Balancing Act
Sweating, sleeping, breathing — explore how your cells keep your body perfectly in balance.
🎯 Focus Questions:
- What is homeostasis?
- How do cells use food to make energy and maintain homeostasis?
- How does photosynthesis help to maintain homeostasis in plant cells?
- How do cells grow and reproduce to maintain homeostasis?
- How does removing waste help maintain homeostasis?
⚖️
Ectotherms (snakes): Use the environment — bask in sun to warm, find shade to cool. Metabolism slows so much in winter they can sleep for weeks without food.
Click each word. Type the definition in your own words — AI will check it, then save it to your notes.
Your body has a superpower that keeps everything balanced — it's called homeostasis. Homeostasis is the body's ability to remain stable and balanced inside, even when outside conditions change.
Examples of homeostasis at work: sweating to cool down after running, shivering to warm up in the cold, your stomach growling when you need energy. Every one of these is your body reacting to stay in balance.
⚡ External Chaos
Running → body overheats
Cold → core temp drops
Exercise → energy depleted
to balance
✅ Internal Stability
Running → sweats to cool. Cold → shivers to warm.
Low fuel → stomach growls to signal hunger.
Exercise → breathing speeds up to deliver more oxygen.
Warm-blooded animals use hormones and metabolism to maintain homeostasis from the inside. Cold-blooded animals like snakes rely on their environment instead.
- Snakes bask in sunlight to warm up and speed up their metabolism
- They find shade or dig underground to avoid overheating
- In winter, their metabolism slows — snakes can sleep for weeks without food
- Antarctica is the only continent with no snakes — it's too cold to survive
| ❤️ Endotherms (Humans) | ☀️ Ectotherms (Snakes) | |
|---|---|---|
| Mechanism | Internal — hormones & metabolism | External — positioning in environment |
| Warming up | Involuntary shivering | Basking in sun's rays (speeds up metabolism) |
| Cooling down | Sweating | Finding shady spots or digging underground |
| Winter strategy | High metabolism maintained; needs constant food intake | Metabolism slows; can sleep for weeks without food. Cannot survive Antarctica. |
🔬 Practice Like a Scientist
Living things get energy through cellular respiration, which happens in the cell's mitochondria.
- Inputs: oxygen + glucose (sugar from food)
- Output/Energy: ATP (usable energy for the cell)
- Waste outputs: carbon dioxide + water
Fill in the blanks for the inputs and outputs. Then click Check.
Plants make their own food through photosynthesis, which happens inside the chloroplasts.
- Inputs: carbon dioxide (from air) + water (from soil) + sunlight energy
- Outputs: glucose (plant food) + oxygen (released through leaves)
Chlorophyll is the pigment that captures sunlight and makes the whole process work.
Fill in the inputs and outputs of photosynthesis.
(Photosynthesis)
= the other's survival
(Respiration)
Cell division (also called mitosis) is how one cell splits into two genetically identical cells. This maintains homeostasis by:
- Growth — building new bone and muscle as you grow
- Repair — replacing damaged cells (like when your knee heals)
- Replacement — worn-out cells get replaced (skin: ~2-3 weeks; red blood cells: ~4 months)
Cells bring in food, water, and molecules through the cell membrane. If they couldn't also push waste out, toxins would build up — destroying the cell's balance.
The cell membrane is the gatekeeper: it controls what gets in AND what gets out. By allowing waste to exit, it keeps the internal environment stable — homeostasis!
Energy & Respiration
Fueling the system. Mitochondria convert O₂ + Glucose → ATP. Every cell in your body depends on this reaction 24/7.
Photosynthesis
Manufacturing resources. Chloroplasts turn CO₂ + Water + Sunlight → Glucose + O₂. Plants feed themselves — and all animals that eat them.
Mitosis & Division
Repairing the structure. One cell → two identical cells. Replaces worn-out skin, blood, muscle, and bone cells constantly.
Membrane Filtration
Clearing the waste. The cell membrane lets resources in and toxic waste out. Without this, cells would poison themselves.
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