The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules: A molecule in the bulk liquid experiences cohesive forces with other molecules in all directions. A molecule at the surface of a liquid experiences only net inward cohesive forces.
1. Tim's symptoms include deteriorated coordination, stamina and school performance, nausea, painful joints and an abnormal increase in growth rate. His personality also changed which manifested as depressive mood, introversion, anxiety and tension. These symptoms could indicate an endocrinological problem, therefore the organ system which could be associated with them is the thyroid gland.
2. The thyroid gland is an organ of the endocrine system which is located in the neck, behind Adam's apple. It regulates metabolism, protein synthesis and development. It does so by producing a number of hormones: calcitonin, thyroxine and triiodothyronine. The two thyroid hormones (thyroxine and triiodothyronine) regulate the body's metabolism by controlling the way cells produce and consume energy.
3. Hyperthyroidism is an endocrine condition in which there is an overproduction of thyroid hormones by the thyroid gland. Under these conditions, the thyroid gland proves to be overactive and the main symptom is the acceleration of the metabolism. Tim's sudden increase of growth rate and inability to gain weight, along with his nervousness and mood swings, and his fatigue and loss of energy could indicate a problem of hyperthyroidism.
4. Cortisol is a steroid hormone which is produced by the thyroid gland. It is often called as the "stress hormone" as it is released in response to a stressful situation. It is also released in response to low blood glucose concentration. Some of cortisol's functions are the increase in blood sugar, the suppression of the immune system and bone formation. Cortisol is also involved in the metabolism of macronutrients.
It is also possible to move substances across membranes against their concentration gradient (from areas of low concentration to areas of high concentration). ... If the energy of ATP is directly used to pump molecules against their concentration gradient, the transport is called primary active transport.
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