Biochemistry Practicals Flashcards
What is glycosuria?
sugar in urine
What is glycosuria indicative of?
diabetes mellitus
What is one of the most common hormonal disorders of cats?
diabetes mellitus
What hormone are diabetic cats deficient in/resistant to?
insulin
What produces insulin?
the pancreas
what is insulin produced in response to?
in response to an increase in blood glucose
What does insulin help to maintain in the body?
normal levels of blood glucose
How does insulin help to maintain normal levels of blood glucose?
allows glucose to be taken up by cells in the body (and used for energy)
What happens in diabetic cats where there is no insulin produced or they are resistant to it?
unable to respond to increases in blood glucose levels and become hyperglycemic
Where can glucose be excreted if hyperglycemia becomes severe?
in the urine
What do reducing sugars have free in their molecular structure?
free aldehyde
In what sort of reaction can an aldehyde be oxidised?
radox
What happens during a radox reaction where an aldehyde is oxidised?
another compound is reduced
What molecules are capable of isomerizing to produce an aldehyde group in solution?
sugars with ketone groups in their open chain form
what colour is Benedict’s reagent?
blue
What does Benedict’s reagent contain?
sodium citrate, sodium carbonate and copper sulphate
what is Benedict’s reagent used to test for?
presence of reducing sugars
What happens if a solution of Benedict’s reagent and a reducing sugar are heated?
copper (II) ions are reduced to copper (I) ions
What effect does the reduction of copper (II) ions to copper (I) ions have on the colour of the solution?
changes from blue to green to orange to red-orange to brick red
What precipitate may appear in the bottom of a test tube when a solution of Benedict’s reagent and a reducing sugar is heated?
copper (I) oxide
What does the amount of precipitate in the bottom of the Benedict’s reagent solution illustrate about the amount of reducing sugar present in the solution?
more precipitate means more reducing sugar
What is the equation for the Benedict’s reagent half reaction with reducing sugars?
2Cu2+ + 2e- = 2Cu+
what is proteinuria?
protein in urine
What are the potential causes of proteinuria?
many but one of the main ones is chronic kidney disease
What happens in normal kidneys to stop proteinuria?
serum proteins are too large to pass across the glomerulus into the tubules to become urine, any that do pass across the glomerulus are usually reabsorbed or broken down
What is a glomerulus?
bundle of capillaries in the kidney
Why can protein end up in the urine if kidneys are damaged?
large proteins may be able to pass into the tubules and there is poor reabsorption of proteins back into the blood and so protein appears in urine
What is the biuret test a chemical test for?
detecting presence of peptide bonds
What happens to copper (II) ion during a positive biuret test?
reduced to copper (I) forms a complex with nitrogens and carbons of the peptide bonds in an alkaline solution
How is the presence of proteins indicated in a biuret test?
violet colour
What can develop in the urinary tracts of cats?
clusters of crystals/stones
What can clusters of crystals or stones in the urinary tract of cats cause?
serious complication particularly if they pass into the ureter and urethra where they may cause a blockage
What are the 2 most common types of crystals/stones found in cats urinary tracts?
struvite, oxalate
When are struvite crystals/stones most likely to develop in the urinary tract?
urine with a pH above 7
When are oxalate crystals/stones most likely to develop in the urinary tract?
urine with a pH below 6