Carbohydrates Flashcards
1
Q
what are monosaccharides?
A
one sugar carbohydrates
2
Q
what are the 3 monosaccharides?
A
- glucose
- fructose
- galactose
3
Q
what are disaccharides?
A
two sugar carbohydrates
4
Q
what are the disaccharides?
A
- maltose = glucose + glucose
- sucrose = glucose + fructose
- lactose = glucose + galactose
5
Q
what are olgiosaccharides?
A
short chains of monosaccharides that of 3-10 sugar units
6
Q
dissacharides mainly make up which structure?
A
makes up part of plant cell walls
7
Q
what are polysaccharides?
A
long chains and branches of monosaccharides
8
Q
what are the 3 polysaccharides?
A
- starch
- fiber
- glycogen
9
Q
what is starch?
A
the storage form of glucose in plants
10
Q
what are the two different forms of starch?
A
- amylose = straight chains of starch
- amylopectin = branched chains of starch
11
Q
what is fiber?
A
a non digestible food component - comes in the form of cellulose
12
Q
what is glycogen?
A
the storage form of glucose in animals
13
Q
what are the functions of carbohydrates?
A
- provides energy for the body
- regulates blood glucose
- protein sparing since glucose is the preferred fuel source
14
Q
what is insulin?
A
a hormone that decreases blood glucose level by transporting glucose into the cell
15
Q
what is glucagon?
A
a hormone that releases glucose into the bloodstream
16
Q
what are steps in the action of insulin?
A
- insulin secretion
- cellular uptake of glucose by increasing the number of GLUT transporters
- glucose storage as glycogen
17
Q
what are the steps in glucagon action?
A
- glucagon secretion from prancreas
- glycogenolysis - breakdown of stored glucagon into glucose
- gluconeogensis - forming glucose from other substances
18
Q
what is glycogenolysis?
A
the process in which glucagon stimulates breakdown of glucagon into glucose in the liver, which is then released into the blood stream and transported to the cells for energy
19
Q
what is gluconeogenesis?
A
the process in which glucagon stimulatates the conversion of glucogenic amino acids in the liver to glucose
20
Q
insulin inhibits ____ which causes the body to store fat instead of breaking it down
A
lipolysis
21
Q
what is lipolysis?
A
the breakdown of fat in the body
22
Q
what happens when there is excess glucose in the body that cant be converted into gluccagon?
A
glucose are converted to fatty acids
23
Q
what is lipogenesis?
A
formation of fatty acids
24
Q
what is the role of epinephrine in maintaining BGL?
A
increases BG levels by stimulating glycogenolysis and gluconeogenesis in the liver
25
what is the role of norepinephrine in maintain BGLs?
increases BGLs by stimulating glycogenolysis and gluconeogenesis in the liver
26
what is the role of cortisol in maintaining BGLs?
stimulates gluconeogenesis which reduced glucose uptake which in turns increases BGLs
27
what is the role of growth hormones in maintaining BGLs?
converses glucose by stimulating fat breakdown (lipolysis) for energy
28
what is hyperglycemia?
elevated BGLs
29
what is hypoglycemia?
decreased BGLs
30
what is reactive hypoglycemia?
when BGLs decreases after a meal
31
what is fasting hypoglycemia?
BGL decrease due to not having anything to eat
32
what are the DRIs (RDA and AMDR) for carbohydrates?
* RDA: 130g CHO/day
* AMDR: 45-65% of total kcals
33
what are the intake recommendations for grains?
6 servings/day; half of grains should be whole grains
34
what are the intake recommendations for veggies?
3 servings/day
35
what are the intake recommendations for dairy?
3 servings/day
36
what are the intake recommendations for fruit?
2 servings/day
37
what is a whole grain?
grains abundant in complex carbohydrates, including starch and fiber
38
what is a phyochemical?
a component of a food that may have unknown health benefits
39
in terms of carbohydrate digestion what happens in the mouth?
* mechanical digestion of food using teeth
* salivary amylase is secreted
40
what is salivary amylase?
an enzyme that breaks down amylose and amylopectin
41
in terms of carbohydrate digestion, what occurs in the stomach?
chemical digestion occurs with the mixing of HCl
42
what are parietal cells?
cells that secrete HCl
43
what are goblet cells?
cells that secrete mucus to protect the stomach lining from HCl
44
in terms of carbohydrate digestion, what occurs in the small intestine?
* brush border enzymes are released
* pancrease releases pancreatic amylase
45
what is pancreatic amylase?
an enzyme that breaks down amylose and amylopectin
46
what is sucrase?
an enzyme that breaks down sucrose
47
what is lactase?
an enzyme that breaks down lactose
48
what is maltase?
an enzyme that breaks down maltose
49
________ bonds are easier to digest compared to ____ bonds which are harder to digest
alpha-glycosidic; beta-glycosidic
50
where are alpha-glycosidic bonds found?
sucrose and maltose
51
where are beta-glycosidic bonds found?
lactose and cellulose
52
what is a resistant starch?
a starch that is harder to digest; higher in amylose
53
* ____ and ____ are absorbed through active transport
* ____ is absorbed through facilitated diffusion
* glucose; galactose
* fructose
54
where does absorption occur in the small intestine?
enterocytes
55
describe the carbohydrate transport after absorption
1. carbohydrate is transported to the liver via the portal vein
2. galactose and fructose are used for energy or converted into glucose and released into the bloodstream
3. glucose is then stored as glycogen via glycogenesis
4. excess glucose is stored as fatty acids and glycerol in adipocytes
5. metabolic needs direct the fate of monosaccharides
56
what are glycemic load and glycemic index?
the measure of effect of carbohydrate containing foods or meals on blood glucose levels
57
what is the difference between glycemic load and glycemic index?
