What is cancer? Differentiate between benign and malignant tumor.

Cancer can be best defined as uncontrolled cell division. Cancer cells can move into other parts of the body. Tumor is the abnormal growth of cells in the particular area that may be normal cells or the cancerous cells. Tumors are classified into two types as benign tumor and malignant tumor. Benign tumors are normal and malignant tumors are cancerous in nature. Characteristics Benign tumor Malignant tumor Features These cells do not spread to other tissues or organs and do not invade other areas of the body. Malignant cells are dangerous and can spread to other organs and tissues.

Name the causative agent of malaria. Explain the mode of infection of malaria.

Malaria can be characterised as a mosquito-borne infectious disease caused by various species of the parasitic protozoan microorganisms called Plasmodium. Malaria is caused by the parasite Plasmodium. P. falciparum causes malignant malaria in humans. Malaria is transmitted by the bite of an infected female Anopheles mosquito, which is the primary host of the malaria parasite. Humans serve as the secondary host. The infection of malaria occurs in three stages as follows Schizogony: In this stage, the parasite asexually reproduces within humans after being inoculated as sporozoites into the blood by mosquito bite. It further has two stages: Hepatic schizogony: In this stage, sporozoites multiply in the liver to form cryptomerozoites. Erythrocyticschizogony: The cryptomerozoites enter RBC and convert haem into a toxic form called hemozoin. Gamogeny: It is the phase of sexual reproduction within the mosquito. Here the merozoites get converted into gametocytes. Further fertilization leads to the formation of ookinete. Sporogeny: It is the stage of asexual reproduction in a mosquito. Here the ookinete gets converted into oocyst containing the sporozoites inside. The oocysts burst to release the sporozoites that are present in the saliva of the mosquitoes until they are inoculated into a human by mosquito bite.

do not react against transplant

Metastasis is a process during which the cancerous cells migrate from one organ to another and invade other healthy tissues, converting them into cancerous forms. This process allows cancer cells to spread throughout the body. During metastasis, the organ from where the cancer cells spread is known as primary cancer, and the organ to which these cells invade and cause their conversion into cancer tissue is known as secondary cancer. For example, the spread of cancer tissues from the liver (primary) to the lungs (secondary).