Chapter 7
Protists and Funji
Section I: Multiple Choice Questions
1. What distinguishes protists from bacteria in terms of cell structure?
Answer: (A) Protists have eukaryotic cells, while bacteria have prokaryotic cells
2. Which term best describes the diverse origins of protists?
Answer: (C) Polyphyletic
3. What is the primary locomotion mechanism employed by foraminifera, a
subgroup of protozoa?
Answer: (A) Cilia
4. Kelp is an example of:
Answer: (D) Brown algae
5. Which type of protist is responsible for causing Paralytic Shellfish Poisoning
(PSP) in humans?
Answer: (C) Dinoflagellates
6. How does green algae contribute to sustainable energy production?
Answer: (B) Green algae can be used to make biofuels
7. Which statement accurately describes the significance of algae in ecosystems?
Answer: (A) Algae are responsible for up to 90% of photosynthesis on our planet
8. What is a distinctive feature of diatoms?
Answer: (C) Their cell wall has two halves, resembling a box
9. Which structure is responsible for the production of sexually produced spores
in Ascomycota?
Answer: (B) Ascocarp
10. Which protist is responsible for causing a gastrointestinal disease known as
amoebic dysentery?
Answer: (C) Entamoeba histolytica
Section II: Short Questions
1. How do dinoflagellates differ from other algae in terms of their locomotion
methods?
Dinoflagellates possess two flagella located in perpendicular grooves, enabling a
unique spinning motion. One flagellum encircles the cell in a transverse groove,
while the other extends longitudinally.
This dual-flagellar arrangement distinguishes them from other algae, which may
rely on a single flagellum or lack flagella entirely. It allows dinoflagellates to
navigate aquatic environments effectively.
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2. List the key components found in the cell structures of protozoa.
Protozoa, being unicellular eukaryotic organisms, possess:
Nucleus: Contains genetic material.
Cytoplasm: Site of metabolic activities.
Plasma membrane: Regulates transport of substances.
Organelles: Includes mitochondria, vacuoles, and sometimes chloroplasts.
These components facilitate diverse functions like feeding, locomotion, and
reproduction.
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3. What distinguishes foraminifera and actinopods from other marine protozoa,
and where are their protective shells found?
Foraminifera and actinopods are unique marine protozoa that produce intricate
protective shells. Foraminifera have calcium carbonate shells, while actinopods
have silica-based shells.
These shells are typically found in marine sediments, contributing to geological
formations like limestone and radiolarian ooze.
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4. Where in the life cycle of plasmodial slime molds are sporangia typically
produced, and what is their role?
Sporangia are produced during the reproductive phase of plasmodial slime molds.
They form when environmental conditions become unfavorable.
Sporangia release spores that germinate into new cells under suitable conditions,
ensuring the survival and dispersal of the species.
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5. What sets brown algae apart from other multicellular algae, and where are
kelps commonly found?
Brown algae differ from other algae due to their brownish color, derived from
the pigment fucoxanthin. They are the largest and most complex algae, forming
structures like holdfasts, stipes, and blades.
Kelps, a subgroup of brown algae, are commonly found in cold, nutrient-rich marine
waters, forming underwater forests that support diverse ecosystems.
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6. How do euglenoids differ from other freshwater organisms in terms of their
nutritional strategies?
Euglenoids exhibit a mixotrophic mode of nutrition. They are autotrophic under
sunlight, using chloroplasts for photosynthesis, and switch to heterotrophy in the
absence of light by ingesting organic matter.
This dual capability allows them to adapt to varying environmental conditions,
distinguishing them from other freshwater organisms.
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7. What characterizes the life cycle of oomycotes, and where are swimming
zoospores typically generated?
The life cycle of oomycotes includes both sexual and asexual phases. In the
asexual phase, swimming zoospores are produced in sporangia. These flagellated
zoospores disperse and colonize new environments.
Their ability to reproduce in water-rich environments makes them well-suited to
aquatic and moist terrestrial habitats.
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8. How do choanoflagellates stand out from other flagellate organisms, and what
is their structural resemblance to?
Choanoflagellates are distinguished by a collar of microvilli surrounding a single
flagellum. This structure aids in capturing food particles from water.
