Advanced Botany

  A biosensor is defined as a device that produces a measurable signal proportional to the concentration of the target analyte, usually incorporating a biological sensing element and measuring signals derived from biological interactions. Biosensors  are self-contained integrated analytical devices that convert a biological response into quantifiable and processable signals. Biosensors required for measurement should have rapid detection, be accurate, be easy to operate, have a low response time, and be low-cost, highly sensitive, and reliable. Working Principle of Biosensors Biosensors are operated based on the principle of signal transduction. These components include a bio-recognition element, a biotransducer and an electronic system composed of a display, processor and amplifier. The bio-recognition element, essentially a bioreceptor, is allowed to interact with a specific analyte. The transducer measures this interaction and outputs a signal. The intensity of the sign...

  Bioenergetics is the branch of biochemistry that focuses on how cells transform energy, often by producing, storing or consuming adenosine triphosphate (ATP). Bioenergetic processes, such as cellular respiration or photosynthesis, are essential to most aspects of cellular metabolism, therefore to life itself. Bioenergetic processes, such as cellular respiration or photosynthesis, are essential to most aspects of cellular metabolism, therefore to life itself. Cellular Respiration  Cellular respiration refers to a catabolic process that cells use to harvest energy from biomolecules. Here, a series of reactions break up macromolecules into their basic units, transforming the potential energy embedded in the chemical bonds into ATPs and the cofactor  nicotinamide adenine dinucleotide (NAD+). Cellular respiration in most organisms takes place in the presence of oxygen ( aerobic respiration),   consisting of the following pathways: Glycolysis ( Embden–Meyerhof–...

Bioenergetics is the branch of biochemistry that focuses on how cells transform energy, often by producing, storing or consuming adenosine triphosphate (ATP). Bioenergetic processes, such as cellular respiration or photosynthesis, are essential to most aspects of cellular metabolism, therefore to life itself. Laws of Bioenergetics 1. Living cells use energy carriers The first bioenergetics law states that living cells do not use the acquired energy directly. Instead, the energy received from external sources is first converted into energy carriers before performing cellular works. Three energy carriers are known to date: Adenosine triphosphate (ATP) Considered the  molecular currency,  ATP consists of adenine attached to one molecule of ribose sugar at carbon one and a triphosphate group at carbon five, where energy is stored in the phosphoanhydride bonds. Energy is released when the triphosphate group of the ATP is broken up into di- and monophosphate, r...

  Photoreceptors allow living organisms to optimize perception of light in the natural environment and thus to gain information about their external world. Analyses performed in different organisms have revealed wonderful examples of structural modifications of the light‐sensing proteins themselves, as well as diversification of the signal pathways they use in relation with their evolutionary history and function. In different organisms, the same photoreceptor may have a very conserved role or may modulate different responses. Two different photoreceptors may be involved in the control of the same physiological response. Light signals are amongst the most important environmental cues regulating plant growth and development which is achieved through a suite of photoreceptor proteins. These photoreceptors can detect the presence, intensity, direction and color of light, and in turn utilize this information to direct their growth. In plants, many types of photore...

  Plants are fixed, so they must encounter abiotic stresses such as drought, salinity, extreme temperatures and more. These stressors alter their growth and development, and reduce crop productivity. Heat stress can be defined as rise in temperature beyond a threshold level for a period of time sufficient to cause irreversible damage to plant growth and development. In general, a transient elevation in temperature, usually 10–15 °C above ambient, is considered heat stress. High temperatures affect plant growth at all developmental stages however, anthesis and grain filling stage is more susceptible. High temperature may adversely affect photosynthesis, respiration, water relations and membrane stability and also modulate levels of hormones and primary and secondary metabolites. The major physiological injuries observed under elevated temperatures include scorching of leaves and stems, leaf abscission and senescence, shoot and root growth inhibition or fruit damage, which ...

  During the last half century, the protection of crops is depended on synthetic pesticides which are highly toxic and have adverse residual effects on crops, groundwater and soil. Moreover, their excessive application, leading to increased resistance of pests.   Few years back, when farmers used pesticides such as DDT and malathion, there was little understanding of how dangerous and long-lasting these chemicals are. It was only later that the degree to which these pesticides remain in the environment was discovered. Organophosphates designed to affect the brain and nervous system of insects, sometimes damage those of humans and animals. These pesticides killed bald eagles, birds, fishes and even people. The World Health Organization (WHO) reported that around two hundred thousand people were killed every year due to chemical pesticide poisoning. World Resource Institute reported that more than 500 insects were resistant to insecticides. Many researchers have suggested usin...