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
