Advanced Botany

Lactose is the main source of sugar from milk and milk products from all mammals except the sea lion. Inadequate lactase activity allows lactose to reach the large intestine. There, the gut flora provides a salvage pathway for lactose digestion by cleaving lactose into short-chain fatty acids and gas, mainly hydrogen (H2), carbon dioxide (CO2), and methane (CH4). Non-digested lactose can cause osmotic diarrhoea; products of its bacterial digestion can lead to secretory diarrhoea and gas distending the intestines, events that are likely to lead to clinical symptoms.  Lactose malabsorption actually refers to inefficient digestion of lactose due to reduced expression or impaired activity of the enzyme lactase. After ingestion, lactose passes into the small intestine where it comes into contact with lactase at the intestinal brush border where it is hydrolysed into the monosaccharides glucose and galactose, which can be readily absorbed. Dis accharide digestion occurs on the brush bord...

  The word 'carbohydrate' was coined more than 100 years ago to describe a large group of compounds include polymers and other compounds synthesized from polyhydroxylated aldehydes and ketones. In general carbohydrates have the empirical formula (CH 2 O) n . They are polyhydroxylated aldehydes or ketones and their derivatives. Chemically, carbohydrates are molecules that are composed of carbon, along with hydrogen and oxygen. The compounds carbohydrates have common same functional groups, glyceraldehydes and gulose are classifed as aldoses and ribulose and dihydroxyacetone as ketoses. All of these compounds are alcohols with many hydroxyl groups. They are polyhydroxylated and either aldehydes or ketones. Classification of carbohydrates Monosaccharides The simplest and smallest unit of the carbohydrates is the monosaccharide, (mono = one, saccharide = sugar). Monosaccharides are either aldehydes or ketones, with one or more hydroxyl groups; the six-carbon monosaccharides g...

  Vitamin D is essential for maintaining healthy bones and teeth. It also has several other important functions in the body such as regulating the absorption of calcium and phosphorus and facilitating normal immune function. According to a study, vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D] < 50 nmol/L or 20 ng/ml) is associated with fractures and bone loss. Severe vitamin D deficiency with a 25(OH)D concentration below <30 nmol/L (or 12 ng/ml) increases the risk of excess mortality, infections, and many other diseases. Poor vitamin D status is a global health problem. Approximately one billion people worldwide suffer from vitamin D insufficiency because most foods including plants contain little vitamin D. Sources of vitamin D Fish have the highest natural content of vitamin D (salmon contains 30 μg/100 g and tuna 2.9 μg/100 g). Other sources of vitamin D 3  are meat (~0.6 μg/100), egg (~1.75 μg/100) and milk products (~0.1 μg/100). Vitamin D 3  ha...

  Sun is the ultimate source of energy for the earth. Plants convert light energy from the sun into  chemical energy  (food) by the process of photosynthesis. All living beings depend on plants for food and oxygen. Animals would disappear from the Earth if photosynthesizing plants were to disappear, since animals require for their nutrition the complex organic compounds that can be synthesized only by plants. The animal excretions and the animal body after death are also converted by a process of decay to simple products that can be re-utilized only by plants. Green plants require carbon dioxide, water, mineral salts, and sunlight for the formation of carbohydrates. Not only carbohydrates, but plants also synthesize amino acids, proteins, lipids, pigments, and other organic components during photosynthesis. Instead of energy, plants also need chemical compounds to interact with their neighbors, to attract animals for pollination and to defend themselves from animals that ...

  Natural photosynthesis is the process where plants convert CO 2 into carbohydrate and water is oxidized to molecular oxygen using solar energy.  Chlorophyll inside the plant cells absorbs energy from blue- and red-light waves, and reflects green-light waves, making the plant appear green.  In artificial photosynthesis photocatalyst or photocatalytic system is used for conversion of solar energy into hydrogen via water-splitting process without the requirement of any external bias.  Photocatalytic system can be divided into three main classes:  (i) suspended nanopowder photocatalysts,  (ii) photoelectrochemical cells (PECs), and  (iii) photovoltaic cell-driven electrolysers.   In natural photosynthesis, plants use light-harvesting complexes to collect incident photons, move them over large distances and direct them to a site where the process takes place. The light-harvesting complex is a highly organized array of chlorophyll molecules. Man...

  Most of the Universe consists of matter and energy . Energy is the capacity to do work. Matter has mass and occupies space. All matter is composed of basic elements that cannot be broken down to substances with different chemical or physical properties. Elements are substances consisting of one type of atom, for example Carbon atoms make up diamond, and also graphite. Atoms are the smallest particle into which an element can be divided. Center of the atom (nucleus) is occupied by proton. Each atom has at least one proton. Protons have a charge of +1, and a mass of approximately 1 atomic mass unit (amu). Elements differ from each other in the number of protons they have, e.g. Hydrogen has 1 proton; Helium has 2. The neutron is also located in the atomic nucleus (except in Hydrogen). The neutron has no charge, and a mass of slightly over 1 amu. The electron is a very small particle located outside the nucleus. Because they move at speeds near the speed of light the pr...