Cell biology flashcards

Cell biology covers the structure and function of animal, plant, and bacterial cells, and how cells are adapted for their roles. Students must understand the differences between prokaryotic and eukaryotic cells, the functions of organelles such as the nucleus, mitochondria, ribosomes, and chloroplasts, and how the cell membrane controls what enters and leaves. Key processes include cell division by mitosis, which produces identical daughter cells for growth and repair, and the movement of substances by diffusion, osmosis, and active transport. Students should also understand how cells become specialised and how stem cells can develop into different cell types. Calculating magnification and understanding the scale of cells using standard form are also required skills.

1. Card 1

   What is the main difference between a prokaryotic and a eukaryotic cell?

   Prokaryotic cells have no membrane-bound nucleus and are smaller. Eukaryotic cells have a true nucleus enclosed by a nuclear membrane.

2. Card 2

   What is the function of the mitochondria?

   Mitochondria are the site of aerobic respiration, releasing energy in the form of ATP for the cell to use.

3. Card 3

   What structures are found in plant cells but NOT in animal cells?

   Plant cells have a cell wall made of cellulose, a permanent vacuole filled with cell sap, and chloroplasts for photosynthesis.

4. Card 4

   What is the role of the ribosome?

   Ribosomes are the site of protein synthesis, where amino acids are joined together following instructions from messenger RNA.

5. Card 5

   Define osmosis.

   Osmosis is the movement of water molecules from a region of higher water potential to lower water potential across a partially permeable membrane.

6. Card 6

   How does active transport differ from diffusion?

   Active transport moves substances against a concentration gradient and requires energy from respiration, whereas diffusion is passive and needs no energy.

7. Card 7

   What happens during mitosis?

   Mitosis produces two genetically identical daughter cells with the same number of chromosomes as the parent cell. It is used for growth and repair.

8. Card 8

   What is a stem cell?

   A stem cell is an undifferentiated cell that can divide and develop into many different specialised cell types through the process of differentiation.

9. Card 9

   What is the formula for calculating magnification?

   Magnification = image size divided by actual size. Written as: magnification = image size / actual size.

10. Card 10

    What is the function of the cell membrane?

    The cell membrane controls the movement of substances into and out of the cell. It is partially permeable, allowing some molecules through but not others.

11. Card 11

    Name two features unique to bacterial cells compared to plant and animal cells.

    Bacterial cells have a plasmid (small circular loop of DNA) and a cell wall made of peptidoglycan, not cellulose. They also lack a nucleus.

12. Card 12

    What is differentiation and why is it important?

    Differentiation is the process by which a cell develops a specific structure to carry out a particular function, producing specialised cells like nerve or muscle cells.

• Many students confuse osmosis with diffusion, forgetting that osmosis refers specifically to the movement of water molecules across a partially permeable membrane, not any substance.
• Students often incorrectly state that mitosis produces four cells or that it is used for sexual reproduction, when in fact it produces two genetically identical cells and is used for growth and repair.
• A common error is to say that plant cells always have chloroplasts, when in reality only cells exposed to light, such as leaf cells, contain chloroplasts, and root cells do not.

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