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Chapter 2- Chemical principles- P1 MICROBIOLOGY

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Terms in this set (28)

  • What is the smallest chemical unit of matter?

    The atom is the smallest chemical unit of matter.

  • What defines an element in chemistry?

    Matter composed of one type of atom is called an element, e.g., Carbon (C), Nitrogen (N), Oxygen (O).

  • What is a molecule and a compound?

    A molecule is two or more atoms combined; if atoms are different types, the molecule is a compound.

  • What particles make up the nucleus of an atom and their charges?

    The nucleus contains protons (positive charge) and neutrons (neutral charge).

  • Where are electrons located and what is their charge?

    Electrons are negatively charged and orbit the nucleus in energy levels called electron shells.

  • How many electrons fill the first three electron shells?

    1st shell = 2 electrons, 2nd shell = 8 electrons, 3rd shell = 8 electrons.

  • What is an ion?

    An ion is an atom or group of atoms with a positive or negative charge due to loss or gain of electrons.

  • Difference between anion and cation?

    Anion: gained electron, negative charge (e.g., Cl-). Cation: lost electron, positive charge (e.g., Na+).

  • What are the three main types of chemical bonds in living organisms?

    Ionic bonds, covalent bonds, and hydrogen bonds.

  • How do ionic bonds form?

    Ionic bonds form by attraction between oppositely charged ions (anions and cations), e.g., NaCl.

  • What characterizes covalent bonds?

    Covalent bonds form when atoms share pairs of electrons; they are very strong and common in carbon-containing compounds.

  • How many covalent bonds can a carbon atom form?

    Carbon atoms can form up to 4 covalent bonds.

  • What causes polarity in water molecules?

    Oxygen pulls electrons closer, creating partial negative charge on O and partial positive charge on H, making water polar.

  • What are hydrogen bonds?

    Hydrogen bonds are weak attractions between oppositely charged regions of different molecules, e.g., between water molecules.

  • Why is water considered the solvent of life?

    Water's polarity allows it to dissolve many ionic compounds by surrounding ions and holding them in solution.

  • What is the pH scale and what does it measure?

    The pH scale measures the concentration of H+ ions; pH 7 is neutral, below 7 acidic, above 7 basic (alkaline).

  • What defines an organic molecule?

    Organic molecules contain both carbon and hydrogen.

  • What are the four major classes of organic molecules in living organisms?

    Carbohydrates, lipids, proteins, and nucleic acids.

  • What are monosaccharides, disaccharides, and polysaccharides?

    Monosaccharides are simple sugars (e.g., glucose), disaccharides are two sugars joined (e.g., sucrose), polysaccharides are many sugars joined (e.g., glycogen).

  • What are lipids and their main characteristics?

    Lipids include fats, phospholipids, and steroids; they are hydrophobic and important for energy storage and membrane structure.

  • What is the structure of phospholipids and their role in membranes?

    Phospholipids have a polar hydrophilic phosphate head and two non-polar hydrophobic fatty acid tails, forming bilayers in membranes.

  • What distinguishes saturated and unsaturated fatty acids?

    Saturated fatty acids have no double bonds; unsaturated fatty acids have one or more double bonds affecting membrane fluidity.

  • What are proteins made of and their functions?

    Proteins are made of amino acids and function structurally and as enzymes to catalyze reactions.

  • How are amino acids linked to form proteins?

    Amino acids are joined by covalent peptide bonds to form polypeptide chains.

  • What are nucleic acids and their building blocks?

    Nucleic acids (DNA and RNA) are made of nucleotides, each with a nitrogenous base, pentose sugar, and phosphate group.

  • What bases are found in DNA and RNA?

    DNA has A, G, T, C; RNA has A, G, U, C.

  • How is DNA structured?

    DNA is double-stranded with a sugar-phosphate backbone and complementary base pairing (A-T, G-C) held by hydrogen bonds forming a double helix.

  • What is the role of RNA?

    RNA is single-stranded and involved in communicating genetic instructions from DNA.