Biology Exam Chapter 3 MC
Enzymes lower activation energy by a. linking to the substrate and weakening bonds within the substrate b. becoming chemically changed and reacting with the substrate c. changing the temperature and pH of the substrate's environment d. linking to the substrate permanently, creating a very large molecule
a
Organic compounds contain a. carbon and usually other elements b. many kinds of elements except carbon c. only carbon d. only carbon and hydrogen
a
The breakdown of a polymer involves a. hydrolysis b. a condensation reaction c. the breaking of hydrogen bonds d. the breaking of ionic bonds
a
The breakdown of polymers into monomers occurs through a process known as a. hydrolysis b. condensation c. dissociation d. removal of a functional group
a
The different shapes and functions of different proteins are determined by a. the R groups of the amino acids they contain b. the amino groups of the amino acids they contain c. the carboxyl groups of the amino acids they contain d. whether or not they contain any amino acids
a
When sodium chloride is dissolved in water, the sodium ions a. are attracted to the oxygen atoms of water molecules b. are attracted to the hydrogen atoms of water molecules c. are attracted to each other d. do not dissociate from the sodium chloride
a
A bond that forms between a positively charged hydrogen atom of one molecule and a negatively charged region of another molecule is a(n) a. ionic bond b. hydrogen bond c. covalent bond d. basic bond
b
A covalent bond formed when two atoms share two pairs of electrons is called a a. single bond b. double bond c. triple bond d. quadruple bond
b
In a water molecule, a. all of the atoms have slight positive charge b. the oxygen atom has a slight negative charge and the hydrogen atoms have a slight positive charge c. the oxygen atom has a slight positive charge and they hydrogen atoms have a slight negative charge d. all of the atoms have a slight negative charge
b
Lipids are good energy-storage molecules because a. they can absorb a large amount of energy while maintaining a constant temperature b. they have many carbon-hydrogen bonds c. they are composed of many simple sugars d. they cannot be broken down by enzymes
b
Organic molecules that catalyze reactions in living systems are a. phospholipids b. enzymes c. polysaccharides d. steroids
b
The large number of carbon-hydrogen bonds in lipids a. make lipids polar b. store more energy than the carbon-oxygen bonds in other organic compounds c. allow lipids to dissolve in water d. are found in the carboxyl group at the end of the lipid
b
A compound found in living things that supplies the energy in one of its chemical bonds directly to cells is a. phosphate b. RNA c. ATP d. alcohol
c
A compound that is stored as glycogen in animals and as starch in plants is a. alcohol b. cellulose c. glucose d. phosphate
c
Glycogen, starch and cellulose are a. monosaccharides b. disaccharides c. polysaccharides d. simple sugars
c
Hydrogen bonds a. form between hydrogen atoms in different molecules b. are strong bonds c. hold water molecules to one another d. hold the two hydrogen atoms together in a molecule of hydrogen gas,H2
c
The number of covalent bonds a carbon atom can form with other atoms is a. 1 b. 2 c. 4 d. 8
c
ATP releases energy when a. it undergoes a condensation reaction b. a hydroxyl group is added to it c. a phosphate group is added to it d. a phosphate group is removed from it
d
Most enzymes a. are changed by the reactions they catalyze b. increase the activation energy of the reactions they catalyze c. strengthen the chemical bonds in their substrate d. are sensitive to changes in temperature or pH
d
The most important function of nucleic acids is a. catalyzing chemical reactions b. forming a barrier between the inside and outside of a cell c. storing energy d. storing information related to heredity and protein synthesis
d
The presence of four electrons in the outermost energy level of a carbon atom enables a. carbon atoms to form four covalent bonds with atoms of other elements b. carbon atoms to form covalent bonds with other carbon atoms c. carbon atoms to form double bonds with other atoms d. all of the above
d
Water is an effective solvent because a. it is a polar molecule b. it dissolves other polar substances c. it dissolves ionic compounds d. all of the above
d
When a glass is filled to the brim with water, the water appears to bulge from the sides of the glass due to a. capillarity b. thermal energy c. adhesion d. cohesion
d
When liquid water is heated, most of the energy that the water initially absorbs is used to a. raise the temperature of the water b. break the covalent bonds between the hydrogen and oxygen atoms in water c. make the water boil d. break the hydrogen bonds between the water molecules
d
