Eukaryotic Cells Overview
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Questions and Answers

What is the primary difference between eukaryotic flagella and bacterial flagella?

  • Eukaryotic flagella are covered by an extension of the cell membrane, while bacterial flagella are not (correct)
  • Eukaryotic flagella are typically shorter than bacterial flagella
  • Bacterial flagella are about ten times thicker than eukaryotic flagella
  • Eukaryotic flagella are structurally simpler than bacterial flagella

    • In what way are eukaryotic cilia similar to eukaryotic flagella?

  • They both are covered in a sheath that extends from the cell membrane
  • They are both found only in a single group of protozoa
  • They both are about ten times thicker than bacterial flagella
  • They both possess a 9 + 2 arrangement of microtubules (correct)

    • How did complex multicellular organisms evolve from primitive eukaryotes?

  • Multicellular organisms developed as a result of mutations that made single-celled organisms larger
  • Primitive eukaryotes developed the ability to survive independently and form multicellular organisms
  • Colonies of primitive eukaryotes formed, with cells specializing in specific functions (correct)
  • Primitive eukaryotes gradually developed internal specialized structures over time

    • What is meant by the phrase '9 + 2 arrangement' in the context of eukaryotic flagella?

    <p>Nine pairs of microtubules surrounding two central microtubules (C)</p> Signup and view all the answers

    What type of structure is responsible for the movement of both cilia and flagella?

    <p>Microtubules (A)</p> Signup and view all the answers

    What is the primary function of the cell wall in fungi?

    <p>To provide structural support and shape (C)</p> Signup and view all the answers

    What is the function of the glycocalyx in a eukaryotic cell?

    <p>To protect the cell, aid in adherence, and signal reception (B)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the cell membrane in eukaryotic cells?

    <p>Contains chitin or cellulose for structural support (A)</p> Signup and view all the answers

    What is the function of the nucleolus?

    <p>To synthesize ribosomal RNA (D)</p> Signup and view all the answers

    Which of the following correctly describes the role of the endoplasmic reticulum?

    <p>Storage and processing of lipids (C)</p> Signup and view all the answers

    What is the main function of the Golgi apparatus?

    <p>Modification and packaging of proteins (A)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of mitochondria?

    <p>Contains a network of flattened sacs called cisternae (A)</p> Signup and view all the answers

    What is the primary function of chloroplasts?

    <p>Conversion of light energy into chemical energy (D)</p> Signup and view all the answers

    Which of the following statements describes the role of ribosomes in protein synthesis?

    <p>Ribosomes synthesize proteins based on instructions from mRNA (C)</p> Signup and view all the answers

    What is the function of the cytoskeleton?

    <p>To anchor organelles, move RNA and vesicles, and permit shape changes and movement (B)</p> Signup and view all the answers

    What are the two basic cell forms found in fungi?

    <p>Yeasts and hyphae (A)</p> Signup and view all the answers

    What is a primary reproductive mode of fungi?

    <p>Spore formation (C)</p> Signup and view all the answers

    What is the difference between community-acquired infections and hospital-associated infections caused by fungi?

    <p>Community-acquired infections are caused by environmental pathogens, while hospital-associated infections are caused by pathogens in clinical settings. (D)</p> Signup and view all the answers

    What is an opportunistic fungal infection?

    <p>An infection caused by a fungal species that normally does not cause disease. (D)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of filamentous fungi?

    <p>Soft, uniform texture (C)</p> Signup and view all the answers

    How do fungi contribute to agricultural impact?

    <p>They can cause disease in crops and domestic animals. (B)</p> Signup and view all the answers

    What is the function of vegetative hyphae in fungi?

    <p>Absorption of nutrients (D)</p> Signup and view all the answers

    What is the main limiting factor for protozoan growth?

    <p>Availability of moisture (D)</p> Signup and view all the answers

    What is the primary way fungi acquire nutrients?

    <p>Through absorption of organic matter (B)</p> Signup and view all the answers

    Why are fungi often found in nutritionally poor or adverse environments?

    <p>Because they can digest a wide range of organic substrates. (A)</p> Signup and view all the answers

    Which of the following protozoans does NOT form cysts?

    <p>Trichomonas vaginalis (A)</p> Signup and view all the answers

    What is the purpose of conjugation in ciliates?

    <p>Sexual reproduction (A)</p> Signup and view all the answers

    Which of the following organisms is NOT a helminth?

    <p>Amoeba (C)</p> Signup and view all the answers

    What is the name given to the host where a helminth larva develops?

