🐱 Cat Cell Fun Fact!
Alishba, did you know that a cat has 230 bones — more than the 206 in a human body? Every single one of those bones started from a single fertilised egg cell that divided over and over using the cell cycle you are about to study. A cat’s cells contain the same organelles as your cells — mitochondria powering every purr, ribosomes building the proteins in their fur, and a nucleus holding all the DNA that makes a tabby different from a Siamese!
✏️ Worked Example — Read This First!
Compare prokaryotic and eukaryotic cells. Give TWO differences between them.
1
Identify the two cell types.
Prokaryotic cells = bacteria and archaea. Eukaryotic cells = plants, animals, fungi, protists.
Prokaryotic cells = bacteria and archaea. Eukaryotic cells = plants, animals, fungi, protists.
2
Difference 1 — Nucleus.
Prokaryotic cells have no membrane-bound nucleus — their DNA floats freely in the cytoplasm. Eukaryotic cells do have a membrane-bound nucleus that encloses the DNA.
Prokaryotic cells have no membrane-bound nucleus — their DNA floats freely in the cytoplasm. Eukaryotic cells do have a membrane-bound nucleus that encloses the DNA.
3
Difference 2 — Organelles.
Prokaryotic cells have no membrane-bound organelles (no mitochondria, no ER, no Golgi). Eukaryotic cells have many membrane-bound organelles that carry out specialised functions.
Prokaryotic cells have no membrane-bound organelles (no mitochondria, no ER, no Golgi). Eukaryotic cells have many membrane-bound organelles that carry out specialised functions.
4
Bonus difference — DNA shape.
Prokaryotic DNA is circular. Eukaryotic DNA is linear and organised into chromosomes.
Prokaryotic DNA is circular. Eukaryotic DNA is linear and organised into chromosomes.
Prokaryotic = no nucleus, no organelles, circular DNA. Eukaryotic = membrane-bound nucleus, organelles, linear DNA.
💡 Alishba’s analogy: Think of a prokaryotic cell like a studio apartment (one open room, everything in one space) and a eukaryotic cell like a house with separate rooms (nucleus = bedroom, mitochondria = kitchen oven, ER = hallways).
EasyQuestions 1–3
Question 1 EasySee Answer →
Label the following as prokaryotic or eukaryotic: bacteria, human liver cell, yeast, amoeba, E. coli. Give ONE feature that distinguishes prokaryotic from eukaryotic cells.
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Question 2 EasySee Answer →
Name FIVE organelles found in an animal cell and give the function of each.
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Question 3 EasySee Answer →
What is the difference between a plant cell and an animal cell? Name TWO structures found in plant cells but NOT in animal cells, and explain the function of each.
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MediumQuestions 4–7
Question 4 MediumSee Answer →
Explain the fluid mosaic model of the cell membrane. What two types of molecules make up most of the membrane? What does “selectively permeable” mean?
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Question 5 MediumSee Answer →
Describe the three types of passive transport: diffusion, osmosis, and facilitated diffusion. For each: a) define it, b) does it require energy? c) give an example.
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Question 6 MediumSee Answer →
What is active transport? How is it different from passive transport? Give TWO examples of active transport in living organisms.
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Question 7 MediumSee Answer →
Describe the stages of the cell cycle: Interphase (G1, S, G2) and Mitosis (PMAT). What happens to the DNA in each phase of mitosis?
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HardQuestions 8–10
Question 8 HardSee Answer →
A cell is placed in a hypertonic solution. a) Define hypertonic. b) In which direction will water move? c) What will happen to the cell? d) What would happen if the same cell were placed in a hypotonic solution?
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Question 9 HardSee Answer →
Explain how cancer is related to the cell cycle. What is a tumour? What is the difference between a benign and malignant tumour? Name TWO factors that can disrupt normal cell cycle regulation.
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Question 10 HardSee Answer →
Compare the surface area to volume ratio of a small cell versus a large cell. Why do cells divide rather than just grow indefinitely? Show with a calculation: if a cube-shaped cell has side length 2μm vs 4μm, calculate surface area, volume, and SA:V ratio for each.
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🌟 Great work, Alishba!
You have just covered the building blocks of all life — from the tiniest bacterium to the 37 trillion cells in your own body. Think of it this way: if your body were a Vocaloid concert, every cell is a tiny Len Kagamine performing its own part perfectly in sync. Tomorrow you will dive into the chemistry that powers these cells!