They resemble the choanocytes of sponges, indicating an evolutionary link
between unicellular and multicellular organisms.
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9. Where in the life cycle of red algae are holdfasts found, and how do they
anchor these multicellular organisms?
Holdfasts are found at the base of red algae and serve as anchoring structures.
They attach the algae to rocks or other substrates in marine environments.
By providing stability, holdfasts enable red algae to withstand strong currents
and waves, ensuring survival in their habitats.
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10. List four different types of locomotion methods used by protists and give an
example of a protist that employs each method.
1. Flagellar movement: Euglena
2. Ciliary movement: Paramecium
3. Amoeboid movement: Amoeba
4. Gliding movement: Plasmodium
These methods demonstrate the diversity of protists in adapting to their
environments.
11. List three examples of parasitic protozoa that infect humans.
Three examples of parasitic protozoa are:
1. Plasmodium - Causes malaria by infecting red blood cells.
2. Entamoeba histolytica - Causes amoebic dysentery, leading to diarrhea and
abdominal pain.
3. Trypanosoma - Causes sleeping sickness by invading the bloodstream and
nervous system.
These parasites are transmitted through vectors, contaminated water, or food.
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12. What are primary modes of obtaining nutrients in fungi?
Fungi obtain nutrients primarily through:
1. Saprophytic nutrition: Decomposing dead organic matter.
2. Parasitic nutrition: Extracting nutrients from living hosts, often causing
diseases.
3. Mutualistic relationships: Benefiting both the fungus and its host, e.g.,
mycorrhizae with plant roots.
Fungi secrete enzymes to break down complex substances into simpler ones for
absorption.
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13. Where can fungi be found in various ecosystems, and what are their diverse
habitats?
Fungi are found in diverse ecosystems, including soil, decaying organic matter,
water, and as symbionts on plants and animals.
Their habitats range from forests, where they decompose dead plant material,
to human-made environments like bread or leather, where molds can grow. Fungi
also thrive in extreme conditions, such as acidic or salty environments.
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14. Why are fungi considered heterotrophic?
Fungi are heterotrophic because they cannot synthesize their food like
autotrophs. Instead, they rely on external organic matter for energy and
nutrients.
They absorb nutrients after breaking down complex organic substances using
extracellular enzymes, which distinguishes them from photosynthetic organisms.
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15. Name the four major groups of fungi based on their methods of reproduction.
The four major groups of fungi are:
1. Zygomycota: Form zygospores, e.g., Rhizopus.
2. Ascomycota: Produce ascospores in asci, e.g., Saccharomyces.
3. Basidiomycota: Form basidiospores on basidia, e.g., mushrooms.
4. Chytridiomycota: Produce flagellated spores, e.g., Batrachochytrium.
These groups highlight the diversity in fungal reproductive strategies.
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16. Differentiate between endomycorrhiza and ectomycorrhiza based on their
interactions with plant roots.
Endomycorrhiza: Fungal hyphae penetrate plant root cells, forming structures like
arbuscules, e.g., Glomeromycota.
Ectomycorrhiza: Fungal hyphae surround root cells but do not penetrate, forming
a sheath around the roots, e.g., Basidiomycota.
Both types enhance nutrient and water uptake for plants.
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17. What makes imperfect fungi unique, and why are they sometimes referred to
as "imperfect"?
Imperfect fungi, classified under Deuteromycota, are unique because their sexual
reproduction has not been observed.
They are called "imperfect" due to the absence of a known sexual cycle. Many of
these fungi are economically significant, producing antibiotics (e.g., Penicillium) or
causing diseases.
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18. What is "zygospore," and how is it formed?
A zygospore is a thick-walled, dormant spore formed during the sexual
reproduction of fungi, particularly Zygomycota.
It is produced when two compatible hyphae fuse, forming a zygote that develops
into a zygospore. This structure ensures the survival of the fungus under
unfavorable conditions.
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19. What is "histoplasmosis"?
Histoplasmosis is a respiratory disease caused by the fungus Histoplasma
capsulatum. It is transmitted through inhalation of spores from soil contaminated
with bird or bat droppings.
Symptoms include fever, cough, and fatigue. It is common in regions with high
humidity and can be severe in immunocompromised individuals.