    <p>Intermediate host (B)</p> Signup and view all the answers

    Which of the following helminths is hermaphroditic?

    <p>Cestodes (C)</p> Signup and view all the answers

    What is the name of the dormant, resting stage that some protozoans enter when conditions become unfavorable?

    <p>Cyst (C)</p> Signup and view all the answers

    Which of the following is a common method of transmission for protozoan infections?

    <p>Ingestion of contaminated food or water (B)</p> Signup and view all the answers

    What is the name of the common intestinal worm that causes enterobiasis?

    <p>Enterobius vermicularis (D)</p> Signup and view all the answers

    What is the primary method of reproduction for protozoans?

    <p>Asexual reproduction (B)</p> Signup and view all the answers

    Which of the following is a characteristic of flatworms?

    <p>Segmented body (D)</p> Signup and view all the answers

    What is the most developed organ in pathogenic helminths?

    <p>Reproductive tract (B)</p> Signup and view all the answers

    What is the name of the host where a helminth reaches adulthood and reproduces?

    <p>Definitive host (A)</p> Signup and view all the answers

    Flashcards

    Eukaryotic Cells

    Cells with a defined nucleus and organelles, often multicellular.

    Flagella

    Long, whip-like structures that aid in cell movement in eukaryotes.

    Cilia

    Short, hair-like structures that help cells move or push substances.

    9 + 2 Arrangement

    Structure of microtubules in flagella and cilia, with 9 pairs surrounding 2 central ones.

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    Cell Specialization

    Process where cells in a colony perform specific functions over time.

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    Glycocalyx

    An outer layer composed of polysaccharides that protects the cell and aids in adherence and signal reception.

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    Cell Wall

    A rigid structure that provides support and shape to fungi, differing chemically from bacterial walls.

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    Cell Membrane

    A phospholipid bilayer with embedded proteins, acting as a selectively permeable barrier.

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    Nucleus

    The prominent organelle in eukaryotic cells that houses genetic material and is enclosed by a nuclear envelope.

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    Nucleolus

    Region within the nucleus responsible for ribosomal RNA synthesis and ribosomal subunit assembly.

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    Endoplasmic Reticulum (ER)

    A network of membrane tunnels for transport; rough ER has ribosomes, smooth ER does not.

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    Golgi Apparatus

    Organelle that modifies proteins from the ER and dispatches them to their destinations.

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    Lysosomes

    Vesicles containing enzymes for digesting food particles and cellular debris.

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    Mitochondria

    Organelles that generate cellular energy (ATP) through aerobic respiration, containing their DNA.

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    Chloroplasts

    Organelles in plant cells that convert sunlight into chemical energy via photosynthesis.

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    Ribosomes

    Cell structures made of ribonucleoprotein responsible for protein synthesis.

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    Cytoskeleton

    A network of protein filaments that provides structural support and aids in cell movement and division.

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    Yeasts

    Single-cell fungi that reproduce asexually through budding and have a round to oval shape.

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    Fungal Nutrition

    Fungi are heterotrophs that obtain nutrients from organic substrates, acting as saprobes and parasites.

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    Opportunistic Infections

    Fungal infections that occur in individuals with weakened immune systems, often by low-virulence fungi.

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    Mycelium

    The woven mass of hyphae forming the body of a mold.

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    Septa

    Structures that divide hyphae, varying from complete walls to porous partitions.

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    Nonseptate hyphae

    Hyphae that consist of one continuous cell without partitions.

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    Vegetative hyphae

    Hyphae that make up the visible mass of fungal growth on surfaces.

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    Reproductive hyphae

    Hyphae that produce spores for fungal reproduction.

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    Sporangiospores

    Asexual spores formed within a sac called a sporangium.

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    Conidia

    Free spores not enclosed by a protective sac, formed asexually.

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    Trophozoite

    The active, feeding stage of protozoa requiring moisture and food.

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    Cyst

    A dormant, resistant stage of protozoa for survival during unfavorable conditions.

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    Heterotrophic

    Organisms that require complex organic substances for food.

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    Conjugation in ciliates

    A form of sexual reproduction where two cells fuse and exchange genetic material.

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    Flatworms (Platyhelminthes)

    Thin, often segmented worms that include tapeworms and flukes.

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    Nematodes

    Roundworms from the phylum Aschelminthes, elongated and unsegmented.

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    Life cycle of helminths

    Includes stages of fertilized egg, larva, and adult, with reproduction in host.

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    Enterobius vermicularis

    Common pinworm causing enterobiasis, usually found in the large intestine.

