Chapter 2
Which of the following is both an anion and a compound?
HCO3-
Explain why small insects can walk on the surface of a pond and why tears protect the surface of the eye from dust particles. (Module 2.5C)
The attraction of water molecules creates a surface tension barrier that prevents small objects from penetrating the water.
Elements that have atoms with full outer shells of electrons
are inert gases
Carbohydrate molecules
are the body's most readily available source of energy.
The group of organic compounds containing carbon, hydrogen, and oxygen in a near 1:2:1 ratio is defined as a
carbohydrate
The molecule CO2 is known as
carbon dioxide
All fatty acids contain a functional group at one end called the ________ group.
carboxyl
Name the participants in a chemical reaction. (Module 2.7A)
reactants
Which of the structural representations of glucose shown below is more common in the body? (Module 2.14B)
ring form
All of the following are correct regarding protein denaturation except secondary structure becomes nonfunctional. quaternary structure becomes nonfunctional. death may occur at very high temperature. tertiary structure becomes nonfunctional. with increase in temperature, enzyme function deteriorates.
secondary structure becomes nonfunctional.
A shortage of cholesterol in the body could interfere with the formation of
sex hormones
Which of the following lists contains only trace elements?
silicon, fluorine,
The three familiar states of matter listed in order from the least to most thermal energy are
solid, liquid, gas
A(n) ________ is a homogeneous mixture containing a solvent and a solute.
solution
Which of the following are large polysaccharides and major dietary source of energy?
starch
Which of the following is a structural component of digestive secretions in bile?
steriods
How many electrons are shared by the oxygen atoms in an oxygen molecule? (Module 2.4B)
two pairs of electrons
Which of the following is/are inorganic substance(s)?
water and carbon dioxide
Describe lipids in terms of their elemental composition and solubility in water. (Module 2.15A)
water-insoluble organic compounds made up of carbon, hydrogen, and oxygen
A carbohydrate is attached to a diglyceride in which type of lipid?
glycolipids
What is an important by-product of exergonic reactions? (Module 2.9C)
heat
The molecule H2 is known as
hydrogen
Which element commonly has only a proton as its nucleus?
hydrogen
Which of the following functional groups of organic compounds link molecules through dehydration synthesis?
hydroxyl group
When electrons are transferred from one atom to another, and the two atoms unite as a result of the opposite charges,
ionic bond is formed
All of the following are correct regarding RNA except
it contains double helix
What is an important characteristic of amino acid uracil?
it is found in only rna
Which of the following lipids are produced in response to cellular injury or disease?
leukotrienes
In dehydration reactions, compounds
lose water molecules
H2O is an example of a(n)
molecular formula
Carbohydrates, lipids, and proteins are classified as
organic molecules
The molecule O2 is known as
oxygen
define ph
pH is a measure of the hydrogen ion concentration in a solution.
The ________ of a solution is the negative logarithm of the hydrogen ion concentration expressed in moles per liter.
ph
Which pH is closest to normal blood pH?
ph7
Every amino acid has a central carbon atom to which all of the followings are attached except a variable side group labeled as R. an amino group. a carboxyl group. a phosphate group. a hydrogen atom.
phosphate group
A sequence of amino acids bonded together in a linear chain is called a
primary structure
Each of the following is an example of an inorganic compound except water. proteins. salts. acids. bases.
proteins
The "atomic number" of an atom is determined by the number of ________ it has.
protons
The mass of an atom is largely determined by the number of ________ it has.
protons and neutrons
The nucleus of an atom consists of
protons and neutrons
The atomic weight of an atom reflects the average number of
protons+neutrons
The mass number represents the number of
protons+neutrons
The atomic weight of an atom reflects the average number of
protons+nuetrons+electrons
The innermost electron shell in an atom holds up to ________ electrons.
2
________ are short-chain fatty acids in which five of the carbon atoms are joined in a ring.
Prostaglandins
If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is
18
Calculate the weight of 1 mol of glucose. (The atomic weight of carbon = 12). (Module 2.7E)
180 grams
Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electrical charge of a calcium ion?
