Bio Quiz 1 Prep Flashcards
how are radioactive isotopes are used to trace and identify biological molecules?
They can trace the radioactive decay of isotopes to identify elements that were once present.
compare potential energy with kinetic energy and give examples of each
Kinetic energy is the energy of motion whereas potential energy is stored energy or the energy of position. Potential energy converts to kinetic energy under the right circumstances. Often used example is a ball that is sitting atop a waterfall. At the top, it has potential energy. The push of the fall changes to kinetic energy that it uses up by the time it reaches the bottom.
What are the different types of chemical bonds and how can we predict what is most likely to engage in each type?
Ionic -
Covalent -
Hydrogen
how can we predict whether a molecule would be polar or non-polar / hydrophyllic or hydrophobic?
charges…electronegativity
If a molecule is polar it will be hydrophilic because the highly charged poles of H20 will attract the charged poles of the polar molecule. The polarity of the molecule is in relation to the electronegativity, or sharing of electrons among the atoms in a molecule. The atoms with higher proton counts and less outershells attract the shared electrons more strongly than atoms less protons and/or more outershells. This causes the polar sides due to the unequal distribution of electron, or negative charges in a molecule.
However when atoms in a molecule have similar or nearly equal electronegativities, they share the electrons more evenly and are then nonpolar. This means they have no charged sides/poles. They are then hydrophobic because they do not form hydrogen bonds and therefore do not mix well with water.
Explain how the structure of water affects its chemical properties, including density, surface tension, specific heat, and heat of vaporization.
Water’s small size, bent shape, highly polar covalent bonds, and overall polarity is unique among molecules. This structure causes properties such as cohesion, adhesion and surface tension.
Define ‘free energy’ and relate the gain or loss of free energy to reactions in biological systems
tbd
When presented with ΔG values for biological reactions, be able to state whether the reaction is exergonic or endergonic / spontaneous or nonspontaneous.
ΔG < 0 = spontaneous, exergonic
ΔG > 0 = non-spontaneous, endergeonic
ΔG = 0 = chemical equilibrium
Predict the general effect of changes in pH on biological molecules.
Discuss the importance of pH and buffers to living systems.
pH can alter the equilibrium in the body and also play an important role in individual molecules. The pH is simply the number of hydrogen ions present in a solution. These are of course highly charged and likely to form bonds with molecules in a way that can perhaps be harmful to the chemistry of the body. This is why we have buffers made up of a weak acid and its conjugate base to bind up these excess protons (hydroxide ions).
