EXAM 4 review questions Flashcards
1
Q
list monosaccharides (1 sugar)
A
- Glucose
- Fructose
- Galactose
2
Q
list disaccharides (2 sugars)
A
- Sucrose
- Lactose
- Maltose
3
Q
describe homopolysaccharides
A
Polysaccharides (>10 sugars) with 1 type of sugar
4
Q
describe heteropolysaccharides
A
Polysaccharides (>10 sugars) with >1 type of sugars
5
Q
compare homopolysaccharides and heteropolysaccharides
A
one type of sugar vs. more than one type of sugar
6
Q
define reducing sugar
A
if the OH on the anomeric carbon is not bound to another sugar
7
Q
compare amylose and amylopectin
A
amylose - makes up 20% of starch and has only linear alpha (1-4) bonds
amylopectin - makes up 80% of starch and has linear alpha (1-4) bonds and branched alpha (1-6) bonds every 24-30 glucoses
8
Q
compare starch and glycogen
A
starch: storage form of carbs in plants branched alpha (1-6) every 24-30 glucose
glycogen: storage form of carbs in animals (found in cytoplasm of muscle and liver cells)
branched alpha (1-6) every 8-12 glucose
therefore, glycogen is more branched than starch
9
Q
list soluble fibers
A
pectin gums beta-glucans konjac glucomannan inulin fructans
10
Q
list insoluble fibers
A
cellulose
11
Q
sources of both soluble and insoluble fibers
A
homoglycans and heteroglycans
fruits and vegetables!
12
Q
what are the health benefits of soluble and insoluble fibers?
A
soluble: delays gastric emptying (increase satiety - feel full longer)
insoluble: decreases GI transit time (speeds motility)
13
Q
list grains that are included in whole grains
A
buckwheat, bulgur, corn, millet, brown rice, rye, oats, sorghum, wheat and wild rice
14
Q
to be considered a whole grain, the grain must contain what?
A
endosperm (starch)
germ (oil)
bran (insoluble fiber)
in same relative proportions!
15
Q
describe benefits/concerns of each portion of whole grain
A
Benefits:
vitamins and minerals - vit E, selenium and zinc
lignan - plant estrogen
antioxidants - decrease oxidation
insoluble fiber - speeds up GI transit
soluble fiber - increases satiety, binds chol, TG, glucose
resistant starch - acts like soluble fiber
plant sterols - decrease cholesterol absorption
Concerns:
phylate - can bind minerals
16
Q
why is phylate considered an antinutrient?
A
can bind minerals
17
Q
is high fructose corn syrup worse than sucrose?
A
no?
18
Q
list enzymes in carb digestion and location
A
mouth: salivary alpha-amylase
stomach: none
pancreas: pancreatic alpha-amylase
small intestine: brush border enzymes (lactase, maltase, sucrase, isomaltase)
19
Q
what impact does insulin have on glucose absorption?
A
pulls GLUT2 out of brushborder membrane to decrease glucose absorption
20
Q
what is the normal range of fasting blood glucose?
A
70-99mg/dL
21
Q
how do insulin and glucagon regulate blood glucose?
A
insulin: helps reduce blood glucose levels
glucagon: helps increase blood glucose levels
22
Q
what holds insulin together?
A
disulfide bridges
23
Q
what is insulin secreted in response to?
A
high plasma glucose conc.
plasma amino acid levels (**arginine)
CCK
gastric inhibitory polypeptide (GIP)
24
Q
does insulin stimulate or inhibit glycogen synthesis?
A
stimulates
25
does insulin stimulate or inhibit glucose uptake by muscle or liver cells?
stimulates
26
does insulin stimulate or inhibit TG synthesis?
stimulates
27
does insulin stimulate or inhibit TG breakdown?
inhibits
28
does insulin stimulate or inhibit protein synthesis?
stimulates
29
does insulin stimulate or inhibit AA uptake by cells?
stimulates
30
how does insulin get glucose from the plasma into muscle cells or adipocytes?
by stimulating production of GLUT4
31
what is glucagon secreted in response to?
low plasma glucose conc.
low plasma aa levels
epinephrine or norepinephrine
32
does glucagon inhibit or stimulate liver glycogen degradation?
stimulates
33
does glucagon inhibit or stimulate TG synthesis?
inhibits
34
does glucagon inhibit or stimulate TG breakdown?
stimulates
35
dpes glucagon inhibit or stimulate glucogenesis?
stimulates
36
does glucagon inhibit or stimulate glucocorticoid synthesis?
stimulates
37
what are the differences between a high GI and low GI food?
high - pure sugars - increase risk of colon, breast and prostate cancers, heart diease and type 2 diabetes
low - fruits and veggies and chocolates
38
according to toxicology data, do we consume toxic quantities of artificial sweetners?
NO - methanol is toxic at 0.0791mg/kg (avg person - 0.061mg/kg)
39
how many calories do we get from sugar substitues?
0Cal/g
40
how many calories do we get from sugar replacers?
