أسئلة ريتين الثالثة بارا دمياط (قبل التعديل)

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Questions and Answers

What is the main function of pseudopodia in protozoa?

Pseudopodia serve as organs for locomotion and for engulfing food.

How do contractile vacuoles help protozoa in regulating osmotic pressure?

Contractile vacuoles remove excess water from the cell, thereby maintaining osmotic balance.

What is the significance of the nucleus in protozoans?

The nucleus regulates various cellular functions and is crucial for reproduction.

Describe the process of binary fission in protozoa.

<p>Binary fission involves the division of a single organism into two identical daughter organisms, either longitudinally or transversely.</p> Signup and view all the answers

What role do food vacuoles play in protozoan digestion?

<p>Food vacuoles store engulfed food particles and release digestive enzymes to assimilate the nutrients.</p> Signup and view all the answers

Explain how protozoa can reproduce sexually.

<p>Sexual reproduction in protozoa occurs through the fusion of a female macrogamete and a male microgamete.</p> Signup and view all the answers

What is the function of the cytopyge in protozoa?

<p>The cytopyge is a specialized opening through which undigested waste materials are expelled.</p> Signup and view all the answers

How does diffusion contribute to waste elimination in protozoans?

<p>Diffusion allows waste products to move across the cell membrane to areas of lower concentration, facilitating removal.</p> Signup and view all the answers

Explain the structure and function of the trilaminar unit membrane in protozoa.

<p>The trilaminar unit membrane surrounds the protozoan cell, providing structural integrity and regulating the exchange of substances.</p> Signup and view all the answers

What are the roles of the two layers of cytoplasm found in protozoa?

<p>The outer hyaline layer aids in locomotion and food engulfment, while the inner granular layer houses organelles like the nucleus and food vacuoles.</p> Signup and view all the answers

Differentiate between the processes of binary fission and multiple fission in protozoan reproduction.

<p>Binary fission involves a single cell dividing into two, while multiple fission involves multiple successive divisions of the nucleus followed by cytoplasmic division to produce several offspring.</p> Signup and view all the answers

Describe the significance of the karyosome in the nucleus of protozoa.

<p>The karyosome, or nucleolus, is essential for ribosome production and plays a role in protein synthesis within the cell.</p> Signup and view all the answers

How do protozoa utilize pseudopodia in their feeding process?

<p>Protozoa form pseudopodia to engulf liquid and solid food by surrounding it, creating food vacuoles for digestion.</p> Signup and view all the answers

In what way does the contractile vacuole respond to changes in osmotic pressure in protozoa?

<p>The contractile vacuole actively expels excess water to maintain osmotic balance and prevent cell lysis.</p> Signup and view all the answers

Identify the method of nutrient uptake in protozoa and explain the process briefly.

<p>Protozoa absorb nutrients through their cell membrane or ingest solid particles via structures like the cytostome and pseudopodia, forming food vacuoles.</p> Signup and view all the answers

Explain how sexual reproduction occurs in protozoa, particularly in Plasmodium.

<p>In sexual reproduction, Plasmodium fusesthe macrogamete (female) with the microgamete (male) to form zygotes, leading to sporozoite development.</p> Signup and view all the answers

Flashcards

What are Protozoa?

Single-celled eukaryotic microorganisms belonging to Kingdom Protista.

What is the Ectoplasm?

The outermost layer of a Protozoan cell, responsible for locomotion, engulfing food, respiration, waste discharge, and protecting the cell.

What is the Endoplasm?

The inner layer of a Protozoan cell containing structures like food vacuoles, Golgi bodies, endoplasmic reticulum, and contractile vacuoles.

What is the Nucleus in a Protozoan?

The most important structure within a Protozoan cell, regulating various functions and responsible for reproduction.

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What is Simple Binary Fission?

A method of Protozoan reproduction where the cell splits into two identical daughters.

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What is Multiple Fission (Schizogony)?

A method of Protozoan reproduction where the nucleus divides multiple times, followed by cytoplasm division, resulting in numerous smaller daughter cells.

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How do Protozoa ingest solid food?

The ingestion of solid food through pseudopodia or cytostome, which then becomes enclosed in food vacuoles.

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How do Protozoa obtain oxygen?

Protozoa can obtain oxygen directly from the environment or utilize oxygen released during metabolic processes.

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Study Notes

Protozoology Lecture 3

  • Protozoa are unicellular eukaryotic organisms found singly or in colonies.
  • They belong to the Kingdom Protista.
  • A single protozoan cell carries out all the necessary functions.

Morphology of Protozoa

  • Trilaminar Unit Membrane: Surrounds the protozoan cell.
  • Cytoplasm:
    • Ectoplasm: Outer, hyaline layer, involved in locomotion, engulfing food (via pseudopodia), respiration, waste removal, and protection.
    • Endoplasm: Inner, granular layer, contains various organelles such as:
      • Food vacuoles
      • Golgi bodies
      • Contractile vacuoles (regulate osmotic pressure)
      • Endoplasmic reticulum

Nucleus

  • The nucleus is the most vital organelle, regulating various functions and reproduction.
  • Structure:
    • Nuclear membrane
    • Nuclear sap (nucleoplasm)
    • Chromatin granules
    • Karyosome (nucleolus): DNA-containing body, positioned centrally or peripherally within the nucleus.

Biology of Protozoa

  • Movement: Achieved through pseudopodia, cilia, and flagella (Some do not move).
  • Respiration: Direct oxygen intake or using oxygen released from metabolic processes.
  • Nutrition:
    • Liquid food absorption.
    • Ingesting solid food material using ectoplasm, creating food vacuoles.
    • Digestive enzymes process the food, and undigested material leaves the cell through a cytopyge.
  • Excretion: Via osmotic pressure, contractile vacuoles, diffusion, or cytopyge.

Reproduction

  • Asexual reproduction:
    • Simple Binary Fission: Longitudinal or transverse division into two organisms.
    • Multiple Fission (Schizogony): Nucleus divides multiple times, followed by the cytoplasm splitting to create numerous merozoites or sporozoites within a schizont. Examples of this include Plasmodium (malaria).
  • Sexual Reproduction: Fusion of two cells (one female macrogamete and one male microgamete)

Classification of Protozoa

  • Protozoa are classified based on their mode of movement: flagella, pseudopodia, cilia, and passive movement.
  • Examples are given in the table relating to specific types of protozoa and diseases they can cause.

Life Cycle of Protozoa

  • Simple Life Cycle: Protozoa live and reproduce within one host (intestinal and luminal).
  • Complex Life Cycle: Protozoa pass between alternating hosts (often vertebrate and invertebrate), displaying an alternation of generations.

### Questions

  • Which kingdom do protozoa belong to?
  • Protista
  • Which protozoa use pseudopodia for movement?
  • Entamoeba

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