Cell Structure and Function
46 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does magnification do to the image of a specimen?

Magnification enlarges the image of a specimen.

What is resolving power?

Resolving power is the ability of a microscope to distinguish two points as separate entities.

What is a disadvantage of the electron microscope?

Samples must be placed in a vacuum and are typically fixed, dehydrated, and sometimes coated with heavy metals, which means you cannot view living cells.

What type of electron microscopy provides 3D images of a specimen's surface topography?

<p>Scanning Electron Microscopy (SEM).</p> Signup and view all the answers

What type of electron microscopy produces detailed, 2D images of thin section, revealing internal structures at high resolution?

<p>Transmission Electron Microscopy (TEM).</p> Signup and view all the answers

What is one of the smallest organelles isolated in cell fractionation?

<p>Ribosomes.</p> Signup and view all the answers

What are the two domains with prokaryotic cells?

<p>Bacteria and Archaea.</p> Signup and view all the answers

In prokaryotes, DNA is enclosed within a nucleus.

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

What rigid structure provides shape and protection to the cell?

<p>Cell Wall.</p> Signup and view all the answers

What regulates material exchange in the cell?

<p>Plasma Membrane.</p> Signup and view all the answers

What part is the region where the chromosome is located?

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

What is the site of protein synthesis?

<p>Ribosomes.</p> Signup and view all the answers

What structure is used for motility?

<p>Flagella.</p> Signup and view all the answers

As a cell increases in size, what grows faster, its volume or its surface area?

<p>Volume.</p> Signup and view all the answers

What is the function of microvilli?

<p>They greatly increase the surface area of a cell (e.g., intestinal epithelial cells), thereby enhancing absorption.</p> Signup and view all the answers

Where does protein folding and modification occur in the endoplasmic reticulum(ER)?

<p>Lumen.</p> Signup and view all the answers

What do transport vesicles do?

<p>Small membrane-bound carriers that shuttle proteins and lipids between ER, Golgi, and other destinations.</p> Signup and view all the answers

Rough ER is studded with ribosomes, while smooth ER lacks ribosomes.

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

What processes is smooth ER involved in?

<p>Lipid synthesis and detoxification.</p> Signup and view all the answers

What process does chronic alcohol use induce that leads to tolerance?

<p>Smooth ER enzyme production, which increases the metabolism (detoxification) of other drugs.</p> Signup and view all the answers

As secretory proteins are synthesized by ribosomes on the rough ER where do they enter?

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

What does the cis face of the golgi apparatus do?

<p>Receives vesicles from the rough ER.</p> Signup and view all the answers

Within the golgi apparatus, what region modifies proteins?

<p>Medial region.</p> Signup and view all the answers

Lysosomes contain what?

<p>Membrane-bound vesicles containing hydrolytic enzymes.</p> Signup and view all the answers

What is the process by which cells such as macrophages engulf large particles or pathogens?

<p>Phagocytosis.</p> Signup and view all the answers

Describe autophagy.

<p>The process by which cells degrade and recycle their own components by sequestering them in autophagosomes that eventually fuse with lysosomes.</p> Signup and view all the answers

What is the cause of Tay-Sachs disease?

<p>A deficiency of a lysosomal enzyme (hexosaminidase A), leading to the accumulation of gangliosides (lipid-sugar complexes) in neurons.</p> Signup and view all the answers

What type of vacuole is used for temporary storage for ingested materials in phagocytic cells?

<p>Food Vacuoles.</p> Signup and view all the answers

What type of vacuole expels excess water in freshwater protists?

<p>Contractile Vacuoles.</p> Signup and view all the answers

What type of vacuole maintains turgor pressure and store nutrients/waste?

<p>Central Vacuoles (in plants).</p> Signup and view all the answers

What does the endosymbiont theroy suggest about mitochodnria and chloroplastss?

<p>Mitochondria and chloroplasts were once free-living prokaryotes that were engulfed by ancestral eukaryotic cells.</p> Signup and view all the answers

Mitochondria and chloroplasts have singular membranes.

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

Mitochondria and chloroplasts their own circular DNA similar to bacterial genomes.

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

What is the folds of the inner membrane of a mitochodnria called?

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

Where does the Calvin cycle take place in the chloroplast?

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

What is the function of mitochondria?

<p>The production of ATP through cellular respiration.</p> Signup and view all the answers

What is the function of chloroplasts?

<p>The conversion of light energy to chemical energy via photosynthesis.</p> Signup and view all the answers

Peroxisomes help with the breakdown of which molecules?

<p>fatty acids</p> Signup and view all the answers

What enzyme do peroxisomes user to detoxify hydrogen peroxide?

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

What are the three types of cytoskeletal fibers?

<p>Microfilaments (actin filaments), Intermediate Filaments, and Microtubules.</p> Signup and view all the answers

What structures are seal adjacent cells to prevent leakage of extracellular?

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

What structures provide strong adhesion between cells, anchoring intermediate filaments?

