End-of-Year Practice Paper: Sec 3 Combined Science (Biology), Chapters 1–6 — question paper

Section A: Multiple-choice questions[10 marks]

Answer all questions. For each question, write the letter (A, B, C or D) of the correct answer.

1. 1

   Chloroplasts are absent from root hair cells because

   1. Aroots store starch instead
   2. Broots grow underground without light
   3. Croot cells are animal cells
   4. Dchloroplasts dissolve in soil water
   ( )
2. 2

   Water moves by osmosis towards the solution that is

   1. Amore dilute
   2. Bmore concentrated
   3. Cwarmer
   4. Dclearer
   ( )
3. 3

   Which reagent turns purple with protein?

   1. Aiodine
   2. BBenedict's
   3. Cbiuret
   4. Dethanol
   ( )
4. 4

   Denaturation stops an enzyme because

   1. Athe substrate is destroyed
   2. Bthe active site loses its shape
   3. Cthe enzyme dissolves
   4. Dthe pH rises to 14
   ( )
5. 5

   Which vessel carries oxygenated blood from the lungs to the heart?

   1. Apulmonary artery
   2. Bpulmonary vein
   3. Caorta
   4. Dvena cava
   ( )
6. 6

   Which blood component transports oxygen?

   1. Aplasma
   2. Bplatelets
   3. Cred blood cells
   4. Dwhite blood cells
   ( )
7. 7

   Coronary heart disease involves blockage of arteries supplying

   1. Athe brain
   2. Bthe heart muscle
   3. Cthe kidneys
   4. Dthe lungs
   ( )
8. 8

   Gaseous exchange in the lungs takes place in the

   1. Atrachea
   2. Bbronchi
   3. Calveoli
   4. Dlarynx
   ( )
9. 9

   Which toxin in tobacco smoke binds haemoglobin?

   1. Anicotine
   2. Btar
   3. Ccarbon monoxide
   4. Dwater vapour
   ( )
10. 10

    Anaerobic respiration in human muscle produces

    1. Acarbon dioxide and water
    2. Blactic acid
    3. Cethanol
    4. Doxygen
    ( )

Section B: Structured questions[30 marks]

Answer all questions in the spaces provided.

1. 1

   The small intestine absorbs the end-products of digestion.

   1. (a)

      Name the end-products of starch digestion and of protein digestion.

      [2]
   2. (b)

      Name the vessel that carries the absorbed nutrients to the liver.

      [1]
   3. (c)

      Describe two roles of the liver, other than storing glucose.

      [4]
   4. (d)

      Name the blood cells that transport oxygen and the pigment they contain.

      [2]
   5. (e)

      State one structural adaptation of a red blood cell and explain how it helps oxygen transport.

      [1]
2. 2

   A runner sprints and then breathes rapidly and deeply for several minutes.

   1. (a)

      Write the word equation for aerobic respiration.

      [2]
   2. (b)

      Explain why her muscles respire anaerobically during the sprint.

      [3]
   3. (c)

      Write the word equation for anaerobic respiration in her muscles.

      [2]
   4. (d)

      Explain why her breathing stays rapid and deep after she stops.

      [3]
3. 3

   Gaseous exchange between the air and the blood happens in the alveoli of the lungs.

   1. (a)

      Name the structures of the air pathway, in order, from the larynx to the site of gaseous exchange.

      [2]
   2. (b)

      Describe three structural features of an alveolus that make it efficient for gaseous exchange, and explain how each feature helps.

      [6]
   3. (c)

      Name the blood cells that transport oxygen and the pigment they contain.

      [2]