Cell Biology Chapter Quiz
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Questions and Answers

Which of these structures are found in both prokaryotic and eukaryotic cells?

  • Ribosomes (correct)
  • Cytoskeleton (correct)
  • Nucleus
  • Plasma membrane (correct)

    • What is the main function of the endoplasmic reticulum (ER)?

  • Photosynthesis
  • Cellular respiration
  • Digestion of waste products
  • Protein synthesis and lipid metabolism (correct)

    • Which organelle is responsible for packaging and modifying proteins for secretion?

  • Golgi apparatus (correct)
  • Mitochondria
  • Endoplasmic reticulum
  • Lysosomes

    • What is the main function of lysosomes?

    <p>Digestion of cellular waste (A)</p> Signup and view all the answers

    Which organelle is responsible for photosynthesis in plant cells?

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

    What is the fluid-filled space inside the nucleus called?

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

    Which of the following is NOT a component of the cytoskeleton?

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

    What is the main difference between rough ER and smooth ER?

    <p>Rough ER has ribosomes attached to its surface, while smooth ER does not. (D)</p> Signup and view all the answers

    What is the primary function of ribosomes in protein synthesis?

    <p>Ribosomes assemble amino acids into polypeptide chains. (B)</p> Signup and view all the answers

    Which of the following is NOT involved in the process of protein synthesis?

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

    What is the significance of a signal peptide in protein synthesis?

    <p>Signal peptides direct proteins to specific organelles within the cell. (B)</p> Signup and view all the answers

    Which of the following correctly describes the role of the endoplasmic reticulum in protein synthesis?

    <p>The endoplasmic reticulum functions as a transport pathway for proteins destined for secretion. (B)</p> Signup and view all the answers

    What happens to a protein if its nuclear localization signal (NLS) is altered?

    <p>The protein will be retained in the cytoplasm. (A)</p> Signup and view all the answers

    What is the main difference between free ribosomes and ribosomes attached to the endoplasmic reticulum?

    <p>Free ribosomes synthesize proteins destined for the cytoplasm, while those attached to the ER synthesize proteins destined for secretion. (D)</p> Signup and view all the answers

    Which of the following is NOT a characteristic common to both ribosomes and the nucleus?

    <p>Both contain DNA. (A)</p> Signup and view all the answers

    Which of the following best describes the process of protein sorting?

    <p>Proteins are directed to specific organelles based on their signal sequences. (D)</p> Signup and view all the answers

    Which of the following components is NOT part of the endomembrane system?

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

    Transfer vesicles aid in communication between components of the endomembrane system by:

    <p>Transporting molecules between different compartments. (A)</p> Signup and view all the answers

    Which of the following statements is TRUE about the endoplasmic reticulum?

    <p>It forms the outer membrane of the nucleus. (A)</p> Signup and view all the answers

    How does the rough endoplasmic reticulum differ from the smooth endoplasmic reticulum?

    <p>Rough ER has ribosomes attached to its surface, while smooth ER does not. (B)</p> Signup and view all the answers

    What is the primary function of the Golgi apparatus in the endomembrane system?

    <p>Modifying, sorting, and packaging proteins and lipids. (C)</p> Signup and view all the answers

    Which of the following statements accurately describes the relationship between the endoplasmic reticulum and the Golgi apparatus?

    <p>The Golgi apparatus receives vesicles that bud off from the endoplasmic reticulum. (C)</p> Signup and view all the answers

    Which of the following is NOT a direct function of the smooth endoplasmic reticulum?

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

    Which of the following statements is TRUE about the role of the endomembrane system in protein synthesis?

    <p>Ribosomes on the rough endoplasmic reticulum synthesize proteins destined for secretion. (C)</p> Signup and view all the answers

    What is the role of the signal recognition particle (SRP) in protein synthesis?

    <p>SRP directs the ribosome with mRNA to the ER membrane. (D)</p> Signup and view all the answers

    Which of the following is NOT a modification that can occur to proteins in the Golgi apparatus?

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

    How does insulin regulate glucose levels in the body?

    <p>Insulin promotes the conversion of glucose into glycogen. (C)</p> Signup and view all the answers

    What is the role of lysosomes in the cell?

