Biology and Chemistry Introduction Quiz
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Questions and Answers

A scientist observes that plants grow taller in sunny areas compared to shady areas. Following the scientific method, what would be the next logical step?

  • Publish the observation in a scientific journal.
  • Formulate a hypothesis about the relationship between sunlight and plant growth. (correct)
  • Analyze the data from previous experiments on plant growth.
  • Draw a conclusion that sunlight is essential for plant growth.

    • Which of the following is NOT a characteristic shared by all living organisms?

  • Ability to perform photosynthesis. (correct)
  • Composed of cells.
  • Ability to maintain homeostasis.
  • Capacity to evolve over time.

    • An atom has an atomic number of 6 and an atomic mass of 14. How many neutrons does it have?

  • 8 (correct)
  • 6
  • 14
  • 20

    • Which of the following statements accurately describes the role of valence electrons?

    <p>Valence electrons are involved in forming chemical bonds. (A)</p> Signup and view all the answers

    Why is the 'octet rule' important in understanding chemical bonding?

    <p>It explains why atoms tend to gain, lose, or share electrons to achieve a full outer shell. (D)</p> Signup and view all the answers

    Which of the statements accurately describes the relationship between anabolic and catabolic reactions?

    <p>Anabolic reactions require energy to build molecules, while catabolic reactions release energy by breaking down molecules. (D)</p> Signup and view all the answers

    According to the first law of thermodynamics, what happens to energy during a biological process?

    <p>Energy is transformed from one form to another, but the total amount remains constant. (C)</p> Signup and view all the answers

    How does the second law of thermodynamics relate to biological systems?

    <p>It suggests that energy transfer leads to an increase in entropy, requiring constant energy input to maintain order. (C)</p> Signup and view all the answers

    Why is ATP considered the primary energy currency of the cell?

    <p>It provides energy immediately for cellular functions through hydrolysis. (D)</p> Signup and view all the answers

    To effectively prepare for an exam on these topics, which approach would be most beneficial?

    <p>Drawing chemical structures and reactions to understand concepts. (D)</p> Signup and view all the answers

    Which characteristic is NOT shared by all living organisms?

    <p>Capable of photosynthesis (D)</p> Signup and view all the answers

    During an experiment, a scientist notices that the data contradicts their initial hypothesis. According to the scientific method, what is the next step?

    <p>Reject or revise the hypothesis and design a new experiment. (B)</p> Signup and view all the answers

    How does increasing the number of neutrons affect an atom?

    <p>It forms an isotope of the same element. (D)</p> Signup and view all the answers

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

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

    What property of water allows insects to walk on its surface?

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

    Which of the following solutions would be considered acidic?

    <p>A solution with a pH of 2 (C)</p> Signup and view all the answers

    What is the primary function of carbohydrates in living organisms?

    <p>Provide a source of energy (C)</p> Signup and view all the answers

    Which type of macromolecule is primarily responsible for catalyzing biochemical reactions in cells?

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

    What happens to an enzyme when it is denatured?

    <p>It loses its specific three-dimensional shape and function. (D)</p> Signup and view all the answers

    Which process describes the synthesis of complex molecules from simpler ones, requiring energy input?

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

    According to the first law of thermodynamics, what happens to energy in a closed system?

    <p>It remains constant but can change form. (A)</p> Signup and view all the answers

    How do buffers stabilize pH levels in biological systems?

    <p>By releasing or absorbing hydrogen ions ($H^+$) as needed. (B)</p> Signup and view all the answers

    Which of the following bonds is the weakest?

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

    Which property of water is most responsible for the moderation of temperature changes in coastal areas?

    <p>High specific heat (D)</p> Signup and view all the answers

    Cellulose is a polysaccharide found in plants. What is its primary function?

    <p>Structural support. (D)</p> Signup and view all the answers

    Flashcards

    Characteristics of Life

    Living organisms share characteristics such as cell composition, energy requirement, homeostasis, growth, reproduction, responses to stimuli, and evolution.

    Scientific Method

    A systematic process for scientific investigation: Observation, Hypothesis, Experiment, Analysis, Conclusion.

    Atoms

    Atoms are the smallest units of matter, composed of protons, neutrons, and electrons.

    Valence Electrons

    Electrons in the outermost shell of an atom that determine its chemical behavior.

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    Octet Rule

    Atoms are most stable when they have 8 valence electrons, except for hydrogen and helium.

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    Catabolic Reactions

    Reactions that break down molecules and release energy, such as cellular respiration.

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    Anabolic Reactions

    Reactions that build molecules and require energy, like photosynthesis.

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    First Law of Thermodynamics

    Energy cannot be created or destroyed; it can only change forms.

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    Second Law of Thermodynamics

    Energy transfer increases entropy or disorder in the system over time.

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    ATP

    Adenosine triphosphate; the primary energy currency for cellular processes.

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    Ionic Bonds

    Formed when electrons are transferred between atoms, creating cations and anions.

