Biology: Characteristics of Life
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Questions and Answers

What do living organisms need to do to sustain life?

  • Only reproduce
  • Only respond to the environment
  • Take in energy, reproduce, respond to the environment, and consist of cells (correct)
  • Only take in energy

    • Death is the return to chemical equilibrium.

    False

    What is the environment preferred by microaerophilic organisms?

    Low concentration of dissolved oxygen

    Living cells are far from _______________________ equilibrium.

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

    Match the following terms with their definitions:

    <p>Equilibrium = The situation in which chemicals no longer have a tendency to react over time. Death = The moment when the system that maintains the far from equilibrium state ceases to exist. Life = A chemical system that uses energy to keep itself from reaching chemical equilibrium.</p> Signup and view all the answers

    What happens when the entire universe reaches equilibrium?

    <p>The heat death occurs</p> Signup and view all the answers

    Ciliates are macroaerophilic organisms.

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

    What are the complicated molecules found in the cytoplasm of cells?

    <p>Far from equilibrium molecules</p> Signup and view all the answers

    What is the characteristic of lipids?

    <p>They are generally water-insoluble.</p> Signup and view all the answers

    Amino acids can form a wide variety of combinations.

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

    What type of bonds do nucleotides form?

    <p>phosphodiester bonds</p> Signup and view all the answers

    Biological polymers are formed through _______ reactions.

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

    Match the following biological polymers with their characteristics:

    <p>Proteins = Form peptide bonds Polysaccharides = Form glycosidic bonds Nucleic Acids = Form phosphodiester bonds</p> Signup and view all the answers

    What is the term for the building blocks of polymers?

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

    Nucleic acids have the same variety as amino acids and proteins.

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

    What is the term for the process of combining monomers to form polymers?

    <p>modular construction</p> Signup and view all the answers

    What is the term for a substance that 'loves' water?

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

    The addition of a nonpolar substance to water increases the entropy of the system.

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

    What is the main reason for the spontaneous aggregation of nonpolar molecules in water?

    <p>The decrease in entropy of nonpolar molecules</p> Signup and view all the answers

    Water molecules have to be oriented with their _______________ ends away from nonpolar molecules.

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

    Match the following terms with their definitions:

    <p>Hydrophobic = water 'hating' Hydrophilic = water 'loving' Nonpolar = not having a permanent electric dipole moment Polar = having a permanent electric dipole moment</p> Signup and view all the answers

    What is the result of the aggregation of nonpolar molecules in water?

    <p>Decrease in entropy of the system</p> Signup and view all the answers

    What is the importance of water as a solvent in the context of the hydrophobic effect?

    <p>It is not just attractive, but also repulsive.</p> Signup and view all the answers

    Lipid bilayers tend to open up to form vesicles.

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

    What happens when amphipathic molecules associate?

    <p>Form diffusion barriers</p> Signup and view all the answers

    Protons exist freely in water.

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

    What is the result of increasing [H+] above 10-7 M?

    <p>The number in the exponent gets smaller</p> Signup and view all the answers

    PH is the power of _______________________

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

    Match the following terms with their descriptions:

    <p>Micelles = Form diffusion barriers pH Scale = Measures concentration of H+ and OH- Amphipathic molecules = Associate in different ways Hydronium ions = H+ combined with H2O</p> Signup and view all the answers

    What is the result of a spontaneous reaction?

    <p>Energy is released from the system</p> Signup and view all the answers

    Living organisms can survive in a state of chemical equilibrium.

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

    What is the term for the process of maintaining a stable, constant condition in an organism?

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

    The more complex the organism, the greater the ______________________ needs.

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

    What type of reactions are most metabolic reactions?

    <p>Oxidation-reduction (redox) reactions</p> Signup and view all the answers

    Prokaryotes have a nucleus and subcellular compartments.

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

    What is the term for the movement of electrons in metabolic reactions?

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

    What is the characteristic of eukaryotes?

    <p>They have a nucleus and subcellular compartments.</p> Signup and view all the answers

    The environment preferred by microaerophilic organisms is characterized by a low ______________________ of oxygen.

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

    Match the following domains with their characteristics:

    <p>Bacteria = Prokaryotic, single-celled Archaea = Prokaryotic, single-celled Eukarya = Eukaryotic, multi-cellular Viruses = Not a cell, can only replicate inside a host cell</p> Signup and view all the answers

    Study Notes

    What is Life?

    • Life is a set of qualifying factors that include: needing to take in energy, needing to reproduce, responding to the environment, and consisting of cells.
    • Life is a chemical system that uses energy to keep itself from reaching chemical equilibrium.

    Death

    • Death is not the return to chemical equilibrium.
    • Death is the moment when the system that maintains the far-from-equilibrium state ceases to exist.
    • Equilibrium is the situation in which chemicals no longer have a tendency to react over time.

    Biological Polymers

    • Biological polymers are macromolecules built from monomers (unit molecules) for structure and/or nutrient storage.
    • Examples include proteins (polypeptides), polysaccharides, and nucleic acids (polynucleotides).
    • These polymers are formed through condensation reactions, which involve the loss of H2O.

    Proteins

    • Proteins are also known as polypeptides.
    • They are formed through peptide or amide bonds.

    Nucleic Acids

    • Nucleic acids are polymers of nucleotides.
    • They form phosphodiester bonds.
    • The combination of nucleotides produces different conformations.

    Energy and Spontaneity

    • Life means order, which means a decrease in entropy (ΔS).
    • To make a reaction spontaneous, the change in free energy (ΔG) must be negative, which requires a decrease in enthalpy (ΔH) and an increase in temperature (ΔT).
    • High entropy means greater disorder and freedom of movement.

    Coupled Chemical Reactions

    • Unfavorable reactions can be "funded" by using the energy from a favorable reaction.
    • This is known as coupled chemical reactions.

    Metabolic Reactions

    • Most metabolic reactions are a series of oxidation-reduction (redox) reactions.
    • OIL RIG = Oxidation Is Loss; Reduction Is Gain (of electrons).
    • Metabolism is all about moving electrons around.

    The Three Domains of Life

    • The three domains of life are Bacteria, Archaea, and Eukarya.
    • Bacteria and Archaea are prokaryotes, which lack a nucleus and subcellular compartments.

    Hydrophobic Effect

    • The hydrophobic effect is the tendency of nonpolar substances to aggregate in water, decreasing the entropy of the system.
    • This is because nonpolar compounds do not dissolve in water.
    • The hydrophobic effect is related to entropy (S), not enthalpy (H).

    Amphiphilic Molecules

    • Amphiphilic molecules, such as palmitate, have both polar and nonpolar regions.
    • These molecules can arrange themselves to improve entropy, such as forming lipid bilayers.

    The pH Scale

    • The pH scale measures the concentration of hydrogen ions (H+) in a solution.
    • pH = power of hydrogen (etymology uncertain).
    • A decrease in pH means an increase in [H+].
    • Most biological acids and bases are not strong.

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    Discover the essential criteria that define life, including energy intake, reproduction, and cell composition. Learn about the fundamental characteristics of living organisms.

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