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40 terms

Biochemistry for Nurses

Chapter two chemistry and metabolism of carbohydrates
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what are carbohydrates
Carbon, Hydrogen, Oxygen, , supplies energy for the cell, forms plant structures, and short term energy storage, Sugars (fruits/vegetables) and starches (potato, pasta, bread) Carbohydrates produce energy
classification of carbohydrates
monosaccharides, disaccharides, polysaccharides
examples of carbohydrates
simple sugars (glucose), complex sugars (starch), sugar (fruits), starch (rice, pasta),
what are differences between types of carbohydrates
monosacchrides like simple sugars ,disacchrides like sucrose,lactose and maltose,polysacchrides like starch ,dextrin
mucopolysacchrides
is proteoglycans or C.H.O containing uronic acid and amino sugars present in connective tissues.
Benedicts test
Tests for presence of carbohydrates, changes blue to red when heated, a test for reducing sugars based on their ability to reduce weak oxidizing agents. (heated)
blue = none
very high - orange/red
starch and glycogen
two important polysaccharides, Starch - storage of sugar in PLANTS (digestible by humans for energy) ; Glycogen is stored glucose in ANIMALS. (liver synthesizes after a meal and breaks down between meals)
can muscle glycogen be a source of blood glucose
No,as it lacks the enzyme glucose-6-phosphate
what is galatosemia
excretion of galactose in urine due to the deficiency of enzyme galactose-1-phosphate uridyl transferase
true glucose
glucose only, without presences of any other reducing substance in the blood
How will you estimate true glucose
by glucose oxidase method
Hypoglycemia is found in these conditions
overdose of insulin in the treatment of diabetes, hypothyroidism, and addisons disease
Hyperglycemia is found in these conditions
diabetes mellitus,hyperthyroidism,hyperadrenalism,hyperpituitarism,and thyrotoxicosis
What is the normal blood sugar level
80-100 mg/dl
What is the kidney threshold of glucose
180 mg/dl
What is the hormone which regulate blood sugar level
insulin
function of insulin
Keep low blood/glucose level by pulling it into the cells., regulates uptake of glucose into fat and muscle cells, produced by the beta cells in the islets of langerhans in the pancreas to promote uptake of glucose, amino acids, and fatty acids as well as converting glucose to glycogen for future need in the liver and muscles
What are the hormones which keep the blood sugar level high
Glucagon,Epinephrine,adrenal cortex hormones,growth and ACTH,thyroid hormones
Why cant insulin be given orally
digested by enzymes of digestive system into amino acids before it reaches in blood
renal glycosuria
defects in renal reabsorption of filtered glucose resulting in appearance of glucose in urine even when blood glucose levels are normal. It is usually a mild and benign condition inherited as an autosomal recessive trait
What is the abnormality in the urine sample of diabetic patient and starving patient
in a diabetic patient,urine will show the presence of glucose and keton bodies,whereas,in starving patient only keton bodies
What are the different reducing sugars that appear in the urine and under what conditions
renal glycosuria and diabetes mellitus/lactose during later stage of pregnancy and lactation /galactose during galactosemia condition
glycolysis
a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP
What is the ATP yield in glycolysis under an areobic condition
two ATP per molecule of glucose metabolism
What is the ATP yield under aerobic conditions
38ATP per molecule of glucose metabolism i.e:glycolysis 8 ATP ,TCA cycle 30 ATP
How many ATP are formed in the TCA cycle
a-from Acetyl CoA is 12 ATP.
b-from Pyruvate is 15 ATP
Why is citric acid cycle considered the common pathway for catbohydrate,fat and protein metabolism
Acetyl CoA comes from all the three metabolism:
carbohydrate metabolism: glycolysis
fat metabolism:B oxidation
protein metabolism:transamination
citric acid cycle provides the complex oxidation of acetyl Co A to carbondioxide and water
What is oxidative decarboxylation
accompanied by decarboxylation
What is the oxidative decarboxylation product of pyruvic acid
Acetyl-CoA
What is B-oxidation
oxidation taking place at B carbon atom and the B carbon is oxidised to carboxyl group and occure in mitochondria
diabete mellitus
is a group of metabolic disorders characterized by hyperglycemia resulting from defects in insulin secretion, insulin action or both
types of diabetes mellitus
Type 1 - insulin dependent young kids normal or thin caucasian rapid onset no prevention
type 2 - non insuling dependent (92%) adults obese african american hereditary slow onset
impaired glucose tolerant - higher than normal levels but not yet diagnostic for diabetes
gestational diabetes - 2% pregnant women during 2nd or 3rd trimester
causes of diabetes mellitus
thought to be auto-immune and results in failure of islets, usually hereditary and results from failure to release enough insulin and or failure of the body cells to recognize insulin(insulin resistance)
hypoglycemia
abnormally low blood sugar usually resulting from excessive insulin or a poor diet
fasting blood glucose
obtain after 8 hours fasting; results 70-110= normal
OGTT
oral glucose tolerance test, oral glucose tolerance test
2-hr postload glucose PG:
<140 mg/dL = normal
140-199 mg/dL = prediabetes
>200 mg/dL = provisional diagnosis of diabetes
anabolism and catabolism
two forms of metabolism, anabolism-require energy to synthesize, catabolism-release energy to destroy
glycosuria
the presence of abnormally high levels of sugar in the urine, glucose in the urine; a sign of diabetes mellitus, glucose in urine, which occurs when blood glucose levels exceed the kidney's ability to reabsorb glucose.
Glucose oxidation per ATP
when one molecules of glucose is broken down , 38 molecules of ATP are produced (30 ATP from citric acid cycle and 8 ATP from glycolysis.so when one mole of glucose (180) gm is converted into carbon dioxide and water, 2868 KJ of energy is released.Rest 62% of energy is liberated as heat and is utilised to keep the body temperature
Renal threshold
Maximum amount of a substance in the blood that is filtered that can be reabsorbed. Threshold for glucose is 200 mg/dl., 160 to 180 mg/dL, conc of substance in blood above which kidneys begin to remove it, The point of spillage. (For most people, when blood glucose reaches 180 to 200 mg/100mL, the kidneys begin to spill glucose into the urine.)