The compounds above is a(n)
Phospholipid
saturated fatty acid
unsaturated fatty acid
triglyceride
Phosphorus (P) has an atomic number of 15. How many unpaired electrons are in its outer shell?
1
2
3
4
5
Which of the following is a polysaccharide found in plants used for storing energy?
amylose
amylopectin
cellulose
amylose and amylopectin
all three
A covalent bond involves:
a pair of electrons exchanged between atoms
an electrostatic attraction between atoms
the sharing of one or more protons between atoms
the sharing of one or more pairs of electrons between atoms
the exchange of one or more electrons between atoms
Unsaturated fatty acids are more likely to
be liquid at room temperature
be synthesized by animal cells
be solid at room temperature
contain more energy than saturated fatty acids
Which of the following functional groups tend to allow an organic compound to dissolve in water?
hydroxyl
methyl
carbonyl
hydroxyl and carbonyl
The number of protons in the nucleus of an atom is referred to as
atomic mass
molecular weight
atomic weight
atomic number
Water is a polar molecule because
it readily forms ionic bonds with many different types of compounds
its oxygen atom is electronegative, while the hydrogens are electropositive
its two hydrogen bonds are equally attached to an oxygen
it has a +2 negative charge
Methyl groups (CH3-R) are generally
hydrophilic
amphipathic
polar
hydrophobic
charged
The breakdown of glycogen into glucose occurs by which of the following
dehydration reactions
hydrolytic reactions
isomerization
dehydration and isomerization
Which of the following are functions of lipids?
genetic information
energy storage
major component of biological membranes
energy storage and major component
A solution with a pH of 8 is more ________ than a solution with a pH of 5.
acidic
concentrated
dense
basic
A pH of 4 has a _____-fold greater hydrogen ion concentration than a pH of 6.
10
100
1000
10000
Using the periodic table of elements, which element is most likely to have properties similar to carbon?
aluminum (Al)
boron (B)
phosphorus (P)
silicon (Si)
nitrogen (N)
In a polar covalent bond
anions and cations are attracted to each other
electrons are transferred between atoms
when water becomes frozen
there is an unequal sharing of electrons between atoms
water molecules attract each other
The energy of light can be temporarily stored in which component of an atom?
protons
photons
neutrons
electrons
introns
The two nucleic acid strands of DNA are held together by
glycosidic linkages
covalent bonding between nitrogenous bases
hydrogen bonding between sugar-phosphate residues
hydrogen bonding between nitrogenous bases
covalent binding between nucelotides
An acid added to water will
decrease the hydrogen ion concentration
decrease the hydroxide ion concentration
increase the hydroxide concentration
increase pH
Which bond contributes to the tertiary structure of a protein?
ionic
hydrogen
glycosidic
ionic and hydrogen
Water is pulled up into a tree due to
hydrogen bonding between water molecules
the cohesive and adhesive properties of water
the fluidity of water at room temperature
ionic bonding between water molecules
Which type of bond maintains the secondary structure of a protein
disulfide bridges
peptide bonds between two peptide subunits
hydrogen bonding between two phospholipid subunits
hydrogen bonding between an amino group of an amino acid and a carboxyl group of another amino acid
Amino acids within a peptide are covalently linked by peptide bonds between
acidic and basic side chains
carbonyl and amino groups
carboxyl and amino groups
polar and non-polar side chains
polar side chains
Insulin protein is soluble in water. A good explanation for this property is
that it does not have any secondary structure
it contains disulfide bridges
many of its amino acids have polar or charged side chains
most of its amino acids are hydrophobic
Hydrogen bonds form between
electropositive hydrogen atoms and an electronegative atom
hydrogen atoms
hydrogen atoms and any other atom
hydrogen atoms that share a pair of electrons with another atom
Of the molecules listed below, which contains the most phosphorus?
