Prokaryotic vs. Eukaryotic Cells: A Comparison
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Questions and Answers

Which of the following best describes the primary function of the nucleolus within a cell?

  • Lipid synthesis and steroid hormone production
  • Detoxification of harmful substances and waste removal
  • Synthesis of ribosomal RNA (rRNA) (correct)
  • Modification and packaging of proteins for secretion

What is the main role of ribosomes in both prokaryotic and eukaryotic cells?

  • Lipid metabolism
  • DNA replication
  • Protein synthesis (correct)
  • Energy production

Which cellular structure is responsible for the post-translational modification of proteins and the formation of vesicles?

  • Mitochondrion
  • Lysosome
  • Endoplasmic reticulum
  • Golgi apparatus (correct)

Which function is primarily associated with lysosomes?

<p>Intracellular digestion (D)</p> Signup and view all the answers

What process occurs primarily within the mitochondria?

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

What is the primary function of microvilli found on the surface of some animal cells?

<p>To increase the surface area for absorption (A)</p> Signup and view all the answers

Which of the following is a key function of the cytoskeleton in eukaryotic cells?

<p>Providing structural support and facilitating movement (A)</p> Signup and view all the answers

What role do actin filaments play in cell motility and structure?

<p>Enabling amoeboid movement and muscle contraction (B)</p> Signup and view all the answers

What is a primary difference between the intermediate filaments and other cytoskeletal elements?

<p>Intermediate filaments provide high tensile strength and cell stability. (C)</p> Signup and view all the answers

Which factor directly influences the polymerization and depolymerization of microtubules?

<p>Levels of calcium ions ($Ca^{2+}$) (C)</p> Signup and view all the answers

What is the major function of microtubules in cellular transport?

<p>To act as tracks for motor proteins carrying vesicles (C)</p> Signup and view all the answers

What is the role of centrioles in animal cells?

<p>Organizing the mitotic spindle (D)</p> Signup and view all the answers

Which type of microtubule is responsible for positioning the centrosomes during cell division?

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

What distinguishes cilia and flagella in eukaryotic cells?

<p>Cilia beat in a wave-like motion, while flagella rotate. (B)</p> Signup and view all the answers

What structural component are cilia and flagella based on?

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

What is the function of the extracellular matrix (ECM) in animal cells?

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

Which of the following describes the key components of the extracellular matrix (ECM)?

<p>Proteoglycans, glycoproteins, and collagen (A)</p> Signup and view all the answers

What is the primary mode of nutrition used by plants (photo-autotrophs) to obtain energy?

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

Which of the following describes how animals, as chemo-heterotrophs, obtain energy?

<p>By consuming pre-existing organic molecules. (B)</p> Signup and view all the answers

What is the primary storage form of glucose in plants?

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

What's the primary storage form of glucose in animal cells?

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

Which type of movement is demonstrated by white blood cells migrating towards an infection site?

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

What is the name applied to the cell type which displays negative phototaxis?

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

Which of these cellular structures is exclusive to animal cells?

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

Which of the following structures provides the cell shape and external protection to plant cells?

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

Through what process does the movement of water and nutrients occur between plant cells, which does not occur in animal cells?

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

Which type of cellular junction provides a tight seal preventing leakage between cells?

<p>Tight junctions (B)</p> Signup and view all the answers

What type of cell junction facilitates direct communication between adjacent cells?

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

What cell components are included in the endomembrane system?

<p>The endoplasmic reticulum and Golgi apparatus (A)</p> Signup and view all the answers

What are the roles of the rough and smooth endoplasmic reticula (ER)?

<p>The rough ER synthesizes proteins, while the smooth ER synthesizes lipids. (C)</p> Signup and view all the answers

What is the first event in the endosymbiotic theory?

<p>The early eukaryote consumed aerobic bacteria. (C)</p> Signup and view all the answers

What does genome refer to?

<p>The complete set of DNA (A)</p> Signup and view all the answers

Which is generally larger: prokaryotic or eukaryotic cells?

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

Which has a nucleus: prokaryotic or eukaryotic cells?

<p>Eukaryotic cells (D)</p> Signup and view all the answers

Which has circular chromosomes: prokaryotic or eukaryotic cells?

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

Which has a more complex number of internal membranes: prokaryotic or eukaryotic cells?

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

Which of the following has cell organelles: prokaryotic or eukaryotic cells?

<p>Eukaryotic cells (B)</p> Signup and view all the answers

What is the word used to describe that prokaryotic cells have only one set of chromosomes?

