Question

1. The table shows the mass of fibres in 100 grams of each food item below.

Food	Mass of fibre (grams per 100 grams)
Beans	3.6
Bread	2.4
Soup	0.7
Cornflakes	2.5
Pasta	3.0

     

1. A small tin of beans contains 200 grams. If you are going to eat two-thirds (2/3) of this small tin of beans, how much fibres will you consume? Show your calculations.
2. List TWO functions of fibres in the diet.
3. What is the consequence of lacking in fibres in the diet? (1 mark)
4. Potatoes contain carbohydrates. Which form of carbohydrate do they contain? (1 mark)
5. Briefly describe the digestion of this form of carbohydrate described in (iv) in mouth and small intestine before absorption.

Answer 1

1) Fiber in 100gm of beans is 3.6mg

Fiber in 200gm of beans is 7.2 mg.

So 2/3 rd of 200gm is 133.33 gm is 4.8 gm.

2) functions of fiber are

A. Adds bulk to the diet , making feel fuller which further reduces the appetite.

B. Adds bulk to stool and reduces the symptoms of constipation.

3) consequences of lacking in fibres in the diet are

Constipation , colorectal cancer ( fibres maintain intestinal ph and prevents colorectal cancer).

4.potatoes containing carbohydrates is starch which is a polysaccharides.

5. Starch digestion starts in mouth .

In mouth salivary anglaise acts on starch and breaks into maltose and polysaccharides.

In stomach - no enzymes are secreted for digestion of carbohydrates

In duodenum - These maltose and polysaccharides is divided into monosaccharides like glucose by pancreatic amylase secreted by pancreas in to the duodenum.

So monosaccharides are absorbed from the intestinal lumen.