🔬 To Observe Disease-Causing Organisms: Ascaris, Entamoeba, Plasmodium & Ringworm (Permanent Slides) | Class 12 Biology Practical
Studying microorganisms under the microscope is a crucial part of Class 12 Biology practicals. In this activity, students observe disease-causing organisms such as Ascaris, Entamoeba, Plasmodium, and Ringworm using permanent slides. These organisms are responsible for common human diseases, and understanding their structure helps us learn how infections spread and how they can be prevented.
Aim
To observe the disease-causing organisms like Ascaris, Entamoeba, Plasmodium and Ringworm through permanent slides.
Materials Required
Preserved slides or specimens of disease-causing organisms like Ascaris, Entamoeba, Plasmodium and Ringworm.
Procedure
Observe the specimens or slides and identify the organism on the basis of its features.
Observations
Ascaris
Phylum: Aschelminthes
Class: Nematoda
Type: Ascaris lumbricoides
Ascaris exhibits the following characteristic features:
- It has a long, cylindrical and unsegmented body.
- The male and female organisms are separate.
- It bears a mouth at the anterior end surrounded by three lips.
- There is an excretory pore on the ventral surface slightly behind the anterior end.
- A pair of penial spicules are present in the male worms close to the cloacal opening.
- The female genitals are present at about one-third distance from the anterior end.
- Ascariasis is the disease caused by Ascaris lumbricoides or roundworm.
Symptoms:
- Abdominal cramping
- Abdominal swelling
- Nausea
- Vomiting
- Fever
Entamoeba
Phylum: Protozoa
Class: Rhizopoda
Type: Entamoeba hystolytica
Following are the characteristic features of Entamoeba:
- It is a unicellular organism with an irregular shape.
- It consists of a few food vacuoles. The contractile vacuole is absent.
- Cysts with four nuclei are present.
- It consists of a nucleus located eccentrically in the cell.
- Entamoeba histolytica is an organism found in the intestines of humans that is responsible for causing amoebic dysentery.
Symptoms:
- Abdominal pain
- Watery diarrhoea with mucus, blood and pus
- Fatigue
- Fever
- Nausea
- Vomiting
- Plasmodium
Phylum: Protozoa
Class: Sporozoa
Type: Plasmodium vivax
Plasmodium can be identified by the following characteristic features:
- It is a unicellular endoparasite found within the red blood cells of the diseased person.
- The parasite is mostly diagnosed at the “signet ring” stage where the parasite appears as a round body.
- There is a big vacuole present inside the cell. The cytoplasm is accumulated at one place and contains the nucleus.
- Plasmodium vivax is a protozoan parasite that causes malaria in humans. The infected female anopheles bites a healthy person and transmits the sporozoite into the peripheral blood vessels of humans, thereby, causing malaria.
Symptoms:
- High fever
- Shaking chills from moderate to severe.
- Headache
- Vomiting
- Nausea
- Ringworm
Kingdom: Fungi
Class: Deuteromycetes
Type: Trichophyton rubrum
Trichophyton or ringworm fungus has the following characteristic features:
- This fungus feeds on the keratin of the skin of human beings.
- The hyphae are waxy and can be smooth or cotton-like.
- Hyphae that are not stained are yellowish-brown, reddish-brown or white in colour.
- Ringworm is a communicable fungal infection of the skin.
Symptoms:
- Scaly, itchy skin
- Red and raised patches
- They are redder at the periphery than at the centre and forms a ring-like appearance.
