Energy and ATP
| English | Chinese | Pinyin |
|---|---|---|
| energy currency | 能量货币 | néng liàng huò bì |
| respiration | 呼吸作用 | hū xī zuò yòng |
| active transport | 主动运输 | zhǔ dòng yùn shū |
| anabolic | 合成代谢 | hé chéng dài xiè |
| phosphorylation | 磷酸化 | lín suān huà |
| chemiosmosis | 化学渗透 | huà xué shèn tòu |
The cell's energy currency 能量货币
- Cells need a steady supply of energy, which they get from respiration 呼吸作用.
- Energy powers active transport 主动运输, movement, and anabolic 合成代谢 reactions (building big molecules).
- The molecule that delivers it is ATP.
Which is a use of energy in a cell?
Energy from respiration drives active transport, movement (e.g. muscle), and anabolic (building) reactions.
ATP is re-made from ADP and a ______ group.
Respiration provides the energy to re-attach the phosphate to ADP.
The energy currency
- ATP is made from ADP + a phosphate; breaking that phosphate off again releases a small, usable burst of energy.
- It is the universal energy currency because it:
- releases energy quickly, in small amounts that match a cell's needs,
- is easily re-made over and over,
- is small and soluble, so it moves easily around the cell.
The ATP cycle
Step around the loop. ATP is split to release a small burst of energy, then rebuilt by respiration — over and over.
Why is ATP a good energy currency?
ATP gives small, quick bursts of energy, is re-made repeatedly, and is small and soluble so it moves easily.
ATP is made by adding a phosphate group to ADP, and broken down again by removing it.
Adding a phosphate to ADP stores energy as ATP; removing it (hydrolysis) releases that energy.
Match each term to its meaning.
ATP holds the energy; hydrolysis releases it (giving ADP + Pi); chemiosmosis is how most ATP is made.
How ATP is made
- by phosphorylation 磷酸化 — direct transfer of a phosphate group.
- by chemiosmosis 化学渗透 — across the membranes of mitochondria and chloroplasts.
During exercise, muscles need a constant supply of energy from respiration.
Chemiosmosis makes ATP using:
Chemiosmosis uses a proton gradient across the inner membrane to drive ATP synthase.
Why ATP, not glucose
- ATP releases a small, usable packet of energy exactly where it is needed.
- Glucose holds far more energy, but releasing it all at once would be wasteful and damaging.
Worked example. A muscle contraction uses ATP directly, not glucose. Respiration steadily re-makes ATP from ADP, so a tiny pool of ATP is recycled thousands of times a day.
Lipids release the most energy per gram, then proteins, then carbohydrates
You've got it
- energy (from respiration) powers active transport, movement, anabolic reactions
- ATP = ADP + phosphate; the universal energy currency (quick, small bursts; re-made; small + soluble)
- ATP is made by phosphorylation and chemiosmosis (across mitochondrial/chloroplast membranes)