Fundamentals of Chemistry Quiz
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Questions and Answers

What happens to glycolysis when glucose levels are low in the blood?

  • Glycolysis continues as normal.
  • Glycolysis is switched off. (correct)
  • Glycolysis becomes more efficient.
  • Glycolysis is activated.

    • Which hormone is released when blood glucose levels are high?

  • Insulin (correct)
  • Glucagon
  • Cortisol
  • Adrenaline

    • Which pathway is an alternative to glycolysis that is utilized by many bacteria?

  • Gluconeogenesis
  • Pentose Phosphate Pathway
  • Entner-Doudoroff Pathway (correct)
  • Krebs Cycle

    • What is produced during the oxidative decarboxylation of pyruvate?

    <p>One molecule of Acetyl-CoA</p> Signup and view all the answers

    What is a key feature of slow regulation of glucose levels?

    <p>It is mediated by hormonal changes.</p> Signup and view all the answers

    What is the main energy yield from glycolysis per glucose molecule?

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

    Which enzyme is responsible for converting pyruvate into acetyl-CoA?

    <p>Pyruvate dehydrogenase</p> Signup and view all the answers

    Which of the following statements correctly describes glucagon's role in glucose regulation?

    <p>It promotes the conversion of glycogen to glucose.</p> Signup and view all the answers

    What role does cytochrome C play in the electron transport chain?

    <p>It shuttles electrons to complex IV.</p> Signup and view all the answers

    What is the primary role of chaperones in protein formation?

    <p>To facilitate the correct folding of proteins</p> Signup and view all the answers

    How does complex IV contribute to the formation of a proton gradient?

    <p>By pumping protons across the inner mitochondrial membrane.</p> Signup and view all the answers

    In globular proteins, hydrophobic side chains are predominantly located where?

    <p>In the center of the protein core</p> Signup and view all the answers

    What is the primary function of ATP synthase?

    <p>To facilitate proton flow for ATP synthesis.</p> Signup and view all the answers

    Which of the following statements correctly describes the proton motive force?

    <p>It combines a chemical gradient and a charge gradient.</p> Signup and view all the answers

    Which chromatography method separates proteins based on their size?

    <p>Size-exclusion chromatography</p> Signup and view all the answers

    What happens to proteins during SDS-PAGE?

    <p>Proteins acquire a negative charge and are denatured</p> Signup and view all the answers

    What effect does oligomycin have on mitochondrial function?

    <p>It decreases mitochondrial respiration.</p> Signup and view all the answers

    What is the outcome of the malate/aspartate shuttle?

    <p>Net yield of 2.5 ATP.</p> Signup and view all the answers

    How do ionizable side chains primarily interact in globular proteins?

    <p>Via London forces and salt bridges</p> Signup and view all the answers

    What is the isoelectric point (pI) of a protein?

    <p>The pH where the protein exhibits a net charge of zero</p> Signup and view all the answers

    What occurs during the conformational changes in the beta subunits of ATP synthase?

    <p>They help release ATP and prepare for the next cycle.</p> Signup and view all the answers

    What is the primary reason the proton gradient is essential for ATP synthase function?

    <p>It allows protons to release ATP from the synthase.</p> Signup and view all the answers

    What characterizes affinity chromatography?

    <p>Interaction with tagged proteins and specific groups in the column</p> Signup and view all the answers

    Which force generally drives the interactions between the hydrophobic side chains of amino acids in proteins?

    <p>London forces</p> Signup and view all the answers

    What are the characteristics of the ring system in sterol lipids?

    <p>It is rigid and hydrophobic.</p> Signup and view all the answers

    What drives the lipid aggregation process in cell membranes?

    <p>Hydrophobic interactions between tails and the stability of the hydrophilic heads.</p> Signup and view all the answers

    How do cholesterol and unsaturated fatty acids influence membrane fluidity?

    <p>They typically both increase membrane fluidity.</p> Signup and view all the answers

    What defines a nucleoside?

    <p>A nucleotide without phosphate.</p> Signup and view all the answers

    Which pairs of nitrogenous bases have the correct number of hydrogen bonds between them?

    <p>Adenine and Thymine: 2 hydrogen bonds.</p> Signup and view all the answers

    What type of bonding primarily stabilizes the secondary structure in proteins?

    <p>Hydrogen bonds between backbone atoms.</p> Signup and view all the answers

    Which of the following is a function of monomeric nucleotides?

    <p>They can act as energy carriers like ATP.</p> Signup and view all the answers

    What characterizes the tertiary structure of proteins?