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

According to thermodynamics, how do cells interact with energy?

<p>Cells take in usable energy and release unusable energy. (A)</p> Signup and view all the answers

Why is 100% recycling of materials not economically feasible for an individual organism?

<p>There is no selective pressure favoring 100% recycling, making the process uneconomical. (D)</p> Signup and view all the answers

Which processes facilitate the movement of substances across biomembranes?

<p>Diffusion, active transport, endocytosis, and exocytosis. (B)</p> Signup and view all the answers

How does secondary active transport primarily function?

<p>It uses the electrochemical gradient created by primary active transport to move other molecules against their concentration gradient. (C)</p> Signup and view all the answers

How do symporters contribute to secondary active transport?

<p>By transporting two different molecules in the same direction across the cell membrane. (A)</p> Signup and view all the answers

What is the primary role of the proton gradient in secondary active transport?

<p>To allow symporters to bring protons into the cytoplasm together with other molecules against their concentration gradients. (B)</p> Signup and view all the answers

What distinguishes pinocytosis from phagocytosis?

<p>Pinocytosis involves the intake of liquids or dissolved small molecules, whereas phagocytosis involves the intake of large particles or cells. (C)</p> Signup and view all the answers

How does the process of exocytosis contribute to cellular interaction?

<p>It expels waste products and facilitates the secretion of proteins and other molecules. (A)</p> Signup and view all the answers

What role do cell-surface receptors play in cellular communication?

<p>They bind to signaling molecules and trigger intracellular responses. (C)</p> Signup and view all the answers

What role does the opening of an Acetylcholin receptor (AChR) have on a muscle cell?

<p>An increase of sodium ions in the cell, leading to muscle contraction. (D)</p> Signup and view all the answers

How does signal transduction modify a cellular response?

<p>It converts extracellular signals into intracellular signals, leading to a cellular response. (B)</p> Signup and view all the answers

What is the primary function of secondary messengers in signal transduction?

<p>To amplify and relay signals within the cell. (D)</p> Signup and view all the answers

In the context of cell signaling, what distinguishes a ligand from a second messenger?

<p>Ligands bind to receptors, initiating a signaling pathway, whereas second messengers relay and amplify the signal inside the cell. (A)</p> Signup and view all the answers

In cell communication, what distinguishes signal transduction from signalleitung?

<p>Signal transduction occurs within a single cell, while signalleitung occurs between cells. (D)</p> Signup and view all the answers

How do plants perceive external stimuli?

<p>Plants use photoreceptors in stomata to detect light. (B)</p> Signup and view all the answers

What makes a cell not considered a closed system?

<p>Cells interact with the environment. (C)</p> Signup and view all the answers

How do antiporters function in active transport?

<p>They transport two different substances in opposing directions across the cell membrane, using energy input. (A)</p> Signup and view all the answers

How do secondary messengers contribute to the process of signal transduction?

<p>They relay and amplify signals within the cell; signal transduction is always intracellular. (B)</p> Signup and view all the answers

What is the key difference between primary and secondary active transport?

<p>Primary active transport uses ATP to directly pump molecules across the membrane; secondary active transport uses an electrochemical gradient. (B)</p> Signup and view all the answers

What role does receptor activation play in signal transduction?

<p>It triggers a series of intracellular events that lead to a cellular response. (C)</p> Signup and view all the answers

Which process describes the uptake of large particles or cells by a cell, involving the engulfment of the material by the plasma membrane?

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

What is the primary advantage of using a proton gradient to drive secondary active transport compared to using ATP directly for every transported molecule?

<p>It is more evolutionarily efficient since proton pump drives diverse transport processes. (B)</p> Signup and view all the answers

Which type of receptor is activated by light?

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

What role does the binding of the hormone Insulin have in an organism?

<p>It activates a signal transduction pathway. (D)</p> Signup and view all the answers

What is the direct result of an activated G protein?

<p>Initiation of membrane potential changes. (D)</p> Signup and view all the answers

What could happen if signalleitung was disrupted between cells?

<p>The signals would be disrupted leading to dysfunction. (C)</p> Signup and view all the answers

In endocytosis, when a cell uptakes large, solid particles, which process is occurring?

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

Is a receptor an intracellular, membrane spanning, or extracellular protein?

<p>Receptors may be intracellular, membrane spanning, or extracellular proteins. (B)</p> Signup and view all the answers

In the context of cellular interaction, how is 'information' transmitted?