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    Study Notes

    Overview of Eukaryotic Cells

    • First primitive eukaryotes were single-celled and independent
    • Over time, cells aggregated to form colonies
    • Cells within colonies specialized for specific functions
    • Complex multicellular organisms evolved as individual cells lost the ability to survive independently

    External Cell Structures

    • Flagella: Similar to cilia but longer. About 10 times thicker than bacterial flagella, more complex in structure, have a membrane extension containing regularly spaced microtubules.
    • Cilia: Similar to flagella in structure but smaller and more numerous, found in certain animal and protozoa cells.

    Microtubules in Flagella

    • Regularly spaced microtubules extend along the entire length of the flagellum
    • Nine pairs of microtubules surround a single pair
    • Arrangement is known as 9 + 2

    The Glycocalyx

    • An outermost layer that directly contacts the environment
    • Composed of polysaccharides
    • Appears as a network of fibers

    Boundary Structures: Cell Walls

    • Protozoa and helminths lack cell walls.
    • Fungal cell walls are rigid, providing structure and shape.
    • Different chemical composition from bacterial and archaeal cell walls
    • Thick inner layer (chitin or cellulose) and a thin outer layer (mixed glycans)

    Boundary Structures: Cell Membranes

    • Composed of a phospholipid bilayer with embedded protein molecules
    • Contains sterols that provide stability
    • Important in cells without cell walls
    • Has a similar function to bacteria and archaea membranes (selectively permeable barriers)

    Internal Structures: The Nucleus

    • Prominent eukaryotic organelle
    • Separated from the cytoplasm by a nuclear envelope composed of 2 membranes
    • Contains pores allowing macromolecule movement between cytoplasm and nucleus
    • Nucleolus: site of ribosomal RNA synthesis
    • Chromatin: made of linear DNA and histone proteins

    Internal Structures: Endoplasmic Reticulum

    • Network of membrane tunnels involved in transport and storage
    • Rough ER has ribosomes attached for protein synthesis
    • Smooth ER involved in lipid synthesis and nutrient processing

    Internal Structures: Golgi Apparatus

    • Involved in protein modification and directing proteins to their destinations
    • Consists of flattened sacs (cisternae)
    • Closely associated with ER
    • Modifies and packages proteins using carbohydrates and lipids

    Vesicles

    • Lysosomes: Contain enzymes for intracellular digestion
    • Bud off from the Golgi apparatus

    Mitochondria

    • Generate energy for the cell
    • Have an outer and inner membrane with cristae forming folds
    • Contain enzymes and electron carriers for aerobic respiration
    • Contain circular DNA/ 70S ribosomes; hypothesized to evolve from bacteria cells

    Chloroplasts

    • Found in algae and plants
    • Convert sunlight into chemical energy via photosynthesis
    • Contain a unique set of pigments

    Ribosomes

    • Scattered in cytoplasm or attached to Rough ER
    • Found inside mitochondria and chloroplasts
    • Large and small subunits of ribonucleoprotein
    • Involved in protein synthesis

    The Cytoskeleton

    • Three types of elements: Actin filaments, Intermediate filaments, Microtubules
    • Provide support, movement, and anchoring for organelles.

    Fungal Cells

    • Two main forms: Yeasts (round to oval) and Hyphae (long threadlike)
    • Yeast cells reproduce by budding
    • Fungi in nature are either heterotrophic (absorb from organic matter) or saprobes/parasites (absorbing from dead organisms or living organisms)
    • Cell walls made of chitin or cellulose

    Fungi and Human Disease

    • Approximately 300 fungal species can cause human disease.
    • Common types include community-acquired, hospital-associated, and opportunistic infections.

    Protozoa

    • Single-celled eukaryotic organisms, found in water and soil environments.
    • Most are harmless, some are pathogens
    • Some have specialized structures (oral grooves) for feeding.
    • Reproduce asexually or sexually, some have life cycles with both trophozoite (feeding) and cyst phases (dormant).
    • Important cause of disease and can be transmitted in water and food.

    Helminths

    • Multicellular animals that reproduce sexually
    • Include tapeworms, flukes, and roundworms
    • Some are harmless, others lead to disease
    • Often have complex life cycles requiring multiple hosts

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    Eukaryotic Cell Overview PDF

    Description

    This quiz covers the fundamental aspects of eukaryotic cells, including their evolution from primitive single-celled organisms to complex multicellular forms. Key topics include the structure and function of flagella and cilia, the arrangement of microtubules, and the composition of the glycocalyx. Test your knowledge on these essential cellular concepts!

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