Biology Chapter: Cell Theory and Characteristics
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Questions and Answers

What does the cell theory state about living organisms?

  • Cells are always microscopic entities.
  • All cells can function independently.
  • All living things are composed of cells. (correct)
  • Cells are a secondary component of life.

    • Which of the following is NOT a characteristic of life exhibited by unicellular organisms?

  • Response to environment
  • Metabolism
  • Reproduction
  • Respiration (correct)

    • As the radius of a cell increases, what happens to the surface area to volume ratio?

  • The SA:V ratio decreases. (correct)
  • The SA:V ratio fluctuates irregularly.
  • The SA:V ratio remains constant.
  • The SA:V ratio increases.

    • What is one way cells can increase their surface area to volume ratio without increasing in size?

    <p>By changing their shape.</p> Signup and view all the answers

    What is the fate of a cell that grows too large relative to its ability to exchange materials?

    <p>It may not meet its metabolic needs and could die.</p> Signup and view all the answers

    Why is the metric system particularly useful in scientific measurements?

    <p>It simplifies conversion between units.</p> Signup and view all the answers

    Which of the following cell types is specifically mentioned as having an atypical size?

    <p>Giant algae cells</p> Signup and view all the answers

    What is the primary role of the surface area to volume ratio in cells?

    <p>To influence material exchange efficiency.</p> Signup and view all the answers

    What is the primary role of cholesterol in the cell membrane?

    <p>It disrupts the packing of phospholipids.</p> Signup and view all the answers

    What is the metric prefix for 1/1,000,000th?

    <p>micro-</p> Signup and view all the answers

    How does surface area increase compared to volume as cell radius increases?

    <p>Surface area increases by 10<sup>2</sup> while volume increases by 10<sup>3</sup></p> Signup and view all the answers

    Why is the cell membrane referred to as the Fluid Mosaic Model?

    <p>It is made up of different embedded parts.</p> Signup and view all the answers

    What characteristic of the phospholipid bilayer contributes to its fluidity?

    <p>The weak hydrophobic interactions between tails.</p> Signup and view all the answers

    What is the maximum magnification typically achieved by a light microscope?

    <p>400x</p> Signup and view all the answers

    At equilibrium, what happens to the molecules in a solution?

    <p>An equal number of molecules move in both directions.</p> Signup and view all the answers

    What does the term 'resolution' refer to in microscopy?

    <p>The minimum distance for two points to be seen separately</p> Signup and view all the answers

    How does cholesterol affect the permeability of the membrane?

    <p>It decreases permeability to small, hydrophilic particles.</p> Signup and view all the answers

    If an image of a red blood cell is 14 mm and the actual diameter is 6 µm, what is the magnification?

    <p>2333.33x</p> Signup and view all the answers

    What describes diffusion in a biological context?

    <p>Molecules move from high concentration to low concentration overall.</p> Signup and view all the answers

    What is the equivalent of 0.000001 m when converted to nanometers?

    <p>100 nm</p> Signup and view all the answers

    What component of the cell membrane allows selective transport?

    <p>Channel proteins</p> Signup and view all the answers

    Given a magnification of 200 and a scale bar labeled 0.75 mm, what is the equivalent size in nanometers for the scale bar?

    <p>750 nm</p> Signup and view all the answers

    What is the smallest size that the human eye can perceive?

    <p>100 µm</p> Signup and view all the answers

    What is a characteristic of the solution in terms of solute concentration?

    <p>It can contain multiple solutes at varying concentrations.</p> Signup and view all the answers

    What is the primary function of the ribosome in prokaryotic cells?

    <p>Protein synthesis</p> Signup and view all the answers

    Which structure in prokaryotic cells provides protection and maintains shape?

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

    How does a scanning electron microscope (SEM) primarily obtain images?

    <p>By bouncing electrons off the surface of a sample</p> Signup and view all the answers

    What is the significance of a prokaryote lacking a membrane-bound nucleus?

    <p>It makes them genetically simpler than eukaryotes</p> Signup and view all the answers

    What is the main component of the cytoplasm in prokaryotic cells?

    <p>Water and organic molecules</p> Signup and view all the answers

    Which of the following structures aids in the mobility of prokaryotic cells?

    <p>Flagellum</p> Signup and view all the answers

    What distinguishes archaea from bacteria within the prokaryotes?

    <p>Their evolutionary lineage and genetic makeup</p> Signup and view all the answers

    What is contained within the nucleoid region of prokaryotic cells?

    <p>Naked DNA</p> Signup and view all the answers

    What is the primary function of mitochondria?

    <p>Make energy for the cell</p> Signup and view all the answers

    Which statement correctly describes the structure of the nucleus?

    <p>Contains many nuclear pores</p> Signup and view all the answers

    What distinguishes rough endoplasmic reticulum from free ribosomes?

    <p>Rough endoplasmic reticulum is surrounded by a membrane with ribosomes attached</p> Signup and view all the answers

    What is the primary role of free ribosomes in a eukaryotic cell?

    <p>Make proteins that function in the cytoplasm</p> Signup and view all the answers

    Which of the following is NOT a benefit of compartmentalization in eukaryotic cells?

    <p>Ability to contain and synthesize all cellular structures in one area</p> Signup and view all the answers

    How is mitochondrial DNA inherited in humans?