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20. If a new deadly fungicide is made by scientists that destroys all existing
fungi, what would be the impact?
The destruction of all fungi would have devastating effects on ecosystems and
human life. Nutrient cycling would halt as fungi decompose organic matter, leading
to the accumulation of waste.
Additionally, mutualistic relationships, such as mycorrhizae aiding plant growth,
would collapse, affecting agriculture. Industries relying on fungi for antibiotics,
food production, and biotechnology would face severe setbacks.
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21. Write two salient features of:
(a) Coenocytic hyphae
Multinucleate hyphae lacking cross walls or septa.
Found in Zygomycota, enabling rapid growth.
(b) Conidia
Asexual spores formed at the tips of hyphae.
Dispersed for reproduction in Ascomycota.
(c) Ascocarp
Fruiting body of Ascomycota fungi.
Contains asci, where sexual spores develop.
(d) Sporangia
Structures producing asexual spores in Zygomycota.
Enclosed and dispersed under favorable conditions.
(e) Basidium
Club-shaped structure in Basidiomycota.
Produces basidiospores during sexual reproduction.
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22. Do the terms "dikaryotic" and "diploid" have the same meaning?
No, they differ:
Dikaryotic: Refers to cells with two genetically distinct nuclei within a shared
cytoplasm, seen in fungi like Basidiomycota.
Diploid: Refers to cells with a single nucleus containing two sets of chromosomes,
typical in most eukaryotic organisms.
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23. How do fungi store carbohydrates?
Fungi store carbohydrates in the form of glycogen, similar to animals. Glycogen
serves as an energy reserve that can be mobilized when required.
This characteristic distinguishes them from plants, which store carbohydrates
as starch.
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24. Name the four major groups of fungi based on their methods of reproduction.
This question overlaps with Q15 and can be answered as follows:
1. Zygomycota: Produce zygospores.
2. Ascomycota: Form ascospores.
3. Basidiomycota: Develop basidiospores.
4. Chytridiomycota: Have flagellated spores.
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25. What are lichens, and why are they important?
Lichens are mutualistic associations between fungi (usually Ascomycota) and
photosynthetic organisms like algae or Cyanobacteria.
They are important because they:
Act as bioindicators of air quality.
Initiate soil formation in barren areas.
Serve as food for animals in extreme habitats.
Section III: Extensive Answer Questions
1. What are the important features of protists?
Protists are a diverse group of eukaryotic organisms that exhibit both plant-like
and animal-like characteristics. One of their key features is cellular complexity;
they possess a true nucleus and membrane-bound organelles like mitochondria
and, in some cases, chloroplasts.
Protists can be autotrophic, heterotrophic, or mixotrophic, depending on their
mode of nutrition. For example, algae perform photosynthesis, while protozoa
ingest food. Their locomotion is facilitated by flagella, cilia, or pseudopodia,
allowing them to adapt to aquatic and moist terrestrial environments.
Another remarkable feature is their reproduction, which includes both sexual and
asexual phases. Protists play critical roles in ecosystems, serving as primary
producers (e.g., algae) and decomposers or as parasites causing diseases like
malaria and dysentery.
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2. Justify the need for establishing a separate kingdom Protista.
The kingdom Protista was established to classify eukaryotic organisms that do
not fit into the kingdoms Plantae, Animalia, or Fungi. These organisms are diverse
in structure, mode of nutrition, and reproduction, which makes grouping them into
other kingdoms impractical.
Unlike plants, protists like algae lack true roots, stems, and leaves. Unlike animals,
protozoa are unicellular. Some protists, like slime molds, resemble fungi but
differ in cellular organization and reproduction.
The separate kingdom highlights the evolutionary significance of protists, as they
represent the ancestral forms of plants, animals, and fungi, serving as a bridge
between prokaryotes and higher eukaryotes.
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3. Discuss general characteristics of algae.
Algae are simple, photosynthetic organisms found in aquatic and moist
environments. They range from microscopic unicellular forms, like
Chlamydomonas, to large multicellular forms, like kelp.