    <p>It forms through covalent and non-covalent interactions.</p> Signup and view all the answers

    What is the primary effect of ketoacidosis on blood pH?

    <p>It lowers blood pH.</p> Signup and view all the answers

    Which enzyme complex is responsible for the oxidation of NADH?

    <p>Complex I: NADH-Q oxidoreductase.</p> Signup and view all the answers

    What role does Ubiquinone play in the electron transport chain?

    <p>Transports electrons from complex I/II to complex III.</p> Signup and view all the answers

    How many protons does complex I transfer to the intermembrane space when NADH is oxidized?

    <p>4 protons.</p> Signup and view all the answers

    What is the main function of cytochrome C in the electron transport chain?

    <p>Carrying one electron at a time.</p> Signup and view all the answers

    What is the primary source of electrons for the electron transport chain?

    <p>FADH2 and NADH.</p> Signup and view all the answers

    Which complex of the electron transport chain accepts electrons from ubiquinone?

    <p>Complex III.</p> Signup and view all the answers

    What distinguishes Ubiquinone from cytochrome C in terms of electron transport?

    <p>Ubiquinone transports two electrons at a time.</p> Signup and view all the answers

    What does the intersection of lines in a skeletal formula represent?

    <p>A carbon atom</p> Signup and view all the answers

    What type of bond is formed by the end-to-end overlap of atomic orbitals?

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

    What is the correct formula to calculate the number of moles?

    <p>n = m/M</p> Signup and view all the answers

    What does the dilution factor describe?

    <p>The volume of one sample aliquot in total volume of diluted solution</p> Signup and view all the answers

    Which of the following statements describes mass concentration?

    <p>Mass of solute divided by volume of solution</p> Signup and view all the answers

    What is represented by Avogadro's number?

    <p>Number of atoms in one mole of a substance</p> Signup and view all the answers

    In the context of chemical reactions, what does the rate constant (K) signify?

    <p>The speed at which reactants form products</p> Signup and view all the answers

    What does the molecular orbital theory primarily focus on?

    <p>Regions of space where electrons are likely to be found</p> Signup and view all the answers

    What does the term 'serial dilution' imply?

    <p>Multiple dilutions where each solution serves as the solute for the next</p> Signup and view all the answers

    What characterizes a pi bond?

    <p>Forms when p, d, or f orbitals overlap sideways</p> Signup and view all the answers

    Study Notes

    Fundamentals of Chemistry

    • Atom: smallest particle with properties of a given element, contains protons, neutrons, and electrons
    • Z: number of protons, determines the number of electrons in an atom
    • A: atomic mass, number of protons and neutrons
    • Electrons are negligible mass compared to protons and neutrons (1/2000)
    • Unified mass unit: 1/12 mass of a carbon-12 atom

    Periodic Table

    • Arranges elements by atomic number (Z)
    • Atomic weight: average mass of an element's isotopes
    • SI prefixes: kilo (k), deci (d), centi (c), milli (m), micro (μ), nano (n), pico (p) for scaling units

    Periodic Properties

    • Ionization energy: energy to remove an electron
    • Electron affinity: energy change when an additional electron is attached
    • Electronegativity: ability of an atom to attract electrons
    • Atomic radius: distance from nucleus to outermost electron shell

    Isotopes

    • Same element, different mass numbers (different number of neutrons)
    • Carbon-12, carbon-13, and carbon-14 are examples

    Nuclide Symbols

    • X: chemical symbol
    • Mass number/atomic number: represents composition of nucleus
    • Example: 14C (carbon-14)

    Quantum Mechanical Model

    • Electrons have wave-like properties
    • Wave functions describe probability of finding an electron at a particular location
    • Orbitals: regions of space where an electron is likely to be found
    • Quantum numbers (n, l, ml, ms) describe properties of electrons

    Orbital Occupancy

    • Auf bau principle: fill orbitals with electrons of lowest energy first
    • Hund's rule: fill orbitals individually before pairing them
    • Pauli exclusion principle: no two electrons can have the same four quantum numbers

    Lewis Dot Structures

    • Depict valence electrons of atoms
    • Used to visualize bonding in molecules

    Ions and Bonding

    • Ionic bonding: transfer of electrons, forms ions
    • Covalent bonding: sharing electrons, forms molecules
    • Polar bonds: unequal sharing of electrons due to differences in electronegativity

    Hill Notation

    • Way to represent chemical formulas for organic molecules, the number of carbon, hydrogen atoms, and alphabetical order of the rest
    • Usually written as CxHyZ, where X is carbon, Y is hydrogen, and Z is the rest of the atoms.

