IGCSE Biology Paper-1: Specimen Questions with Answers 150 - 151 of 208

Question 150

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Question

MCQ▾

Which graph shows the effect of temperature on the activity of an enzyme?

Effect of Temperature on the Activity of Enzyme

Effect of Temperature on the Activity of Enzyme

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Choices

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

Answer

d.

Explanation

  • Temperature: Enzyme functions optimally at certain temperature. As the temperature increases the kinetic energy also increases, molecules move faster, and it increases the chance of substrate colliding the enzyme’s active site and binding followed by reaction. But if the temperature is too high, the enzyme protein denatures (cools), thereby destroying the shape of active binding site (cannot bind to the substrate anymore) and decreasing the enzyme reaction rate.
Effect of Temperature on the Activity of Enzyme

Effect of Temperature on the Activity of Enzyme

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Question 151

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Question

MCQ▾

Which feature is characteristic of both annelids and arthropods?

Choices

Choice (4)
a.wings
b.segmented bodies
c.compound eyes
d.jointed limbs

Answer

b.

Explanation

  • Features of Annelida: - Bilateral and Protostomia, Eucoelomate, eumetazoans whose long, narrow and worm like body is divided into ring-like, true or metameric segments (Gr. , annulus = little ring), and the skin usually bears unjointed, chitinous appendages, termed setae. Commonly known as “segmented worms. “
  • Features of Arthropoda: - Bilateral, triploblastic body segmented and divided into head, thorax, and abdomen. Segmentation marked only externally; number of segments or somite’s fixed and each has its separate exoskeleton of thick and hard, chitinous cuticle secreted by epidermis of body wall. Head somite’s always fused. Each segment bears a pair of lateral jointed appendages adapted for food ingestion, locomotion, respiration, copulation, etc.
Features of Arthropoda

Features of Arthropoda

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