BIOL 2130-Mastering Ch. 2
Identify the nucleic acid: oxidase triglyceride cholesterol DNA glucose
DNA
Nucleotides are composed of:
a phosphate group, a five-carbon sugar, and a nitrogen-containing base
Which of the following DNA base pairs is complementary?
adenine and thymine
Proteins are synthesized from __________ during synthesis reactions.
amino acids
What is an ion?
an atom that has either gained or lost electron(s)
What type of bond is formed when electrons are transferred from one atom to another?
an ionic bond
Elements are composed of building blocks known as ________.
atoms
Which of the following is not produced through chemical bonding?
atoms
In a covalent bond,
atoms share one or more pairs of electrons.
Enzymes
biological catalysts
calcium
found in bones and teeth, and is required for blood clotting
sodium
major extracellular cation
potassium
major intracellular cation
chlorine
most abundant extracellular anion
A solution with a pH of 7 is:
neutral
Which subatomic particles contribute to an atom's mass number but not its atomic number?
neutrons
Isotopes have different numbers of _____________; thus they also have different _____________.
neutrons; atomic masses
What is the main type of lipid found in cellular membranes?
phospholipids
What ion is found in bone, nucleic acids, and ATP?
phosphorous
A molecule of water (H2O) is formed by what type of bond?
polar covalent bond
Formation of hydrogen bonds requires hydrogen atoms and what else?
polar covalent bonds
In which category of organic molecules would you place compounds that catalyze chemical reactions?
proteins
An acid is a molecule that releases (donates) ____________.
protons (hydrogen ions)
Which type(s) of subatomic particles can be located within the nucleus of an atom?
protons and neutrons
Molecule
two or more atoms combined chemcally
Polar molecules, like water, result when electrons are shared __________.
unequally between atoms
An atom's outermost shell is known as its ___________ shell.
valence
Which parts of atoms can interact (react) to form chemical bonds?
valence electrons
Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electoral charge of a calcium ion?
+2
What is the number of neutrons in an atom with atomic mass of 35, three energy levels, and 7 valence electrons?
18
Shell 1 of an atom can hold a maximum of __________ electron(s).
2
An atomic symbol is ________.
a one- or two-letter abbreviation for an element
An atom of oxygen has an atomic number of 8 and a mass number of 18. How many of each type of subatomic particles does it contain?
8 protons, 8 electrons, and 10 neutrons
A salt is an ionic compound containing cations other than hydrogen and anions other than the hydroxyl ion. In writing the formula for salt, the symbol of the cation is first listed and the symbol of the anion is listed second. Which of these is a salt?
CaPO4
How do ions form ionic bonds?
Ions of opposite electrical charges are attracted to each other to balance the charges
Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not?
No, because the atoms have only 6 valence electrons, but need 8 for stability
Which of the following distinguishes hydrogen bonds from covalent bonds?
Only hydrogen bonds can form between molecules
Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not?
Yes, because they can become more stable by doing so
Which is the most accurate description of C6H12O6?
a compound
Compound
a molecule composed of two or more elements
Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest?
covalent, ionic, hydrogen
What type of chemical reaction is used by liver cells when synthesizing glycogen from glucose?
dehydration synthesis
Which of the following choices describes the structure of a nucleotide found in DNA?
deoxyribose sugar, nitrogen-containing base, phosphate group
Unsaturated fatty acid chains contain one or more ___________ bonds between carbon atoms.
double
Nerve impulses involve the flow of an electrical current, a type of energy known as __________ energy.
electrical
The subatomic particles that are responsible for the chemical behavior of atoms are the ___________.
electrons
Which of these determines the chemical behavior of an atom?
electrons in the valence shell
Which of these statements reflects the relationship between elements, atoms, and chemical symbols?
elements are composed of atoms
At the beginning of glycolysis, ATP transfers a phosphate group of glucose. What type of chemical reaction is this?
exchange reaction
Which carbohydrate is also known as blood sugar?
glucose
Which of the properties of water is most closely associated with the body's ability to maintain a relatively constant internal temperature?
high heat capacity
Which of the following leads to an increase in the rate of chemical reaction?
increased temperature
Covalent bonds:
involve the sharing of one to three pairs of electrons
Atoms that have lost of gained electrons are known as:
ions.
Which statement best describes energy?
it does not have mass or occupy space
Which of these is an example of kinetic energy? a. battery in a flashlight with no bulb b. high-energy phosphate bonds in ATP c. skeletal muscles contracting as a person lifts weights d. glycogen within liver cells
skeletal muscles contracting as a person lifts weights
In our body, many salts dissociate into their ions. Which ions are essential for nerve impulses?
sodium and potassium
Which of the following is true of polar covalent bonds?
the electrons are shared unequally
When an ionic bond forms, which part(s) of the atoms are directly involved?
the outermost electrons
Which of these events occurs when salts dissolve in body fluids?
they easily dissociate into their ions
The building blocks of a triglyceride are _________.
three fatty acid chains and one glycerol molecule
Iron
transports oxygen inside red blood cells
Which of the following is not a result of hydrogen bonds?
two hydrogen atoms join together to form a molecule of hydrogen gas.
