General Questions
1. ________ forms when two atoms share electrons.
A) ion
C) covalent bond
B) hydrogen bond
D) ionic bond
2. A hydrogen atom has one electron. How many covalent bonds can hydrogen form?
A) one covalent bond
C) four covalent bonds
B) four covalent bonds
D) two ionic bonds
3. Which of the following statements regarding the oxygen atom of a water molecule is true?
A) Oxygen is more positively charged than the hydrogen atoms.
B) Oxygen attracts electrons less strongly than the hydrogen atoms.
C) Oxygen is more electronegative than the hydrogen atoms.
D) Oxygen is attracted to the negatively charged atoms of other molecules.
4. In a water molecule, hydrogen and oxygen are held together by a(n) ________ bond.
A) double covalent
C) nonpolar covalent
B) ionic
D) hydrogen
5. ________ are weak bonds that are not strong enough to hold atoms together to form molecules
but are strong enough to form bonds within and around large molecules.
A) Ionic bonds
C) Anionic bonds
B) Covalent bonds
D) Hydrogen bonds
6. A solution with a pH of 7 is
A) strongly acidic.
C) neutral.
B) weakly acidic.
D) weakly basic.
7. Which of the following statements about pH is true?
A) The pH scale is a measure of oxygen ion concentration.
B) The pH of solutions inside most cells is close to 9.0
C) An increase in hydrogen ion concentration means a decrease in pH scale units.
D) Basic pH levels are less than 7.
8.
9.
Organic compounds are
A) always contain nitrogen.
C) always contain carbon and hydrogen.
B) are synthesized only by animal cells.
D) can be synthesized only in a laboratory
Which of the following statements regarding carbon is false?
A) Carbon has a tendency to form covalent bonds
B ) Carbon has the ability to bond with up to four other atoms.
C ) Carbon has the capacity to form single and double bonds.
D ) Carbon has the capacity to form polar bonds with hydrogen
10.
Which of the following statements about the functional groups of organic compounds is false?
A) Functional groups help make organic compounds hydrophilic.
B) Many biological molecules have two or more functional groups.
C) Functional groups participate in chemical reactions.
D) Functional groups help make organic compounds insoluble in water
11.
Name the following functional group ?
A) CO
:
B) OH
:
C) NH2
:
D) COOH :
E) SH
:
Macromolecules
12. Which of the following statements about the monomers and polymers found in living organisms is false?
A) Cells typically make all of their macromolecules by itself
B) Monomers serve as building blocks for polymers.
C) DNA is built from just four kinds of monomers.
D) Monomers are joined together by the process of hydrolysis
13. The results of dehydration synthesis can be reversed by
A) condensation.
C) polymerization.
B) hydrolysis.
D) the addition of a phosphate group
14. Which list below consists of only macromolecules?
A) sugars, amino acids, nucleic acids, lipids
B) proteins, lipids, nucleic acids, amino acids
C) proteins, lipids, nucleic acids, polysaccharides
D) polysaccharides, lipids, amino acids, nucleic acids proteins, lipids, nucleotides, sugars
15.
What is the general function of enzymes within a cell?
A) to promote the synthesis of monomers
B) to induce chemical reactions
C) to stop chemical reactions
D) to speed up chemical reactions
16.
Sucrose is formed
A) from two glucose molecules.
B) from two monosaccharides through dehydration reaction.
C) when ionic bonds link two monosaccharides.
D) when glucose and lactose are combined.
17.
A disaccharide forms when
A) two monosaccharides join by dehydration synthesis.
B) two starches join by dehydration synthesis.
C) two monosaccharides join by hydrolysis.
D) two starches join by hydrolysis.
18.
19.
20.
21.
22.
High-fructose corn syrup is composed primarily of a polysaccharide called
A) sucrose.
C) lactose.
B) starch.
D) cellulose.
Which of the following lists contains only polysaccharides?
A) sucrose, starch, and cellulose
C) cellulose, starch, and glycogen
B) starch, amino acids, and glycogen
D) nucleotides, glycogen, and cellulose
The storage form of carbohydrates is ________ in animals and ________ in plants.
A) chitin . . . glycogen
C) cellulose . . . glycogen
B) glycogen . . . starch
D) glycogen . . . cellulose
Which of the following organisms contain the polysaccharide chitin?
A) animals and plants
C) fungi and insects
B) plants and bacteria
D) insects and plants
Fatty acids are
A) composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio.
