1-4 Chem of Life and 2-1 Cell Theory Test
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Questions and Answers

What primarily determines the kind of element an atom is?

  • The number of protons (correct)
  • The number of electrons
  • The atomic mass
  • The number of neutrons

    • Which statement is true regarding electron configuration?

  • Electrons are positively charged particles.
  • Electrons orbit the nucleus at fixed distances. (correct)
  • Electrons exist solely in the nucleus.
  • Electrons are found in the nucleus.

    • Which of the following elements has an atomic number of 6?

  • Nitrogen
  • Carbon (correct)
  • Oxygen
  • Hydrogen

    • Which type of particle in an atom has no charge?

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

    What term is used to describe the smallest unit of matter?

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

    How many electrons does a hydrogen atom have?

    <p>1</p> Signup and view all the answers

    Which of the following describes an ionic bond?

    <p>Transfer of electrons between atoms</p> Signup and view all the answers

    What defines an element?

    <p>A substance made up of only one type of atom</p> Signup and view all the answers

    What forms when atoms gain or lose electrons form what type of bond?

    <p>Larger structures or molecules</p> Signup and view all the answers

    Which type of bond is formed when electrons are shared?

    <p>Covalent bond</p> Signup and view all the answers

    Which of the following statements is true about compounds?

    <p>Compounds are when two or more atoms are involved</p> Signup and view all the answers

    What causes the attraction between cations and anions in ionic bonds?

    <p>Opposite charges attracting</p> Signup and view all the answers

    Which of the following statements about molecules is incorrect?

    <p>All molecules are compounds</p> Signup and view all the answers

    Which type of bond is characterized by the sharing of electrons between atoms?

    <p>Covalent bond</p> Signup and view all the answers

    What type of bond forms through the loss and gain of electrons?

    <p>Ionic Bond</p> Signup and view all the answers

    What is the defining characteristic of covalent bonds?

    <p>Electrons are shared between atoms</p> Signup and view all the answers

    How does a water molecule achieve stability?

    <p>By sharing electrons with hydrogen and oxygen</p> Signup and view all the answers

    Which type of bond stabilizes the double helix structure of DNA?

    <p>Hydrogen Bonds</p> Signup and view all the answers

    Which bond requires a large amount of energy to break?

    <p>Covalent Bond</p> Signup and view all the answers

    What type of attraction causes hydrogen bonds to form?

    <p>Electrostatic attraction between electrons of elements</p> Signup and view all the answers

    What does the cell theory state regarding living organisms?

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

    Which principle of the cell theory explains the origin of new cells?

    <p>A new cell comes from a pre-existing cell.</p> Signup and view all the answers

    What is the significance of hereditary information in cell reproduction?

    <p>It is passed from a parent cell to a daughter cell.</p> Signup and view all the answers

    How does energy flow in relation to cells according to cell theory?

    <p>Energy flow occurs within cells.</p> Signup and view all the answers

    Which of the following statements accurately describes cellular structure according to cell theory?

    <p>Cells are the basic structural unit of all living organisms.</p> Signup and view all the answers

    What early invention contributed significantly to the discovery of cells?

    <p>The compound microscope.</p> Signup and view all the answers

    Which common characteristic is shared by all cells according to cell theory?

    <p>All cells contain DNA.</p> Signup and view all the answers

    What do all cells share in terms of composition, according to cell theory?

    <p>They have similar chemical compositions.</p> Signup and view all the answers

    Who first described the cellular structure of plants and identified the plant cell nucleus?

    <p>Matthias Schleiden</p> Signup and view all the answers

    Which statement accurately describes one of the conclusions drawn by Theodor Schwann?

    <p>The cell is the fundamental structure of life.</p> Signup and view all the answers

    What was later disproven and rejected regarding cell theory?

    <p>Cells are formed through spontaneous generation.</p> Signup and view all the answers

    Rudolph Virchow's studies led to the conclusion that cells arise from which of the following?

    <p>Pre-existing cells</p> Signup and view all the answers

    Which of the following scientists' work marked the beginning of modern cell theory?

    <p>Matthias Schleiden and Theodor Schwann</p> Signup and view all the answers

    What does the cell theory define as the main unit of life?