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

What structures Allow direct communication by permitting ions and small molecules to pass between cells?

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

What is the primary function of the cytoskeleton?

<p>It maintains cell shape, organizes intracellular components, and facilitates cellular movement.</p> Signup and view all the answers

In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?

<p>Eukaryotic cells are compartmentalized, which allows for specialization.</p> Signup and view all the answers

The extracellular matrix of the animal cell has all of the following molecular components except which of these?

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

Flashcards

Magnification

The process of enlarging the image of a specimen under a microscope.

Resolving Power

Ability to distinguish two close points as separate entities in microscopy.

Electron Microscope Disadvantage

Cannot view living cells due to vacuum and sample preparation.

Scanning Electron Microscopy (SEM)

A type of electron microscopy that provides 3D images of a specimen's surface.

Signup and view all the flashcards

Transmission Electron Microscopy (TEM)

Produces detailed 2D images of thin sections of specimens.

Signup and view all the flashcards

Cell Fractionation

A technique to separate organelles based on size and density using centrifugation.

Signup and view all the flashcards

Prokaryotic Domains

Two domains with prokaryotic cells: Bacteria and Archaea.

Signup and view all the flashcards

DNA Location in Prokaryotes

In prokaryotes, DNA is in a non-membrane-bound nucleoid region.

Signup and view all the flashcards

Cell Wall Function

Rigid structure providing shape and protection to bacterial cells.

Signup and view all the flashcards

Plasma Membrane Function

Lipid bilayer that regulates material exchange in cells.

Signup and view all the flashcards

Microvilli Function

Increase cell surface area for enhanced absorption.

Signup and view all the flashcards

Surface Area-to-Volume Ratio

As a cell grows, volume increases faster than surface area, limiting exchange rates.

Signup and view all the flashcards

Nuclear Envelope

A double membrane that encloses the nucleus and regulates passage of materials.

Signup and view all the flashcards

Nuclear Lamina

A network of protein filaments providing structural support to the nucleus.

Signup and view all the flashcards

Role of Ribosomes

Sites of protein synthesis composed of rRNA and proteins.

Signup and view all the flashcards

Bound vs. Free Ribosomes

Bound ribosomes are attached to rough ER; free ribosomes float in the cytosol.

Signup and view all the flashcards

Endomembrane System

A system of membranes in eukaryotic cells including ER, Golgi, and lysosomes.

Signup and view all the flashcards

Rough ER Function

Synthesizes proteins that are usually exported or used in membranes.

Signup and view all the flashcards

Smooth ER Functions

Involved in lipid synthesis, detoxification, and calcium ion storage.

Signup and view all the flashcards

Golgi Apparatus

Processes, modifies, and packages proteins for secretion or transport.

Signup and view all the flashcards

Lysosomes

Organelles containing hydrolytic enzymes for digestion and waste processing.

Signup and view all the flashcards

Phagocytosis

Process where cells engulf large particles or pathogens.

Signup and view all the flashcards

Vacuoles

Storage organelles in cells, varying types for different functions.

Signup and view all the flashcards

Mitochondria Function

Produce ATP through cellular respiration, acting as the energy factory.

Signup and view all the flashcards

Chloroplast Function

Convert light energy into chemical energy through photosynthesis.

Signup and view all the flashcards

Cytoskeleton Definition

Network of protein fibers maintaining cell shape and enabling movement.

Signup and view all the flashcards

Cilia vs. Flagella

Cilia are short and numerous; flagella are long and few, both aiding in movement.

Signup and view all the flashcards

Intercellular Junctions

Structures allowing communication and adhesion between cells, like tight junctions and gap junctions.

Signup and view all the flashcards

Brain Cell Function

Important for nutrient and waste management in the brain, linked with lysosomes.

Signup and view all the flashcards

Extracellular Matrix (ECM)

A network providing structural support and facilitating intercellular communication.

Signup and view all the flashcards

Cell Wall Composition

Primarily cellulose in plants, providing strength and structure.

Signup and view all the flashcards

Study Notes

Cell Structure and Function

  • Magnification vs. Resolving Power:

    • Magnification enlarges the image of a specimen.
    • Resolving power is the ability of a microscope to distinguish two points as separate entities. Higher resolving power yields clearer images.

  • Electron Microscopy Disadvantages:

    • Samples must be placed in a vacuum and are typically fixed, dehydrated, and coated with heavy metals. This prevents the study of living cells.

  • Electron Micrograph Types:

    • Scanning Electron Microscopy (SEM) produces 3D images of the specimen's surface topography.
    • Transmission Electron Microscopy (TEM) produces detailed 2D images of thin sections, revealing internal structures at high resolution.

  • Cell Fractionation:

    • Ribosomes are among the smallest organelles isolated through high-speed centrifugation.

  • Prokaryotic Domains:

    • Bacteria and Archaea are domains with prokaryotic cells.

  • DNA Location Difference:

    • In prokaryotes, DNA is located in a region called the nucleoid, not enclosed by a membrane.
    • In eukaryotes, DNA is enclosed within a nucleus.

