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Biochemistry: Atoms, Water, Carbon, and Macromolecules

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Terms in this set (20)

  • What is matter and what defines an element?

    Matter is any substance that occupies space and has mass. An element is a unique form of matter with specific chemical and physical properties that cannot be broken down by ordinary chemical reactions.

  • What subatomic particles make up an atom and where are they located?

    Atoms consist of protons and neutrons in the nucleus, and electrons orbiting the nucleus in electron shells.

  • How do protons, neutrons, and electrons differ in charge and mass?

    Protons have a +1 charge and mass of 1 amu, neutrons have no charge and mass of 1 amu, electrons have a -1 charge and negligible mass (~1/1800 amu).

  • What determines an element's atomic number and mass number?

    The atomic number is the number of protons. The mass number is the sum of protons and neutrons in the nucleus.

  • What are isotopes?

    Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, resulting in different mass numbers.

  • What is the octet rule in electron shells?

    The octet rule states that atoms are most stable when their outermost electron shell contains eight electrons, except the first shell which is stable with two.

  • How do atoms achieve a full valence shell?

    Atoms can gain, lose, or share electrons through chemical bonds to fill their outermost shell and achieve stability.

  • What is the difference between ionic and covalent bonds?

    Ionic bonds form by transfer of electrons creating charged ions. Covalent bonds form by sharing electrons between atoms.

  • What are cations and anions?

    Cations are positively charged ions formed by losing electrons. Anions are negatively charged ions formed by gaining electrons.

  • What is a polar covalent bond and how does it affect water molecules?

    A polar covalent bond involves unequal sharing of electrons, creating partial charges. In water, oxygen is partially negative and hydrogen partially positive, making water polar.

  • Why is water an excellent solvent?

    Water's polarity allows it to form hydrogen bonds with ions and polar molecules, dissolving them by surrounding and separating particles (hydration shells).

  • What causes water's high heat capacity and why is it important?

    Hydrogen bonding between water molecules requires a lot of energy to change temperature, helping organisms regulate body heat.

  • What is cohesion and adhesion in water?

    Cohesion is attraction between water molecules; adhesion is attraction between water and other surfaces, enabling phenomena like surface tension and capillary action.

  • What is pH and how is it related to hydrogen ion concentration?

    pH measures acidity or alkalinity as the negative logarithm of hydrogen ion concentration; low pH means high H+ concentration (acidic), high pH means low H+ (basic).

  • How do buffers maintain pH homeostasis in biological systems?

    Buffers absorb excess H+ or OH- ions, stabilizing pH. For example, blood uses the carbonic acid-bicarbonate buffer system to maintain near-neutral pH.

  • Why is carbon essential for life and what is its bonding capacity?

    Carbon forms up to four covalent bonds, allowing it to serve as the backbone for complex macromolecules essential to life.

  • What are hydrocarbons and their significance?

    Hydrocarbons are organic molecules made of carbon and hydrogen, storing energy in their covalent bonds and forming linear chains or rings.

  • What are isomers and their types?

    Isomers have the same formula but different structures: structural isomers differ in bond arrangement, geometric isomers differ in spatial arrangement around double bonds, and enantiomers are mirror images.

  • What are functional groups and their role in biological molecules?

    Functional groups are specific atom groups attached to carbon backbones that confer chemical properties and reactivity to molecules.

  • What are dehydration synthesis and hydrolysis reactions?

    Dehydration synthesis forms polymers by covalently bonding monomers and releasing water. Hydrolysis breaks polymers into monomers by adding water.