Question

Q1) Glucose and starch are both carbohydrates however, glucose was detected in milk samples but not starch. Explain why. marks) Q2) Did you expect to find Vitamin C in liver? Explain your answer. marks) Q3) Why do you think that some tests did not confirm your expectation? (For example, Aibika and sweet potato should reveal the presence of glucose but that did not happen, or fat was not detected on egg white, which should have). (5 marks) (1 Q4) Apart from glucose, which other monosaccharide is also found in milk? mark) Q5) Which two biomolecules would be predominant in Aibika? (2 marks) 06) Which two selected food samples were expected to show no sign of fats? marks) Q7) Name all food samples that would test negative for starch? marks) Q8) Name the food samples that would not reveal the presence of Vitamin C? marks)

Biomolecules:
* Glucose
*Starch
*Protein
*Fat
*Vitamin C

Food samples :
*Kaukau
*Aibika
*Egg yolk
*Egg white
*Liver
*Milk

An experiment to determine biomolecules in food samples.

Answer 1

1. Glucose is present in lactose as well as starch. It is not detected in the starch because starch is a complex polysaccharide whereas lactose is a disaccharide.

Lactose can be hydrolysed easily to produce glucose and galactose. But since starch is a complex polysaccharide it is difficult to break starch easily. Starch is made up of amylose and amylopectin. Amylose is a straight chain of glucose and amylopectin is branched. So, it is difficult to hydrolyse starch.

Thus glucose can be easily tested in the milk not in starch.

2. No we cannot expect to find vitamin C in liver as it is a water soluble vitamin. It cannot be stored in the liver.