Cell Theory True or False Quiz
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Questions and Answers

What is the primary function of mitochondria?

  • Production of cellular membranes
  • Site of aerobic respiration for ATP synthesis (correct)
  • Site of photosynthesis
  • Storage of genetic material

    • What unique feature do mitochondria possess that allows them to be semi-autonomous?

  • Presence of a double membrane
  • Containment of circular mitochondrial DNA (correct)
  • Ability to perform photosynthesis
  • Storage of fatty acids

    • Which part of the mitochondrion is responsible for generating a proton gradient?

  • Intermembrane space (correct)
  • Mitochondrial matrix
  • Cristae
  • Outer membrane

    • What is the shape of chloroplasts?

    <p>Biconvex discs</p> Signup and view all the answers

    What process allows chloroplasts to move through the cell?

    <p>Cytoplasmic streaming</p> Signup and view all the answers

    Which component of the mitochondrion is specifically involved in ATP synthesis?

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

    What is held in the mitochondrial matrix?

    <p>Circular mitochondrial DNA and 70S ribosomes</p> Signup and view all the answers

    What is the maximum length range for the mitochondrion?

    <p>2.5-10 µm</p> Signup and view all the answers

    Which statement accurately describes a principle of the cell theory?

    <p>All living organisms are comprised of one or more cells.</p> Signup and view all the answers

    Why are most cells small?

    <p>To have a high surface-area-to-volume ratio.</p> Signup and view all the answers

    Which organelle is continuous with the nuclear envelope?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    In eukaryotic cells, where are secretory proteins synthesized?

    <p>On rough endoplasmic reticulum.</p> Signup and view all the answers

    Which statement about ribosomes is correct?

    <p>Chloroplasts and mitochondria contain 70S ribosomes.</p> Signup and view all the answers

    What does the term 'obligate intracellular parasites' refer to?

    <p>Viruses that can only reproduce within host cells.</p> Signup and view all the answers

    Which of the following statements about viruses is false?

    <p>Viruses can reproduce on their own.</p> Signup and view all the answers

    What is the primary function of ribosomes?

    <p>To synthesize proteins.</p> Signup and view all the answers

    Where are proteins destined for secretion synthesized?

    <p>At bound ribosomes on rough ER</p> Signup and view all the answers

    Which of the following correctly describes the structure of centrioles?

    <p>Exist as a pair of rod-like structures at right angles to each other</p> Signup and view all the answers

    What is one of the primary functions of the cytosol?

    <p>Storage of vital chemicals</p> Signup and view all the answers

    Which protein components are transported into the nucleolus for ribosomal assembly?

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

    Which statement accurately reflects the cytoskeleton's composition?

    <p>It is composed of microtubules, intermediate fibers, and microfilaments</p> Signup and view all the answers

    What critical role do centrioles serve during cell division?

    <p>Organization of spindle fibers</p> Signup and view all the answers

    Which of the following is a function of the cytoskeleton?

    <p>Maintain cell shape and facilitate movement</p> Signup and view all the answers

    What is the percentage of water typically found in the cytoplasmic matrix?

    <p>90%</p> Signup and view all the answers

    What is the primary stain used in the Gram staining process?

    <p>Crystal violet</p> Signup and view all the answers

    How does the structure of Gram-positive bacteria differ from Gram-negative bacteria in terms of peptidoglycan?

    <p>Gram-positive bacteria have a thick layer of peptidoglycan.</p> Signup and view all the answers

    What role does the outer membrane play in Gram-negative bacteria?

    <p>It aids in bacterial survival.</p> Signup and view all the answers

    Which of the following statements about mesosomes is correct?

    <p>They facilitate the separation of daughter DNA molecules.</p> Signup and view all the answers

    Where is bacterial genetic material found?

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

    What is the composition of bacterial ribosomes?

    <p>70S ribosomes.</p> Signup and view all the answers

    Which type of bacteria contains photosynthetic membranes?

    <p>Only photosynthetic bacteria.</p> Signup and view all the answers

    What is the role of the peptidoglycan layer in bacterial cells?

    <p>It provides rigidity and shape.</p> Signup and view all the answers

    What is the primary role of the capsid in a virus?

    <p>To protect and introduce the genome into host cells</p> Signup and view all the answers

    What are the structural units that make up the capsid known as?

