Biochemistry Chapter on Cell Structure
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Questions and Answers

What is the primary function of the endoplasmic reticulum?

  • Transport of nutrients
  • Protein synthesis (correct)
  • Storage of molecules
  • DNA replication

    • What does the nuclear membrane primarily do?

  • Stores genetic information
  • Facilitates muscle contraction
  • Produces ribosomes
  • Surrounds and protects the nucleus (correct)

    • Which of the following is NOT a component of the nucleus?

  • Nucleoplasm
  • Chromatin
  • Ribosomes (correct)
  • Nucleolus

    • What is a key feature of nuclear pores?

    <p>They permit exchange between nucleoplasm and cytoplasm.</p> Signup and view all the answers

    Which organelle is responsible for molecule export?

    <p>Golgi apparatus</p> Signup and view all the answers

    Nucleoplasm is most similar to which part of the cell?

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

    What is the primary composition of the nucleolus?

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

    What is chromatin primarily composed of?

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

    What is the primary function of RNA polymerases in the nucleus?

    <p>To synthesize RNA from a DNA template</p> Signup and view all the answers

    What do transcription factors primarily do in the process of transcription?

    <p>They bind to specific DNA sequences to regulate gene expression</p> Signup and view all the answers

    Which process requires energy for the transport of macromolecules like RNA and proteins?

    <p>Active transport</p> Signup and view all the answers

    What essential role do topoisomerases play during transcription?

    <p>They change the level of supercoiling in DNA</p> Signup and view all the answers

    How do small molecules behave when entering the nucleus?

    <p>They can enter without regulation or energy</p> Signup and view all the answers

    What happens to the nucleus during the process of cell division?

    <p>It disappears and is broken down</p> Signup and view all the answers

    What is NOT a function of the proteins found in the nucleus?

    <p>Synthesizing DNA molecules</p> Signup and view all the answers

    Which statement about nuclear transport is false?

    <p>Energy is not needed for macromolecule transport.</p> Signup and view all the answers

    What is the primary technique used to study cells?

    <p>Biochemistry techniques</p> Signup and view all the answers

    Which process is NOT part of cell fractionation?

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

    How are different organelles separated during differential centrifugation?

    <p>Based on their size and density</p> Signup and view all the answers

    What is the composition of the cell membrane?

    <p>Two layers of phospholipids</p> Signup and view all the answers

    What is a primary result of using microscopy in cell fractionation?

    <p>Identifying organelles in each pellet</p> Signup and view all the answers

    Which organelles are specifically mentioned as being identified through biochemical methods?

    <p>Lysosomes and mitochondria</p> Signup and view all the answers

    What type of cell is primarily being referred to in the study of organelles?

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

    What does the term 'homogenate' refer to in cell fractionation?

    <p>A mixture of unreduced cell contents</p> Signup and view all the answers

    What are ribosomes primarily made of?

    <p>rRNA and ribosomal proteins</p> Signup and view all the answers

    What type of ribosomes are found in prokaryotes?

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

    Where are bound ribosomes located?

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

    Which structure is essential for the production of energy in a cell?

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

    What is a common disorder related to ribosome function?

    <p>Shwachman diamond syndrome</p> Signup and view all the answers

    What component of the mitochondrion is responsible for producing the majority of ATP during cellular respiration?

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

    Which ribosomal subunits are found in eukaryotes?

    <p>40S and 60S</p> Signup and view all the answers

    What part of the mitochondrion is known to contain its DNA?

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

    What is the main role of the Golgi apparatus in relation to proteins?

    <p>Shipping and sorting proteins</p> Signup and view all the answers

    Which of the following is NOT a defect associated with issues in Golgi function?

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

    What do vesicles produced by the Golgi apparatus primarily transport?

    <p>Proteins for secretion</p> Signup and view all the answers

    How do products modify as they pass through the Golgi apparatus?

    <p>They undergo enzymatic modifications</p> Signup and view all the answers

    What type of disorders can result from mistakes made by the Golgi apparatus?

