Exam 2: Carbohydrates Flashcards

1
Q

What are carbohydrates

A

organic compounds that contain carbon,
hydrogen, and oxygen in various combinations

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2
Q

CHO nomenclature typically ends in “ose”?

A

not always true

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3
Q

What are the 3 major categories of CHO?

A
  1. simple
  2. complex
  3. dietary fiber
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4
Q

Types of simple sugars

A

Monosaccharides
Disaccharides

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5
Q

What are monosaccharide

A

Glucose
Fructose
Galactose

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6
Q

What are the 3 disaccharides

A

Maltose=
Lactose
Sucrose

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7
Q

What are refined sugars

A

Monosaccharides and disaccharides, such as glucose and
sucrose, may be isolated from foods in purified forms

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8
Q

corn syrup

A

Trisaccharides and higher saccharides also exist
and may be found in commonly used sweeteners such as corn
syrup. For example, high-fructose corn syrup, a common food
additive, is a manufactured carbohydrate derived from the conver-
sion of glucose in corn starch to fructose. Other food additives
that are primarily sugar include honey, brown sugar, maple syrup,
molasses, and fruit juice concentrate.

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9
Q

What are complex CHO made up of?

A

three or more glucose molecules combine

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10
Q

Types of complex carbohydrates

A
  1. Polysaccharides
  2. Oligosaccharides
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11
Q

complex carbohydrates are commonly known as _______

A

starches

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12
Q

What are polysaccharides composed of?

A

more than
ten glucose molecules are combined

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13
Q

Types of polysaccharide

A
  1. Dextrins
  2. Starch
  3. Glycogen
  4. Dietary Fiber
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14
Q

Forms of Starches, starch is the storage of what?

A
  1. amylose
  2. amylopectin
  3. resistant starch

Plants

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15
Q

Glycogen is storage form of

A

storage form in humans

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16
Q

3 types of Fiber

A
  1. Dietary Fiber
  2. Functional Fiber
  3. Total Fiber
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17
Q

What are glucose polymers?

A

polysaccharides prepared commercially by con-
trolled hydrolysis of starch

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18
Q

Which is common glucose
polymers used in sports drinks

A

maltodextrins

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19
Q

Dietary Fiber is

A

nondigestible
carbohydrates and lignin that are intrinsic and intact in plants;
this would include resistant starch

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20
Q

Functional Fiber is

A

Functional fiber consists of iso-
lated, nondigestible carbohydrates that have beneficial physiologi-
cal effects in humans

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21
Q

Total Fiber is

A

Total fiber is the sum of dietary fiber and
functional fiber. These nondigestible substances, which means
that they are not digested and absorbed in the human small intes-
tine, are usually a mixture of polysaccharides found in the plant
wall or intracellular structures.

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22
Q

Primary sources of digestible CHO

A
  • Grains
  • Fruits
  • Vegetables
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23
Q

Other sources of digestible CHO

A
  • Dairy group: ice cream, chocolate milk
  • Protein group: beans, lentils, nuts,
  • Sweets:
  • Sports drinks/food
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24
Q

What is soluble fiber

A

found to dissolve or swell in water and may be metabo-
lized by bacteria in the large intestine

