IGCSE Biology Paper-4: Specimen Questions with Answers 266 - 268 of 279

Passage

The diagram shows a human egg cell and a human sperm cell.

Human Egg Cell and Sperm Cell

Question 266 (5 of 6 Based on Passage)

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Sperm cells and egg cells are haploid. State the meaning of the term haploid.

Explanation

Haploid is the term used when a cell has half the usual number of chromosomes. A normal eukaryote organism is composed of diploid cells, one set of chromosomes from each parent. However, after meiosis, the number of chromosomes in gametes is halved. That is the haploid condition.

Question 267 (6 of 6 Based on Passage)

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Three hormones that control the menstrual cycle are:

  • follicle stimulating hormone (FSH)
  • luteinizing hormone (LH)
  • oestrogen.

Name the site of production and release of oestrogen.

Explanation

The oestrogen is secreted from theca interna (granulosa cells) of graafian follicles but after ovulation the secretion continues from corpus luteum. (site- ovary) .

Question 268

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Bile is made in the liver, stored in the gall bladder, and passes into the small intestine.

Describe the role of bile in digestion.

Explanation

Functions of Bile

  • Emulsification of fats.
  • Helps in absorption of fat-soluble vitamins.
  • Increases alkalinity to make the medium suitable for enzymatic action.
  • Elimination of heavy metals such as Cu, Hg, Zn etc.
  • Elimination of excess of bile pigments.
  • Stercobilin and urobilin is formed by bilirubin and biliverdin is responsible for coloration of faeces.