biology - limiting factor - chapter 6 - plant nutrition - pratice test

What is the definition of a limiting factor in photosynthesis?

An environmental factor present in such short supply that it restricts the rate of a life process

How does increasing light intensity affect the process of photosynthesis up to its peak rate?

It speeds up the splitting of water molecules into hydrogen and oxygen

What happens to the rate of photosynthesis when light intensity continues to increase beyond the light saturation point?

It levels off because light is no longer the limiting factor

Why does increasing carbon dioxide (CO2) concentration increase the rate of photosynthesis?

It provides more carbon atoms to combine with hydrogen to build carbohydrates

What is the approximate concentration of carbon dioxide (CO2) naturally present in the Earth's atmosphere?

0.04%

Why does temperature affect the rate of photosynthesis?

Temperature directly controls the rate of enzyme-catalysed reactions

What happens to the rate of photosynthesis if the temperature rises past the optimal level?

The rate drops sharply because essential enzymes become denatured

How do commercial glasshouses use knowledge of limiting factors to maximize crop yields?

By artificially controlling temperature, optimizing light, and raising CO2 levels

If a plant is kept at high light intensity and 25°C, but the rate of photosynthesis remains constant, what is most likely the limiting factor?

Carbon dioxide concentration

During a cold, bright winter morning outdoors, what is primarily limiting the rate of photosynthesis in wild plants?

Temperature