Chapter 2 Learning Outcomes - Chemical Level of Organization Flashcards
2.1 Define an atom, and describe the properties of its subatomic particles. p. 51
Atoms = the smallest stable units of matter.
Subatomic particles include the proton, neutron, and electron. The positively charged protons and uncharged neutrons are both contained in the nucleus while the negatively charged electron whirls around outside of the nucleus, creating an electron cloud. Atoms interact by means of their electrons to produce larger, more complex structures.
2.2 Describe an atom and how atomic structure affects the mass number and atomic weight of the various chemical elements. p. 52
mass number and atomic weight are both determined by the numbers of subatomic particles.
atomic number = # of protons
(atoms contain equal numbers of protons and electrons)
mass number = # of protons + # of neutrons
(electrons have negligible mass and aren’t factored)
isotopes = (definitions from multiple sources below)
- atoms of A SINGLE element whose nuclei contain a different number of neutrons
- each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
- one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties. Every chemical element has one or more isotopes.
atomic weight/atomic mass = the mass/weight of an atom = WEIGHTED average mass of an atom of an element based on the relative natural abundance of that element’s isotopes
2.3 Explain the relationship between electrons and energy levels. p. 54
the *number of electrons in the outermost level/layer/shell determines the atom’s ability to participate in chemical reactions.
Electrons occupy an orderly series of energy levels, and energy increases as the distance from the nucleus increases.
2.4 Compare the ways in which atoms combine to form molecules and compounds. p. 56
Atoms combine to form molecules and compounds through a process called chemical bonding.
The most common chemical bonds are
- IONIC BONDS = atoms transfer electrons to form bonds; transferring results in bonds because of the resulting electrical attractions between the cation (+) element and the anion (-) element
- COVALENT BONDS = atoms share electrons to form bonds
Also polar covalent bonds - bonds that involve an unequal sharing of electrons. Molecule is POLARIZED like a magnet
2.5 Describe the three states of matter and the importance of hydrogen bonds in liquid water. p. 58
3 states = solid (maintains volume and shape at ordinary temps and pressure), liquid (constant volume but no shape), and gas (neither volume nor a fixed shape)
Water is the only substance that occurs as all 3 forms.
Hydrogen bonds are continually forming and breaking, which is necessary for water to maintain a liquid state. Water becomes vapor (gas) when all hydrogen bonds are broken and becomes ice when all hydrogen bonds are locked in place.
2.6 Define metabolism and distinguish among work, kinetic energy, and potential energy. p. 61
Metabolism = all of the chemical reactions (bonds forming and breaking) underway in cells and tissues at any given moment.
Work = movement of an object or change in the physical structure of matter
Kinetic Energy = energy of MOTION; energy that can be transferred and do work
Potential Energy = STORED energy; energy that has the potential to do work
(example: a seesaw)
2.7 Use chemical notation to symbolize chemical reactions. p. 62
2H + O = H20
2.8 Distinguish among the major types of chemical reactions that are important for studying physiology. p. 64
Decomposition (catabolism) - breaks a molecule into smaller fragments; AB > A + B
Synthesis - combines molecules to form a larger fragment; A+B > AB
Exchange reaction - parts of the molecule are shuffled around to create new products; AB + CD > AD + CB
2.9 Describe the crucial role of enzymes in metabolism. p. 66
Enzymes increase speed and decrease required energy.
They serve a crucial role in metabolism by controlling complex reactions necessary for processing nutrients and metabolites.
Enzymes act as a catalyst that help speed up chemical reactions and lower the activation energy required.
2.10 Describe four important properties of water and their significance in the body. p. 69
4 important properties:
- Lubricant - reduces friction within joints and body cavities
- Solvent - many solutes will dissolve in water
- Chemical reactant - in our bodies, chemical reactions occur in water. Water molecules are also participants in some reactions.
- High heat capacity - helps keep the skin cool through perspiration, as water carries heat away as it changes from a liquid to a gas.
2.11 Explain how the chemical properties of water affect the SOLUBILITY of inorganic and organic molecules. p. 70
Inorganic compounds are held together by polar bonds. Dissociation (ionization) occurs when ionic bonds are broken as individual ions interact with positive or negative poles of polar water molecules.
The ionic bonds allow inorganic compounds to dissociate (ionize) into positive and negative ions in water, making them highly soluble in water, meaning easily dissolved.
Some organic molecules are hydrophilic (glucose) and dissolve. Some organic molecules lack polar covalent bonds or have very few. When nonpolar molecules are exposed to water, hydration spheres do not form and molecules do not dissolve.
Don’t confuse this with the 4 GENERAL important properties of water - activities driven by chemical properties (as those don’t AFFECT solubility)
- Lubrication
- Chemical reactant
- High heat capacity
- Solvent
2.12 Discuss the importance of pH and the role of buffers in body fluids. p. 72
pH = the concentration of hydrogen ions. The pH scale ranges from 0-14, and 7 or below is acidic.
Buffers = compounds that stabilize the pH of a solution by removing or replacing hydrogen ions.
The regulation of pH is vital for homeostasis, as the concentration of hydrogen atoms in body fluid must be regulated precisely. Buffers help maintain normal ranges for homeostasis (ex. antacid)
2.13 Describe the common elements of organic compounds and how functional groups modify the properties of organic compounds. p. 75
Organic compounds ALWAYS contain carbon and hydrogen, and generally contain oxygen as well.
These 4 functional groups greatly influence the channel (acid or base) and physical (solubility) properties of a molecule.
- Amino group, -NH2 = acts as a base, accepting H+
ex. amino acids - Carboxyl group, -COOH = acts as an acid, releasing H+
ex. fatty acids, amino acids - Hydroxyl group, -OH
ex. carbohydrates, fatty acids, amino acids, alcohols - Phosphate group, -PO42- = may link to other molecules, may store energy
ex. phospholipids, nucleic acid, high-energy compounds
2.14 Discuss the structures and functions of carbohydrates. p. 76
Carbohydrates are most important as energy sources that have been catabolized rather than stored. All carbohydrate molecules must be broken down to monosaccharides before absorption.
- Monosaccharides = energy source
ex. glucose, fructose - Disaccharides = energy source
ex. sucrose, lactose, maltose - Polysaccharides = glucose storage
ex. glycogen
2.15 Discuss the structures and functions of the 5 types of lipids. p. 78
Fatty acids Glycerides Eicosanoids Steroids Phospholipids/Glycolipids
- Fatty acids = long carbon chains with hydrogen atoms attached. (saturated or unsaturated) function - energy sources
- Glycerides = fatty acids strung together with lipisol function - energy sources, energy storage, insulation, and physical protection
- Eicosanoids = [structure] function - chemical messengers coordinating local cellular activity
- Steroids/cholesterol [structure] function - structural components of cell membranes, hormones, digestive secretions in bile
- Phospholipids and glycolipids - hydrophilic heads and hydrophobic tails function - structural components of plasma membranes.
