Biology Unwinding

1 . What is a virus ? A virus is a small infectious agent that repl icates only inside the living cells of other organisms . Vir uses can infect all types of life forms , from animals and plants to micro organisms , including bacteria and fungi . They are considered as non living organism. 2 . How do viruses spread ? V ir uses spread through contact with an infected person or animal , through contact with contaminated surfaces , and through the air by coughing and sne ez ing . They can also be spread through contact with body fluids , such as blood , saliva , and semen . 3 . What are the symptoms of a virus ? The symptoms of a virus vary depending on the type of virus . Common symptoms include fever , fatigue , sore throat , coughing , and body ac hes . Other symptoms may include nausea , vomiting , diarrhea , and rash . 4 . How can a virus be prevented ? Th...

 What are the common diseases found in humans ?  Typhoid Pneumonia Common cold Malaria Ascariasis Elephantiasis / filariasis Ringworms 1. Typhoid fever Causative agent :   Salmonella typhi Pathogenesis :-  Pathogen enter through contaminated food and water. Enter small intestine and migrate to other organs through blood. Symptoms - Higher fever (39° to 40°) Weakness Stomach pain Constipation Headache Loss of appetite Test perfomed -   Widal test 2. Pneumonia Causative agent :  Streptococcus pneumonia Haemophilus influenza Pathogenesis :- Pathogen enter through inhaling the droplets /aerosols released by infected person. Infects alveoli (air filled sacs) of the lungs. Alveoli get filled with fluid leading to severe problems in respiration. Symptoms :- Fever Chills Cough Headache How healthy person get infected ? Healthy person get infected by inhaling the droplets /aerosols released by infected person through sharing glasses, utensils. 3. Common cold Co...

  What are Pathogens? Pathogens are the organisms which cause disease in living things. For example., Bacteria, viruses, Fungi, protozoa, helminth, parasites etc.  How parasites cause harm to host ? Parasites causes harm to the host by living in (or on ) them and multiply in large numbers. For example, Malaria, a disease caused by parasite. How pathogen invade host ? Pathogens enter the body by various places of the body like skin ,mouth, etc and multiply , interfere with normal necessary activities. It results in morphological & functional damage. How Pathogens survive in the body of host ? Pathogens have to adapt to life within the environment of the host. For example., The pathogens that enter the gut must know a way of surviving in the stomach at low pH (1.5 to 3.5) which is acidic in nature. And survive in the presence of digestive enzymes.

It is easy to cultivate. It has a short life cycle which made it possible to study several generations within a short period. Large quantity of samples can be available for analysis. It has different contrasting characters. For example; tall or dwarf plants, yellow or green seeds.  It was easy to track the passing of these characters in the progeny. Pea plants are naturally Self pollinating. It has perfect bisexual flowers containing both males and females part.  Because of self pollination,plants are homozygous . It is , therefore easy to get purelines for several generations. It is easy to practice cross pollination because pollen from one plant can be introduced to the stigma of another plant.