<p>Information is taken in, then given off by various organisms. (C)</p> Signup and view all the answers

Flashcards

Endosymbiotic Theory

Theory that proposes some eukaryotic organelles, like mitochondria and chloroplasts, originated as symbiotic prokaryotes

Prokaryotic Cell

Cell type that lacks a nucleus or other membrane-bound organelles.

Eukaryotic Cell

Cell type with a nucleus and other membrane-bound organelles.

Ribosomes

Small, prokaryotic cellular structures that synthesize protein

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Endoplasmic Reticulum (ER)

Membranous organelle in eukaryotic cells where many metabolic reactions occur

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Rough ER

ER with ribosomes attached, involved in protein synthesis

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Smooth ER

ER that lacks ribosomes and synthesizes lipids and steroid hormones

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Golgi apparatus

Organelle responsible for modifying, sorting, and packaging proteins and lipids

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Lysosome

A membrane-bound cell organelle that contains digestive enzymes

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Mitochondrion

Organelle where cellular respiration occurs and ATP is produced

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Microvilli

Small, finger-like projections of the cell membrane that increase surface area

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Cytoskeleton

Network of protein filaments that support the cell and enable movement

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Actin Filament

A filamentous structure made of actin proteins

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Intermediate Filament

Component responsible for cell shape, elasticity, and stability

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Microtubules

Hollow tubes made of tubulin proteins that help with cell division and transport

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Actin Polymerization

The process of building a polymer from individual actin molecules

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Centrioles

Short structures involved in cell division (animal cells).

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Ameboid movement

The ameboid movement using actin-myosin complexes

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Myosin

Specialized motor proteins that interact with actin filaments

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Cilia and Flagella

Hair-like structures primarily used for cell movement

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Basal Plate

Region where new cell wall is synthesized.

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Extracellular Matrix (ECM)

Complex mix of proteins and polysaccharides secreted by cells

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Photo-Autotroph

Cell gains energy from light via photosynthesis

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Chemo-Heterotrophie

Organisms that obtain energy by ingesting organic molecules

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Storage Polysaccharide

Carbohydrate for long term energy storage

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Taxis

Orientation or movement toward or away from a stimulus.

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Chemotaxis

Cell's movement toward chemical stimuli

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Phototaxis

Cell's movement toward light stimuli.

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Thigmotaxis

Cell's movement triggered by touch, physical contact

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Basic Concept of Interaction

The basic concept of biology focuses on the exchange of energy, materials, and information to maintain life processes.

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Cells and Thermodynamics

Cells are not closed systems; they constantly exchange energy with their surroundings.

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Energy Uptake

The process of taking in usable energy by a cell.

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Energy Release

The process of releasing unusable energy from a cell.

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Raw Material Uptake

The uptake of usable raw materials for cellular processes.

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Waste Release

The release of unusable materials (waste) from cellular processes.

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Diffusion

The movement of substances across cell membranes from high to low concentration.

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Active Transport

The movement of substances across cell membranes against the concentration gradient, requiring energy.

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Endocytosis

The cellular process of engulfing large molecules or particles by inward folding of the plasma membrane.

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Exocytosis

The cellular process of expelling large molecules or particles by fusion of vesicles with the plasma membrane.

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Uniporters

Membrane proteins that transport a single type of molecule across the cell membrane.

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Symporters

Membrane proteins transporting two different molecules across the cell membrane in the same direction.

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Antiporters

Membrane proteins transporting two different molecules across the cell membrane in opposite directions.

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Osmotic Potential

A difference in solute concentration across a membrane, influencing water movement.

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Membrane Potential

Difference in electrical potential that exists across the cell membrane.

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Primary Active Transport

Uses ATP hydrolysis for transport against concentration gradient

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Secondary Active Transport

Uses energy from ion gradients created by primary active transport to move other substances.

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Information Uptake

The process of taking up information by the cell

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Information Release

The process of sending out information by the cell.

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Signal Transduction

The process by which a cell converts one kind of signal or stimulus into another.

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Cellular Reaction

The cell's response to a signal, leading to a change in activity or behavior.

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Second Messengers

Intracellular molecules that relay signals received at receptors on the cell surface.

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Ligand

A molecule that binds to a receptor.

