Chapter 2: Chemical Basis of Life

An organic compound always contains...

carbon and hydrogen

Organic substances contain _____, while inorganic substances do not.

carbon and hydrogen

Atoms with ___, ____, or _____ electrons would be inert.

2; 10; 18

Gastric juice (fluid in the stomach) has a pH value of 2.0. Therefore, this solution is:

Acidic

Electrolytes that release hydrogen ions in water are...

Acids

What type of chemical bond involves the sharing of a pair of electrons by two atoms in a molecule?

Covalent bonds

Which of the following is(are) ionizing radiation?

Both cosmic radiation and gamma radiation

Glucose and Glycogen are examples of what group organic compounds.

Carbohydrates

Examples of ______________ include the breakdown of glucose by cells to provide energy, the bonding of oxygen to hemoglobin, and the digestion of your meal by your gastrointestinal tract.

Chemistry

Stores genetic information, including instructions for enzymes that synthesize fats and carbohydrates.

DNA

Nucleic acids include...

DNA and RNA

he primary type of chemical reaction involved in the digestion of a meal by the digestive system is a(n):

Decomposition reaction

Water causes ionically-bonded atoms to...

Dissociate

Salts and acids are examples of inorganic compounds called _____, which dissociate in water to release ions.

Electrolytes

Name the subatomic particle that participates in chemical bond formation.

Electrons

When an acid such as HCl reacts with a base such as NaOH, the products are a salt (NaCl) and water (H2O). What term best describes this type of chemical reaction?

Exchange reaction

A complex carbohydrate consists of a phosphate group attached to a sugar molecule.

False

A person with alkalosis has a blood pH less than 7.3.

False

A phospholipid differs structurally from a triglyceride in that it has three phosphate groups attached to the glycerol molecule rather than three fatty acid chains.

False

A substance that releases hydrogen ions in water is a base.

False

An acid is an electrolyte that releases hydroxide ions (OH-) in water.

False

An atom with 10 protons and which has lost 2 electrons is electrically neutral.

False

Cholesterol, a type of lipid, is comprised of three fatty acid chains attached to glycerol.

False

Glycogen is a complex carbohydrate that we get directly by eating plants.

False

Nucleic acids are composed of building blocks called amino acids.

False

Proteins encode nucleic acids.

False

Radioactive isotopes have stable nuclei.

False

Sodium and chloride atoms combine readily because they both lose electrons.

False

The number of protons in an atom of an element always equals its atomic weight.

False

The organic molecule called _____________ is formed by branched chains of sugar units. It is used by humans and other mammals to store carbohydrate in the liver and skeletal muscles.

Glycogen

Carbonic Acid is a compound consisting of one carbon, two hydrogen atoms, and three oxygen atoms. Indicate the correct molecular formula for this compound.

H2CO3

The atomic weight of an atom equals...

Number of protons plus neutrons

______ bonds occur between polar molecules.

Hydrogen

The secondary structure of a protein molecule is the result of...

Hydrogen bonds

Name the type of organic molecule that is hydrophobic.

Lipid

A cation is formed when an atom ___________ an electron.

Loses

Name the class of organic compound that is comprised of subunits consisting of a phosphate group, a sugar, and a nitrogen-containing base.

Nucleic Acid

The type of organic molecule that can replicate is a...

Nucleic Acid

Composed of building blocks called nucleotides.

Nucleic acids

In phenylketonuria, an individual cannot break down the amino acid phenylalanine. Molecules that include phenylalanine build up in the blood, which causes intellectual disability and other symptoms. This inherited disease can be controlled by following a diet that is very low in...

Protein

The atomic number of an atom equals the number of...

Protons

The ______ uses iodine in a synthesis reaction.

Thyroid gland

A base is an electrolyte that releases ions that combine with hydrogen ions.

True

A protein is formed from a sequence of amino acids.

True

A strong acid reacting with a strong base produces a salt.

True

An electrolyte ionizes in water.

True

At atom that has gained or lost electrons is called an ion.

True

Chemically inert atoms always have their outermost electron shell full.

True

Chemistry is the study of the composition of matter and how matter changes.

True

DNA and RNA are nucleic acids.

True

The symbol Na+ represents a sodium atom that has lost an electron.

True

Water is an example of a compound.

True

Sodium ions and calcium ions are examples of...

cations

When cations and anions meet, they...

form ionic bonds

Carbon can form ___ covalent bonds.

four

List the components of a phospholipid:

glycerol, two fatty acids, and a phosphate group

The isotope most likely to be used to study the thyroid gland is...

iodine-131

In an ionic bond...

oppositely charged atoms attract.

The pH scale measures the...

the concentration of hydrogen ions in a solution

The first electron shell of an atom can hold a maximum of...

two electrons