    <p>Congenital glycosylation disorders</p> Signup and view all the answers

    What is the function of vacuoles as mentioned in the content?

    <p>Storing substances for later use</p> Signup and view all the answers

    Which of the following is an example of a substance transported by vesicles from the Golgi apparatus?

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

    What could be a potential consequence if the Golgi apparatus incorrectly ships proteins?

    <p>Cellular functions may cease</p> Signup and view all the answers

    Study Notes

    Studying Cells

    • Biochemistry techniques are used to study cells
    • Cell fractionation separates cell components based on size and density
      • Homogenization - Process of breaking open cells
      • Ultracentrifugation - Separates organelles based on density

    Cell Fractionation

    • Larger organelles separate first during centrifugation
    • Organelles are identified using microscopy
    • Biochemical methods determine the functions of organelles

    Cell Membrane

    • Also known as the plasma membrane
    • Composed of two layers of phospholipids
    • Endoplasmic reticulum and Golgi apparatus are connected through the endomembrane system

    The Nucleus

    • The largest cellular organelle in animals
    • Components of the nucleus include:
      • Nuclear membrane
      • Nucleoplasm
      • Nucleolus
      • Chromatin and chromosomes

    Nuclear Membrane

    • Consists of a double membrane layer and contains nuclear pores
    • Provides structural support and protection for the nucleus
    • Enables the movement of molecules between the nucleus and cytoplasm

    Nucleoplasm

    • Liquid found inside the nucleus
    • Contains DNA, RNA, and other cellular materials
    • Similar to the cytosol within the cytoplasm

    Nucleolus

    • Sub-organelle of the cell nucleus
    • Composed of rRNA and proteins
    • Site of ribosome synthesis

    Chromatin

    • Composed of DNA and proteins
    • Found inside the nucleus of eukaryotic cells
    • Condensed to form chromosomes during cell division

    Nuclear Transport

    • Small molecules can enter the nucleus passively, without energy
    • Macromolecules like RNA and proteins require active transport across the nuclear membrane
      • This process is regulated by nuclear pore complexes

    Assembly and Disassembly of the Nucleus

    • During cell division, the nucleus breaks down
    • Nucleus reforms during the final stages of cell division

    The Golgi Apparatus

    • Important role in protein synthesis
    • Modifies and packages proteins
    • Defects in Golgi function can cause disorders like congenital glycosylation disorders, muscular dystrophy, diabetes, cancer, and cystic fibrosis

    Ribosomes

    • Consist of a large subunit and a small subunit
    • Found in both prokaryotic and eukaryotic cells
      • Prokaryotic ribosomes are smaller (70S)
      • Eukaryotic ribosomes are larger (80S)
    • Synthesize proteins for use within the cell and for export

    Ribosome Types

    • Free ribosomes are suspended in the cytoplasm
      • Involved in making proteins that function within the cytoplasm
    • Bound ribosomes are attached to the endoplasmic reticulum
      • Involved in making proteins destined for export or packaging within organelles

    Disorders of Ribosomes

    • Defects in ribosome function can cause various disorders:
      • Anemia
      • Cartilage hair hypoplasia
      • Shwachman-Diamond Syndrome
      • Dyskeratosis congenita

    Mitochondria

    • Powerhouse of the cell responsible for energy production
    • Consists of:
      • Outer membrane
      • Inner membrane
      • Matrix
      • Cristae
      • Intermembrane space
    • Mitochondria contain their own DNA and ribosomes, allowing them to self-replicate

    Biomedical Importance of Mitochondria

    • Mitochondria are essential for cellular respiration, which produces energy for the cell

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    Cell Structure and Function PDF

    Description

    This quiz covers key concepts related to cell structure and function, focusing on biochemistry techniques such as cell fractionation and the composition of cellular organelles. Students will explore the details of cell membranes, the nucleus, and the processes involved in studying these components. Perfect for those studying biochemistry or cell biology!

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