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25
3 types of Soluble Fiber
- pectins - gums - algal polysaccharides
26
Key sources of Soluble fiber
- fruits - most grains - beans
27
What is Insoluble Fiber
do not dissolve or metabolized by bacteria
28
3 types of insoluble fiber
- cellulose - hemicellulose - lignin
29
key sources of insoluble fiber
- wheat
30
Which part of a triglyceride can be used for glucose production?
Glycerol
31
What is the glycemic load formula?
GL = gly ind x gram of nonfiber carb in 1 service/ 100
32
True or False It is now generally thought that the component of fatigue correlated with lactate results from the lactate itself rather than the effects of an increased free hydro ion and the associated acidity
True
33
What is Amylose
34
What is Amylopectic
35
what is resistant starch
36
What is the typical dietary fiber recommendations for athletes (% calories
45-65% of calories
37
What is the typical dietary fiber recommendations for athletes (DRV)q
300 g for every 2000Cal diet
38
What is the typical dietary fiber recommendations for athletes (male and women)
- 25g women - 38g men
39
Osmosis is
the passive diffu- sion of water.
40
facilitated diffusion
, a receptor in the cell mem- brane is needed to transport the substance from the intestine into the villi. no energy
41
active transport
energy supplied by the villi cells in order to be absorbed
42
Carbohydrates usually are ingested in the forms of
polysaccharides (starches), disaccharides (sucrose, maltose, and lactose), and monosaccharides (glucose and fructose).
43
The enzyme that digests complex carbo- hydrates is ____________, which is secreted by the _____________ and ____________________
amylase, salivary glands, pancrease
44
Saliva amylase initiates digestion of the polysaccharides to disaccharides, but most digestion is done in the ___________________ by _______________________
small intestine by pancreatic amylase
45
sports drinks may be designed to take advantage of the different_____________________ receptors in the villi.
monosaccharide
46
although there is very little digestion of carbohydrate in the stomach, the_____________ with which carbohydrate leaves the stomach, and its impact upon the _______________ of water, may be important considerations for ath- letes involved in prolonged exercise under _____________ environmental conditions.
rapidity, absorption, warm
47
High concentrations of simple sugars, particularly______________, may exert a reverse _____________ effect in the intestines, drawing water from the circulatory system into the intestinal lumen. The resulting symptoms are referred to as the dumping syndrome and include _________________________.
fructose, osmotic, weakness, sweating, and diarrhea
48
Most dietary carbohydrates are broken down to _______________ for absorption into the blood, while the majority of the absorbed ______________- and _______________ are converted to glucose by the liver. Glucose is the blood sugar.
glucose, fructose and galactose,
49
The ________________ represents a ranking system relative to the effect that consumption of 50 grams of a particular carbohy- drate food has upon the blood glucose response over the course of 2 hours. The normal baseline measure is 50 grams of glucose, and the resultant blood glucose response is scored as _______.
glycemic index (GI), 100,
50
glycemic index (GI) 70 or more
high GI foods ●
51
glycemic index (GI) 69–55
medium GI foods ●
52
glycemic index (GI) 55 or less
low GI foods ●
53
Many factors other than a food’s carbohydrate content, such as the ________________ (coarse or fine) and __________________`(raw or cooked), may influence the glycemic index of any given food
physical form, serving mode
54
The ______________ also repre- sents a ranking system relative to the effect that eating a carbohydrate food has on the blood glucose level, but GL also includes the portion size. While the glycemic index is based on 50 grams of a particular food, a typical serving size for that food may be 6–8 ounces (180–240 grams).
glycemic load (GL),
55
GL =
(glycemic index) × (grams of nonfiber carbohydrate in 1 serving) / 100
56
glycemic load 20 or omre
high GL foods
57
glycemic load 19-11
medium GL foods
58
glycemic load 10 or less
low GL foods
59
normal blood glucose level
80 - 100 mg/mL
60
the human body possesses a variety of mechanisms, primar- ily ________________, to help keep blood glucose levels under precise con- trol
hormones
61
explain Insulin role in detail
The rise in blood glucose, also known as serum glucose, stimulates the pancreas to secrete insulin into the blood. Insulin is a hormone that facilitates the uptake and utilization of glucose (facilitated diffusion) by various tissues in the body, most notably the muscles and adipose (fat) tissue.
62
The primary receptors in muscle and fat cell membranes are known as _______ receptors, which are directly activated by insulin
GLUT-4
63
what two factors activate GLUT-4 receptors?
Insulin and exercise
64
The major fates of blood glucose
1. Blood glucose may be used for energy, particularly by the brain and other parts of the nervous system that rely primarily on glucose for their metabolism. 2. Blood glucose may be converted to either liver or muscle gly- cogen 3. Blood glucose may be converted to and stored as fat in the adipose tissue. 4. blood glucose also may be excreted in the urine if an excessive amount occurs in simple sugars
