Biological World

 Q. 1. What is non-parasitic plant disease? Ans. When the disease is caused by non-parasitic causal agent it is called non-parasitic plant disease. Q. 2. What is an alternate host? Ans. When a pathogen needs two hosts to complete its life cycle then one host is designated as the principal host and the other as alternate host. Q. 3. What is pathogenesis? Ans. The chain of metabolical event which brings about the disease is pathogenesis.It involves the action of the pathogen, susceptibility of the plant and impact of the environment. Q. 4. Name one toxin produced by a plant pathogen. Ans. Wild fire toxin produced by Pseudomonas tabaci. Q. 5. What is disease triangle? Ans.In order for disease to occur, three factors must be present. Because of this,disease is often pictured as a triangle having three equal sides. Each side of the disease triangle is necessary in order for disease to occur. The three factors are host, causal agent and environment. Q. 6. What is a disease cycle? Ans. In...

Q. 1. What is facultative parasite? Ans. When fungi pass their mode of life as saprophyte in the beginning and later or under certain condition, becomes parasite causing a disease they are known as facultative parasite. Q. 2. What is macrocyclic rust? Ans. Macrocyclic is long-cycled life cycle in this case at least one or more than one type of binucleate spores in addition to telutospores are produced in a complete life cycle. Q. 3. What is mycorrhiza? Ans. Sometimes fungi also live in close association with the roots of gymnosperms and angiosperms; this association between fungal hyphae and roots of higher plants is known as mycorrhiza. Q. 4. What is hypertrophy? Ans. The most apparent effect is some disease is the over-growth of one or more plant organs or some parts of them and when this phenomenon occurs due to increase of cell size it is called hypertrophy. Q. 5. What is ectoparasite? Give an example. Ans. When parasitic fungi grow superficially on the surface of the host plant wi...

Crying is a more complicated process than one would at first imagine. First of all, there are really three different types of tears. Basal tears keep our eyes lubricated constantly. Reflex tears are produced when our eyes get irritated, like with onions or when something gets into our eyes. The third kind of tear is produced when the body reacts emotionally to something. Each type of tear contains different amounts of chemical proteins and hormones. Scientists have discovered that the emotional tears contain higher levels of manganese and the hormone prolactin, and this contributes in a reduction of both of these in the body; thus helping to keep depression away. Many people have found that crying actually calms them after being upset, and this is in part due to the chemicals and hormones that are released in the tears. How then actually do we cry? The psychic tears (or emotional tears) require an emotional response, or trigger to be activated. This response can be caused by an outside...

 

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