Cells, ATP & Homeostasis
Why is ATP essential for living cells?
ATP provides immediate energy for cellular processes.
Which organelle captures light energy and stores it in chemical bonds?
The chloroplast.
Why does energy decrease at higher trophic levels?
Energy is lost as heat through metabolism.
What process initiates eutrophication in aquatic ecosystems?
Nutrient enrichment.
What is the primary role of models in biology?
They help explain and predict biological systems.
Why do cells with high energy demands contain many mitochondria?
Mitochondria produce ATP through cellular respiration.
Why do muscle cells contain more mitochondria than skin cells?
Muscle cells require more ATP for contraction.
Which diagram best represents energy movement in ecosystems?
A linear flow with losses.
Why does oxygen decrease when algae die in eutrophic lakes?
Decomposers consume oxygen during cellular respiration.
Why do scientists use controlled variables in experiments?
To ensure that changes in results are caused by the independent variable.
Why are buffers important in biological systems?
They resist drastic changes in pH and help maintain homeostasis.
What process links photosynthesis and cellular respiration?
Glucose production and use.
Why are producers critical to ecosystems?
They introduce new energy into food webs through photosynthesis.
Which trophic level is most immediately affected by oxygen loss?
Primary consumers.
Why is energy considered a unifying concept in biology?
All biological processes depend on energy transformation and transfer.
Why is enzyme activity sensitive to temperature and pH?
Because enzyme shape determines function, and temperature or pH changes can alter that shape.
What evidence best supports structure–function relationships in cells?
Muscle cells contain many mitochondria because their function requires high energy output.
Why are keystone species essential to ecosystem stability?
Their removal causes disproportionate effects on the ecosystem.
How does deforestation directly disrupt ecosystem energy flow?
By reducing photosynthesis, which limits energy entering food webs.
How does evidence support the idea that structure determines function at multiple biological levels?
From enzymes to cells to ecosystems, structure affects how energy and matter are processed.
Which failure would most directly disrupt cellular homeostasis, and why?
Failure of feedback mechanisms, because cells could not regulate internal conditions.
Predict the most immediate global effect if chloroplasts stopped functioning.
Food webs would collapse due to reduced energy input from producers.
Why does biodiversity increase ecosystem stability?
Multiple species provide overlapping roles, allowing systems to recover from disturbance.
Which feedback loop is created by deforestation and rising CO₂?
A positive feedback loop increasing atmospheric CO₂.
Explain why biological systems are described as interconnected rather than isolated.
Changes in one part of a system affect energy flow, matter cycling, and stability in other parts.