Organism level systems Study Guide

Diabetes is a chronic condition characterized by high blood glucose (sugar) levels. The body usually regulates blood glucose using the hormone insulin, produced by the pancreas. Insulin helps glucose move from the blood into cells for energy or storage. When this system doesn't work correctly, blood glucose levels rise. There are two main types of diabetes: Type 1 and Type 2.

Type 1 diabetes is an autoimmune condition where the body's immune system attacks and destroys the insulin-producing cells in the pancreas. This means the individual produces little to no insulin. It typically develops in childhood or adolescence and is not linked to lifestyle factors. Treatment involves regular insulin injections or an insulin pump to replace the insulin the body cannot produce. Managing diet, regular exercise, and frequent blood glucose monitoring are also crucial.

Type 2 diabetes occurs when the body either doesn't produce enough insulin, or the cells become resistant to insulin (insulin resistance), meaning they don't respond effectively to the insulin that is produced. This type is often linked to lifestyle factors such as obesity, lack of exercise, and a poor diet, and it usually develops in adults, though it can occur in younger people. Initial treatment often focuses on lifestyle changes, including a balanced diet and increased physical activity. If lifestyle changes are not sufficient, medication (oral tablets) may be prescribed to improve insulin sensitivity or stimulate insulin production. In some cases, insulin injections may also become necessary. Regular monitoring of blood glucose is essential for both types to prevent complications.

Plants, like animals, use chemical messengers called hormones to coordinate their growth and responses to the environment. These hormones are produced in one part of the plant and transported to other parts where they have their effects. Three important plant hormones are auxins, gibberellins, and ethene, each with distinct roles in plant development. Auxins are primarily known for controlling cell elongation in shoots and inhibiting it in roots. They also play a role in tropisms (growth responses to stimuli like light and gravity), apical dominance (the main central stem growing more strongly than side stems), and the development of fruits. Gibberellins are vital for promoting stem elongation, breaking seed dormancy, and stimulating flowering and fruit development. Ethene, a gaseous hormone, is crucial for fruit ripening and senescence (ageing) of plant parts like leaves and flowers. Understanding these hormones helps explain how plants grow, develop, and adapt.