IGCSE Biology Paper-4: Specimen Questions with Answers 185 - 186 of 279

Passage

shows a young plant with its roots submerged in a container filled with a solution containing mineral salts and a colored dye.

Structure of Plant

Fig. shows a section of a root and Fig. shows a section of a stem.

Root and Stem

Question 185 (4 of 4 Based on Passage)

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Describe how you would compare the rate of uptake of the colored solution by the plant in Fig. with another plant that has had its roots cut off.

Explanation

Roots absorb water and minerals and if the roots are cut off the plant won՚t get water and minerals and it will die. It will die because the plant will not get support and it will not get water and minerals.

Three major functions of root: absorbing water and minerals, anchoring and supporting the plant, and storing food.

  • Absorbing water and minerals: Thin-walled epidermal cells and root hairs are well suited to absorb water and dissolved minerals from the soil. The roots of many plants also have a mycorrhizal relationship with fungi for greater absorption.
  • Anchoring and supporting the plant: Root systems help anchor plants to the ground, allowing plants to grow tall without toppling over. A tough covering may replace the epidermis in older roots, making them ropelike and even stronger.
  • Storing food: In many plants, ground tissues in roots store food produced by the leaves during photosynthesis.

Passage

Suggest and explain the effects on a person of a diet with:

Question 186 (1 of 2 Based on Passage)

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too much animal fat.

Explanation

Effects of Too Much Animal

  • raise cholesterol levels in the blood
  • risk for heart disease
  • person will become overweight or obese
  • risk of endometrial, breast, prostate and colorectal cancers