| Question | Answer |
| what is the trend in the type of reactions as organism lifetime increases | Phenomena involving weak interactions and proteins dominate shorter times More stable interactions (covalent bonds) and phenomena involving the agents of genetic information (nucleic acids) come into play as time increases |
| what kind of thermodynamic systems are cells? | open. exchanging matter and energy with their environment and functioning as highly regulated isothermal chemical engines |
| homeostasis | Maintaining conditions of essentially constant temperature and pressures and maintaining a constant internal environment with no outwardly apparent changes. |
| how is metabolic regulation achieved | controls on enzyme activity so that the rates of cellular reactions are appropriate to cellular requirements Cellular reactions conform to same thermodynamic principals that govern any chemical reaction. Enzymes no influence over energy changes in their reactions, only influence reaction rates |
| enzymes | biomolecular catalysts that mediate cell reactions. Accelerate reaction rates many order of magnitude and, by selecting the substances undergoing reaction, determine the specific reaction that takes place. In virtually every reaction. |
| how do organisms catalyze metabolic reactions | Common ways chemists accelerate reactions cannot be done in cells because would compromised environmental conditions Living systems use enzymes |
| metabolism | The ordered reaction pathways by which cellular chemistry proceeds and biological energy transformations are accomplished. Cannot have too much energy, so sequences of reactions organized to provide release of useful energy to the cell form the breakdown of food or to take energy and use it to drive synthesis of biomolecules essential to living state. |
| denaturation | Loss of structural order in complex macromolecules |
| why are living systems limited to a narrow range of conditions | because they are governed by weak forces |
| what mediates biomolecular recognition | Weak chemical forces underlie interactions of biomolecular recognition Readily reversible. Transient. Interactions initiated by specific recognition between complementary molecules and culminates in unique physiological activities Biological function achieved through mechanisms based on structural complementarity and weak chemical interactions. If sufficient number of weak bonds can be formed, as in macromolecules complementary in structure to one another, larger structures assemble spontaneously. |
| ligand | "key" that binds to a macromolecule |
| structural complementarity | Means of recognition in biomolecular interactions To make life, biomolecules must be able to recognize and interact with each other Interactions are most precise if one structure is complementary to the other “Lock and key” analogy |
| induced dipoles | having a temporary separation of positive and negative charge induced by the environment |
| permanent dipoles | having a permanent separation of positive and negative charge |
| ions | species possessing discrete charges |
| ionic interactions | Result of attractive forces between oppositely charged structures Can impart high degree of structural specificity because opposite charges are restricted to sterically defined positions Strength depends on nature of interacting species and the distance (r) between them Three types of species: ions, permanent dipoles and induced dipoles |
| hydrogen bonds | Form between a hydrogen atom covalently bonded to an electronegative atom (O, N, F) and a second electronegative atom that serves as the hydrogen bond acceptor Stronger than van der Waals forces Form straight bonds between donor H and acceptor atoms. More specific than van der Waals forces |
| van der Waals contact distance | The interatomic distance that results if only van der Waals forces hold two atoms together |
| van der Waals forces | Result of induced electrical interactions between closely approaching atoms or molecules as their negatively charged electron clouds fluctuate instantaneously in time. Work over very limited distance. Effective only at physiological temperatures only when a number of atoms in a molecule can interact with several atoms in a neighboring molecule Weak forces. But sum of many interactions between macromolecules can be substantial Also can be repulsive in molecules get too close to each other |
| weak chemical forces/noncovalent bonds | hydrogen bonds, van der Waals forces, ionic interactions, hydrophobic interactions. Intramolecular or intermolecular attractions between atoms. Create interactions that are constantly forming and breaking at physiological temperature, unless by cumulative number they impart stability by collective action. |
| How are biological macromolecules informational? | When read along the length of a molecule, has capacity to specify information in the same manner that letters of the alphabet can form words. Not all macromolecules are rich in information (polysaccharides, eg, are often repetitive) To discern the meaning, requires a mechanism for recognition |
| structural polarity | Biomolecules are not symmetrical. Macromolecules are built of units that have a head and a tail. Polymerization of these units form macromolecules that have head-to-tail linear connection. Macromolecules therefore have a “sense” or direction to their structure |
| What 3 attributes of biomolecules render them fit as components of growing, replicating systems, several relevant themes of structure and organization arise? | Have a "sense" or directionality. Informational. Characteristic 3D architecture maintained by weak forces. |
| compartments | Creation of discrete volumes. Inevitable consequence of presence of membranes but usually an essential condition for proper organelle function. |