+2
Magnesium atoms have two electrons in the outermost shell. As a result, you would expect magnesium to form ions with a charge of
+2
What kind of bond forms during the dehydration synthesis of two amino acids, and which functional groups are involved? (Module 2.17B)
A peptide bond forms between the amino group of one amino acid and the carboxyl group of the other amino acid.
Using chemical notation, write the molecular formula for glucose, a compound composed of 6 carbon (C) atoms, 12 hydrogen (H) atoms, and 6 oxygen (O) atoms. (Module 2.7D)
C6H12O6
Define electrolytes. (Module 2.11B)
Electrolytes are ions that will conduct an electrical current in a solution.
Which of the following statements about hydrogen bonds is false?
Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.
Distinguish between hydrophilic and hydrophobic molecules. (Module 2.11C)
Hydrophilic molecules are attracted to water, whereas hydrophobic molecules do not interact with water molecules.
How do ions form ionic bonds?
Ions of opposite electrical charges are attracted to each other to balance the charges.
An important buffer in body fluids is
NaHCO3.
The gravitational field of the moon is 17% of Earth's. How would the weight and mass of a 100-pound astronaut change on the moon? (Module 2.1D)
On the moon, the astronaut would have the same mass as on Earth but would weigh 17 pounds (100 × 0.17).
In the hydrolysis of a triglyceride, what are the reactants and the products? (Module 2.15D)
The reactants are a triglyceride and three water molecules; the products are a glycerol molecule and three fatty acids. Submit
Describe the structure and role of prostaglandins. (Module 2.16A)
They are a type of eicosanoid released by cells to coordinate local cellular activities and produce pain sensations.
Explain how the complementary strands of DNA are held together. (Module 2.20B)
They are held by complementary base pairing; adenine to thymine and guanine to cytosine. Submit
Describe trace elements. (Module 2.2D)
Trace elements are present in small amounts in the body and are required for normal growth and maintenance.
Describe the kind of bonds that hold the atoms in a water molecule together. (Module 2.4C)
Water molecule bonds are polar covalent bonds, in which unequal sharing of electrons occurs.
Cations are smaller in diameter than their electrically neutral atom. Why? (Module 2.3D)
When electrons are lost, the remaining electrons are pulled closer toward the nucleus. Submit
What is a functional group? (Module 2.13B)
a grouping of atoms that confer specific chemical properties to the rest of the molecule to which it is attached.
Substrate molecules bind to enzymes at the ________ sites.
active
Adenosine is formed by combining
adenine and ribose
The purines found in DNA are ________ and ________.
adenine; guanine
What product is formed from the addition of a phosphate group to ADP?
adenosine triphosphate
What is an ion?
an atom that has either gained or lost electron(s)
In an aqueous solution, cations are attracted toward
anions
Ions with a negative charge are called
anions
The actual mass of an atom is known as its
atomic weight
A functional group is best described as reoccurring clusters of
atoms that greatly influence the chemical properties of molecules they are part of.
A(n) ________ removes hydrogen ions, and a(n) ________ releases hydrogen ions.
base, acid
Carbohydrate molecules
bodys most readily energy source
Ions with a + charge are called
cations
Oxygen is required in biological systems for
cellular respiration
Which of the following is not a cation?
cl-
During ionization, water molecules disrupt the ionic bonds of a salt to produce a mixture of ions. These ions can carry a current and so are called
electrolytes
________ are soluble inorganic compounds whose solutions will conduct an electric current.
electrolytes
Ionic bonds are formed when
electrons are completely transferred from one atom to another.
A(n) ________ is a pure substance composed of atoms.
element
Chemical reactions that absorb energy are called
endergonic
________ accelerate chemical reactions that occur in the human body.
enzymes
When placed in water, an inorganic compound dissociates 99 percent, forming hydrogen ions and anions. This compound would be a
strong acid
AB → A + B is to decomposition as A + B → AB is to
synthesis
The reaction N2 + 3 H2 → 2 NH3 is an example of a(n)
synthesis reaction
When an ionic bond forms, which part(s) of the atoms are directly involved?
the outermost electrons
Which property of water helps keep body temperature stabilized?
thermal inertia
What is the most important function of carbohydrates? (Module 2.14A)
they are the primary energy source
Which one of the following must be broken down to fatty acids and glycerol for use as an energy source?
triglycerides