    Molecular Geometry

    • Different arrangement of atoms in a molecule and their bonds.
    • Steric number : number of groups attached to an atom and lone pairs
    • The various geometries describe how the atoms are arranged in space.

    Molecular Orbital Theory

    • Molecular orbitals describe regions of space where electrons are likely to be found
    • Accurately predicts bond lengths and energies.

    Moles and Molar Mass

    • Mole: number of discrete particles
    • Avogadro's number: 6.022 × 10^23
    • Molar mass: mass in grams of one mole of a substance (g mol⁻¹)

    Solutions (Concentration)

    • Molarity: moles of solute/volume of solution
    • Mass concentration: mass of solute/volume of solution
    • Concentration of solutions depends on solute (amount of dissolved substance) and solvent (liquid which the solute is dissolved in)
    • Serial dilution: solution is generated by one dilution step and used as the solution for the next dilution step

    Acids and Bases

    • Rate of dissociation = k1 [AB] (k is rate constant)
    • Rate of association = k2 [A] [B]
    • At equilibrium, k1 [AB] = k2 [A] [B] so [A] [B] / [AB] =K1 /K2 = Kd (dissociation constant)
    • Ionic product of water (Kw) = 1 × 10⁻¹⁴ M²
    • Brønsted-Lowry Acids and Bases: proton donors (acids) and proton acceptors (bases)
    • pKa = -log₁₀(Ka) and high Ka is equal to low pKa and vice versa.

    Buffers

    • Solutions that resist changes in pH
    • Contains a weak acid and its conjugate base(or a weak base and its conjugate acid)
    • Used to maintain a relatively constant pH in biological systems
    • Henderson-Hasselbalch equation calculates pH of a buffer solution.

    Biomolecular Interactions

    • Thermodynamics: properties related to energy changes during reactions
      • Enthalpy (ΔH): total internal energy of a system
      • Equilibrium: concentrations of reactants and products remain constant over time
      • Entropy (ΔS): measure of energy dispersal
      • Gibbs Free Energy (ΔG): energy available for work in a system at constant temperature and pressure.
      • ΔG= ΔH – TAS

    Chemical Kinetics

    • Activation energy: energy needed for a reaction to occur
    • Catalysts: speed up reactions by lowering activation energy
    • Transition state: highest energy state during a reaction
    • Rate determining step in a reaction is always the step with the highest activation energy

    Enzymes

    • Catalysts for biochemical reactions
    • Bind to specific substrates at the active site.
    • Lower the activation energy of a reaction
    • Classification of enzymes: Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, Ligases
    • Michaelis-Menten equation relates reaction velocity to substrate concentration.
    • Km (Michaelis constant): substrate concentration at half-maximal velocity, indicates affinity between enzyme and substrate
    • Vmax: maximum reaction velocity, when all enzyme active sites are occupied

    Protein Structure and Function

    • Primary structure: linear sequence of amino acids
    • Secondary structure: local folding patterns (α-helices, β-sheets)
    • Tertiary structure: overall 3D arrangement of a polypeptide chain
    • Quaternary structure: arrangement of multiple polypeptide chains
    • Protein purification techniques: separating proteins based on size, charge or binding affinity
      • Size-exclusion chromatography
      • Ion-exchange chromatography
      • Affinity chromatography

    Carbohydrates

    • Empirical formula (CH₂O)ₙ
    • Monosaccharides: simple sugars
    • Disaccharides: two monosaccharides linked together
    • Polysaccharides: long chains of monosaccharides, cellulose, starch, and glycogen.

    Lipids

    • Long hydrocarbon chains with a carboxylic acid group at the end
    • Amphiphilic: hydrophobic tails and hydrophilic heads
    • Examples: fatty acids, triglycerides, phospholipids, and sterols
    • Functions: energy storage, membrane structure

    Nucleic Acids

    • Nucleotides: building blocks of nucleic acids
    • Composed of a 5-carbon sugar, a nitrogenous base, and a phosphate group.
    • DNA and RNA store genetic information

    Other

    • E/Z Isomerism: describing how molecules are oriented around double bonds
    • Optical Isomerism:Describing enantiomers (mirror image forms) of molecules, their rotations and how they differ from each other.
    • Anomer: special type of epimer that forms at anomeric carbon of a cyclic saccharide
    • Corn/Cahn-Ingold-Prelog Rules: Rules to show configuration.

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    CBI 1: Fundamentals of Chemistry PDF

    Description

    Test your knowledge on key concepts in chemistry, including atoms, atomic structure, and the periodic table. This quiz covers essential definitions and properties such as ionization energy and electronegativity. Discover how isotopes vary within the same element and enhance your understanding of the subject.

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