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Study Notes

  • Basics of Biology
  • Winter semester 2024/25
  • Date: Day 23, 17.01.2025
  • Basic concept 2: Interaction
  • Includes exchange, information, and communication
  • Also includes control, regulation, perception, and responsiveness
  • For teaching at secondary levels 1 and 2, vocational school teaching, special needs education teaching at secondary level, biology as a minor
  • Instructor is PD Dr. Dirk Warnecke

Energy

  • Cells aren't closed systems according to thermodynamics
  • Cells take in usable energy
  • Cells release unusable energy

Substances

  • Cells take in usable substances (raw materials)
  • Cells release unusable substances (waste)
  • 100% substance recycling is theoretically possible for an individual
  • Reproduction, propagation, and growth create a need for substance intake
  • Carbon is an example: autotroph/heterotroph refers to the method of carbon intake
  • Diffusion through biological membranes occurs
  • Active transport through biological membranes occurs
  • Endocytosis/exocytosis transports large molecules and particles

Transport through Biomembranes

  • Often ligand-regulated
  • Includes simple diffusion
  • Also includes passive transport
  • Primary active transport is utilized
  • Shows different permeability coefficient of different substances

Active Transport

  • Active transport based on three protein types
  • Transport is directional
  • Symporters and antiporters transport two different substances, but are coupled
  • These require energy supply
  • Uniporters transport a single substance

Concentration Gradient of Ions

  • Importing and exporting substances is achieved
  • Influences osmotic potential
  • Necessary for energy sources using ATPases
  • Important for membrane potential, which is steering channels

Secondary Active Transport

  • Most transporters are specific, needing an individual transporter for each molecule that must be imported
  • Organisms utilize proton pumps in the plasma membrane, creating a proton gradient with a pH of 7 inside the cell.
  • Symporters allow protons to flow into the cytoplasm, dragging other molecules against their concentration gradient
  • The proton gradient drives the transport of molecules

Plasmamembrane Transport

  • Includes Endocytosis and Exocytosis
  • Facilitated by active and passive transport
  • Involves an exchange of ions and molecules
  • Moves macromolecules, protein complexes, or cells
  • Necessary for vesicle transport

Phagocytosis

  • Found in plant and animal cells; showcases physiological differences
  • Includes the uptake of solid substances through the cell membrane
  • Mechanism:
    • Uptake of solid material (cell debris, dead cells, foreign cells, or bacteria) by surrounding the plasma membrane
    • Subsequent separation inwards to form a food vacuole
    • A food vacuole plus lysosomes creates phagolysosomes

Information

  • Information is received and released
  • Signals received by receptors cause a reaction through signal transduction and processing

Organisms / Sensory Organs / Receptors / Sources

  • Prokaryotes, protists, fungi, plants, and animals have different reactions to stimuli:
    • Light, temperature, sound, mechanical pressure, position, acceleration, humidity, chemical substances, pheromones, time, magnetic and electric fields
  • Light: Photoreceptors
  • Temperature: Cold/heat receptors
  • Sound: Ears, Cochlea
  • Mechanical Pressure: Mimosa
  • Location: Ears
  • Chemical substances and hormones: Odor, nose

Receptors

  • Intracellular and plasma membrane receptors
  • Includes receptors for external and internal stimuli

External Stimuli (Reiz)

  • Light alters rhodopsin's conformation
  • The light-absorbing molecule 11-cis-retinal bonds to opsin
  • Together they form the pigment rhodopsin, the molecular basis for perception
  • Examples of membrane bond receptors

Ligand-Gated Channels

  • The acetylcholinesterase receptor is a ligand-controlled channel for sodium ions with 5 binding points
  • The receptor opens channels and lets Na+ flow into the cell
  • The influx alters membrane charge & leads to an electrical signal in the muscle cell

G-Proteins

  • Hormone binding activates receptors to activate G-Proteins
  • GTP displaces GDP in the process

Signal Transduction (Intrazellulär)

  • Uses a "second messenger" mechanism
  • Creates cAMP and introduces Ca2+ ions

Zielmoleküle

  • Protein kinases and proteins

  • Transcription factors and nucleic acids

  • “Before” Receptor:

    • When receptor responds to chemical substance
    • Ligand is a first messenger (agent)
    • A signal molecule with limited change confusion within intracellular mechanisms

  • “After” Receptor

    • Signal transduction is the second messenger and signal molecule

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Explore the fundamental differences between prokaryotic and eukaryotic cells, focusing on size, structure, and genomic organization. Comparing cell diameters, surface areas, and genome characteristics, highlighting key distinctions relevant to various teaching degrees.

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