cup = 12 g)
- cheese only contains traces of lactose
36
What are sugars and sweets?
another important source of carbohydrates
37
What are empty calories?
foods that do no contain any amount of other nutrients aside from carbohydrates
38
Effects of starch and fibers on weight control
- low fat
- added sugars
- promotes weight loss
39
Effects of starch and fibers on heart disease
high carbohydrate diets can protect an individual against heart disease and stroke
40
Effects of starch and fibers on cancer
high carbo diets can help prevent many types of cancer
41
Effects of starch and fibers on diabetes
low fat diets help control weight
42
Effects of starch and fibers on gastrointestinal health
dietary fibers enhance the health of the large intestine
