Biological Psychology: Ch. 1

Question 1

Elements

Answer 1

Elements are materials that cannot be broken down into other materials. Chemists have found 92 elements in nature, and they have constructed more in the laboratory. (Actually, one of the 92––technetium––is so rare as to be virtually unknown in nature.) Compounds are materials made up by combining elements.

Question 2

Molecules

Answer 2

A molecule is the smallest piece of a compound that retains the properties of the compound.

Question 3

Atomic Number

Answer 3

The number of protons is the atomic number of the element. In the periodic table it is recorded at the top of the square for each element. The number at the bottom

Question 4

Atomic Weight

Answer 4

In the periodic table, the number at the bottom of each square is the element’s atomic weight, which indicates the weight of an atom relative to the weight of one proton. A proton has a weight of one unit, a neutron has a weight just trivially greater than one, and an electron has a weight just trivially greater than zero. The atomic weight of the element is the number of protons in the atom plus the average number of neutrons.

Question 5

Ion

Answer 5

An ion is an atom that has gained or lost one or more electrons.

Question 6

Ionic vs. Covalent Bonds

Answer 6

The attraction of positive ions for negative ions forms an ionic bond. In other cases, instead of transferring an electron from one atom to another, some pairs of atoms share electrons with each other, forming a covalent bond. Atoms that are attached by a covalent bond cannot move independently of one another.

Question 7

Each carbon atom ordinarily forms how many covalent bonds?

Answer 7

4

Question 8

What are enzymes?

Answer 8

Enzymes are proteins that control the rate of chemical reactions. Each reaction is controlled by a particular enzyme. Enzymes are a type of catalyst. A catalyst is any chemical that facilitates a reaction among other chemicals without being altered itself in the process.

Question 9

The Role of ATP

Answer 9

The body relies on ATP (adenosine triphosphate) as its main way of sending energy where it is needed. Much of the energy derived from food goes into forming ATP molecules that eventually provide energy for the muslces and other body parts.

ATP consists of adenosine bound to ribose and three phosphate groups (PO₃). Phosphates form high-energy covalent bonds. That is, a large amount of energy is required to form the bonds, and a large amount of energy is released when they break. ATP can break off one or two of its three phosphates to provide energy.

Question 10

Summary of Chemsitry

Answer 10

1. Matter is composed of 92 elements that combine to form an endless variety of compounds.
2. An atom is the smallest piece of an element. A molecule is the smallest piece of a compound that maintains the properties of the compound.
3. The atoms of some elements can gain or lose an electron, thus becoming ions. Positively charged ions attract negatively charged ions, forming an ionic bond. In some cases two or more atoms may share electrons, thus forming a covalent bond.
4. The principal carrier of energy in the body is a chemical called ATP.