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    Hydrogen Bonds

    Weak attractions between partially charged molecules, such as water.

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    Cohesion

    Water molecules stick together, creating surface tension.

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    Adhesion

    Water molecules stick to other substances, enabling capillary action.

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    pH Scale

    Ranges from 0 (acidic) to 14 (basic), with 7 being neutral.

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    Buffers

    Substances that help maintain stable pH by absorbing excess H+ or OH-.

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    Carbohydrates

    Macromolecules serving as energy sources and structural support.

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    Lipids

    Hydrophobic molecules used for energy storage and cell membranes.

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    Proteins

    Made of amino acids; perform various cellular functions.

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    Nucleic Acids

    Molecules like DNA and RNA that store and transmit genetic information.

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    Enzymes

    Catalysts that speed up biochemical reactions by lowering activation energy.

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    Active Site

    The region on an enzyme where the substrate binds.

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    Denaturation

    Loss of enzyme function due to changes in temperature or pH.

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    Study Notes

    Chapter 1: Introduction to Biology

    • Biology studies life, characterized by shared traits
    • Living organisms are composed of cells
    • Organisms require energy for metabolic processes
    • Homeostasis regulates internal conditions
    • Growth, development, and reproduction (asexual/sexual) are essential
    • Organisms respond to stimuli and evolve over time
    • Scientific method: Observation, Hypothesis, Experiment, Analysis, Conclusion
    • Molecular and cellular biology is crucial for various fields (medicine, pharmacy, genetics, microbiology)

    Chapter 2: Chemistry of Life

    Matter and Atoms

    • Matter has mass and occupies space
    • Atoms are made of protons (+), neutrons (0), and electrons (-)
    • Atomic number is the number of protons
    • Atomic mass is the sum of protons and neutrons
    • Isotopes have the same element but different neutron counts
    • Electron shells have fixed electron capacity.

    Electron Configuration

    • Electrons occupy energy levels (shells)
    • Valence electrons, in the outermost shell, dictate chemical behavior
    • Octet rule: Atoms (except H and He) seek stability with 8 valence electrons.

    Chemical Bonds

    • Covalent bonds involve shared electrons (polar/nonpolar)
    • Ionic bonds involve electron transfer (forming cations and anions)
    • Hydrogen bonds are weak attractions between polar molecules

    Properties of Water

    • Cohesion (water-water attraction) creates surface tension
    • Adhesion (water-other substance attraction) causes capillary action
    • High specific heat regulates temperature
    • Ice is less dense than liquid water, causing ice to float
    • Water dissolves polar and ionic substances (hydration shells), thus serving as a universal solvent.
    • Hydrophobic substances repel water, while hydrophilic substances attract water.

    pH Scale and Buffers

    • pH scale measures H⁺ ion concentration (0-14)
    • Acids release H⁺ ions; bases accept them or release OH⁻ ions
    • Buffers maintain stable pH by absorbing or releasing H⁺ ions.

    Macromolecules

    • Carbohydrates: Energy source (monosaccharides, polysacchrides)
    • Lipids: Hydrophobic energy storage and membrane components (fats, phospholipids, steroids)
    • Proteins: Made of amino acids, perform cellular functions (enzymes, structure, transport).
    • Nucleic acids: Store genetic information (DNA and RNA), and ATP (energy carrier).

    Enzymes and Metabolism

    • Enzymes speed up reactions by lowering activation energy
    • Active site is where the substrate binds
    • Lock-and-key model describes a precise substrate-enzyme fit
    • Denaturation disrupts enzyme function (through changes in temperature or pH)
    • Anabolic reactions build molecules, requiring energy; catabolic reactions break down molecules, releasing energy

    Thermodynamics in Biology

    • First Law: Energy cannot be created or destroyed
    • Second Law: Energy transfer increases disorder (entropy)
    • Living systems maintain order by constant energy input like ATP production

    Quick Review Questions

    • Three subatomic particles and their charges: proton (+), neutron (0), electron (-)
    • Differences between covalent and ionic bonds: Covalent bonds share electrons, whereas ionic bonds transfer electrons
    • Four properties of water supporting life: Cohesion, adhesion, high specific heat, and density properties
    • Enzymes’ role in metabolism: Enzymes catalyze reactions by lowering activation energy
    • pH definition, and buffer role: pH measures H⁺ concentration; buffers stabilize pH
    • Thermodynamics in biology: First law: Energy conservation; Second law: Entropy increase

    Study Tips

    • Focus on understanding concepts instead of memorizing definitions
    • Use flashcards for key terms and macromolecules
    • Practice drawing chemical structures and reactions
    • Watch animations about enzymes and thermodynamics
    • Take practice quizzes for knowledge retention.

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    Description

    Test your knowledge on the fundamentals of biology and chemistry. This quiz covers essential concepts from living organisms, cellular structures, atomic composition, and the scientific method. Perfect for students beginning their studies in the life sciences.

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