Biochemistry for Nurses

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40 terms · Chapter two chemistry and metabolism of carbohydrates

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.)

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