What measures must be taken to reduce the incidence of malaria and dengue?
Write a short note on nitrogen fixation
ng amewer type questions
List the various methods used for food preservation
1 What are the various steps of Nitrogen cycle?
What are communicable diseases and how are they spread
Why do we use yeast in bakeries and breweries?
HOTS Questions
Why are protocoans known as an important link for aquatic food chains?
2. Most of the preservatives are chemicals still we use them in our foods to preserve Why?
Answers
Answer:
1. Avoid mosquito bites by covering your arms and legs, and using a mosquito net. Use insect repellent in sleeping environments (sprays, sticks, and creams). Dengue fever is a mosquito-borne disease caused by the dengue virus. Dengue prevention achieve through mosquito control and insect repellent.
2. nitrogen cycleNitrogen fixation is the process by which atmospheric nitrogen is) converted by either a natural or an industrial means to a form of nitrogen such as ammonia. In nature, most nitrogen is harvested from the atmosphere by microorganisms to form ammonia, nitrites, and nitrates that can be used by plants.
3. Among the oldest methods of preservation are drying, refrigeration, and fermentation. Modern methods include canning, pasteurization, freezing, irradiation, and the addition of chemicals. Advances in packaging materials have played an important role in modern food preservation.
4. In general, the nitrogen cycle has five steps:
* Nitrogen fixation (N2 to NH3/ NH4+ or NO3-)
* Nitrification (NH3 to NO3-)
* Assimilation (Incorporation of NH3 and NO3- into biological tissues)
* Ammonification (organic nitrogen. compounds to NH3)
* Denitrification(NO3- to N2)
5. A communicable disease is one that is spread from one person to another through a variety of ways that include: contact with blood and bodily fluids; breathing in an airborne virus; or by being bitten by an insect.
6. Baker's yeast is the common name for the strains of yeast commonly used in baking bread and bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ethanol.
7. Protozoans are known to the important link for aquatic food chain because they consume and digest algae as a predator, which help to decrease the chances of eutriphication of the surrounding water.
8. A preservative is added to food and beverages to prevent decomposition of these products which can be caused by microbial growth or by undesirable chemical changes. These preservatives are chemical but used in the edibles because they contain components that prevent degradation by bacteria.