65
Hypoglycemia can impair the normal function of the ____________
brain
66
liver glycogen may later be reconverted to _____________ but not in the ______________. Why?
blood glucose, muscle glycogen lack of a specific enzyme needed to change its form so that it can cross the cell membrane back into the bloodstream
67
why is blood glucose converted and stored as fat?
dietary carbo- hydrate, in combination with caloric intake of other nutrients, exceeds the energy demands of the body and the storage capac- ity of the liver and muscles for glycogen
68
The chemical formula for glucose is
C6H12O6, so it contains 6 parts of carbon and oxygen and 12 parts of hydrogen
69
he body has three major energy sources of carbohydrate:
blood glucose, liver glycogen, and muscle gly- cogen
70
The ________- has the greatest concentration of glycogen in the body
liver
71
the liver normally contains only about 75–100 g of glycogen, or 300–400 kcal.
72
One hour of aerobic exercise uses more than half of the liver glycogen supply
73
the liver glycogen content may be decreased by starvation or increased by a carbohydrate-rich diet
74
The greatest amount of carbohydrate stored in the body is in the form of muscle glycogen
because the muscles com- pose such a large proportion of the body mass as contrasted to the liver
75
gluconeogenesis
formation of glucose from protein, fats,
76
what componenets of protein and fat are converted to glucose?
amino acids (alanine) and glycerol
77
What are the major functions of carbohydrate in human nutrition?
1. supply energy other 2. produce trioses and pentoses (glycolipids, glycoproteins) Ribose for RNA
78
Carbohydrates can be used to produce energy either
aerobically or anaerobically
79
oxidation of glucose produces
water, CO2, energy
80
Explain lactic acid system produce ATP
ATP is produced rapidly via anaerobic gly- colysis, but for this system to continue functioning, the end prod- uct of glycolysis, pyruvic acid or pyruvate, must be converted into lactic acid anaerobic metabolism yields 3 ATP when starting with glycogen and only 2 ATP when start- ing with glucose
81
Explain oxygen system produce ATP
aerobic glycolysis predominates and pyruvic acid is converted into acetyl CoA, which enters into the Krebs cycle and electron transfer system for complete oxida- tion and the production of relatively large amounts of ATP aerobic metabolism yields about 32 ATP
82
In what types of activities does the body rely heavily on carbohydrate as an energy source?
person is working at 65–85 percent of capacity for high-intensity anaerobic events lasting for less than 1 minute and high-intensity aerobic events lasting more than an hour or two.
83
Why is carbohydrate an important energy source for exercise?
can be used for anaerobic energy production in the lactic acid sys- tem, it is also the most efficient fuel for the oxygen sys- tem 2. metabolic pathways for carbohydrate are also more efficient than those for fat. more ATP than fat
84
The primary carbohydrate source of energy for physical perfor- mance is muscle glycogen, specifically the glycogen in the muscles that are active
As the muscle glycogen is being used during exercise, blood glucose enters the muscles and the energy pathways. In turn, the liver will release some of its glucose to help maintain or elevate blood glucose levels and prevent hypoglyce- mia.
85
Because carbohydrate is a primary fuel for exercise, as you initiate an endurance exercise program, a major proportion of your energy will be derived from your muscle glycogen stores. A single bout of exercise can activate the genes that produce GLUT-4 receptors, which can exert an insulin-type effect by facilitating the transport of blood glucose into the muscle both during and immediately following the exercise bout.
86
What effect does endurance training have on carbohydrate metabolism?
- increase GLUT-4 receptor production
87
Which CHO need to be digested?
all except for monosaccharides
88
Where does CHO absorption occur
Small intestine
89
How does CHO absorption occur
- Depends on type of monosaccharides - Almost all get absorbed as monosaccharides
90
Glucose and galactose are absorbed via which transport? How?
- by active transport (SGLT1/GLUT2) - Require energy - Pump mole against conc gradient - SGLT1 carrier to take into epithelial cells - GLUT2 carrier takes into circulatory system
91
Fructose is absorbed via which transport? How?
- by facilitated diffusion (GLUT5/GLUT2) - High to low concentration - Abs a lot of fructose carriers get saturated so can get in bc carriers are full, fructose go to large intestine. Fruc sit in LI. needs water, cause diarrhea, fructose is food for bacteria, release gas - Consume fructose with other carbs makes symptoms better
92
What 3 Factors may impact performance
- Rate of stomach emptying - Rate of absorption - Effect on water absorption
93
What affects rate of stomach emtyping
Fiber rich meal and fat content in meal
94
What affects rate of absorption
pure or high fructose feeding
95
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