Chapter 1. Biochemistry: An Evolving Science

Question 1

a measure of the degree of randomness or disorder in a system; denoted by the symbol S in thermodynamics, the change in entropy (delta S) increases when a system becomes more disordered and decreases when the system becomes more ordered or less random.

Answer 1

Entropy

Question 2

The domain of life that comprises single cell organisms lacking a nucleus. Formerly believed to be member of the domain Bacteria, Archaea are now known to have a unique evolutionary history with biochemical characteristics different from the other two domains of life.

Answer 2

Archaea

Question 3

Low-molecular-weight molecules such as glucose and glycerol that are chemically transformed in biological processes.

Answer 3

Metabolite

Question 4

The tendency of hydrophobic molecules to associate with one another in water. The association is powered by the resulting increase in the entropy of water.

Answer 4

Hydrophobic effect

Question 5

A thermodynamic property that corresponds to the heat content of a system.

Answer 5

Enthalpy (H)

Question 6

Large molecules such as proteins and nucleic acids, that are key functional and structural components of living systems.

Answer 6

Biological macromolecule

Question 7

The domain of life that comprises single cell organisms lacking a nucleus. Members of this domain differ evolutionarily and biochemically from the Archaea, with whom they were formerly grouped.

Answer 7

Bacteria

Question 8

a bond formed when two relatively electronegative atoms, such as oxygen or nitrogen, unequally share a hydrogen atom that is covalently bonded to one of the electronegative atoms.

Answer 8

Hydrogen bond

Question 9

A member of the domain Eukarya. The defining characteristic of eukaryotes is the presence of a well-defined nucleus within each cell.

Answer 9

Eukaryote

Question 10

A chemical bond formed by the sharing of pairs of electrons between adjacent atoms. Covalent bonds are the strongest chemical bonds.

Answer 10

Covalent bond

Question 11

The domain of life that comprises all multicellular organisms, including human beings, as well as many microscopic unicellular organisms such as yeast. The defining characteristic of eukaryotes is the presence of a well-defined nucleus within each cell.

Answer 11

Eukarya

Question 12

A charged group on one molecule can attract an oppositely charged group on the same or another molecule.

Answer 12

ionic interaction

Question 13

the relationship between nucleic acid sequence information and protein sequence information.

Answer 13

genetic code

Question 14

An aqueous solution consisting of a weak acid and it conjugate base (or vice versa) that resists changes in pH when strong acids or bases are added.

Answer 14

buffer

Question 15

an organic acid with an alpha-carbon linked to a carboxylic acid, an amino group, a hydrogen and a side chain (the R group).

Answer 15

amino acid

Question 16

Molecule that encodes genetic information in all cellular organisms.

Answer 16

deoxyribonucleic acid (DNA)

Question 17

A structure composed of two intertwined DNA strands such that the sugar-phosphate backbone lies on the outside and the bases on the inside. The two strands run in opposite directions.

Answer 17

double helix

Question 18

Refers to the tendency of nonpolar molecules in water to interact with one another; the interactions are driven by an increase in the entropy of water when the water molecules in contact with the nonpolar molecules are released into bulk water.

Answer 18

Hydrophobic interaction

Question 19

form of energy capable of doing work under conditions of constant temperature and pressure. Also, a measure of the usable energy generated in a chemical reaction; denoted by the symbol G in thermodynamics. The change in free energy (delta G) of a system undergoing transformation at constant pressure is equal to the change in enthalpy (delta H) minus the product of the absolute temperature (T) and the change in entropy (delta S).

Answer 19

Free energy (Gibbs free energy)

Question 20

Unicellular organisms, such as bacteria, which lack a nucleus.

Answer 20

Prokaryote

Question 21

a biological macromolecule composed of a linear array of amino acids joined by peptide bonds. Roles of proteins in biological processes include catalysis, transport and storage, motion, mechanical support, immune protection, generation and transmission of nerve impulses and control of growth and differentiation.

Answer 21

Protein

Question 22

The concentration of hydrogen ions in solution. Specifically, the pH of a solution is defined as pH = -log[H+].

Answer 22

pH

Question 23

A measure of the susceptibility of a proton on an acid to removal by reaction with a base. pKa=-(log Ka), where Ka is the proton dissociation constant of the acid.

Answer 23

pKa value

Question 24

alternative covalent bonding patterns for a molecule that are equally, or nearly so, likely.

Answer 24

Resonance structure

Question 25

the attraction between two molecules based on transient electron asymmetry around an atom that induces a complementary asymmetry in a nearby molecule.

Answer 25

Van der Waals interaction

Question 26

All of the microorganisms that live on and in humans that play roles in health and diseases.

Answer 26

microbiome

Question 27

The tendency of the presence of a particular genetic variation or set of variations to result in the onset of a disease.

Answer 27

predisposition