WA1 Practice Paper: Weighted Assessment 1 — 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

   Which structure is found in plant cells but not in animal cells?

   1. Aa cell membrane
   2. Bchloroplasts
   3. Ca nucleus
   4. Dmitochondria
   ( )
2. 2

   The organelle that releases energy from glucose in respiration is the

   1. Aribosome
   2. Bchloroplast
   3. Cmitochondrion
   4. Dvacuole
   ( )
3. 3

   A red blood cell is biconcave and has no nucleus. These adaptations help it to

   1. Acarry more haemoglobin and exchange gases quickly
   2. Bmove using a tail
   3. Cphotosynthesise in the bloodstream
   4. Dengulf bacteria
   ( )
4. 4

   Root hair cells absorb water mainly by

   1. Acondensation
   2. Bactive transport
   3. Cphotosynthesis
   4. Dosmosis
   ( )
5. 5

   Which movement requires energy from respiration?

   1. Aoxygen diffusing into a cell
   2. Bwater entering a vacuole by osmosis
   3. Cmineral ions taken up by root hair cells
   4. Dcarbon dioxide leaving a leaf
   ( )
6. 6

   A cell is placed in a solution with a LOWER water potential than the cell sap. The cell will

   1. Again water and swell
   2. Blose water and shrink
   3. Cstay exactly the same
   4. Ddivide by mitosis
   ( )
7. 7

   Diffusion is best defined as the net movement of particles

   1. Aof water through a partially permeable membrane
   2. Bfrom lower to higher concentration using energy
   3. Calong a cell’s cytoplasm by cilia
   4. Dfrom a region of higher concentration to lower concentration, down a gradient
   ( )
8. 8

   The turgor of a plant cell depends on

   1. Awater entering the vacuole and pressing the cytoplasm against the cell wall
   2. Bthe cell losing all its water
   3. Cthe cell wall dissolving
   4. Dchloroplasts filling with sap
   ( )
9. 9

   Which adaptation increases the rate of absorption by a root hair cell?

   1. Aa thick waxy cuticle
   2. Ba hard lignified wall
   3. Ca long narrow projection giving a large surface area
   4. Dgreen chloroplasts
   ( )
10. 10

    Gaseous exchange surfaces are moist because

    1. Awater carries oxygen into the blood
    2. Bmoisture kills bacteria
    3. Cdry surfaces repel oxygen
    4. Dgases dissolve before diffusing across
    ( )

Section B: Structured questions[30 marks]

Answer all questions in the spaces provided.

1. 1

   The described diagram shows a generalised animal cell: a round nucleus, thread-like mitochondria, small dots scattered in the cytoplasm, all enclosed by a thin cell membrane.

   1. (a)

      Name the parts labelled: the control centre containing chromosomes; the dots that build proteins; the boundary that controls what enters and leaves.

      [3]
   2. (b)

      State the function of the mitochondria.

      [2]
   3. (c)

      Name one structure present in a plant cell but absent from this animal cell, and state its function.

      [2]
2. 2

   A student weighs a cylinder of potato, places it in pure water for one hour, and weighs it again.

   1. (a)

      Predict whether the cylinder gains or loses mass, and explain why in terms of water potential.

      [3]
   2. (b)

      State two variables the student must control for a fair comparison with a second cylinder placed in concentrated salt solution.

      [2]
   3. (c)

      Describe what would happen to a plant cell placed in the concentrated salt solution, using the term plasmolysis.

      [3]
3. 3

   The small intestine absorbs glucose against its concentration gradient; the alveoli absorb oxygen down a gradient.

   1. (a)

      Name the process by which glucose is absorbed against its gradient, and state the energy source.

      [2]
   2. (b)

      Explain why oxygen enters the blood by diffusion rather than active transport.

      [2]
   3. (c)

      State two features shared by effective exchange surfaces such as the alveoli and root hairs.

      [2]
   4. (d)

      A root hair absorbs ions at 20 units per hour at 15 °C. At 25 °C the rate doubles. Calculate the new rate.

      [2]
4. 4

   Cells in different tissues are specialised for their jobs.

   1. (a)

      Name the specialised cell that transports oxygen in humans and state one adaptation.

      [2]
   2. (b)

      Name the plant cell specialised to photosynthesise and state its key organelle.

      [2]
   3. (c)

      Explain why an unfolded root hair projection absorbs faster than a flat epidermal cell of the same volume.

      [3]