IGCSE Biology Paper-1: Specimen Questions with Answers 140 - 141 of 208

Question 140

Edit

Question

MCQ▾

Lignin is the important constituent in the cell wall of

Choices

Choice (4)
a.Parenchyma
b.Phloem
c.Cambium
d.Xylem

Answer

d.

Explanation

Lignin is one of the most important secondary metabolites which is produced by the phenylalanine/tyrosine metabolic pathway in plant cells. It is the second most profuse biopolymers that accounts for 30 % of the organic carbon content in biosphere. Lignin is a natural resin that fills spaces between plant cells and strengthens cell walls by covering cellulose microfibrils.

Functions of Lignin in Plants

  • Provides strength
  • Barrier against the attack of insects and microbes
  • Enables transportation of water and ions from the soil
Structure of Plant Cell

Structure of Plant Cell

Loading image

Question 141

Edit

Question

MCQ▾

The table shows some of the nutrients in four meals.

Which meal will be the most likely to stimulate peristalsis in the alimentary canal?

The Table Shows Some of the Nutrients in Four MealsThe Table Shows Some of the Nutrients in Four Meals
g/100g
carbohydratefatproteinroughage
A1514235
B3530238
C43181015
D3251538

Choices

Choice (4)
a.B
b.A
c.C
d.D

Answer

d.

Explanation

  • Roughage is simply referred to as dietary fiber. It is the indigestible portion of food obtained from plants. They do not provide any nutrient to our body but play an essential part of a healthy diet plan.
  • Functions of roughage: Its main function is to add bulk to the diet, which in turn aids in the digestion process and healthy function of the bowel system. Prevents constipation and helps in getting rid of undigested food. They help in retaining water in the body. Some roughage foods include fruits, apples, pears, and whole grapes, whole grains, and green leafy vegetables.
Insoluble Fiber

Insoluble Fiber

Loading image