    <p>Only from the mother</p> Signup and view all the answers

    What is the main function of the Golgi apparatus?

    <p>Process and package proteins</p> Signup and view all the answers

    Which cellular component is involved in the movement of a eukaryotic cell?

    <p>Flagellum</p> Signup and view all the answers

    What characteristic distinguishes facilitated diffusion from simple diffusion?

    <p>It allows the passive movement of large hydrophilic molecules.</p> Signup and view all the answers

    Which term describes a solution with a lower concentration of solutes compared to another solution?

    <p>Hypotonic</p> Signup and view all the answers

    Which of the following processes can occur without the use of ATP?

    <p>Simple diffusion</p> Signup and view all the answers

    What is the primary function of the sodium-potassium pump?

    <p>To transport sodium out and potassium into the cell using ATP.</p> Signup and view all the answers

    In which scenario would osmosis occur preferentially to reach equilibrium?

    <p>When solute concentration is higher on one side of the membrane.</p> Signup and view all the answers

    Which statement about tonicity is correct?

    <p>Hypertonic solutions have a higher solute concentration.</p> Signup and view all the answers

    What is the role of transmembrane proteins in facilitated diffusion?

    <p>To create a channel for molecules to passively diffuse.</p> Signup and view all the answers

    How does the concentration gradient influence active transport?

    <p>It drives the movement of solutes against their concentration gradient.</p> Signup and view all the answers

    Study Notes

    Cell Theory

    • All living things are composed of cells
    • The cell is the fundamental unit of life
    • All cells arise from pre-existing cells

    Cell Characteristics of Life

    • Metabolism: acquiring food and materials necessary for growth and survival
    • Growth: an increase in size
    • Response: the ability to react to changes in the environment
    • Reproduction: the ability to produce offspring
    • Regulation: keeping conditions within organism within tolerable limits
    • Unicellularity: a single cell carrying out all characteristics of life

    Surface Area to Volume Ratio

    • The surface area of a cell determines the rate of material exchange
    • The volume determines the amount of materials the cell needs
    • As cells get larger, the surface area to volume ratio decreases, which impacts cellular function

    Metric System Prefixes

    • Deci- (d): 1/10th
    • Centi- (c): 1/100th
    • Milli- (m): 1/1000th
    • Micro- (μ): 1/1,000,000th
    • Nano- (n): 1/1,000,000,000th

    Cell Size

    • Cells are small to maintain a high surface area to volume ratio, facilitating material exchange

    Magnification

    • Magnification is the ratio of the image size to the actual size
    • Magnification = Image size/Actual size

    Resolution

    • Resolution is the shortest distance between two points where the points can still be seen as separate entities
    • Light microscopes have a maximum resolution of approximately 0.2 micrometers

    Prokaryotic Cells

    • Prokaryotes are simple cells lacking a nucleus and other membrane-bound organelles.
    • They are extremely varied in shape. (e.g., spherical, rod-shaped, spiral)
    • Common prokaryotic structures include: nucleoid region, ribosomes, cell wall, cell membrane, capsule, pili, and flagella

    Eukaryotic Cells

    • Eukaryotic cells are complex cells containing a nucleus and other membrane-bound organelles.
    • They have a much larger range of structures and shapes.
    • Nucleus: holds the genetic material.
    • Ribosomes: responsible for protein synthesis.
    • Mitochondria: generate energy for the cell by cellular respiration.
    • Endoplasmic Reticulum (ER): a network of membranes involved in lipid synthesis, protein folding, and transport.
    • Golgi apparatus: processes, packages, and delivers proteins.
    • Lysosomes: contain digestive enzymes to break down molecules, cell parts, and foreign material
    • Vacuoles: store water and other substances. (large central vacuole in plants)
    • Chloroplasts: enable photosynthesis in plants and algae.
    • Cytoskeleton: composed of microtubules, microfilaments, and intermediate filaments to maintain cell shape and structure and to enable cell movement.
    • Cytoplasm: the jelly-like substance that fills the cell and holds all the organelles

    Cell Membrane

    • The cell membrane is a selectively permeable barrier, regulating the movement of substances into and out of the cell.
    • Major components include phospholipids, proteins, and cholesterol.
    • Phospholipids: amphipathic molecules forming a bilayer.
    • Proteins: diverse in structure and function including transport, recognition, and adhesion.
    • Cholesterol: strengthens the membrane and maintains fluidity.

    Membrane Transport

    • Passive Transport: diffusion, osmosis, and facilitated diffusion (high to low concentration, no energy required)
    • Active Transport: movement against the concentration gradient (low to high concentration, energy required)
    • Vesicular Transport: material transport in vesicles (endocytosis and exocytosis)

    Tonicity

    • Hypotonic: lower solute concentration than the cell (cells swell or burst)
    • Isotonic: equal solute concentration as the cell (cells maintain normal size)
    • Hypertonic: higher solute concentration than the cell (cells shrink)

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    Description

    Test your knowledge on cell theory, characteristics of life, and the impact of cell size on function. This quiz covers essential topics such as metabolism, growth, reproduction, and the metric system prefixes related to cells. Dive into the fundamental aspects of cellular biology.

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