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Combined Science: Biology

GCSE · Edexcel · higher

QuestionsFlashcards

Disease
Defence Against Disease
Development of Medicines
- Antibiotics
  4
- Discovery & Development of New Drugs
  6
Non-Communicable Diseases
- Lifestyle & Non-Communicable Disease
  8
- Cardiovascular Disease
  6

The Organism in the Environment
Human Influences on the Environment
- Human Impact on Biodiversity
  6
- Benefits of Maintaining Biodiversity
  6
Cycles within Ecosystems

Limiting Factors Flashcards

All 5 cards in this deck

What is a limiting factor in photosynthesis?: A factor that is in short supply and so holds back the rate of photosynthesis.
e.g. light intensity, carbon dioxide concentration, temperature.
What is the effect of increasing carbon dioxide concentration on the rate of photosynthesis?: The rate increases, then levels off when carbon dioxide ceases to be the limiting factor.
True or false? Increasing the temperature always increases the rate of photosynthesis.: False. The rate rises to a maximum at the optimum temperature for the enzymes; above the optimum the enzymes are denatured and the rate falls.
On a graph of rate of photosynthesis against light intensity, what happens to the curve if the carbon dioxide concentration is increased?: It levels off at a higher rate, because carbon dioxide was the factor limiting the rate at high light intensity.
If light intensity and carbon dioxide concentration are both high, which factor limits the rate of photosynthesis?: Temperature — the enzymes that control photosynthesis work slowly if it is too cool.