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

    How do enveloped viruses acquire their membrane?

    <p>By budding from host cell membranes</p> Signup and view all the answers

    What role do glycoprotein spikes serve in enveloped viruses?

    <p>They assist in attaching the virus to host cell receptors</p> Signup and view all the answers

    What distinguishes naked viruses from enveloped viruses?

    <p>Naked viruses have no surrounding membrane</p> Signup and view all the answers

    What type of viruses are bacteriophages?

    <p>Viruses that exclusively infect bacteria</p> Signup and view all the answers

    Which statement is true regarding the assembly of capsids?

    <p>The information for capsomere assembly is encoded in the proteins' structure</p> Signup and view all the answers

    What components primarily make up the viral envelope?

    <p>Phospholipids and glycoproteins</p> Signup and view all the answers

    Study Notes

    Cell Theory

    • Modern Cell Theory developed by Schleiden and Schwann in 1938.
    • Cells are the smallest unit of life and perform all necessary life processes (e.g., ATP and protein synthesis).
    • Living cells arise from pre-existing living cells through processes like mitosis, meiosis, cytokinesis, and binary fission in prokaryotes.
    • All living organisms consist of one or more cells, where all life-sustaining chemical reactions occur.

    Mitochondria

    • Mitochondria are rod-shaped or cylindrical with sizes ranging from 0.5-1.5 μm in diameter and 2.5-10 μm in length.
    • Enclosed by a double membrane: smooth outer membrane is permeable to small solutes, while the inner membrane forms cristae to increase surface area for enzyme attachment.
    • The intermembrane space is crucial for generating a proton gradient for the electron transport chain.
    • The mitochondrial matrix contains circular mitochondrial DNA (mtDNA) and 70S ribosomes, allowing mitochondria to grow and divide independently.
    • Mitochondria are the site of aerobic respiration and ATP synthesis.

    Chloroplasts

    • Chloroplasts are biconvex, lens-shaped organelles that move within cells via cytoplasmic streaming to optimize light absorption.
    • Enclosed by a double membrane known as the chloroplast envelope, with a narrow intermembrane space.

    Ribosome Synthesis in Eukaryotes

    • Ribosomal RNA (rRNA) is transcribed in the nucleolus, and ribosomal proteins are produced in the nucleus.
    • Proteins and rRNA combine in the nucleolus to form ribosomal subunits, which are assembled on mRNA during translation.

    Centrioles

    • Centrioles are found in animal cells and lower plant cells but absent in higher plant cells.
    • Exist as pairs of perpendicular rod-like structures composed of microtubule triplets arranged in a ring.
    • Organize spindle fibers during cell division.

    Cytosol

    • The cytosolic matrix is composed of 90% water, organic molecules, inorganic ions, and waste products.
    • Functions include storage of vital chemicals and serving as the site for various metabolic pathways like glycolysis and translation.

    Cytoskeleton

    • A dynamic network of fibres providing structural support and facilitating cell movement.
    • Comprises microtubules, intermediate fibers, and microfilaments, maintaining cell shape and anchoring organelles.

    Plasma Membrane

    • The plasma membrane is partially permeable, similar to eukaryotic membranes, and plays a role in cellular function.
    • Mesosomes are infoldings found in some bacteria, aiding in the separation of DNA during binary fission and increasing surface area for enzymatic reactions.

    Genetic Material in Bacteria

    • Bacteria have a single circular double-stranded DNA chromosome located in the nucleoid region, associated with histone-like proteins.
    • Transcriptionally active genes are found in loosely coiled regions, while inactive genes are in supercoiled regions.

    Ribosomes

    • Bacterial ribosomes are 70S, distinct from eukaryotic ribosomes, and crucial for protein synthesis.

    Viral Structure

    • The capsid is a protective protein coat surrounding the viral genome, composed of capsomeres.
    • Some viruses are naked, containing only a genome and capsid.
    • Enveloped viruses possess a membranous envelope derived from host cell membranes, incorporating viral and host proteins for cell recognition and attachment.
    • Bacteriophages specifically infect bacteria.

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    Description

    Test your understanding of the key principles of cell theory with this True or False quiz. Determine whether statements about cells and their characteristics are accurate or not. Perfect for students studying biology or life sciences.

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