Algae contain chlorophyll and other pigments like carotenoids and phycobilins,
which aid in capturing light energy. They lack vascular tissues, roots, and stems,
differentiating them from plants. Reproduction occurs sexually and asexually,
with flagellated spores or gametes in many species.
Ecologically, algae are primary producers, contributing significantly to oxygen
production and forming the base of aquatic food chains. Economically, they are
used in food, biofuels, and pharmaceuticals.
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4. Describe the structure and life cycle of a slime mold.
Slime molds are unique protists with characteristics of both fungi and amoebas.
Structurally, they exist as plasmodial or cellular forms. Plasmodial slime molds
are multinucleated masses of cytoplasm, while cellular slime molds are composed
of individual cells.
Their life cycle alternates between an active feeding stage and a reproductive
stage. In the feeding stage, they engulf organic matter and bacteria. Under
adverse conditions, they form sporangia that produce spores. Spores germinate
into new cells under favorable conditions.
Slime molds are essential decomposers, recycling nutrients in ecosystems.
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5. Write distinguishing features of oomycotes that set them apart from fungi.
Oomycotes, or water molds, differ from fungi in several ways:
Cell walls: Oomycotes have cell walls made of cellulose, while fungi have chitin.
Reproduction: Oomycotes produce flagellated zoospores, a feature absent in
fungi.
Nutritional mode: Oomycotes are predominantly aquatic and saprophytic or
parasitic, while fungi inhabit diverse terrestrial and aquatic environments.
These distinctions place oomycotes in the kingdom Protista rather than Fungi.
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6. Discuss the important features of mushrooms in detail.
Mushrooms are the fruiting bodies of fungi, primarily belonging to Basidiomycota.
Structurally, they consist of a cap, gills, and a stalk. The gills house basidia, where
sexual spores (basidiospores) are produced.
Mushrooms are heterotrophic, relying on organic matter for nutrients. They play
ecological roles as decomposers, breaking down dead organic material, and as
mutualists in mycorrhizal associations, enhancing plant nutrient uptake.
Mushrooms are economically significant, serving as food, sources of medicinal
compounds, and bio-remediators in environmental cleanup.
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7. How do fungi obtain nutrients, and what role do enzymes play in their nutrition?
Fungi obtain nutrients through absorption. They secrete extracellular enzymes
that break down complex organic substances into simpler molecules, such as
sugars and amino acids, which are absorbed through the fungal cell wall and
membrane.
These enzymes include cellulases, ligninases, and proteases, allowing fungi to
decompose plant material, animal remains, and other organic matter. This
saprophytic mode of nutrition makes fungi essential decomposers in ecosystems.
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8. Discuss the key differences between Zygomycota and Basidiomycota fungi in
terms of their reproductive strategies and ecological roles.
Zygomycota reproduce sexually by forming zygospores and asexually by producing
sporangiospores. They are saprophytic or parasitic, decomposing organic matter
in soil and food.
Basidiomycota reproduce sexually through basidiospores formed on basidia. Their
fruiting bodies, like mushrooms, play significant ecological roles as decomposers
and symbionts in mycorrhizal associations.
These differences highlight their varied evolutionary adaptations and ecological
niches.
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9. Give an account of beneficial and harmful fungi.
Beneficial fungi include:
Mycorrhizal fungi: Enhance plant nutrient uptake.
Penicillium: Produces antibiotics like penicillin.
Saccharomyces: Used in baking and brewing.
Harmful fungi include:
Aspergillus: Causes respiratory infections and food spoilage.
Candida: Causes opportunistic infections in humans.
Puccinia: Causes rust diseases in crops.
Fungi impact human life positively and negatively, emphasizing their ecological and
economic significance.
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10. Explain Ascomycota (Sac Fungi) in detail.
Ascomycota, or sac fungi, is the largest fungal phylum. They produce sexual
spores (ascospores) within sac-like structures called asci, often housed in fruiting
bodies called ascocarps.
They exhibit diverse forms, including yeasts, molds, and morels. Ascomycota are
saprophytic, decomposing organic matter, and some are parasitic or symbiotic.
Economically, Ascomycota include species used in food production
(Saccharomyces cerevisiae), antibiotics (Penicillium), and research (e.g.,
Neurospora). Their ecological role as decomposers and mutualists underscores
their importance.
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