Chapter 2: Chemistry of Life

Question 1

What kinds of particles make up matter?

Answer 1

Atoms, elements, molecules, compounds

Question 2

What is a compound?

Answer 2

Compounds have molecules with more than one element in them.

Question 3

What is an element?

Answer 3

An element is a pure substance, composed of only one type of atoms.

Question 4

What is an energy level?

Answer 4

Orbitals are arranged into energy levels (shells), depending on their distance from the nucleus. The farther an orbital extends from the nucleus, the higher its energy level is. The energy level closest to the nucleus has one orbital, so it can hold two electrons. The next energy level has up to four orbitals, so it can hold eight electrons.

Question 5

What are the four kinds of atoms that make up the majority of the human body?

Answer 5

oxygen, carbon, hydrogen, and nitrogen

Question 6

How is an ion formed?

Answer 6

An ionic bond forms between an atom that has only one or two electrons in the outermost level (that would normally hold eight) and an atom that needs only one or two electrons to fill its outer level. The atom with one or two electrons simply “donates” its outer shell electrons to the one that needs one or two.

Question 7

What is meant by an electrolyte dissociating in water?

Answer 7

Ionic compounds usually dissolve easily in water because water molecules are attracted to ions and wedge between the ions—thus forcing them apart. When this happens, we say the compounds dissociate to form free ions.

Question 8

What is covalent chemical bonding?

Answer 8

Atoms also may fill their energy levels by sharing electrons rather than donating or receiving them. When atoms share electrons, a covalent bond forms.

Question 9

Why are hydrogen bonds important?

Answer 9

Hydrogen bonds keep water molecules loosely joined together, giving water a weak gluelike quality that helps hold your body together

Question 10

How is the charge of an ion indicated in a formula?

Answer 10

The formula of an ion always shows its charge by a “+” or “−” superscript after the chemical symbol. Positive ion: Has more protons than electrons
Negative ion: Has gained electrons

Question 11

What is an organic compound?

Answer 11

Organic compounds are composed of molecules that contain carbon-carbon (C–C) covalent bonds, carbon-hydrogen (C–H) covalent bonds, or both

Question 12

What are the chemical characteristics of water?

Answer 12

Although water is an inorganic compound, it is essential to life. Found in and around each cell, water is the most abundant compound in the body. Its slightly gluelike properties help to hold the tissues of the body together.

Question 13

What is the difference between dehydration synthesis and hydrolysis?

Answer 13

In dehydration synthesis, reactants combine only after water is removed. Dehydration synthesis is a reaction in which water is lost from the reactants. In hydrolysis, water (hydro-) disrupts the bonds in large molecules, breaking them down into smaller molecules (lysis). Hydrolysis is virtually the reverse of dehydration synthesis.

Question 14

Explain the concept of pH.

Answer 14

A higher pH value indicates a low relative concentration of H+—a base. A lower pH value indicates a higher H+ concentration—an acid.

Question 15

Does an acid have a low or high pH?

Answer 15

Low pH

Question 16

Does an base have a low or high pH?

Answer 16

High pH

Question 17

What is the difference between alkalosis and acidosis?

Answer 17

Acidosis is low blood pH and alkalosis is high blood pH

Question 18

What prevents alkalosis and acidosis from occurring frequently in the body (there are 3 ways)?

Answer 18

The body can remove excess H+ ions by excreting them in the urine. Another way to remove acid is by increasing the loss of CO2 (an acid) by way of the respiratory system. A third way to adjust the body’s pH is by using buffers—chemicals in the blood that maintain pH.

Question 19

Which types of organic molecules does monosaccharides form?

Answer 19

Monosaccharides are single carbohydrate units

Question 20

Which types of organic molecules does fatty acids form?

Answer 20

The fatty acid components can be classified as saturated or unsaturated. Saturated fatty acids tend to be solid at room temperature and are found in butter and lard. Unsaturated fatty acids tend to be liquids and are found in oils such as corn oil and olive oil.

Question 21

Which types of organic molecules does amino acids form?

Answer 21

Proteins are very large molecules composed of basic units called amino acids.

Question 22

Which types of organic molecules does nucleotides form?

Answer 22

the basic building blocks of nucleic acids are called nucleotides. Each nucleotide consists of a phosphate unit, a sugar (ribose or deoxyribose), and a nitrogen base.

Question 23

Why is the structure of protein molecules important?

Answer 23

Functional proteins have shapes that enable them to participate in chemical processes of the body. Functional proteins include some of the hormones, growth factors, cell membrane channels and receptors, and enzymes.

Question 24

What is the role of DNA in the body?

Answer 24

The sequence of different nucleotides along the DNA double helix is the “master code” for assembling proteins and other nucleic acids.

Question 25

What is the role of ATP in the body?

Answer 25

Adenosine triphosphate (ATP) plays an important energy-transfer role in the body. Adenosine has not just one phosphate, but instead has three phosphates. The “extra” phosphates are attached to the molecule with unstable “high-energy” bonds that require a great amount of energy to form. Therefore they release a large amount of energy when broken.

Question 26

What is the role of RNA in the body?

Answer 26

Messenger RNA (mRNA) molecules have a sequence that forms a temporary “working copy” of a portion of the DNA code called a gene.

Question 27

What are enzymes?

Answer 27

Enzymes are chemical catalysts. This means that they help a chemical reaction to occur but are not reactants or products themselves.

Question 28

Explain the importance of enzymes in the body.

Answer 28

Enzymes are vital to body chemistry. No reaction in the body occurs fast enough unless the specific enzymes needed for that reaction are present.

Question 29

How does organic chemistry differ from inorganic chemistry?

Answer 29

Inorganic chemistry consists of inorganic compounds such as water, acids, bases and salts whereas organic chemistry consists of organic compounds like carbohydrates, lipids (fats and oils), proteins, and nucleic acids.