    <p>Lysosomes degrade damaged or unwanted macromolecules. (A)</p> Signup and view all the answers

    What is the order of events in the synthesis and secretion of insulin?

    <p>Preproinsulin -&gt; Proinsulin -&gt; Insulin (B)</p> Signup and view all the answers

    What is the function of the Golgi apparatus in protein sorting?

    <p>The Golgi apparatus modifies and packages proteins for their final destination. (B)</p> Signup and view all the answers

    How do insulin-containing secretory vesicles release their contents?

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

    What is the difference between preproinsulin and proinsulin?

    <p>Preproinsulin contains a signal peptide, while proinsulin does not. (D)</p> Signup and view all the answers

    What is the primary function of chloroplasts?

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

    What is the name of the stacks of thylakoids within chloroplasts?

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

    What is the name of the theory explaining the origin of mitochondria and chloroplasts?

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

    Which characteristic of mitochondria and chloroplasts supports the endosymbiotic theory?

    <p>Presence of circular DNA (B)</p> Signup and view all the answers

    Which of the following is NOT evidence supporting the theory of endosymbiosis?

    <p>Mitochondria and chloroplasts are surrounded by a single membrane. (D)</p> Signup and view all the answers

    What is the primary functional difference between mitochondria and chloroplasts?

    <p>Mitochondria break down sugars to generate energy, while chloroplasts synthesize sugars using sunlight. (B)</p> Signup and view all the answers

    What is the name of the fluid-filled space within a mitochondrion, where the Krebs cycle occurs?

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

    What is the primary function of the proton pumps within lysosomes?

    <p>To maintain an acidic pH within the lysosome, optimal for enzymatic activity (A)</p> Signup and view all the answers

    Which of the following cellular components is NOT part of the endomembrane system?

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

    What is the role of vacuoles in plant cells?

    <p>Regulation of turgor pressure (A)</p> Signup and view all the answers

    Which type of vacuole acts like a lysosome in plant cells?

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

    Which of the following statements is TRUE about mitochondria?

    <p>Mitochondria have a smooth outer membrane and a highly folded inner membrane (B), Mitochondria are involved in the breakdown of glucose to produce ATP (D)</p> Signup and view all the answers

    Why are there typically more mitochondria in cells with high energy demands?

    <p>Because mitochondria are responsible for breaking down glucose to produce ATP (A)</p> Signup and view all the answers

    What is autophagy?

    <p>The process of breaking down damaged organelles by lysosomes (A)</p> Signup and view all the answers

    Which of the following is a function of the Golgi apparatus?

    <p>Packaging and modification of proteins (B)</p> Signup and view all the answers

    Study Notes

    Biology 1 - Cells, Molecular Biology and Genetics (Biol 1000)

    • Course offered by Dr. Michael Cardinal-Aucoin during Winter 2025 at York University.
    • Course code is Biol 1000.

    The Eukaryotic Cell

    • Eukaryotic cells have internal membranes forming compartments called organelles, specialized for specific functions.
    • Plant, animal, and protist cells share most of the same organelles.
    • Organelles include:
      • Nucleus
      • Endomembrane system (endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles)
      • Mitochondria
      • Chloroplasts
      • Peroxisomes
      • Cytoskeleton

    Eukaryotes

    • Eukaryotic cells possess internal membranes dividing the cell into compartments called organelles, each specialised for a specific task.
    • Plant, animal, and protist cells have similar organelles.
    • Organelles vary in size.

    Nucleus

    • Nucleus (most prominent organelle) stores the cell's DNA.
    • Nuclear envelope: a double membrane boundary of the nucleus
    • Nuclear pores: allow molecules to enter/exit the nucleus.
    • Nucleolus: a structure within the nucleus where ribosomal RNA (rRNA) is made.
    • Chromatin: DNA organized with proteins (e.g., histones).
    • Chromosomes: During cell division, chromatin condenses.

    Nucleus (continued)

    • DNA in a single cell stretches 6.5 kilometers if laid out end-to-end
    • DNA is organized into chromatin, a complex of DNA and proteins.
    • During cell division, chromatin condenses to form chromosomes.

    Nuclear Pore

    • Nuclear pores: multi-protein complexes controlling material traffic into and out of the nucleus.
    • Molecules like proteins and building blocks of DNA and RNA travel through nuclear pores.

