Applied A & P: Chapter 2 Checkpoints

Define "chemical bond" and identify several types of chemical bonds.

A chemical bond is an attractive force acting between two atoms that may be strong enough to hold them together in a molecule or compound. The strongest attractive forces result from the gain, loss, or sharing of electrons. Examples of such chemical bonds are ionic bonds and covalent bonds. In contrast, the weaker hydrogen bonds occur between molecules or compounds.

Describe a nucleic acid.

A nucleic acid is a large organic molecule made of carbon, hydrogen, oxygen, nitrogen, and phosphorous. Nucleic cells regulate protein synthesis and make up the genetic material in cells.

Describe ATP.

Adenosine triphosphate (ATP) is a high-energy compound consisting of adenosine to which three phosphate groups are attached. The second and third phosphate groups are each attached by a high-energy bond.

Define the following terms: acid, base, and salt.

An acid is a compound whose dissociation in solution releases a hydrogen ion and anion; a base is a compound whose dissociation releases a hydrogen ion (OH-) or removes a hydrogen ion (H+) from the solution; a salt is an inorganic compound consisting of a cation other than H+ and an anion other than OH-.

What is an atom?

An atom is the smallest stable unit of matter.

What is an enzyme?

An enzyme is a protein that lowers the activation energy of a chemical reaction, which is the amount of energy required to start the reaction.

Both oxygen and neon are gases at room temperature. Oxygen combines readily with other elements, but neon does not. Why?

Atoms combine with each other to gain a complete set of electrons in their outer energy level or valence shell. Oxygen atoms do not have a full outer energy level, so they readily react with many other elements to obtain this stable arrangement. Neon already has a full outer energy level so it cannot combine with other elements.

A large organic molecule made of the sugar ribose, nitrogenous bases, and phosphate groups is which kind of nucleic acid?

Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) contain nitrogen bases and phosphate groups, but the nucleic acid described is RNA because it contains the sugar ribose.

Which lipids would you find in human plasma membranes?

Human plasma membranes contain mainly phospholipids, plus small amounts of cholesterol and glycolipids.

How is it possible for two samples of hydrogen to contain the same number of atoms, yet have different weights?

Hydrogen has three isotopes: hydrogen-1, with a mass number of one, deuterium, with a mass number of two, and tritium, with a mass number of three. The heavier sample must contain a higher proportion of one or both of the heavier isotopes.

What is the significance of pH in physiological systems?

If the body is to maintain homeostasis and thus health, the pH of different body fluids must remain within a fairly narrow range.

Describe lipids.

Lipids are a diverse group of compounds that include fatty acids, eico-sanoids, glycerides, steroids, phospholipids, and glycolipids. They are organic compounds that contain carbon, hydrogen, and oxygen in a ratio that does not approximate 1:2:1.

Compare inorganic compounds with organic compounds.

Organic compounds always contain carbon and hydrogen. Inorganic compounds do not contain carbon and hydrogen atoms as structural components.

What molecule is produced by the phosphorylation of ADP?

Phosphorylation of an ADP molecule yields a molecule of ATP.

Describe a protein.

Proteins are organic compounds formed from amino acids that contain a central carbon atom, a hydrogen atom, an amino group (-NH2), a carboxyl group, (-COOH), and an R group or variable side chain. Proteins function in support, movement, transport, buffering, metabolic regulation, coordination and control, and defense.

Explain how the chemical properties of water make life possible.

Specific chemical properties of water that make life possible include: its strong polarity (enables it to be an excellent solvent), its reactivity (it participates in many chemical reactions), its high heat capacity (it absorbs and releases heat slowly), and its ability to serve as a lubricant.

How does an antacid help to decrease stomach discomfort?

Stomach discomfort is commonly the result of excessive stomach acidity ("acid indigestion"). Antacids contain a weak base that neutralizes the excess acid.

Which kind of bond holds atoms in a water molecule together? What attracts water molecules to each other?

The atoms in a water molecule are held together by polar covalent bonds. Water molecules are attracted to one another by hydrogen bonds.

Which functional group acts as an acid?

The functional group that acts as an acid is the nucleic acids.

How does boiling a protein affect its structural and functional properties?

The heat of boiling breaks bonds that maintain the proteins tertiary structure, quaternary structure, or both. The resulting structural change, known as denaturation, affects the ability of the protein molecule to perform it normal biological functions.

What macro-molecules are are important to living things?

The macro-molecules important to life are carbohydrates, lipids, proteins, and nucleic acids.

Using the rules for chemical notation. write the molecular formula for glucose, a compound composed of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.

The molecular formula for glucose, a compound composed of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms, is C6H12O6.

Plant starch and glycogen are both polysaccharides. What monomer do they have in common?

The monomer common to both plant starch and glycogen is glucose.

Define pH, and explain how the pH scale relates to acidity and alkalinity.

The pH is a measure of the concentration of hydrogen ions in fluids. Acid and base concentrations are measured in pH, which is the negative logarithm of hydrogen ion concentration, expressed in moles per liter. On the pH scale, 7 represents a neutral solution; values below 7 indicate acidic solutions, and values above 7 indicate base (alkaline) solutions.

In cells, glucose, a six carbon molecule, is converted into two three-carbon molecules by a reaction that releases energy. What type of reaction is this?

This reaction involves a large molecule being broken down into two smaller ones, so it is a decomposition reaction.

Identify and describe three types of chemical reactions important to human physiology.

Three types of chemical reactions important to the study of human physiology include decomposition reactions, synthesis reactions, and exchange reactions. In a decomposition reaction, a chemical reaction breaks a molecule into smaller fragments. A synthesis reaction assembles smaller molecules into larger ones. In an exchange reaction, parts of the reacting molecules are shuffled around to produce new products.

Using the rules for chemical notation, how is an ion's electrical charge represented?

Using chemical notation, an ion is represented by a superscript plus or minus sign following the symbol of an element. If more than one electron has been lost or gained, the electric charge on the ion is represented by a number preceding the plus or minus sign.

Why are enzymes needed by our cells?

Without enzymes, chemical reactions would proceed only under conditions that the cells could not tolerate (e.g. high temperatures). By lowering the activation energy, enzymes make it possible for chemical reactions to rapidly proceed under conditions compatible for life.

Atoms of the same element that have different numbers of neurons are called...

isotopes.