How dyes bind to fabric

I read this information from Organic Chemistry. To be classified as a dye, a compound must be colored and it must bind to fabric. There are many ways for this binding to occur. Compounds that bind to fabric by some type of attractive forces are called direct dyes. These attractive forces may involve electrostatic interactions. The type of interaction depends on the structure of the dye and the fiber. Thus, a compound that is good dyeing wool or silk, both polyamides, may be poor for dyeing cotton, a carbohydrate. Wool and silk contain charged functional groups, such as NH₃⁺ and COO¯. Because of this, they bind to ionic dyes by electrostatic interactions. For example, positively charged NH₃⁺ groups bonded to the protein backbone are electrostatically attracted to anionic groups in a dye like methyl orange. Cotton, on the other hand, binds dyes by hydrogen bonding interactions with its many OH group. Thus, Congo red is bound to the cellulose backbone by hydrogen bonds.

Magnetic Resonance Imaging (MRI)

An MRI instrument is specially useful for visualizing soft tissues. In 2002, 60 million MRI procedures were performed. The 2003 Nobel Prize in Physiology or Medicine was awarded to chemist Paul C. Lauterbur and physicist Sir Peter Mansfield for their contributions in developing magnetic resonance imaging. MRI, NMR spectroscopy in medicine, is a powerful diagnostic technique. The “sample” is the patient, who is placed in a large cavity in a magnetic field, and then irradiated with RF energy. Because RF energy has very low frequency and low energy, the method is safer than X-rays or computed tomography (CT) scans that employ high-frequency, high-energy radiation that is known to damage living cells. Living tissue contains protons in different concentrations and environments. When irradiated with RF energy, these protons are excited to a higher energy spin state, and then fall back to the lower energy spin state. These data are analyzed by a computer that generates a plot that delineates tissues of different proton density. MRIs can be recorded in any plane. Moreover, because the calcium present in bones is not NMR active, an MRI instrument can “see through” bones such as the skull and visualize the soft tissue underneath.

Histrionicotoxin

I read this information from Organic Chemistry. Histrionicotoxin is a diyne isolated in small quantities from the skin of Dendrobates histrionicus, a colorful South American frog. This toxin, secreted by the frog as a natural defense mechanism, was used as a poison on arrow tips by the Choco tribe of South America. These small “poison dart” frogs inhabit the moist humid floor of tropical rainforests, and are commonly found in western Ecuador and Colombia. Histrionicotoxin acts by interfering with nerve transmission in mammals, resulting in prolonged muscle contraction.

Asthma and Leukotrienes

I read this information from Organic Chemistry. Asthma is an obstructive lung disease that affects millions of Americans. Because it involves episodic constriction of small airways, bronchodilators such as albuterol and inhaled steroids
reduced inflammation )are used to treat symptoms by widening airways.Leukotrienes are molecules that contribute to the asthmatic response. Structure determination and chemical synthesis were difficult because leukotrienes are highly unstable and extremely potent, and are therefore present in tissues in exceedingly small amounts.

Ethanol

I read this information from Organic Chemistry. Ethanol formed by the fermentation of the carbohydrates in grains, grapes, and potatoes, is the alcohol present in alcoholic beverages. It is perhaps the first organic compound synthesized by human, because alcohol production has been known for at least 4000 years. Ethanol depresses the central nervous system, increases the production of stomach acid, and dilates blood vessels, producing a flushed appearance. Ethanol is also a common laboratory solvent, which is sometimes made unfit to ingest by adding small amount of benzene or methanol. Ethanol is used as a gasoline additive because it readily combusts with the release of energy.

Vitamin A

I read this information from Organic Chemistry. Vitamin A or retinol helps to maintain the health of mucous membranes and the skin, so many anti-aging creams contain vitamin A. A deficiency of this vitamin leads to a loss of night vision. Vitamin A may be obtained directly from the diet. In addition, β-carotene, the orange pigment found in many plant including carrots, is readily converted to vitamin A in our bodies. Ingesting a moderate excess of vitamin A does not cause any harm, but a large excess causes headaches, loss of appetite, and even death. Early Arctic explorers who ate polar bear livers, which contain an unusually large amount of vitamin A are thought to have died from consuming too much vitamin A.

Vitamin

I read this information from Organic Chemistry. The name vitamin was first used in 1912 by the Polish chemist Casimir Funk, who called them vitamines because he thought that they all contained an amine functional group. Later the word was shortened to vitamin, because some are amines but others, like vitamins A and C, are not. Vitamins are organic compounds needed in small amounts for normal cell function. Our bodies cannot synthesize these compound, so they must be obtained in the diet. Most vitamins are identified by letter, such as A, C, D, E, and K. There are several different B vitamins, though, so a subscript is added to distinguish them: for example, B₁, B₂, and B₁₂.

How a diet high in cholesterol may cause cardiovascular disorders.

