IGCSE Biology Paper-2: Specimen Questions with Answers 145 - 146 of 203

Question 145

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Question

MCQ▾

Which of the following graph shows the effect of increasing temperature on the rate of diffusion?

Choices

Choice (4)
a.
The rate of diffusion
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b.
The rate of diffusion
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c.
The rate of diffusion
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d.
The rate of diffusion
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Answer

c.

Explanation

Diffusion

  • The movement of molecules of gases, Liquid solid from the region of higher concentration to the region of lower concentration is called diffusion.
  • Process of Diffusion is based on kinetic energy of molecules. The molecules move from the higher concentration to lower concentration due to kinetic energy until an equilibrium is obtained. Ex: Diffusion of coppersulphate particles in water, , Diffusion of Ammonia in air.

Factor affecting the rate of diffusion:

  • Temperature: Rate of diffusion is directly proportional to temperature. If temperature increases than the rate of diffusion is increased.
  • Rate of diffusion Temperature.

Question 146

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Question

MCQ▾

The diagram shows a diploid cell and alleles Y and on one pair of chromosomes.

A diploid cell and alleles Y and y

A Diploid Cell and Alleles Y and Y

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When this cell divides by mitosis, which daughter cells will be produced?

Choices

Choice (4)
a.Chromosome number-Diploid, Genotype-Heterozygous
b.Chromosome number-Diploid, Genotype-Homozygous
c.Chromosome number-Haploid, Genotype- Homozygous
d.Chromosome number-Haploid, Genotype-Heterozygous

Answer

a.

Explanation

Features of Mitosis:

  • Mitosis leads to production of two daughter cells from a mother cell in each cycle of cell division. In other words, nucleus divides once in each cell cycle.
  • The daughter cells are similar to the mother cell in shape, size, and chromosome complement. Since the chromosome number is the same in the daughter cells as compared to that of mother cell, this is also known as homotypic or equational division.
  • In plants, mitosis takes place in somatic organs like root tip, stem tip and leaf base. It leads to growth of vegetative parts.
  • The complete process of mitosis consists of only one homotypic or equational division.
  • Segregation and recombination do not take place during mitosis.