| hydrophobic interactions | Result from strong tendency of water to exclude nonpolar groups or molecules Nonpolar regions of biological macromolecules are often buried in the molecule’s interior to exclude them from the aqueous milieu. Maintain membrane structure. Presence of non-polar molecules lessens range of opportunities for water-water interaction by forcing water molecules into ordered arrays around the non-polar groups. Ordering is minimized if non-polar molecules redistribute from a dispersed state to aggregated organic phase surrounded by water |
| membranes | Define boundaries of cells and organelles, not classified as supramolecular assemblies or organelles. Construction is complexes of proteins and lipids maintained by non-covalent forces. Membranes of organelles differ from one another, with each having a characteristic protein and lipid composition tailored to organelle’s function. |
| chloroplasts | Endow cells with the ability to carry out photosynthesis. Biological agents for harvesting light energy and transforming it into metabolically useful chemical forms. |
| mitochondria | “Power plants” of cells by virtue of their ability to carry out the energy-releasing aerobic metabolism of carbohydrates and fatty acids, capturing the energy in metabolically useful forms such as ATP |
| nucleus | Repository of genetic information as contained with the linear sequences of nucleotides in DNA of chromosomes |
| What are some examples of organelles | Eg: nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, vacuoles, etc. |
| what two attributes do organelles share? | cellular inclusions (usually membrane-bound), and dedicated to important cellular tasks |
| eukaryotic cells | Only place where organelles are found |
| supramolecular complexes | Interactions between macromolecules. Various members of one or more of the classes of macromolecules come together to form specific assemblies that serve important subcellular functions (eg. enzyme complexes, ribosomes, chromosomes, and cytoskeletal elements) |
| macromolecules | Made of building blocks. Proteins, polysaccharides, polyneucleotides (DNA and RNA), and lipids (contain relatively few building blocks. Not really polymeric like other macromolecules). |
| building block | Made from metabolites. Amino acids, sugars, nucleotides, fatty acids and glycerol. |
| metabolites | Made of precursors. Simple organic compounds that are intermediates in cellular energy transformation and in biosynthesis of various sets of building blocks. |
| what are some major precursors for biomolecules and what do they have in common? | Inorganic: Water, carbon dioxide, ammonium, nitrate and dinitrogen |
| why do we say that biomolecules have a structural hierarchy? | Simple molecules units for building complex structures. |
| What element do all biomolecules contain and why | Carbon: Unparalleled in versatility. Makes strong covalent bonds. Up to four bonds. Can link to C, H, O and N. Can make double bonds with C, O and N. 2 particularly important characteristics of carbon that gives it versatility of linear, branched, and cyclic compounds: 1. Form covalent bonds with itself. 2. Tetrahedral nature of four covalent bonds with only single bonds. |
| Why are the most common atoms in biomolecules so common in living systems? | Ability to form covalent bonds by electron-pair sharing unites these atoms to make them the most suitable for chemistry of life. Lightest elements = strong covalent bonds |
| Most common atoms in biomolecules | H, O, C, N. 99% of human body. |
| DNA | Polymeric chains of deoxyribonucleic acid. Where self-replication resides ultimately. The genetic material. Molecules structurally complement one another. |
| steady state | State of apparent constancy so that organism can maintain its intricate order and activity far removed from equilibrium with its surroundings. Actually a very dynamic condition. Energy and material are consumed by the organism and used to maintain its stability and order. |
| when does an organism reach equilibrium with the environment | when it dies |
| 2 macromolecules that store useful forms of chemical energy | ATP and NADPH |
| NADPH | macromolecules that store useful forms of chemical energy. When they react with other molecules in the cell, energy released can be used to drive unfavorable processes. |
| ATP | macromolecules that store useful forms of chemical energy. When they react with other molecules in the cell, energy released can be used to drive unfavorable processes. |
| how do organisms capture energy? | (from photosynthesis, metabolism of food, etc.) by forming biomolecules that store useful forms of energy. |
| conformation of macromolecules | Complex three-dimensional structure of a macromolecule. Consequence of interactions between monomeric units, according to their individual biological properties |
| macromolecules | Large polymeric molecules |
| organelles | Subcellular structures made up of complex assemblies of macromolecules |
| cells | make up living organisms. unit of life. Smallest entity capable of displaying attributes associated uniquely with living state: growth, metabolism, stimulus response and replication However, no obvious explanation within the features making up the cell for its living characteristics. |
| 4 properties of living organisms | 1. Complicated and highly organized. 2. Biological structures serve functional purposes. 3. Actively engaged in energy transformations. Characterized by the flow of energy through the organism. 4. Living systems have a remarkable capacity for self-replication. |
| biomolecules | Cellular constituents. Must conform to chemical and physical properties that govern all matter. Make life functions interpretable by chemical terms. |
54 cards - created jan 3, 1:49pm