1. A highly probable explanation of something, based on a large amount of evidence, would be a/an:

  Hint

    a) procedure.
    b) aim.
    c) theory.
    d) hypothesis.
    e) inference.

2. Plastids are found in plant cells. Identify the correct response that contains only plastids.

  Hint

    a) Vacuoles, chromoplasts and leucoplasts
    b) Chloroplasts, chromoplasts and leucoplasts
    c) Chromoplasts, leucoplasts and mitochondria
    d) Chloroplasts, phagocytes and lysosomes
    e) Chloroplasts, chromoplasts and phagocytes

3. Identify the definition that best represents the structure and function of the cytoskeleton.

  Hint

    a) Composed mainly of cellulose, allowing transport of substances in and out of cells
    b) A system of membranes within the cell where most of the cell’s chemical activity takes place
    c) Consisting of small sacs called vesicles that form at the ends of the membranes. Involved in the transport of substances to the cell membrane
    d) A fine meshwork of fibres called microtubules and microfilaments that support the cytoplasm and organelles in eucaryotic cells
    e) A large, dense, slightly circular organelle surrounded by a nuclear membrane (or nuclear envelope). Contains the blueprint of life

4. What is the name of the structure described in the following definition?

‘The selectively permeable surface contains receptor molecules that detect signals from the environment, enabling cells to communicate with their environment.’

  Hint

    a) Barrier
    b) Lysosome
    c) Membrane
    d) Nucleus
    e) Grana

5.



The fluid mosaic model of the cell membrane consists of a double lipid layer sometimes called a lipid bilayer. This is two layers of phospholipids with their water-soluble ends facing inwards towards the cytoplasm and outwards towards the extracellular fluid. The label that identifies the phospholipid is:

  Hint

    a) W
    b) V
    c) U
    d) Z
    e) X

6. Recognition molecules in the surface of the membrane called glycoproteins are actually a carbohydrate joined to a protein molecule. Which of the letters U–Z represents the correct label for a glycoprotein?

  Hint

    a) W
    b) U
    c) V
    d) Z
    e) X

7. One of the roles of the part labelled Z in the diagram is to:

  Hint

    a) allow all membrane organelles to 'float' in the membrane.
    b) block the passage of substances such as amino acids.
    c) provide a rigid structure made of a carbohydrate – cellulose – to block all entry of substances.
    d) help specific substances such as amino acids cross the membrane through a central channel or pore.
    d) change glucose into a more usable source of energy for the cell.

8. Cells placed in a hypertonic solution would tend to become:

  Hint

    a) generally larger in size.
    b) unchanged but smaller.
    c) shrivelled and eventually die.
    d) swollen and may burst (lyse).
    e) flaccid and remain normal.

9. Examples of organic molecules consisting of carbon, hydrogen, oxygen and nitrogen are most likely :

  Hint

    a) glycerol, sugar and proteins.
    b) polysaccharides, amino acids and glycerol.
    c) nucleic acids, amino acids and sugars.
    d) fatty acids, nucleic acids and glycerol.
    e) amino acids and proteins.

10. Which of the following chemical reactions best represents general reaction known as photosynthesis?

    Hint

    a)
    b)
    c)
    d)
    e)

11. The diagram of a leaf in cross-section is shown.



The parts represented by labels D, E, G are respectively:

    Hint

    a) chloroplast, vacuole and phloem element.
    b) chloroplast, cytoplasm and phloem element.
    c) epidermis, cytoplasm and xylem element.
    d) cuticle, cytoplasm and phloem element.
    e) chloroplast, cytoplasm and xylem element.

12. Cells are composed of chemical elements that join together to produce molecules, which are then used to build the components of a cell’s structure such as organelles. Which of the following represents increasing complexity?

    Hint

    a) elements, molecules, organelles and cells.
    b) molecules, organelles, elements and cells.
    c) cells, molecules, organelles and elements.
    d) organs, tissues, molecules and organelles.
    e) elements, molecules, organs and organelles.

13. Diffusion is the movement of a substance from:

    Hint

    a) one solution to another across an impervious membrane.
    b) particles bouncing off each other and the impervious membrane.
    c) where it is more concentrated to where it is less concentrated.
    d) where it is less concentrated to where it is more concentrated.
    e) ordered motion (due to kinetic energy) of atoms and molecules.

14. When we eat food, we convert the chemicals in it to the chemicals in our bodies and so it becomes part of us. These processes are called:

     Hint

    a) ingestion and chemosynthesis.
    b) photosynthesis and chemosynthesis.
    c) photosynthesis and assimilation.
    d) ingestion and assimilation.
    e) digestion and chemosynthesis.

15. Some types of intestinal bacteria can produce organic molecules that some animals cannot manufacture for themselves, but are essential (in small amounts) for normal metabolism. These organic molecules would be known as:

    Hint

    a) proteins.
    b) monomers.
    c) vitamins.
    d) minerals.
    e) carbohydrates.

16. Cells carry out their metabolism (chemical reactions) in the volume or space within the cell. The larger the cell, the larger its volume and so more metabolism will take place in the cell. If a cell becomes too large, however, there is a danger that wastes will collect in the cell so that it will not be able to function properly. A cell can function better when:

     Hint

    a) absorption capacity is at a maximum.
    b) surface area is reduced compared to volume.
    c) volume of the cell is large and surface area is small.
    d) surface area is high compared to volume.
    e) the shape of the cell is a perfect sphere.

17. A scanning electron microscope:

     Hint

    a) can be used to study living specimens with a high degree of resolution.
    b) can produce 3D images, but has less resolving power than a transmission electron microscope.
    c) has higher resolving power than a transmission electron microscope.
    d) has less resolving power than a light microscope.
    e) can produce 3D images, and has higher resolving power than a transmission electron microscope.

