Microbiology CH. 2 Study and Review
When the nucleus of an atom contains a constant number of protons but a variable number of neutrons, the atom is called a(n) __________.
isotope
Methane is classified as a compound because __________.
it contains atoms of more than one element
Pure water has a neutral pH because __________.
it dissociates into equal numbers of hydrogen and hydroxyl ions
Which of the following is NOT a type of lipid? waxes triglycerides peptidoglycan steroid
peptidoglycan
Cranberry juice has a pH of 2.4, while grape juice has a pH of 3.3; which juice is more acidic?
cranberry
If you know that sodium chloride molecules contain ionic bonds, which of the following electronegativity values would be appropriate for the elements sodium and chlorine?
0.9 and 3.0
An oxygen atom has two electron shells and 6 valence electrons. How many total electrons does this atom have?
8
Which of the following is NOT true of hydrogen bonds?
Hydrogen bonds are important only in the interaction between water molecules.
Which of the following is a molecule, but NOT a compound?
O2
If you know that a particular chemical reaction involves the production of smaller molecules from the breakdown of larger molecules, which of the following statements would you expect to be true?
The reaction releases energy.
What is the common trait of all lipids?
They are at least partially hydrophobic.
Which of the following is a bond in which electrons are shared unequally?
a polar covalent bond
KH2PO4 acts as a buffer by __________.
combining with hydrogen ions
Catabolism includes all of the following types of reactions EXCEPT __________. dehydration synthesis reactions decomposition reactions hydrolysis reactions exothermic reactions
dehydration synthesis reactions
Sucrose is an example of which of the following? - a nucleotide - steroid - a dipeptide - disaccharide
disaccharide
A synthesis reaction is also considered which of the following types of reactions?
endothermic
Which of the following subatomic particles does NOT have a charge?
neutron
Which of the following is the most alkaline (basic) pH? pH 2.0 pH 7.0 pH 9.0 pH 13.0
pH 13.0
An endothermic reaction __________.
requires energy
In discussions of atomic mass, electrons are often ignored because __________.
their mass makes a negligible contribution to the atom's overall mass