  • Prokaryotic Cell Diagram Labels:

    • Cell Wall: Rigid structure providing shape and protection

  • Cell Size and Microvilli:

    • As a cell increases in size, its volume grows faster than its surface area, limiting material exchange.
    • Microvilli increase the surface area of cells like intestinal epithelial cells to enhance absorption.

Surface Area to Volume Ratio

  • Cell A (125 × 1 × 1):

    • Volume: 125 cubic units
    • Surface Area: approximately 502 square units
    • SA:Volume Ratio: approximately 4.02

  • Cell B (5 × 5 × 5):

    • Volume: 125 cubic units
    • Surface Area: approximately 150 square units
    • SA:Volume Ratio: approximately 1.2

  • Conclusion: Cell A (elongated) has a higher SA:Volume ratio, facilitating efficient material exchange.

Eukaryotic Cell Structures and Functions

  • Nuclear Envelope:

    • Double membrane enclosing the nucleus.
    • Nuclear pores allow molecules to pass between the nucleus and cytoplasm

  • Nuclear Lamina and Matrix:

    • Nuclear Lamina provides structural support to the inner nuclear membrane.
    • Nuclear Matrix organizes chromatin and maintains the shape of the nucleus.

  • Chromatin and Condensation:

    • Chromatin consists of DNA and histone proteins.
    • During interphase, chromatin is loosely organized; during cell division, it condenses into visible chromosomes.

  • Nucleolus: Synthesizes ribosomal RNA and assembles ribosomes.

  • Ribosomes:

    • Function in protein synthesis.
    • Two subunits (small and large)
    • Free ribosomes synthesize proteins for the cytosol.
    • Bound ribosomes synthesize proteins for secretion, membranes, or lysosomes

Endomembrane System

  • Endoplasmic Reticulum (ER):

    • Lumen: Interior space for protein folding and modification.
    • Transport Vesicles: Shuttle proteins and lipids between ER, Golgi, and other destinations.
    • Rough ER: Studded with ribosomes for protein synthesis; smooth ER with no ribosomes for lipid synthesis and detoxification.

  • Golgi Apparatus:

    • Cis face receives vesicles from the rough ER.
    • Modifies proteins (e.g., glycosylation, phosphorylation).
    • Trans face sorts and packages proteins into vesicles for secretion.

  • Lysosomes:

    • Membrane-bound vesicles containing hydrolytic enzymes for breaking down macromolecules.
    • Involved in phagocytosis and autophagy.

  • Vacuoles:

    • Food vacuoles: Temporarily store ingested materials.
    • Contractile vacuoles: Expel water in freshwater protists.
    • Central vacuoles (in plants): Large, persistent storage organelles.

  • Endomembrane System Coordination:

    • Proteins synthesized on rough ER are packaged into vesicles transported to the Golgi.
    • Golgi modifies and sorts them, dispatching vesicles that fuse with the plasma membrane or lysosomes.

Mitochondria and Chloroplasts

  • Mitochondria:

    • Double membranes (inner folded into cristae).
    • Matrix contains enzymes for cellular respiration.
    • Produce ATP (energy).

  • Chloroplast:

    • Double membranes.
    • Thylakoids where light reactions occur.
    • Stroma for the Calvin cycle (photosynthesis).
    • Convert light energy into chemical energy.

Cytoskeleton

  • Cytoskeleton:

    • Dynamic network of protein fibers maintaining cell shape, positioning organelles, and enabling movement.
    • Three types: Microfilaments, Intermediate filaments, Microtubules
    • Functions: Maintaining shape, Facilitating movement, Organizing organelles.

  • Microtubules:

    • Serve as tracks for motor proteins during vesicle and organelle transport.
    • Form the spindle apparatus during cell division.
    • Form cilia and flagella.

  • Cilia and Flagella:

    • Motility (movement).
    • Cilia are numerous, short, coordinated movements. Flagella are longer, fewer, whip-like motions.

  • Centrioles:

    • Organize microtubules and the formation of the mitotic spindle during cell division.

Cell Walls (Plant Cells)

  • Cell Wall:
    • Provides structural support and protection in plant cells.
    • Composed of cellulose (plants). Peptidoglycans (bacteria).
    • Primary cell wall is relatively thin and flexible during growth.
    • Middle lamella: Cements adjacent plant cells.
    • Secondary cell wall in some cells, thicker and rigid, for support.

Extracellular Matrix (Animal cells)

  • Extracellular Matrix:
    • Comprised of proteins (e.g., collagen, elastin) and glycoproteins.
    • Provides structural support, facilitates cell adhesion, and enables intercellular communication

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Chapter 6 Study Guide: A Tour of the Cell PDF

Description

Explore cell structure, magnification, and resolving power. Learn about electron microscopy, including SEM and TEM techniques. Understand cell fractionation and the differences between prokaryotic domains Bacteria and Archaea and DNA location.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser