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Preliminary Examination Practice Paper: Sec 4 Combined Science (Biology), Full Syllabus — question paper

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QQ/S4CBI/PRELIM

Secondary 4 · Combined Science (Biology) (G2 / G3)

Preliminary Examination Practice Paper

Sec 4 Combined Science (Biology), Full Syllabus

Duration: 120 minutes
Total: 80 marks
Name:
Class:
Register No.:
Date:

READ THESE INSTRUCTIONS FIRST

  • Answer all questions.
  • Section A: for each question, write the letter (A, B, C or D) of the correct answer.
  • Section B: answer in the spaces provided.
  • The use of a calculator is permitted.

Original practice material written for the MOE Combined Science (Biology) syllabus. It is not an official MOE or school examination paper. All twelve topics, emphasising the Sec 4 half: infectious diseases; flowering plants; organisms and their environment; molecular genetics; reproduction; inheritance.

For Examiner’s Use
Section A/ 20
Section B/ 60
Total/ 80

Section A: Multiple-choice questions[20 marks]

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

  1. 1

    Antibiotic resistance accelerates when

    1. Acourses are completed as prescribed
    2. Bantibiotics treat only bacterial infections
    3. Cdoses are skipped and courses stopped early
    4. Dvaccines are given
    ( )
  2. 2

    Translocation is the transport of

    1. Awater in the xylem
    2. Bwater vapour out of stomata
    3. Cfood (mainly sucrose) in the phloem
    4. Dmineral salts into root hairs
    ( )
  3. 3

    In a food chain, only about 10% of energy passes to the next level because energy is lost by

    1. Aphotosynthesis and feeding
    2. Brespiration as heat, uneaten parts and waste
    3. Cdecomposers refusing food
    4. Dplants reflecting sunlight
    ( )
  4. 4

    Which process removes carbon dioxide from the atmosphere?

    1. Arespiration
    2. Bcombustion
    3. Cphotosynthesis
    4. Ddecomposition
    ( )
  5. 5

    DNA is a

    1. Asingle-stranded protein
    2. Bdouble helix of two nucleotide strands
    3. Ctype of chromosome
    4. Dstorage sugar
    ( )
  6. 6

    In DNA, thymine pairs with

    1. Aadenine
    2. Bguanine
    3. Ccytosine
    4. Duracil
    ( )
  7. 7

    Fertilisation in humans normally occurs in the

    1. Aovary
    2. Boviduct
    3. Cuterus
    4. Dvagina
    ( )
  8. 8

    The event that sheds the uterus lining is

    1. Aovulation
    2. Bmenstruation
    3. Cfertilisation
    4. Dimplantation
    ( )
  9. 9

    An organism with genotype Tt is

    1. Ahomozygous dominant
    2. Bhomozygous recessive
    3. Cheterozygous
    4. Dunable to reproduce
    ( )
  10. 10

    Down syndrome results from a change in

    1. Achromosome number (an extra chromosome)
    2. Bone base of a single gene
    3. Cthe sex hormones only
    4. Dred blood cell shape
    ( )
  11. 11

    A plant cell placed in pure water becomes firm but does not burst because

    1. Awater cannot enter plant cells
    2. Bthe cellulose wall resists the swelling
    3. Cplant cells have no membrane
    4. Dthe vacuole pumps water out
    ( )
  12. 12

    Which food test uses ethanol?

    1. Astarch
    2. Breducing sugar
    3. Cfat
    4. Dprotein
    ( )
  13. 13

    Human enzymes work fastest at about

    1. A0 °C
    2. B20 °C
    3. C37 °C
    4. D60 °C
    ( )
  14. 14

    The hepatic portal vein carries nutrient-rich blood

    1. Afrom the liver to the heart
    2. Bfrom the small intestine to the liver
    3. Cfrom the heart to the lungs
    4. Dfrom the kidney to the liver
    ( )
  15. 15

