Biology Chapter: Cells
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Questions and Answers

What is the primary function of the plasma membrane in a cell?

  • Regulate the entry and exit of materials (correct)
  • Aid in protein synthesis
  • Facilitate energy production
  • Store genetic information

    • Which of the following elements is not primarily composed of cells?

  • Hydrogen
  • Nitrogen
  • Carbon
  • Helium (correct)

    • What role does cytoplasm play within a cell?

  • It regulates temperature
  • It provides structural rigidity
  • It stores genetic material
  • It is the site of most chemical reactions (correct)

    • What is a key characteristic of the cell wall?

    <p>It provides shape and support to plant cells</p> Signup and view all the answers

    Which component of a cell is responsible for protein synthesis?

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

    Which of the following best describes the composition of the plasma membrane?

    <p>A bilayer of lipids and proteins</p> Signup and view all the answers

    What percentage of a cell's composition is made up of oxygen?

    <p>24%</p> Signup and view all the answers

    What process allows cells to grow and divide?

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

    What is the primary function of the nucleus in a cell?

    <p>To control cell activity</p> Signup and view all the answers

    Which organelle is known as the powerhouse of the cell?

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

    What is the function of ribosomes in a cell?

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

    Which part of the endoplasmic reticulum is involved in making fats?

    <p>Smooth ER</p> Signup and view all the answers

    How does the Golgi body contribute to protein shipment?

    <p>It modifies, sorts, and packages proteins</p> Signup and view all the answers

    What role do lysosomes play in a cell?

    <p>To engulf foreign bodies and renew the cell</p> Signup and view all the answers

    What genetic material is contained within the nucleus?

    <p>Long strands of DNA</p> Signup and view all the answers

    What is the significance of proteins made by ribosomes?

    <p>They perform various essential functions in the cell</p> Signup and view all the answers

    What happens to enzymes when the body temperature exceeds 42°C?

    <p>They denature and stop functioning.</p> Signup and view all the answers

    How does carbon dioxide affect the pH of the blood?

    <p>It lowers the pH, making the blood more acidic.</p> Signup and view all the answers

    What is the consequence of a lack of vitamin C in the body?

    <p>Development of scurvy.</p> Signup and view all the answers

    What role does excess carbon dioxide play in regulating breathing rate?

    <p>It triggers an increase in breathing rate and depth.</p> Signup and view all the answers

    What is the optimal internal body temperature for human functioning?

    <p>37°C</p> Signup and view all the answers

    What is the primary reason enzymes denature at extreme temperatures?

    <p>Alteration of their three-dimensional structure.</p> Signup and view all the answers

    Which process helps in maintaining the balance of pH in the blood?

    <p>Removal of excess carbon dioxide.</p> Signup and view all the answers

    How are chemical substances transported to cells in the body?

    <p>By blood vessels in mammals.</p> Signup and view all the answers

    Study Notes

    Cells: The Building Blocks of Life

    • Cells are the smallest units of life, providing structure and performing essential functions.
    • Main functions include structural support, growth via mitosis, transportation of materials, energy production, metabolic reactions, and aiding in reproduction.

    Characteristics of Cells

    • Composed mainly of carbon, hydrogen, nitrogen, and oxygen: 59% Hydrogen, 24% Oxygen, 11% Carbon, 4% Nitrogen, and 2% other elements (Phosphorus, Sulfur, etc.).
    • All cells share basic parts: plasma membrane, cytoplasm, and nucleus.

    Common Parts of a Cell

    • Plasma Membrane:
      • A lipid bilayer that forms a barrier between the cell and its environment.
      • Semi-permeable, allowing selective material entry/exit.
    • Cytoplasm:
      • Gel-like substance where cellular chemical reactions occur.
      • Contains organelles such as nucleus, ribosomes, mitochondria, and more.
    • Ribosomes:
      • Sites for protein synthesis found in the cytoplasm.
    • DNA:
      • Genetic material providing instructions for life functions and traits.

    Specific Cell Structures

    • Cell Wall:
      • Present only in plant cells, composed of cellulose, hemicellulose, and pectin.
      • Provides rigidity, shape, and protection from mechanical injury.
    • Nucleus:
      • Controls cell activity and contains DNA, crucial for protein synthesis.

    Cell Organelles and Their Functions

    • Nucleolus: Produces ribosomes.
    • Endoplasmic Reticulum (ER):
      • Rough ER: Transports ribosomes; involved in protein production.
      • Smooth ER: Synthesizes lipids and detoxifies cell.
    • Golgi Bodies: Modifies, sorts, and packages proteins for transport.
    • Mitochondria: Known as the powerhouse of the cell; produces ATP, the energy currency.
    • Lysosomes: Contain digestive enzymes that help break down waste and protect the cell from foreign bodies.

    Protein Shipment Process

    • Ribosome synthesis begins in the nucleolus, continues in the rough ER, gets modified in the Golgi body, and is ultimately released from the cell via vesicles.

    Homeostasis and Temperature Regulation

    • Optimal body temperature is around 37°C; fluctuations can impair enzyme function.
    • Enzymes are sensitive to temperature, and extreme deviations can lead to denaturation, affecting life processes.

    Nutrient Maintenance

    • Insufficient nutrient intake can lead to diseases (e.g., scurvy from lack of vitamin C).
    • Essential for maintaining overall health and avoiding symptoms like bleeding gums and lack of appetite.

    Gas Exchange and pH Balance

    • Carbon dioxide lowers blood pH and needs rapid removal to prevent acid buildup.
    • Increased carbonic acid leads to elevated breathing rates to restore pH balance.

    Chemical Substances in the Body

    • Body activities are controlled by various chemical substances, transported through blood in mammals or vascular tissues in plants for cellular function.

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    Description

    Explore the fundamental unit of life with this quiz on cells. Learn about their characteristics, main functions, and how they contribute to the body's structure and processes. Test your knowledge about the building blocks of life!

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