A molecule is smaller than an atom. True or False?
False.Atom is the smallest stable unit of matter. Two or more elements make a molecule.
Isotopes of an element differ in the number of
neutrons in the nucleus
The atomic number represents the number of
protons in an atom
The mass number of an atom indicates the number of
protons and neutrons in the nucleus.
Radioisotopes have unstable
nuclei
The chemical behavior of an atom is determined by
the number and arrangement of electrons
Ions with a positive charge are called
cations
In living cells, the weakest bond between two or more atoms is the ________ bond.
hydrogen
Ionic bonds are formed when
electrons are completely transferred from one atom to another
In a molecule of nitrogen, three pairs of electrons are shared by two nitrogen atoms. The type of bond that is formed would be an example of a(n)
triple covalent bond.
If a pair of electrons is unequally shared between two atoms, a(n) ________ occurs.
polar covalent bond
Elements that have atoms with full outer shells of electrons
are inert
All of the following are true concerning enzymes, except that they
become a part of the reaction's product
Substrate molecules bind to enzymes at the ________ sites.
active
Each of the following is an example of an inorganic compound, except
Water, Acids, Bases, Salts, Glucose.
Glucose. It contains Carbon, Hydrogen and Oxygen.
A solution containing equal numbers of hydrogen ions and hydroxide ions is
neutral
Which of the following substances would be least acidic?
lemon juice, pH = 2
urine, pH = 6
tomato juice, pH = 4
white wine, pH = 3
stomach secretions, pH = 1
urine, pH = 6
If a substance has a pH that is greater than 7, it is
alkaline
An important buffer in body fluids is
NaHCO3
Inorganic compounds that are soluble and whose ions will conduct an electrical current are called
electrolytes
Carbohydrate molecules
E) contain the genetic information found in cells.
B) are the body's most readily available source of energy
The most important metabolic fuel molecule in the body is
glucose
Molecules that have the same molecular formula but different structural formulas are called
isomers
A polysaccharide that is formed in liver and muscle cells to store glucose is
glycogen
The group of organic compounds containing carbon, hydrogen, and oxygen in a near 1:2:1 ratio is defined as a
carbohydrate
A fatty acid that contains three double covalent bonds in its carbon chain is said to be
polyunsaturated
Most of the fat found in the human body is in the form of
triglycerides
Cholesterol, phospholipids, and glycolipids are examples of
dietary fats
You would expect a peptide bond to link
two amino acids.
Each amino acid differs from another in the
nature of the R group
Glycoproteins and proteoglycans are combinations of proteins and
carbohydrates
Molecules that store and process genetic information are the
nucleic acids
Nucleic acids are composed of units called
nucleotides
A nucleotide consists of
a five-carbon sugar, a nitrogenous base, and a phosphate group
According to the rules of complementary base pairing, a nucleotide
containing the base cytosine would pair with a nucleotide containing the
base
guanine
The most important high-energy compound in cells is
adenosine triphosphate (ATP)
When atoms complete their outer electron shell by sharing electrons, they form
covalent bonds
Carbohydrates, lipids, and proteins are classified as
organic molecules
If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is
18
Which has the greater concentration of hydrogen ions, a substance with a pH of 5 or a substance with a pH of 4?
