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Flashcards · Biology

Cell Structures

50 cards from 3 lessons

  1. What is the main difference between eukaryotic and prokaryotic cells?

    Eukaryotic cells have a nucleus enclosing their DNA. Prokaryotic cells have no nucleus.

  2. Which kinds of living things have eukaryotic cells?

    Animals, plants, fungi and single-celled organisms such as Amoeba.

  3. What type of cell is a bacterium?

    A prokaryotic cell.

  4. Where is the DNA in a bacterial cell?

    In a single loop lying free in the cytoplasm.

  5. What is a plasmid?

    A small extra ring of DNA in a bacterial cell, often carrying genes such as antibiotic resistance.

  6. What is the bacterial cell wall for?

    It supports the cell and protects it. It is not made of cellulose.

  7. Name three structures found in both bacterial and animal cells.

    Cell membrane, cytoplasm and ribosomes.

  8. Roughly how much bigger is an animal cell than a bacterium?

    About 10 times: around 20 µm compared with around 2 µm.

  9. What does the prefix micro mean?

    One millionth, so \(1\ \mu\text{m} = 1 \times 10^{-6}\text{ m}\).

  10. What does the prefix nano mean?

    One billionth, so \(1\text{ nm} = 1 \times 10^{-9}\text{ m}\).

  11. Write 0.000 03 m in standard form.

    \(3 \times 10^{-5}\text{ m}\).

  12. One cell is 100 times bigger than another. How many orders of magnitude is that?

    Two, because \(100 = 10^{2}\).

  13. How many micrometres are there in 1 mm?

    1000.

  14. What is the usual mistake about bacteria and DNA?

    Thinking bacteria have no DNA. They do, but it is not enclosed in a nucleus.

  15. A bacterial cell with a pointer marked X to a small ring of DNA. What is the structure marked X in this bacterial cell?

    A plasmid: a small extra ring of DNA that can carry genes such as antibiotic resistance.

  16. A rod-shaped bacterial cell with no labels. Label every structure of this bacterial cell. The same bacterial cell with every structure labelled.

  17. What does the nucleus do?

    It contains the genetic material (DNA) and controls the activities of the cell.

  18. What happens in the cytoplasm?

    Most of the cell's chemical reactions.

  19. What does the cell membrane do?

    It controls which substances pass into and out of the cell.

  20. What is the function of mitochondria?

    They are where aerobic respiration takes place, releasing energy for the cell.

  21. What do ribosomes do?

    They make proteins.

  22. What is the cell wall of a plant cell made from?

    Cellulose.

  23. What does the cell wall do?

    It strengthens the cell and supports the plant.

  24. What do chloroplasts contain, and why?

    The green pigment chlorophyll, which absorbs light for photosynthesis.

  25. What is the permanent vacuole filled with?

    Cell sap, a solution of sugars and salts.

  26. Name three structures found in plant cells but not in animal cells.

    Cell wall, chloroplasts and a permanent vacuole.

  27. Why do muscle cells contain many mitochondria?

    Contraction needs a lot of energy, which mitochondria release in respiration.

  28. Why do root cells have no chloroplasts?

    Roots are underground where there is no light, so photosynthesis cannot happen.

  29. Do mitochondria make energy?

    No. They release energy from glucose in respiration. Energy cannot be made.

  30. An animal cell with a pointer marked X to a mitochondrion. What is the structure marked X, and what does it do?

    A mitochondrion. It is where aerobic respiration takes place, releasing energy for the cell.

  31. A plant cell with a pointer marked X to a chloroplast. Name the structure marked X, and say what it does.

    A chloroplast. It contains chlorophyll, which absorbs light for photosynthesis.

  32. A plant cell with a pointer marked X to the large central vacuole. Name the large structure marked X in this plant cell. What does it contain?

    The permanent vacuole. It is filled with cell sap, a solution of sugars and salts.

  33. A plant cell with no labels. Label every structure of this plant cell. The same plant cell with every structure labelled.

  34. Write the magnification formula.

    Magnification = size of image ÷ size of real object.

  35. How do you find the real size from the image size and the magnification?

    Real size = image size ÷ magnification.

  36. What is resolution?

    How clearly two points that are close together can be told apart.

  37. Which has higher magnification and resolution: light or electron microscope?

    The electron microscope.

  38. Name two disadvantages of an electron microscope.

    It is large and expensive, and the specimen must be dead.

  39. Name an advantage of the light microscope.

    It is cheap and easy to use, and living cells can be viewed.

  40. A ×10 eyepiece and a ×40 objective lens are used. What is the total magnification?

    ×400.

  41. How many micrometres are in 1 mm?

    1000.

  42. How many nanometres are in 1 µm?

    1000.

  43. Why is a stain used on a slide?

    It makes the cell structures easier to see.

  44. Which objective lens should you start with?

    The lowest power one, which gives the widest view.

  45. Which wheel do you use to find the image, and which to make it sharp?

    The coarse focus wheel finds it, then the fine focus wheel sharpens it.

  46. Why is a coverslip lowered at an angle?

    To avoid trapping air bubbles.

  47. How should a biological drawing be done?

    Sharp pencil, clear single lines, no shading, labelled, with the magnification written.

  48. A light microscope with no labels. Label every part of this light microscope. The labelled light microscope.

  49. A light microscope with a pointer marked X to the stage. Name part X of the microscope and say what it does.

    The stage. It is the platform that holds the slide, kept in place by the clips.

  50. A light microscope with a pointer marked X to the fine focus wheel. Name part X of the microscope and say what it does.

    The fine focus wheel. It makes small adjustments to give a sharp, clear image, after the coarse wheel has found it.