1.5-2Cal/g
41
how many calories do we get from soluble fibers?
2Cal/g
42
how are sugar alcohols formed?
reduction (adding H)
43
what are GAGs?
glycosaminoglycans - repeating disaccharides of acidic sugar and amino sugar
44
what are the 6 GAG classes?
1) chondroitin sulfate
2) hyaluronic acid
3) keratin sulfate
4) dermatan sulfate
5) heparin
6) heparin sulfate
45
where are GAGs found?
mucus and synovial fluid
46
what are proteoglycans?
protein core with all other GAGs bound to it (except hyaluronic acid)
47
where are proteoglycans found
aggrecan in cartilage
48
what are Glycoproteins?
protein + branched oligosaccharide
49
what do Glycoproteins do?
cell surface recognition
ABO blood group antigens
biological lubricants as part of mucins in GI and urogenital tracts
50
which carbs taste sweet?
simple carbs
51
which carbs do not taste sweet?
complex carbs
52
what are the simple carbs?
mono and disaccharides
53
what are the complex carbs?
oligo and polysaccharides
54
what is mutorotation?
flip back and forth between alpha and beta
| if mutorotates = reducing sugar
55
what reaction are disaccharides formed from?
dehydration/condensation
56
what type of bond/linkage is formed between disaccharides?
glycosidic linkage
57
what happens with soluble fiber?
swells in water, not digested, FERMENTED in LI to short chain FA and gas
58
what happens with insoluble fiber?
does not swell in water, not digested or fermented, EXCRETED UNCHANGED
59
is pectin a soluble or insoluble fiber?
soluble
60
is pectin a homo/heteroglycan?
heteroglycan
61
where is pectin found?
inside fruits and veggies
| active ingredient in Luden's cough drops
62
are gums soluble or insoluble fibers?
soluble
63
are gums homo/heteroglycan?
heteroglycan
64
where are gums found?
oatmeal, legumes and barley
65
are beta-glucans soluble or insoluble?
soluble
66
are beta-glucans homo/heteroglycans?
homoglycans
67
what are beta-glucans important for?
decreasing cholesterol, TG and glucose absorption
68
is konjac glucomannan soluble/insoluble?
soluble
69
is konjac glucomannan homo/heteroglycan?
heteroglycan
70
are fructans soluble/insoluble?
soluble
71
are fructans homo/heteroglycan?
homoglycan
72
where are fructans found?
chicory root, bananas, tomatoes
73
function of fructans?
prebiotic bacteria - stimulates growth of good bacteria in gut
74
is cellulose soluble/insoluble?
insoluble
75
is cellulose homo/heterglycan?
homoglycan
76
where is cellulose found?
fruit and veggie peels, bran, legumes, root veggies, nuts
77
what is cellulose important for?
directing water flow
78
what is an excellent source of soluble fiber?
oatmeal
79
what 2 sugars form maltose? (include bonds)
glucose-alpha(1-4)-glucose
80
what 2 sugars form sucrose?
glucose-(alpha1-beta2)-fructose
81
what structure is repeated in cellulose?
glucose-beta(1-4)-glucose
82
what 2 sugars form lactose?
galactose-beta(1-4)-glucose
83
insulin is synthesized by which cells of the pancreas?
beta cells
84
what are the usages of glucose in cell with increasing glucose concentration?
1) use glucose for ATP
2) store glucose as glycogen in liver and muscles
3) turn glucose into TG in the liver
85
glucagon is synthesized by which cells of the pancreas?
alpha cells
86
how much energy do carbohydrates provide?
4Cal/g
87
how many carbs are required by the brain?
130g/day
88
how many Cals (energy) should come from carbs?
45-65%
89
true or false: carbs are usually found in cyclic structures
true
90
what enzyme is used to form glycosidic linkages?
glycosyltransferases
91
what happens in the large intestine?
no digestion
soluble fiber fermented to short chain FA and gas
insoluble fiber excreted unchanged in feces
92
age of onset for type 1 diabetes?
<30 years old and develops rapidly
93
age of onset for type 2 diabetes?
>35 years old, develops gradually
94
nutritional status of type 1 diabetes?
undernourished
95
nutritional status of type 2 diabetes?
obese
96
prevalence of type 1 diabetes?
10%
97
prevalence of type 2 diabetes?
