Carbohydrates Flashcards
What are carbs?
compounds containing C,H,O
all contain C=O groups and -OH groups
What are the 4 classifications of Carbs?
size of base of carbon chain
location of CO functional group
# of sugar units
stereochemistry of compound
What are the two forms of carbohydrates?
aldose and ketose -> carb group in the middle ketone
What is the primary energy source of the Brain?
Carbs, natural are the best like grains
What is the smallest carb?
glyceraldyhede (3 carbs)
What is a fisher projection?
aldehyde group at top, straight chain or link for circular function
Is a fisher projection more accurate than a Haworth projection?
No, Haworth is more accurate
Describe a stereoisomer
same bonds, different spacial arrangement, assigned as D or L by height of highest carbon
D - natural, metabolize
L - version body can’t handle
Describe a monosaccharide
simple sugars that can’t be hydrolyzed to simpler forms
(hydrolysis splits sugar via water release
when two carbs join it uses water)
What are most common monosaccharides?
Glucose, fructose and galactose
T/F: we use D-glucose and need D-galactose to convert to glucose
true
Describe Disaccharides
common forms?
two monosaccharide units joined by glycosdic linkage
common forms: maltose/sucrose
Describe polysaccharides
Common forms?
formed by linkages of monosaccharides or oligosaccharides (3-10 units)
Common forms: starch (plant) and glycogen (animal)
What are some chemical properties of carbs?
some are reducing substances
most commonly are NON reducing - sucrose
can reduce other compounds when oxidized
MONO/DISACCHARIDES ARE REDUCERS
Metabolism of glucose and carbs are primary energy source for what? what cannot store carbs?
primary energy source for CNS
Nervous tissues can’t store carbs
Describe Glycogen
create or synthesize
increased glucose = don’t need glycogen
usage/storage/can be converted to fats
(glucose energy)
T/F Intestinal absorption is via jejunum villi/microvili and increases surface area/energy absorbed
True
T/F: Monosaccharides are easier to absorb
true
What uses the most glucose, then what else?
brain uses the most glucose, then rbc/wbc, then muscle or its conv to fat cells
T/F 3/4th of glucose comes from glycogen stored in the kindey
false, 3/4th glucose comes from glycogen stored in the liver
What is glycogenesis
glucose to glycogen (liver/muscle)
What is glycogenoisis
glycogen - glucose
What is gluconeogenesis
non CHO source (fatty acid) - glucose
What is glycolysis
glucose - CO2+H20+ATP
What is the renal threshold
proximal convoluted tubule 180mg/dl
>180mg spill over into urine
What is lipogenesis
carbs - fatty acids
What is lipolysis
decomposition of fats
Describe the “Fed State”
what kind of synthesis
what cells
uptake of ?
increased insulin =
decreased insulin =
insulin from pancreatic Beta cells
anabolic synthesis
Promotes cellular uptake of glucose
Increased insulin = lipogenesis
glycogenesis
Decreased insulin = lipolysis
ketone formation
gluconeogenesis
glucogenosis
Describe the “Fasting state”
glucagon release from pancreatic alpha cells
catabolic synthesis
liver: glycogen - glucose –> blood
Muscle: glycogen conv. to G6PO4 in muscle for energy
Describe “Fight or flight” state
epinephrine from adrenal medulla action similar to glucagon
Action of Hormones: Insulin increases what, decreases
increases : glycogenesis/glycolysis
lipogenesis
Decrease: glycogenolysis
Action of hormones: Glucagon increases what?
increases glycogenolysis
gluconeogenesis
Describe Hyperglycemia
diabetes mellitus, endocrine disorders, untreated leads to type 2 diabetes (acromegaly, Cushing syndrome)
Drugs: anesthetics
steroids
What are some symptoms of diabetes?
Hgb A1C
Fasting plasma glucose
2hr plasma glucose
random plasma glucose
polyuria
polydipsia
unexplained weight loss
Hbg A1C >6.5%
fasting plasma glucose >126
2hr plasma glucose >200
random plasma glucose >200
Describe T1D:
Type 1A:
Type 1B:
Juvenile onset 5-10yrs
Type 1A: beta cell destruction by autoimmune absolute insulin decreases pt must take insulin
acute onset/days to weeks
islet cell Ab
Type 1B: Idiopathic adults
Describe T2D:
insulin resistant in peripheral tissues, secretory deficiency of B cells
variable insulin
associated w family hxt >40 obesity/lack of exercise
Describe Gestational diabetes:
glucose intolerance during pregnancy in 2/3rd trimester of pregnancy
Lab findings of hyperglycemia
decrease or absent insulin
increase glucose in plasma/urine
increase urine spec. gravity/serum osmolality
Ketones in serum/urine
decreased blood/urine pH
Ref ranges:
normal fasting glucose
Impaired fasting glucose
Provisional diabetes diagnosis
N fasting glucose: 70-99
Impaired fasting: 100-125
Provis diabetes: >126
Describe gestational diabetes:
1hr
2hr
3hr
frequent but transitory
greater risk of prenatal complication
Human placental lactogen
>140 on hour after 50g glucose
1hr: >180
2hr: >155
3hr: >140
Describe the glucose tolerance test:
pt prep
pt prep
normal diet 3 days prior
no food after reg evening meal on day before
blood/urine
allow water but not gum
describe Hypoglycemia:
caused by what
disease states?
insulin overdose
drugs: sulfon/antihistamines
alcoholism
insulinoma
galactosemia
glycogen storage disease
Glucose tolerence test
Normal 2hr
impaired
provisional diabetes
2hr <140
impaired 140-199
provisional >200
Glucose Tolerence test, describe level 1, 2 and 3
1: glucose alert value <70
2: clinical significance hypoglycemia <54
3: severe hypoglycemia no specific threshold
T/F if serum/plasma are not separated from cells, glucose will continue to increase
false, glucose will be used and will cause a false decreased glucose result
What is the renal threshold for reabsorbance of glucose
what does glycosuria look like?
threshold is <180
glycosuria looks like >180
Determination of glucose uses what
decrease per hour?
what preserves?
whole blood, examples glucose monitors or at home
7% decrease/hr
sodium fluoride preserves 24hr at RT
T/F lithium iodoacetate preserves glucose with no interference w urease
true
T/F plasma and serum are 10-15% higher level than whole blood glucose
true
CSF glucose
Urine glucose levels
CSF 40-70
Urine <500/24hr
Briefly describe these measurements
Glucose oxidase
glucose hexokinase
Clinitst
GO: cheap
GHex: we use, end point reaction
Clinitst: least specific reducing in urine
T/F you usually use glucose to measure/treat diabetes
false
Describe Glycated hgb A
non enzymatic process of conversion of HgbA to HgbA1
T/F alb can bind to proteins/glucose in cells that get glycolated and stays for whole time of your life
True it tis forever
Describe Glycated Hgb
irreversible, reflects glucose levels 4-8wks
HgbA1c = 80% total glycogen
3-6% total hgb
T/F HgbA1c decrease by 1% = microvascular complications being reduced by 40%
false, reduced by 35%
Describe the Roche diagnostics briefly
Glycated serum Pt:
automated, doesn’t have risk w hgb variants
whole blood tests
avg blood glucose
Glycated serum Pt: alb turn over 2-3 wks
fructosanin?
Describe carb. inborn errors of metabolism
glycogen storage disorders
lack of enzymes
increase tissue glycogen
limited lifespan
Describe lactose intolerence
deficient intestinal mucosal lactase
GTT baseline
non flat curve (pain)
