39 Questions
What do living organisms need to do to sustain life?
Take in energy, reproduce, respond to the environment, and consist of cells
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.
chemical
Match the following terms with their definitions:
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.
What happens when the entire universe reaches equilibrium?
The heat death occurs
Ciliates are macroaerophilic organisms.
False
What are the complicated molecules found in the cytoplasm of cells?
Far from equilibrium molecules
What is the characteristic of lipids?
They are generally water-insoluble.
Amino acids can form a wide variety of combinations.
True
What type of bonds do nucleotides form?
phosphodiester bonds
Biological polymers are formed through _______ reactions.
condensation
Match the following biological polymers with their characteristics:
Proteins = Form peptide bonds Polysaccharides = Form glycosidic bonds Nucleic Acids = Form phosphodiester bonds
What is the term for the building blocks of polymers?
Monomers
Nucleic acids have the same variety as amino acids and proteins.
False
What is the term for the process of combining monomers to form polymers?
modular construction
What is the term for a substance that 'loves' water?
Hydrophilic
The addition of a nonpolar substance to water increases the entropy of the system.
False
What is the main reason for the spontaneous aggregation of nonpolar molecules in water?
The decrease in entropy of nonpolar molecules
Water molecules have to be oriented with their _______________ ends away from nonpolar molecules.
polar
Match the following terms with their definitions:
Hydrophobic = water 'hating' Hydrophilic = water 'loving' Nonpolar = not having a permanent electric dipole moment Polar = having a permanent electric dipole moment
What is the result of the aggregation of nonpolar molecules in water?
Decrease in entropy of the system
What is the importance of water as a solvent in the context of the hydrophobic effect?
It is not just attractive, but also repulsive.
Lipid bilayers tend to open up to form vesicles.
False
What happens when amphipathic molecules associate?
Form diffusion barriers
Protons exist freely in water.
False
What is the result of increasing [H+] above 10-7 M?
The number in the exponent gets smaller
PH is the power of _______________________
hydrogen
Match the following terms with their descriptions:
Micelles = Form diffusion barriers pH Scale = Measures concentration of H+ and OH- Amphipathic molecules = Associate in different ways Hydronium ions = H+ combined with H2O
What is the result of a spontaneous reaction?
Energy is released from the system
Living organisms can survive in a state of chemical equilibrium.
False
What is the term for the process of maintaining a stable, constant condition in an organism?
homeostasis
The more complex the organism, the greater the ______________________ needs.
energy
What type of reactions are most metabolic reactions?
Oxidation-reduction (redox) reactions
Prokaryotes have a nucleus and subcellular compartments.
False
What is the term for the movement of electrons in metabolic reactions?
redox
What is the characteristic of eukaryotes?
They have a nucleus and subcellular compartments.
The environment preferred by microaerophilic organisms is characterized by a low ______________________ of oxygen.
concentration
Match the following domains with their characteristics:
Bacteria = Prokaryotic, single-celled Archaea = Prokaryotic, single-celled Eukarya = Eukaryotic, multi-cellular Viruses = Not a cell, can only replicate inside a host cell
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.
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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