The graph shows the blood glucose concentrations of two people, over an eight-hour period, after eating a meal - Edexcel - GCSE Biology - Question 5 - 2013 - Paper 1

At the two-hour mark, the blood glucose concentration for the person with diabetes is 350 mg per dm³, while for the person without diabetes, it is 100 mg per dm³. The difference in concentration is calculated as follows:

$350 ext{ mg per dm}^3 - 100 ext{ mg per dm}^3 = 250 ext{ mg per dm}^3$

Thus, the difference is 250 mg per dm³.

The blood glucose concentration changed the most for the person with diabetes in the 0 – 2 hours period, as indicated by the steep rise immediately after the meal.

The pancreas is the organ that releases insulin to regulate blood glucose concentrations.

Plant growth hormones, particularly auxins, play a crucial role in both phototropism and gravitropism.

Phototropism

When a plant is exposed to light from one direction, auxins are produced in the shoot tip and redistributed unevenly. The side of the plant that is in shade accumulates more auxins, which promotes cell elongation on that side. As a result, the shaded side grows faster than the illuminated side, causing the plant to bend toward the light source, which enhances photosynthesis and growth.

Gravitropism

In response to gravity, auxins are also involved. When a plant's orientation changes, auxins accumulate on the lower side of the root or stem. In roots, auxins inhibit growth, causing the root to bend downwards, which helps the plant anchor itself better and access nutrients and water. In stems, auxins promote growth on the upper side, causing the stem to bend upwards. This coordinated response allows plants to grow toward light and against gravitational forces.