    Ribosomes

    • Ribosomes are found in both prokaryotes and eukaryotes.
    • Eukaryotic ribosomes are manufactured in the nucleolus.
    • Ribosomes are complexes of rRNA and proteins, making polypeptides (proteins).
    • Ribosomes can be free in the cytosol or attached to the endoplasmic reticulum.

    Protein Synthesis

    • Free ribosomes synthesize proteins for use inside the cell.
    • Ribosomes bound to the rough endoplasmic reticulum synthesize proteins destined for secretion or for insertion into membranes.

    How proteins end up where they should

    • Proteins destined for certain organelles have signal peptides (signal sequences) to direct them.
    • These signal sequences direct the protein to specific organelles.

    Proteins destined for nucleus

    • Proteins destined for the nucleus contain a nuclear localization signal (NLS).
    • This signal helps direct them towards the nucleus.

    Endomembrane System

    • Contains various interconnected organelles involved in protein and lipid synthesis, modification, sorting, and transport.
    • Nuclear envelope, Endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, plasma membrane
    • Endomembranes are interconnected but not continuous.

    Endomembrane System (continued)

    • The endomembrane system communicates through physical connections or via transfer vesicles (small membrane-bound sacs).
    • The endomembrane system consists of the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles, along with the plasma membrane.

    Endoplasmic Reticulum (ER)

    • The ER, an extensive network of membranes, is continuous with the nuclear envelope.
    • It is a major site for protein and lipid synthesis.
    • Two types of ER:
      • Rough ER: studded with ribosomes, processing proteins (e.g., proteins secreted from the cell or proteins to be inserted into membranes).
      • Smooth ER: lacks ribosomes, involved in processes like lipid synthesis, carbohydrate metabolism, etc., detoxification.

    Golgi Apparatus

    • The Golgi apparatus receives proteins and lipids from the ER, modifies them, sorts them, and packages them into vesicles for delivery to other organelles or secretion.
    • It resembles flattened membrane sacs called cisternae, surrounded by vesicles.
    • It is a sorting station for proteins.

    Lysosomes

    • Lysosomes are vesicles containing hydrolytic enzymes, breaking down macromolecules: proteins, nucleic acids, lipids, and complex carbohydrates.
    • Lysosomes maintain an acidic pH, optimal for the hydrolytic enzymes.
    • Lysosomes are found only in animal cells.

    Vacuoles

    • Vacuoles are large vesicles that perform various roles, including storing nutrients.
    • Plant cells typically contain a central vacuole that helps maintain turgor pressure.
    • Digestive vacuoles analogous to animal lysosomes, degrade macromolecules.
    • Contractile vacuoles assist in regulating water balance (found in some protists).

    Mitochondria

    • Mitochondria are sites of cellular respiration, extracting energy from sugars, fats, and other fuels to produce ATP.
    • They are double-membraned organelles.
    • They have inner membrane in folds (cristae).
    • Some cells have many mitochondria; others have few (based on function).
    • The mitochondria have their own DNA and ribosomes.

    Chloroplasts

    • Chloroplasts capture light energy to make sugars through photosynthesis.
    • Also double-membraned
    • Internal membranes in stacks (grana)
    • Thylakoid membranes contain pigments.
    • Innermost space (stroma) contains enzymes for photosynthesis.

    Origins of Mitochondria and Chloroplasts (Endosymbiosis Theory)

    • Mitochondria and chloroplasts evolved from engulfed prokaryotic bacteria, respectively, aerobic bacteria and cyanobacteria, forming symbiotic relationships.
    • Evidence for this theory includes similar size to bacteria.
    • The engulfed bacteria have their own DNA and ribosomes.

    Peroxisomes

    • Peroxisomes are small metabolic compartments involved in various functions, including fatty acid breakdown and detoxification.
    • Peroxisomes produce hydrogen peroxide as a byproduct.
    • The hydrogen peroxide is broken down into water and oxygen using the enzyme catalase.

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    Biology 1 – Cells, Molecular Biology and Genetics (Biol 1000) PDF

    Description

    Test your knowledge on cell structures and functions in this quiz. Explore topics including the endoplasmic reticulum, ribosomes, and the role of various organelles in both prokaryotic and eukaryotic cells. Perfect for students studying cell biology concepts.

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