carbohydrates
proteins
fatty acids
nucleic acids
Although cellulose is a polymer of glucose molecules, humans cannot use it as a source of energy. Why?
cellulose is covered by a waxy coating protecting it from digestion
cellulose is hydrophobic
humans don't like the taste of cellulose
the molecule is too large to be broken down by hydrolytic enzymes
humans do not express specific enzymes to digest cellulose
All inert gases, such as neon (atomic number = 10) have which of the following in common?
they have the same number of protons
they have the same number of valence electrons
their outer electron shell is completely filled
they are all highly reactive
The ionic bond of NaCl arises from
attraction of a hydrogen atom and an electronegative atom
transfer of an electron to the nucleus of another atom
sharing of a pair of electrons
the attraction between two anions
an electrostatic attraction between two ions of opposite charge
The properties of an atom are determined by its
ionic number
half-life
mass number
When NaCl dissolves in water
the entire molecule becomes surrounded by water
each ion becomes surrounded by water
the covalent bonds between sodium and chlorine atoms are broken
entire molecule surrounded by water and each ion surrounded by water
Which of the functional groups above is a carboxyl?
Two compounds that are structural isomers
have the same total mass
have the same shape
have the same names
have the same properties
The tertiary structure of a protein is maintained by
hydrogen bonding
ionic bonds
hydrogen bonding and disulfide bridging
Why does ice float?
Non-uniform spacing of dissolved ions
bubbles formed during freezing makes ice more buoyant
hydrogen bonds forming between water molecules in ice creates crystal lattice structure that keeping the water molecules farther apart
liquid water is translucent and ice is opaque
ice contains impurities that keep water molecules away from each other and therefor less dense
Which of the following molecules is a major component of biological membranes?
phospholipids
triglycerides
Phospholipids contain
a hydrophobic head group
two hydrophobic tails
a ribose sugar
hydrophobic head and tails
If a sample of DNA is composed of 20% guanine, what is the percentage of thymine?
10%
20%
30%
60%
80%
The side-chain of the amino acid shown above is
non-polar, charged
non-polar
polar, uncharged
polar, charged
Water acts as a solvent because
it can dissolve any compound
it can be surrounded by both non-polar molecules and ionic compounds
it is liquid at room temperature
it is a polar molecule
it forms hydrogen bonds with itself
What kind of reaction is required to synthesize a polymer?
anxiolytic
dehydration
hydrolytic
anabolic
A cation
is a positively charged atom
is produced by a covalent bond
is a negatively charged atom
contains more neutrons than protons
A mutation that affects the primary structure of a protein, in turn, may affect
the secondary structure of the protein
the tertiary structure of a protein
the quaternary structure of the protein
secondary and tertiary
Which of the following molecules is a carbohydrate?
C18H9O18
C10H12O10
C4H8O4
C24H2O24
C1H3O6
Which of the following is not true regarding isomers?
isomers have different shapes
they have the same number of atoms
they have the same chemical properties
they may differ in how atoms are arranged across double bonds
they have different properties
Carbon Dioxide (CO2) consists of a carbon atom with double covalent bonds to each oxygen. How many electron pairs are shared between a carbon and oxygen atom?
8
Which atoms, when covalently bonded to hydrogen, are generally electronegative?
oxygen
nitrogen
sodium
oxygen and nitrogen
An atom with an atomic number of 12 has how many electrons in its most outer shell?
0
12
Glycogen in animals and amylose in plants
are disaccharides
are polymers that store glucose
cannot both be digested by humans
are long chains of amino acids
are hydrophobic compounds
Of the atoms in the first two rows of the periodic table, carbon atoms are unique because they
have four valence electrons
readily form polar covalent bonds with oxygen atoms
are molecularly stable
four valence electrons and molecularly stable
Which of the following are components of a nucleotide?
polar and non-polar amino acids
nitrogenous base and phosphate group and sugar
glycerol and three fatty acids
glycerol and two fatty acids and phosphate group