I read this information from PRE-U TEXT STPM BILOLOGY, a diet rich in cholesterol may result in high blood cholesterol. CO, nicotine, hypertension and high blood cholesterol level cause damage to arterial endothelium. There is invasion by monocytes which develop into macrophages. Macrophages ingest cholesterol from LDLs. Smooth muscle cells also ingest cholesterol. The macrophages and smooth muscle cells transformed into foam cells. The foam cells together with accumulation of lipid( mainly cholesterol), Ca²⁺ and fibrous deposits from the athermatous plaque which is covered by a fibrous cap. It protrudes into the arterial lumen. The plaque causes narrowing of the arterial lumen, reduces oxygen supply to the heart and increases the risk of developing cardiovascular disorders example heart attack.

The effects of cocaine on the nervous system

I read this information from PRE-U TEXT STPM BILOLOGY, there are some of the effects of cocaine on the nervous system. It begin when drug users take in cocaine example snorting (inhaling) or smoking, cocaine enters into the synaptic cleft and binds to the transport molecules. This blocks the reuptake of dopamine by the presynaptic cell. The level of dopamine is higher than normal and remains longer in the synapse. This stimulates the pleasure pathway which gives drug users an intense feeling of euphoria and increased sense of energy. The feeling last for 5-30 minutes. The users then begin to feel irritable, restless and depressed. To overcome these symptoms, users have to repeat the usage of cocaine. With continued cocaine use, the body responds to the ‘excess’ supply in the synaptic cleft by producing less neurotransmitter dopamine and decreasing the numbers of receptors. The cocaine users then experience withdrawal symptoms. They become extremely dependent (addicted) to the drug and increase the cocaine intake to produce the euphoric effect. High doses of cocaine can cause nasal bleeding (from snorting), seizures, cardiac and respiratory arrest, as well as brain damage. Babies born to addict may suffer from developmental and neurological problems. Diseases such as hepatitis B and AIDS are spread when drug addicts share needles.

How cigarette smoking may cause cardiovascular disorders.

I read this information from PRE-U TEXT STPM BILOLOGY, there are some of the effects of cigarette smoking. Carbon monoxide and nicotine damage the endothelium of the blood vessels, making penetration by fats, cholesterol and macrophage easier. Carbon monoxide combines with haemoglobin and reduce oxygen carrying capacity in smokers. Insufficient supply of oxygen may cause angina and heart attack. Nicotine causes constriction of blood vessels and increases blood pressure and heart rate. Nicotine stimulates the sticking of blood platelets to the surface of endothelium and are involved in blood clotting and formation of thrombus. Smoking stimulates production of fibrinogen to form blood clots and reduced levels of enzymes involved in dissolving the blood clots. Nocotine increases the blood fat and cholesterol levels. Destruction of antioxidants, more free radicles present. Smoking increases incidence of atherosclerosis, formation of blood clots at atheromatous plaques and hearts attack. Smoking can also cause lung cancer and other respiratory disorders.

Why a high haemoglobin concentration in the blood is necessary for people living at high altitude?

I read this information from PRE-U TEXT STPM BILOLOGY, why a high haemoglobin concentration in the blood is necessary for people living at high altitude? It is because people living at high altitude face the problem of low partial pressure of oxygen in the atmosphere. Loading tension in lungs decreases. Less oxygen is taken into the lungs, lowers the concentration gradient of oxygen between alveolus and blood capillaries in the lungs. Haemoglobin is not fully saturated. There is less oxygen carried in the blood (hypoxia). Less oxygen is supplied to tissues for aerobic respiration. An increase in haemoglobin in the blood is an adaptation to maintain oxygen carrying capacity.

Why haemoglobin molecules are not found in blood plasma?

I read this information from PRE-U TEXT STPM BILOLOGY, why haemoglobin molecules are not found in blood plasma? It is because if haemoglobin molecules were suspended in the plasma rather than enclosed within erythrocytes, the blood would become too viscous for the heart to pump the blood through the blood vessels. Haemoglobin would also affect the solute potential in the blood. Membrane of Bowman’s capsule in the nephron allows only proteins of molecular weight below 68 000 to pass. The haemoglobin molecules are smaller than the 680 000 threshold molecular weight. If present in the plasma, the haemoglobin can pass through the filtration membrane and be lost in the urine.

Why do many organisms store fats rather than carbohydrates in their bodies?

I read this information from PRE-U TEXT STPM BILOLOGY,why do many organisms store fats rather than carbohydrates in their bodies? It is because fat contains more carbon-hydrogen bonds. They therefore have less than half the mass of carbohydrates for a similar quantity of energy stored. This helps to reduce body weight to make movement easier from place to place. Fats are insoluble in water and do not diffuse out of their place of storage. They also protect the body and internal organs, acts as heat insulator and waterproofing. Oxidation of fats produces metabolic water which can be used by some animals example desert animals.

The importance of calcium and phosphorus in human body

I read this information from PRE-U TEXT STPM BILOLOGY, there are many important of calcuim and phosphorus in human body:
Calcium is important in teeth and bone formation. The skeleton gives support and shape to the body. It provides attachment for muscle to enable movement. Besides that it important in blood clotting, nerve trasmission across the synapse, muscle contraction and intracelullar signalling.
For phosporus, it important in bone formation, components of phospolipids needed to form cell surface membranes and membranes of organelles. It also components of nucleic acids, DNA carries genetic information, RNA in protein synthesis. Beside that, it also components of ATP and ADP needed in energy transfer.