18. The field of view of an image at ×400 magnification:

   Hint

    a) is four times that of ×100 magnification.
    b) is four times less than ×100 magnification.
    c) depends on the eyepiece used.
    d) depends on the objective lens being used.
    e) is fourteen times less than ×100 magnification.

19. The digestive system of a nectar feeder is usually characterised by:

    Hint

    a) the presence of a long caecum and lack of prominent canine teeth, and incisors.
    b) the absence of a long caecum and presence of prominent canine teeth, and incisors.
    c) the presence of a short caecum and incisors and canines that are usually narrow, rounded structures.
    d) the absence of a caecum, and presence of incisors and canines that are usually narrow, pointed structures.
    e) the presence of a long caecum and incisors and canines that are usually narrow, pointed structures.

20. The digestive system of a herbivore is usually characterised by:

  Hint

    a) the presence of a long caecum and lack of prominent canine teeth, and incisors.
    b) the absence of a long caecum and presence of prominent canine teeth, and incisors.
    c) the presence of a short caecum and incisors and canines that are usually narrow, rounded structures.
    d) the absence of a caecum, and presence of incisors and canines that are usually narrow, pointed structures.
    e) the presence of a long caecum and incisors and canines that are usually narrow, pointed structures.

21. The diagram shows the movement of oxygen across the gills of a fish and represents:

    Hint

    a) counter-current flow, which reduces the exchange of gases between the blood and water.
    b) oxygen is entering the cells through diffusion at A, while carbon dioxide is entering the alveolus through diffusion.
    c) parallel flow, which helps to make the exchange of gases very efficient.
    d) counter-current flow, which helps to make the exchange of gases very efficient.
    e) counter-current flow, involving a small diffusion gradient acting over a small surface area.

22. Enzymes that stimulate the breakdown of complex molecules to simpler ones are helping the completion of which type of chemical reaction?

     Hint

    a) Catabolic reaction
    b) Anabolic reaction
    c) Synthesis reaction
    d) Neutralisation reaction
    e) Substrate reaction

23. Breathing out is caused by muscles relaxing to decrease the volume of the chest cavity. This reduces the volume and increases pressure in the lungs. As a consequence this causes:

    Hint

    a) the pressure in the lungs to become equal to the air outside the lungs with no movement of air.
    b) the pressure in the lungs to become the same as the external air pressure so air is forced out.
    c) the pressure in the lungs to become less than the external air pressure so air is forced out.
    d) the pressure in the lungs to become greater than the external air pressure so air is forced out.
    e) none of the above.

24. The diagram shows an alveolus in cross-section.



A suitable explanation for what is happening to the gases oxygen and carbon dioxide in blood cells labelled A and B would be:

    Hint

    a) oxygen is entering the cells through diffusion at A, while carbon dioxide is entering the alveolus through osmosis.
    b) oxygen is entering the cells through diffusion at A, while carbon dioxide is entering the alveolus through diffusion.
    c) oxygen is entering the cells through diffusion at A, while carbon dioxide is entering the alveolus due to movement against a concentration gradient.
    d) carbon dioxide is entering the cells through diffusion at A, while oxygen is entering the alveolus through diffusion.
    e) carbon dioxide is entering the cells through osmosis at A, while oxygen is entering the alveolus through diffusion.

25. The diagram shows the movement of gases into and out of the roots of a plant.



Oxygen gas is moving into the cells from the:

    Hint

    a) water in the roots through root epidermal cells and root hair cells.
    b) water in the soil through root epidermal cells and root hair cells.
    c) air into the leaves through epidermal cells and hair cells.
    d) soil into the roots through root epidermal cells and root hair cells.
    e) an unknown source that scientists are still trying to understand.

26. The circulatory system of vertebrates is made up of a heart, which pumps blood, and many blood vessels, which carry the blood. Which of the following responses is correct?

    Hint

    a) Birds and reptiles have three-chambered hearts.
    b) Birds and mammals have four-chambered hearts.
    c) Mammals and amphibians have four-chambered hearts.
    d) Birds and amphibians have four-chambered hearts.
    e) Fish and amphibians have three-chambered hearts.

27. The circulatory system of mammals, birds, reptiles and amphibians is often called a/an:

    Hint

    a) single circulatory system because it has only one circuit.
    b) open circulatory system as the blood remains within tubes and materials.
    c) single circulatory system, ensuring that blood flows in the right direction through the heart.
    d) valve system, ensuring that blood flows in the right direction through the heart.
    e) double circulatory system because it has two circuits.

28. All animals eat to provide their nutrient needs. One of the nutrients they take in is protein, which is broken down in digestion into amino acids. The amino acids released in this process are:

    Hint

    a) transported in the bloodstream to the liver for processing when they are in excess.
    b) used by cells to build enzymes and cellular structures.
    c) absorbed and transported to cells where they are used by cells to produce new proteins.
    d) unable to be stored by the cells in the body.
    e) all of the above.

29. Nitrogenous (nitrogen) wastes include:

    Hint

    a) ammonia and urea only.
    b) ammonia, urea and uric acid.
    c) urea and uric acid only.
    d) carbohydrates, urea and uric acid.
    e) proteins, urea and uric acid.

30. In multicellular organisms, most cells specialise and eventually die and break down to be replaced by new cells. Some cells do not specialise but continue to divide. These cells provide a source of new cells for growth or to replace damaged cells. This process of growth and division is known as:

    Hint

    a) the lifespan cycle.
    b) sexual reproduction.
    c) zygote reproduction.
    d) the cell cycle.
    e) the meiosis cycle.