    Gaseous exchange in the lungs takes place in the

    1. Atrachea
    2. Bbronchi
    3. Calveoli
    4. Dlarynx
    ( )
  16. 16

    Vaccination protects against disease because it

    1. Akills pathogens already in the body
    2. Bstimulates white blood cells to produce antibodies in advance
    3. Ccoats pathogens so they cannot enter cells
    4. Dthickens the blood
    ( )
  17. 17

    Water travels upwards through a plant in the

    1. Aphloem
    2. Bxylem
    3. Cepidermis
    4. Droot hair membrane only
    ( )
  18. 18

    A food web shows several interconnected food chains because most organisms

    1. Aeat one food only
    2. Bhave several foods and several predators
    3. Cphotosynthesise
    4. Dare decomposers
    ( )
  19. 19

    A DNA sample contains 24% cytosine. Guanine makes up

    1. A24%
    2. B26%
    3. C48%
    4. D76%
    ( )
  20. 20

    Which parents could have a child with a blood group neither parent shows?

    1. Aimpossible — children always match a parent
    2. Bpossible — each parent carries a recessive allele not shown in their phenotype
    3. Cpossible — but only for boys
    4. Donly if a mutation occurred during fertilisation
    ( )

Section B: Structured questions[60 marks]

Answer all questions in the spaces provided.

  1. 1

    A meadow ecosystem contains grass, rabbits, foxes and soil bacteria and fungi.

    1. (a)

      Assign each organism to its role: producer, consumer (state level) or decomposer.

      [3]
    2. (b)

      The grass contains 30 000 kJ of energy. Assuming 10% transfer per level, calculate the energy reaching the fox.

      energy =kJ[2]
    3. (c)

      Explain why energy flow through the ecosystem is non-cyclical while carbon cycles.

      [3]
    4. (d)

      State two human actions that would reduce atmospheric carbon dioxide, one cutting emissions and one strengthening sinks.

      [2]
  2. 2

    A strand of DNA reads A–T–G–C–C–A.

    1. (a)

      Write its complementary strand.

      [2]
    2. (b)

      Name the three parts of one nucleotide.

      [3]
    3. (c)

      Explain the relationships among DNA, genes and chromosomes.

      [3]
    4. (d)

      State what one gene codes for, and what this product then becomes.

      [2]
  3. 3

    In pea plants, the allele for tall plants (T) is dominant over short (t). A heterozygous tall plant is crossed with a heterozygous tall plant.

    1. (a)

      Draw a genetic diagram: parents, gametes, offspring genotypes.

      [4]
    2. (b)

      State the phenotype ratio and the percentage of tall offspring.

      [2]
    3. (c)

      The cross produces only 12 offspring: 11 tall and 1 short. Explain why this does not disprove the 3:1 ratio.

      [4]
  4. 4

    A school notices several students catch chickenpox from one infected classmate, and the school gardener explains how the greenhouse tomatoes stay healthy.

    1. (a)

      State the type of organism (pathogen group) that best matches a virus, and one feature that makes viruses hard to treat with antibiotics.

      [2]
    2. (b)

      Describe two measures that would reduce the spread of the infection in the school, each linked to a transmission route.

      [4]
    3. (c)

      Explain how the leaves of the tomato plants provide the sugars the growing fruits need, naming the tissue and the substance transported.

      [4]
  5. 5

    A couple has four children — three girls and one boy.

    1. (a)

      Explain, using XX and XY, why each pregnancy has about a 50 : 50 chance of a boy or a girl, and state which parent determines the sex.

      [4]
    2. (b)

      Calculate the chance of exactly three girls and one boy in a family of four children.

      chance =[3]
    3. (c)

      The couple’s eldest child carries the sickle-cell allele but shows no symptoms. Explain how a person can carry an allele without showing its effect.

      [3]
  6. 6

    A sandwich lunch is digested and its products put to work.

    1. (a)

      Name the enzyme that digests the bread’s starch, its end-product, and the vessel that carries that end-product to the liver.

      [3]
    2. (b)

      Describe how oxygen from each breath reaches the runner’s leg muscles during an afternoon match.

      [4]
    3. (c)

      At the end of the match the player keeps breathing deeply for several minutes. Name the process that caused this and the substance being cleared.

      [3]

— End of paper —