Skip to content
Login Register

#protozoa

16 public questions tagged with this topic.

ZOOLOGY

Which of the following diseases is caused by a protozoan?

Malaria is caused by Plasmodium, a protozoan transmitted by female Anopheles mosquitoes. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

View Details
Protista - Euglenoids Slime Moulds Protozoans

Protozoan X captures prey using pseudopodia, protozoan Y directs food-bearing water into a gullet using cilia, and proto

Amoeboid protozoans use pseudopodia for movement and food capture. Ciliated protozoans use coordinated cilia to direct food-bearing water into a gullet, while sporozoans possess an infectious spore-like stage in their life cycle.

Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Protista - Euglenoids Slime Moulds Protozoans

View Details
Protista Classification

Euglenoids show mixotrophy because they

Euglenoids exemplify mixotrophy by combining phototrophic and heterotrophic nutrition modes within single cell demonstrating metabolic versatility. In illumination they utilize chloroplasts for oxygenic photosynthesis producing paramylon, while in darkness they lose chlorophyll and switch to absorbing dissolved organics or engulfing bacteria via cytostome. Pellicle rather than rigid cell wall permits flexibility for phagocytosis. This plasticity arises from secondary endosymbiotic acquisition of green algal plastid retaining photosynthetic genes while preserving ancestral phagotrophic machinery. Hence they simultaneously photosynthesize and ingest food depending on conditions.

Ref: Campbell Biology 12th ed., Chapter 28: Mixotrophy Euglenoids; NCBI Bookshelf, Protist Metabolism - Euglena Physiology

View Details
Protista Classification

Euglenoids are mainly

Euglenoids within Euglenozoa predominantly perform photoautotrophy using secondary plastids surrounded by three membranes containing chlorophyll a and b plus paramylon storage polysaccharide as beta-1,3-glucan granules. Genera like Euglena possess photoreceptive eyespot and flagellum for phototaxis, enabling light-directed movement toward optimal irradiance for photosynthesis. While capable of osmotrophy and phagotrophy when light limited, natural freshwater populations are chiefly photosynthetic in euphotic zone. Parasitic, saprophytic or obligate heterotrophic lifestyles remain minor compared to dominant autotrophic nutrition supported by functional chloroplasts. Flagellar arrangement with phototactic eyespot enables vertical migration optimizing light capture and avoiding photooxidative damage near surface.

Ref: Campbell Biology 12th ed., Chapter 28: Euglenozoa Euglenoids; NCERT Class 11 Biology Chapter 2 Euglenoid Flagellates Nutrition

View Details
Protista Classification

The kinetoplast contains

Kinetoplast represents highly specialized mitochondrial nucleoid unique to kinetoplastids defining order. Composed of catenated circular DNAs: 20-50 maxicircles encoding canonical mitochondrial proteins like cytochrome oxidase and NADH dehydrogenase, plus thousands of minicircles encoding guide RNAs for extensive RNA editing of maxicircle transcripts. This network resides within single large mitochondrion near flagellar base, linked to basal body via tripartite attachment complex. It is not nuclear, plastid or plasmid genome but authentic mitochondrial DNA condensed into disk-shaped inclusion, providing molecular marker. Editing requires hundreds of guide RNAs, illustrating extraordinary mitochondrial genetic complexity unique among eukaryotic protists examined.

Ref: Campbell Biology 12th ed., Chapter 28: Kinetoplast DNA; NCBI: Kinetoplast DNA Network - PMC - Trypanosoma cruzi Mitochondrial Genome

View Details
Protista Classification

Kinetoplastids are characterized by

Kinetoplastids including Trypanosoma and Leishmania belong to Euglenozoa, distinguished by single enormous mitochondrion extending throughout cell body as branched network. Unlike typical eukaryotes with numerous discrete mitochondria, kinetoplastids consolidate mitochondrial function into one reticulum positioned near flagellar basal body requiring coordinated segregation. Within its posterior region condenses kinetoplast DNA network. Presence of multiple nuclei, photosynthetic capability or ciliature absent. Single mitochondrion reflects cell cycle-linked organelle division strategy requiring precise timing with kinetoplast segregation before cytokinesis ensuring inheritance. This single large mitochondrion organization demands tight coordination with basal body duplication ensuring faithful organelle inheritance during binary fission.

Ref: Campbell Biology 12th ed., Chapter 28: Kinetoplastids Single Mitochondrion; NCBI: Mitochondrial Biology of Trypanosomatids - Review

View Details