GradeGen

A horizontal region of a graph in which the dependent variable remains constant while the independent variable continues to increase.

Eventually the graph reaches a plateau. Photosynthesis is still occurring, but increasing light intensity no longer makes it faster. Light is no longer in short supply, so some other condition prevents a further increase.

A stage of a graph where the dependent variable remains approximately constant even though the independent variable continues to increase.

Describe separate regions of a curve. State where the rate rises, where it reaches a maximum or plateau, and—on a temperature graph—where it falls.

A plateau does not mean photosynthesis has stopped. It means that increasing the factor on the x-axis no longer increases the rate.

A plateau means the rate is no longer increasing; it does not mean that photosynthesis has stopped.

A level section of a graph where increasing the factor on the horizontal axis no longer increases the measured rate.

At the plateau, extra light alone makes no difference: another condition now restricts the rate. The plateau does not by itself tell you whether that condition is carbon dioxide concentration or temperature.

A flat region of a graph where increasing the value on the horizontal axis causes little or no further increase in the value on the vertical axis.

This effect also reaches a plateau. Once carbon dioxide is sufficiently available, adding more has little effect because carbon dioxide is no longer restricting the rate. The plant cannot use the additional carbon dioxide any faster under the existing light and temperature conditions.

A flat section of a graph where the dependent variable no longer increases as the independent variable increases.

Plateau

Definition

How each exam board covers it

AQA GCSE Biology · 8461

Exam tips

Revise Biology with GradeGen

Edexcel GCSE Biology · 1BI0

OCR GCSE Biology A · J247