General Biology 1115 Ch 2 Learning Outcomes

Describe the properties of three types of subatomic particles, and explain how the properties of an atom are determined by the number of each of the three particles.

Electron: negatively charged

The number of electrons determines the ionization state.

Neutron: not charged

The number of neutrons determines the isotope.

Proton: positively charged

The number of protons of an atom determine the element of the atom.

Differentiate between and discuss the biological importance of non-polar and polar covalent bonds, ionic bonds, and hydrogen bonds.

Non-polar: electrons are shared equally

Non-polar covalent bonds form the oxygen we breathe and help make up our living cells.

Polar: electrons are pulled closer to the more electronegative atom, making it partially negative and the other atom partially positive

Polar covalent bonds form water. Water, as we all know, is essential for life.

Ionic: play an important role in shaping tertiary and quaternary proteins.

Hydrogen: Hydrogen bonds play an important role in DNA as they connect nitrogenous bases to their complementary base pairs.

Discuss the importance of water in biological systems, and describe at least 5 key properties of water that arise due to its structure.

Water is important as it is a very versatile solvent. Life's chemical reactions are more available to react when they are dissolved in water.

5 key properties are as follows: cohesion, adhesion, surface tension, versatile solvency, and expanding when frozen.

Differentiate between an element, a compound, and a molecule.

Element: An atom with a given number of protons.

Compound: Ionic or covalent. Consisting of 2 or more different atoms held together.

Molecule: Multiple atoms held together by covalent bonds. Can be multiple of the same atom.

Contrast hydrophilic and hydrophobic substances.

Hydrophilic: "Water-loving" substances that stay in solution because they interact with water's partial charges.

Hydrophobic: "Water-fearing" molecules that are uncharged/non-polar, and do not dissolve in water.

Define the terms "solute", "solvent", and "solution".

Solute: a substance that is dissolved

Solvent: dissolving agent of the solution

Solution: liquid homogenous mixture of multiple substances

Explain the pH scale, and correctly apply the terms acid, base, and buffer.

The pH scale ranges from 0-14 and represents the acidity of a solution. Acids have a pH < 7, bases have a pH > 7. When pH = 7, solution is said to be neutral. A buffer minimizes changes in pH. Buffers often consist of a weak acid and its corresponding weak base pair.

Differentiate between potential and kinetic energy, and give examples of each.

Potential energy: energy stored in a molecule/system due to its position

E.g. chemical energy stored in molecular bonds

Kinetic energy: energy that a molecule/system possesses due to its motion

E.g. heat, light

Explain how potential energy of an atom or molecule is related the position of its electrons.

The further away electrons are from the nuclei, the higher its potential energy. The closer electrons are to its nuclei, the lower its potential energy. This is because as you stray further away from the nuclei, bonds become longer and weaker, giving the electron a higher potential to form stronger bonds through chemical reactions.

Describe the difference between temperature and heat.

Heat is the total amount of kinetic energy in a system due to its molecular motion. Temperature is the average intensity of the heat due to the kinetic energy of molecules.

Explain the importance of the two laws of thermodynamics in living systems.

The first law of thermodynamics is important because living systems take the energy they get and convert it into usable forms, like ATP and sugar for food. The second law of thermodynamics is important because every conversion has some energy converted to heat or other unusable molecules.

Recognize six functional groups that are important in organic molecules, and describe at least one important property of each.

Carbonyl: reacts with certain other compounds to produce large molecules

Carboxyl: tend to release a proton (act as a weak acid)

Phosphate: bonds between phosphate groups store a large amount of chemical energy

Hydroxyl: Highly polar (can release proton to act as a weak acid)

Sulfhydryl: may covalently bond to one another to form disulfide bridges

Amino: tend to attract protons (act as a weak base)