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

    Which advancement in science expanded the theory of cells to cover heredity and energy production?

    <p>Cellular Reproduction</p> Signup and view all the answers

    Which statement about cell theory is true based on historical contributions?

    <p>Cells are the essential building blocks of all living organisms.</p> Signup and view all the answers

    What did Robert Hooke observe in the cork that led to his naming of cells?

    <p>Allowed him to see the empty cell walls of the cork</p> Signup and view all the answers

    How did Robert Hooke enhance his ability to observe cells?

    <p>By building a compound microscopy device</p> Signup and view all the answers

    What did Antonie van Leeuwenhoek call the tiny moving organisms he observed?

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

    What was a significant contribution of Antonie van Leeuwenhoek to cell theory?

    <p>He disproved the theory of spontaneous generation.</p> Signup and view all the answers

    What led Leeuwenhoek to believe that the tiny creatures he observed were living organisms?

    <p>Their visible movement</p> Signup and view all the answers

    Which observation by Hooke was crucial in the development of cell theory?

    <p>He described the empty cell walls as partitions.</p> Signup and view all the answers

    What method did Leeuwenhoek use to observe tiny structures that had never been seen before?

    <p>Grinding and polishing lenses</p> Signup and view all the answers

    Which achievement is NOT associated with Antonie van Leeuwenhoek?

    <p>Naming the term cell</p> Signup and view all the answers

    In the organization of organisms which is the first step

    <p>Small molecules</p> Signup and view all the answers

    In the organization of organisms which is the second level

    <p>Large molecules</p> Signup and view all the answers

    What is the third step In the organization of organisms?

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

    What is the fourth step In the organization of organisms?

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

    What is the 5th step In the organization of organisms?

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

    What is the 6th step In the organization of organisms?

    <p>organ systems</p> Signup and view all the answers

    What is the final step In the organization of organisms?

    <p>complexed organisms</p> Signup and view all the answers

    The four main macromolecules are found in ______________?

    <p>All cells have a similar chemical composition</p> Signup and view all the answers

    Which microscopic organisms did Antonie van Leeuwenhoek first observe?

    <p>Bacteria and protozoa</p> Signup and view all the answers

    How did Antonie van Leeuwenhoek’s contributions influence future scientists?

    <p>He laid the groundwork for microbiology and cell biology.</p> Signup and view all the answers

    The cell is the basic __________ of life?

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

    What misconception did people hold before Leeuwenhoek's discovery that was later disproven?

    <p>Living organisms could arise from non-living things.</p> Signup and view all the answers

    What does the cell theory state about the composition of living organisms?

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

    What process do cells undergo to ensure continuity of life?

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

    Which of the following scientists contributed to the cell theory by studying animal cells?

    <p>Theodor Schwann</p> Signup and view all the answers

    Which limitation of cell theory involves organisms that do not consist of cells?

    <p>It does not encompass viruses.</p> Signup and view all the answers

    Study Notes

    Atoms and Elements

    • Elements are pure substances made of one type of atom; 94 naturally occurring elements known.
    • Six main elements in biological molecules: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Sulfur (S), Phosphorus (P).
    • Atomic structure consists of a nucleus (protons and neutrons) and electron shells or orbitals (electrons).

    Structure of Atoms

    • Protons are positively charged, neutrons are neutral, and electrons are negatively charged.
    • Atomic number defines the element, equal to the number of protons; e.g., Carbon has an atomic number of 6.
    • Hydrogen atom is an exception, containing one proton and one electron, but no neutrons.

    Chemical Bonds

    • Chemical bonding occurs through the gain, loss, or sharing of electrons, leading to larger stable structures.
    • Bonds formed by atoms can be classified into three main types: ionic, covalent, and hydrogen bonds.

    Ionic Bonds

    • Formed when atoms gain or lose electrons, resulting in positively charged cations and negatively charged anions.
    • Opposite charges lead to attraction between ions, creating strong ionic bonds requiring significant energy to break.
    • Common biologically relevant ions: sodium (Na), potassium (K), calcium (Ca) are essential for nerve function, muscle contraction, and water balance.

