Protists

Here’s a set of flashcards based on the provided information about protists, their characteristics, locomotion, nutrition, sensation, and other key features. These cards are designed to help you study and understand the diversity and unique adaptations of protists.

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### General Characteristics of Protists

Q1: What is the size range of most protists?

A1: Most protists are microscopic, ranging from about 5 to 500µm.

Q2: Why is the term "protist" no longer taxonomically correct?

A2: Protists are not a monophyletic group; they are being subdivided into multiple kingdoms based on evolutionary lineages.

Q3: What are the two major "supergroups" of protists?

A3: Archaeplastida (plant-like protists) and Unikonta (animal- or fungus-like protists).

Q4: What environments do protists inhabit?

A4: Marine, freshwater, terrestrial, and symbiotic (including pathogenic) environments.

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### Locomotion in Protists

Q5: What are the three main types of locomotion in protists?

A5: Flagella, cilia, and pseudopodia.

Q6: How do flagella move?

A6: Flagella move with a whip-like motion, either pushing or pulling the cell forward.

Q7: How do cilia move?

A7: Cilia beat in a coordinated, breaststroke-like motion, propelling the cell forward.

Q8: What are cirri in ciliates?

A8: Cirri are fused cilia that act like little legs, allowing the cell to "walk" along surfaces.

Q9: How do pseudopodia work?

A9: Pseudopodia extend through the flow of cytoplasm (plasmasol) into a bulge, driven by microfilaments made of actin.

Q10: What is the difference between plasmasol and plasmagel?

A10: Plasmasol is the liquid cytoplasm in the cell's core, while plasmagel is the thicker, gel-like cytoplasm beneath the cell membrane.

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### Water Balance (Osmotic Regulation)

Q11: How do protists regulate water balance?

A11: Using contractile vacuoles, which collect and expel excess water.

Q12: What is the role of microtubules in contractile vacuoles?

A12: Microtubules contract around the vacuole, forcing water out through a pore on the cell surface.

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### Nutrition in Protists

Q13: What are the two main nutritional modes in protists?

A13: Autotrophic (photosynthesis or chemosynthesis) and heterotrophic (ingesting food).

Q14: What is phagocytosis?

A14: The process of engulfing solid food particles using extensions of the cell membrane.

Q15: What is a cytostome?

A15: A "cell mouth" where food is ingested in some protists.

Q16: How do some protists survive in harsh environments?

A16: By forming protective cysts and becoming dormant until conditions improve.

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### Sensation in Protists

Q17: How do protists sense their environment?

A17: Using cilia, flagella, and chemical receptors for touch and chemotaxis.

Q18: What is chemotaxis?

A18: Movement toward or away from chemicals in the environment.

Q19: How do predatory protists like Coleps hunt?

A19: They use sharp, tooth-like projections to bore into prey and consume it.

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### Sensing Light

Q20: How do photosynthetic protists sense light?

A20: Using a light-sensitive flagellum and a light-blocking eyespot (stigma).

Q21: What is the function of the eyespot (stigma)?

A21: It helps the cell determine the direction of light by blocking and unblocking light to the flagellum.

Q22: What is phototaxis?

A22: Movement toward or away from light, which is advantageous for photosynthetic protists.

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### Examples of Protists

Q23: What are foraminiferans, and how large can they be?

A23: Foraminiferans are protists that can be visible to the naked eye, sometimes larger than small multicellular animals.

Q24: What are ciliates, and how do they move?

A24: Ciliates are protists that move using cilia and often have complex feeding structures like a cytostome.

Q25: What are amoebas, and how do they move?

A25: Amoebas are protists that move using pseudopodia and engulf food through phagocytosis.

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### Unique Adaptations

Q26: What is the role of microfilaments in amoeboid movement?

A26: Microfilaments, made of actin, contract to push cytoplasm into pseudopodia, enabling movement.

Q27: How do protists like Coleps protect themselves?

A27: Coleps have calcium carbonate plates that act as armor and sharp projections for feeding.

Q28: What is the advantage of dormancy in protists?

A28: It allows protists to survive in harsh or dry environments by forming