Chapter 2 Practice Test

Electrons bear a positive charge equal in strength to the negative charge of the proton. True/False

False

Match the following organic molecules to their biochemical building blocks, or monomers. 1. DNA 2. carbohydrates 3. proteins 4. triglycerides A. amino acids B. nucleotides C. glycerol and fatty acids D. monosaccharides

1-B, 2-D, 3-A, 4-C

Colloids (emulsions) are heterogeneous mixtures. True/False

True

In biochemistry, and thus in the body, the universal solvent is __________. 1. water 2. alcohol 3. lymph 4. blood 5. oxygen

water

Which of the following does NOT represent an accurate hierarchy in the natural combination of matter? 1. Mixtures are substances composed of two or more components physically blended. 2. When two or more similar kinds of atoms bind, they form an isotope. 3. A molecule contains two or more atoms. 4. Protons, neutrons, and electrons compose atoms, which chemically bond with other atoms to form molecules.

when two or more similar kinds of atoms bind, they form an isotope

Which of the following is the primary energy-transferring molecule in cells? 1. DNA 2. ATP 3. NADH 4. adenine

ATP

Which of the following is FALSE regarding DNA? 1. DNA carries out the orders for protein synthesis issued by RNA. 2. DNA provides the basic instructions for building every protein in the body. 3. DNA replicates itself before cell division, ensuring that all genetic information in the descendant cells is identical. 4. The DNA molecule is coiled into a spiral staircase-like structure called a double helix.

DNA carries out the orders for protein synthesis issued by RNA

Polar molecules are electrically balanced as a result of the equal sharing of electrons between the atoms of the molecules. True/False

False

Which of the following is NOT a way to distinguish an acid from a base? 1. A basic substance will have a bitter taste. 2. A basic substance will have a slippery feel. 3. An acidic substance will have a sticky feel. 4. An acidic substance will have a sour taste.

an acidic substance will have a sticky feel

Which of the following is true of atoms? 1. Depending upon the number of neutrons, an atom may possess a positive, negative, or neutral electrical charge. 2. Atoms are composed of more or less identical particles or building blocks, called elements. 3. An atom will always display a negative electrical charge. 4. Atoms of any given element will differ from those of all other elements and provide its unique physical and chemical properties.

atoms of any given element will differ from those of all other elements and provide its unique physical and chemical properties

If the pH or temperature of the environment that contains a protein is altered dramatically, then the protein may __________. 1. take on an a-helical structure 2. become denatured 3. take on a quaternary structure 4. become overly active

become denature

Something with a pH of 5 would __________ 1. be described as being neutral 2. be described as being basic 3. have fewer H+ ions than OH- ions 4. have more H+ ions than OH- ions

have more H+ ions than OH- ions

Which of the following is a property of matter? 1. Matter can exist in solid, liquid, or gaseous state. 2. In all cases, matter can be seen, smelled, and felt. 3.Mass of an object can change depending upon a variety of factors, including gravitational pull, atmospheric pressure, and temperature. 4.The weight of matter remains constant wherever the object is.

matter can exist in solid, liquid, or gaseous state.

Which of the following is true of an isotope? 1. Isotopes have the same number of neutrons but differ in the number of protons they contain. 2. All isotopes of a given element are found in equal amounts in nature 3. Isotopes exist only for a few elements. 4. Isotopes have the same number of protons but differ in the number of neutrons they contain.

osotopes have the same number of protons but differ in the number of neutrons they contain

Which of the following is NOT one of the four basic elements that compose approximately 96% of a human's body weight? 1. potassium 2. hydrogen 3. oxygen 4. carbon

potassium

Which of the following best defines potential energy? 1. Potential energy is stored energy that has the capacity to do work but is not presently doing so. 2. Potential energy is energy that cannot be converted to kinetic energy. 3. Potential energy is energy that travels in waves. It includes visible light and radio waves. 4. Potential energy is energy in action, seen in the constant movement of the tiniest particles of matter, as well as in larger objects.

potential energy is stored energy that has the capacity to do work but is not presently doing so.

Buffers __________ 1. serve as an energy source for a cell 2. are strong acids 3. build carbohydrates 4. stabilize pH

stabilize pH

Which of the following types of chemical reactions always involves atoms or molecules combining to form a larger, more complex molecule? 1. catabolic 2. synthesis 3. hydrolysis 4. decomposition

synthesis

In an ionic bond, __________. 1. there is a transfer of one or more electrons from one atom to the other 2. shared neutrons occupy a single orbital common to both atoms within a molecule 3. a hydrogen atom, already covalently linked to one electronegative atom (usually nitrogen or oxygen), is attracted by another electron-hungry atom, so that a bridge forms between them 4. atoms share electrons equally

there is a transfer of one or more electrons from one atom to the other

All organic molecules contain carbon. True/False

true

Enzymes are unchanged in a reaction; they can be reused, and are NOT needed in large quantities. True/False

true

The atomic number of any atom is equal to the number of protons in its nucleus. True/False

true

The major function of RNA is to carry out the genetic instructions for protein synthesis. True/False

true