    Covalent Bonds

    • Formed by the sharing of electrons between atoms, as observed in water and many organic molecules.
    • In water, each hydrogen atom shares one electron with oxygen, stabilizing the molecule by completing the outer electron shells.

    Hydrogen Bonds

    • Weaker bonds that require less energy to break, arising from electrostatic attraction between a proton in one molecule and an electronegative atom in another.
    • Crucial for the structural stability of DNA, where covalent bonds form the backbone and hydrogen bonds stabilize the double helix structure.

    Cell Theory Overview

    • Central principle in biology asserting that all living organisms consist of one or more cells, which are the basic unit of life.
    • Comprises six core principles:
      • All living organisms are composed of cells.
      • The cell is the fundamental unit of life.
      • New cells arise from pre-existing cells.
      • Hereditary information is transferred from parent to daughter cells during reproduction.
      • All cells share similar chemical compositions.
      • Energy flow occurs within cells.

    Historical Development of Cell Theory

    • Discovery of the cell originated with the invention of the microscope.
    • Robert Hooke (1665) observed cork under a microscope, identifying the empty cell walls and coining the term "cell" from the Latin word cella.
    • Hooke’s publication, Micrographia, documented his findings, including drawings of cells and observations like those of a flea.

    Contributions of Key Scientists

    • Antonie van Leeuwenhoek:

      • First to observe live microorganisms he named "animalcules" through custom-crafted lenses.
      • Identified red blood cells, bacteria, and protozoa and observed fertilization, debunking spontaneous generation.

    • Henri Dutrochet (early 19th century):

      • Established cells as fundamental elements of life, both structurally and physiologically.

    • Matthias Schleiden and Theodor Schwann (1838-1839):

      • Proposed cell theory; Schleiden focused on plant cells while Schwann examined animal cells.
      • Concluded that cells are the basic structural units of both plants and animals.

    • Rudolph Virchow:

      • Advanced the cell theory by asserting that all cells arise from existing cells, rejecting the notion of spontaneous generation.

    Comprehension Check Points

    • Principles identified for comprehension checks:
      • The functional unit of living things: all organisms consist of cells.
      • Cell division and reproduction: new cells come from pre-existing cells.
      • DNA transmission: hereditary information is conserved between parent and daughter cells.
      • Metabolic processes: energy flow occurs within cells.
      • Chemical composition: all cells exhibit similar macromolecular structures.

    Significance of Discoveries

    • Hooke and Leeuwenhoek's pioneering work laid the foundation for microscopy and cellular biology, enabling subsequent discoveries.
    • Cell theory provides a framework for understanding the complexity of life, integrating findings from various scientific disciplines.

    Cell Theory

    • Fundamental principle in biology establishing that all living organisms are made up of cells, which are the basic units of life, and that all cells originate from pre-existing cells.

    Historical Development

    • Formulated in the mid-19th century by:
      • Matthias Schleiden: contributed to the understanding of plant cells.
      • Theodor Schwann: focused on animal cells.
      • Rudolf Virchow: emphasized the process of cell division, introducing the idea that cells arise from existing cells.

    Key Concepts

    • Cell Structure:
      • Cells are classified as unicellular (single-celled organisms) or multicellular (organisms made of multiple cells).
    • Cell Function:
      • Cells perform vital life activities including metabolism, reproduction, and response to environmental stimuli.
    • Cell Division:
      • Reproduction occurs via processes such as mitosis (cellular division producing two identical cells) and meiosis (production of gametes).

    Types of Cells

    • Prokaryotic Cells:
      • Simplest cellular form, lacking a nucleus and membrane-bound organelles, exemplified by bacteria.
    • Eukaryotic Cells:
      • More complex cells that contain a nucleus and various organelles, includes plant and animal cells.

    Importance

    • Provides a foundational framework for biological studies and research, influencing cell biology, medicine, and genetics.

    Limitations

    • Cell theory does not encompass viruses, as these entities do not possess cellular structures and are not classified as living organisms.

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    Quiz Team

    Description

    This test covers the fundamental concepts of the chemistry of life, including the structure of atoms and the six key elements that make up biological molecules. Students will explore different types of chemical bonding such as covalent and ionic bonds. Mastery of the key vocabulary related to atoms and molecules is crucial for understanding biological chemistry.

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