90%
98
genetic correlation of type 1 diabetes?
moderate
99
genetic correlation of type 2 diabetes?
very strong
100
defects of type 1 diabetes?
autoimmune disease destroying beta-cells
101
defects of type 2 diabetes?
insulin resistance, beta cells cant keep up
102
plasma insulin in type 1 diabetes?
low to absent
103
plasma insulin in type 2 diabetes?
high early in disease
104
type 1 diabetes respond to oral hypoglycemic drugs?
nope
105
type 2 diabetes respond to oral hypoglycemic drugs?
yes
106
treatment for type 1 diabetes?
insulin
107
treatment for type 2 diabetes?
diet, exercise, oral meds
108
what is a glucosamine?
glycosaminoglycan (GAG)
109
which is the most abundant GAG in vivo?
chondroitin sulfate
110
where is chondroitin sulfate found?
cartilage, tendons, ligaments and aorta
111
function of chondroitin sulfate?
binds collagen in cartilage for tensile strength
112
which class of GAGs forms proteoglycan aggregates with hyaluronic acid?
chondroitin sulfate
113
glucosamine is a precursor for which GAG class?
hyaluronic acid
114
function of hyaluronic acid?
lubricant and shock absorber
115
where is hyaluronic acid found?
synovial fluid of joints, umbilical cord, cartilage, loose connective tissue
116
which GAG class is found in loose connective tissue proteoglycans with chondroitin sulfate?
keratin sulfate
117
which GAG class is found in skin, blood vessels and heart valves?
dermatan sulfate
118
which GAG class in found in the intracellular component of mast cells in liver, lungs and skin?
heparin
119
what is the function of heparin?
anticoagulant
120
which GAG class is the extracellular GAG?
heparin sulfate
121
how do diabetics watch their sugar intake?
sugar substitutes - no Calories
| sugar replacers - minimal Calories
122
list sugar substitutes?
```
saccharin
aspartame
acesulfame-K
sucralose
neotame
stevia
```
123
is saccharin heat stable?
yes
124
what is the acceptable daily intake of saccharin?
5mg
125
is aspartame (Nutrasweet) heat stable?
no
126
what is the acceptable daily intake of aspartame?
50mg
127
is acesulfame-K (Sunett) heat stable?
no
128
what is the acceptable daily intake of acesulfame-K?
15mg
129
is sucralose (Splenda) heat stable?
yes
130
what is the acceptable daily intake of sucralose?
5mg
131
is neotame heat stable?
yes
132
what is the acceptable daily intake of neotame?
18mg
133
is stevia stable?
yes
134
what is the acceptable daily intake for stevia?
4mg
135
what is the function of liver glycogen?
regulates blood glucose
if high - stores as glycogen
if low - digest glycogen and releases to blood
136
what is the function of muscle glycogen?
used for energy during short term exercise
137
more branches means __________ non reducing ends
more
138
more non reducing ends means?
digested faster
139
describe carb digestion in the mouth
salivary alpha-amylase randomly digests alpha(1-4) bonds
140
describe carb digestion in the stomach
salivary amylase denatured, no digestion
141
describe carb digestion in the pancreas
pancreatic alpha-amylas randomly digests only alpha(1-4) bonds
142
describe carb digestion in the small intenstine
brush border enzymes (lactase, maltase, sucrase, isomaltase) digests alpha(1-4) and alpha(1-6) bonds
143
what are the products of mouth digestion?
dextrins (short oligosaccharides)
144
what are the products of pancreas digestion?
glucose, maltose, isomaltose (mono+disaccharides)
145
what are the products of digestion in the small intestine?
glucose, galactose and fructose (monosaccharides)
146
what mechanism is used for glucose and galactose absorption between meals?
active transport
147
what 4 things are required for active transport of glucose and galactose between meals?
sodium-glucose transporter-1 (SGLT-1)
ATP
Na
K
148
how are monosaccharides transported out of the basolateral membrane between meals?
GLUT2 transport protein
149
what mechanism is used for glucose and galactose absorption after a sugar-rich meal?
active transport and facilitated diffusion
150
what is the role of GLUT2 in glucose and galactose absorption after a sugar-rich meal?
embedded in brush border membrane to absorb glucose via facilitated diffusion
also to transport monosaccharides out of basolateral membrane
151
what is the role of insulin in glucose and galactose absorption after a sugar-rich meal?
pulls out GLUT2 from brush border membrane (stays within enterocyte) to decrease glucose absorption
152
what mechanism is used for fructose absorption?
facilitated diffusion
153
what transport protein is used to absorb fructose into enterocyte?
GLUT5
154
what transport protein transports fructose out of the basolateral membrane?
GLUT2
155
what are the hormones (transport proteins) used in carb absorption and transport?
GLUT2
GLUT4
GLUT5
156
which transport protein transports glucose, galactose and fructose out of basolateral membrane?
GLUT2
157
which transport protein is membrane-bound?
GLUT4
| GLUT5
158
which transport protein is insulin-stimulated and required to transport glucose from plasma to muscle and adipose tissue?
GLUT4
159
which transport protein is required for fructose absorption?
GLUT5
160
what is the condition called for persistent high blood glucose?
hyperglycemia
161
what blood glucose level is classified as prediabetic?
100-125mg/dL (fasting)
162
what blood glucose level is classified as diabetic?
>126mg/dL (fasting)
163
what are the symptoms of hyperglycemia?
frequent urination
dehydration
thirst
164
what is the anomeric carbon?
carbon with double bond O
165
what is the anomeric carbon on an aldose?
carbon 1
166
what is the anomeric carbon on a ketose?
carbon 2
167
are alpha or beta bonds harder to digest?
beta bonds
168
starch is a polymer of what monosaccharide?
glucose