* glycemic load takes carbohydrate quanity and preparation methods into account
* glycemic index is bases off of white bread
58
what is lactose intolerance?
the absense of lactase in the body which prevents lactose from being broken down
59
what happens as a result of lactose intolerance?
* undigested lactose pulls water through the GI tract - causes diarrhea
* lactose is digested by bacteria in large intestine which is then fermented - causes gas production
60
what is lignin?
a fiber/glue that holds cellulose together
61
what are the two classifications for fiber?
* insoluable fiber = fiber that doesn't dissolve in water
* soluable fiber = fiber that does dissolve in water
62
what is functional fiber?
fiber that is manufactured by the food industry and included in products for health benefits
63
what are the dietary fiber recommendations (AI)?
* adult females <50 years: 25g/day
* adult males <50 years: 38g/day
* >50 years: 21-30g/day
* ages 1-3: 19g/day
64
what is adquate fiber intake associated with?
* regular bowel movements
* increased satiety
* decreased risk of heart disease
* improved diabetes
* lower risk of cancer
65
what is constipation?
infrequent or difficult bowel movement; less than 3x/week
66
what is diverticulosis?
increased pressure in the colon causes weak spots along the wall forming pouches called diverticula
67
what is diverticulitis?
infection of diverticula.
68
how does soluable fiber reduce blood cholestrol levels?
* soluable fiber is a bile acid sequestrant
* bile acids contain cholesterol
* Soluable fiber prevents bile acids from being reabsorbed and instead causes it to be secreted through feces
69
how does soluable fiber help reduce BGLs?
viscous gel helps slow digestion and absorption of glucose
70
how does soluable fiber help decrease cancer risk?
viscous gel decreases the time in which cancer-promoting substances spend in contact with the GI tract
71
what are GI flora?
bacteria of the GI tract
72
what are the major strain of GI flora?
* firmicutes
* bacteroidetes
73
what is dysbiosis?
the imbalance of the body's microbial composition
74
what are probiotics?
bacteria that are associated with health benefits
75
what are prebiotics?
non-digestible resistance starches that support the growth of gut bacteria populations
76
what is insulin resistance?
when the body doesn't respond to insulin which results in higher levels of glucose in the blood
77
true or false: reduced diversity of gut microbiota is associated with an increase in metabolic disorders
true
| this can be in the form of changes in weight, insulin resistance, etc.
78
what are the two most common added sugars?
sucrose and fructose
79
what is the connection between sugar and dental caries?
* sugar is a food source for the bacteria in the mouth
* acid is produce as a result of digestion of sugar from mouth bacteria
* this acid is associated with erosion of tooth enamel
80
what are the different sugar substitutes?
* polyols/sugar alcohols
* stevia
* aspartame
81
what are the charecteristics of polyols/sugar alcohols?
* fewer kcals than sucrose
* decreased impact on BG and risk of dental carries
82
what are some examples of polyols/sugar alcohols?
* xylitol
* mannitol
* sorbitol
83
what are the charecteristics of stevia?
* higher concentration of sweet flavor (250x sweeter than sugar)
* no kcals
* does not raise BG
84
what are the charecteristics of aspartame?
* made of amino acids phenylalanine and modified aspartic acid
* provides 4 kcals/g
* 200x sweeter than sugar
* not appropriate for phenylketonuria (PKU)
85
what is phenylketonuria (PKU)?
a genetic disorder in which the body is not able to break down the amino acid phenylalanine
86
what is gastroesophageal reflux disease (GERD)?
inadquate/improper closing of the the lower esophageal sphincter causing stomach acid to flow back into the esophagus
87
what is belching/burping?
expelling air from the stomach
88
what is aerophagia?
swallowing air
89
what is gastroenteritis?
infection and inflammation of the stomach due to bacteria/virus
90
what are some symptoms of gastroenteritis?
* nausea
* vomiting
* diarrhea
* cramping
91
what are ulcers
formation of sores/erosion of the stomach lining or duodenum
92
what causes ulcers?
a bacteria called heliobacter pylori (H.pylori)
93
what is gallbladder disease?
a group of conditions that can affect the gallbladder
94
what is celiac disease?
an autoimmune disease that results in flattened villi and malabsorption
95
what is diarrhea?
condition involving loose watery stools more than 3x a day
96
what is the pathophysiology behind diarrhea?
the enterocytes become inflammed and instead of absorbing fluid they secrete fluid
97
what is inflammatory bowel disease?
inflammation of the GI tract; includes ulcerative colitis (large intestine) and crohns disease (entire GI tract)
98
what is diabetes mellitus?
inadequate regulation of blood glucose
99
describe the different types of diabetes?
* type 1 diabetes = the pancrease stops producing insulin
* type 2 diabetes = insulin resistance
* gestational diabetes = insulin resistance in pregnancy
100
what is the normal range for fasting BG?
<100 mg/dL
101
what is the prediabetic range for fasting BG?
100-125 mg/dL
102
what is the diabetic range for fasting BG?
>126 mg/dL
103
what is the normal range for BG?
70-110 mg/dL
104
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