B) composed of carbon, hydrogen, glycerol, and a phosphate group.
C) Hydrophobic molecules
D) composed of four linked rings.
23.
Which of the following statements regarding triglyceride molecules is false?
A) Triglycerides consist of three fatty acids attached to a glycerol.
B) Triglycerides are hydrophobic.
C) Triglycerides play a structural role in cells.
D) Triglycerides are a type of fat.
24.
25.
Fatty acids with double bonds between some of their carbons are said to be
A) unsaturated.
C) completely hydrogenated.
B) saturated.
D) triglycerides.
Which of the following statements about animal cell lipids is false?
A) Fats are a form of lipid that function to store energy.
B) Phospholipids are important components of cell membranes.
C) Steroids are fatty acid that function as store energy.
D) Many lipids function as enzymes.
26.
A phospholipid is composed of
A) one glycerol molecule linked to three fatty acids.
B) one glycerol molecule linked to one phosphate group and two fatty acids
C) one glycerol molecule linked to three phosphate groups.
D) one fatty acid molecule linked to one glycerol molecule and two phosphate groups.
27.
28.
Which of the following substances is a lipid?
A) DNA
B) enzymes
C) cellulose
D) steroids
Which one of the following would be correctly classified as a protein?
A) cholesterol
C) enzymes
B) starch
D) cellulose
29.
30.
A major type of lipid found in cell membranes is
A) cellulose.
C) phospholipids.
B) triglycerides.
D) glycerol.
Which of the following statements about enzymes is false?
A) They increase the rate of chemical reactions.
B) They function as chemical catalysts.
C) They are monomers used to build proteins.
D) They are produced by cells.
31.
Amino acids can be distinguished from one another by
A) the number of R groups found on the amino acid molecules.
B) the chemical properties of their R groups.
C) the type of bond between the R group and the rest of the amino acid molecule.
D) the chemical properties of their amino and carboxyl groups.
32.
Proteins differ from one another because
A) the peptide bonds linking amino acids differ from protein to protein.
B) the sequence of amino acids in the polypeptide chain differs from protein to protein.
C) each protein contains its own unique sequence of sugar molecules.
D) the number of nucleotides found in each protein varies from molecule to molecule.
33.
34.
Glucose molecules are to starch as ________ are to proteins.
A) oils
C) fatty acids
B) amino acids
D) monosaccharides
Peptide bonds
A) are used to form amino acids.
C) bind monosaccharides
B) form between fatty acids
D) link amino acids.
35.
36.
37.
Which of the following characteristics of protein will remain intact if the protein is
denatured?
A) the shape of the protein
C) the solubility of the protein in water
B) the function of the protein
D) the number of amino acids in the protein
Proteins cannot be denatured by
A) heat.
C) chemicals that destroy hydrogen bonds.
B) changes in pH.
D) freezing
The primary structure of a protein is
A) an α helix or a pleated sheet.
B) the amino acid sequence of the polypeptide chain.
C) composed of two or more polypeptide chains.
D) maintained by hydrogen bonds.
38.
Which of the following is an example of secondary structure in a protein?
A) a particular amino acid sequence
B) an alpha helix
C) a globular shape
D) the joining of two polypeptide chains
39.
40.
The tertiary structure of a polypeptide refers to
A) its size.
C) the amino acids of which it is made.
B) the presence of pleated sheets.
D) the overall three-dimensional structure.
A protein containing more than one polypeptide chain exhibits the ________ level of
protein structure.
A) primary
C) tertiary
B) secondary
D) quaternary
41.
Which of the following statements regarding nucleotides is false?
A) Nucleotides have a nitrogenous base backbone.
B) Nucleotides contain sugar molecules.
C) Nucleotides contain phosphate groups.
D) Nucleotides can be linked together to form nucleic acids.
42.
43.
Which of the following options correctly pairs a polymer and its monomer?
A) cellulose, amino acids
C) DNA, nucleotides
B) RNA, ribose
D) collagen, nucleic acids
DNA differs from RNA because DNA
A) contains thymine in place of uracil.
B) consists of a single rather than a double polynucleotide strand.
C) contains the sugar ribose rather than the sugar deoxyribose.
D) contains phosphate groups not found in RNA.
44.
Genetic information is encoded in the
A) quaternary structure of a protein.
B) sequence of nucleotides in DNA.
C) degree of saturation of fatty acids.
D) linear sequence of amino acids in a polypeptide.
45.
Which of the following statements about enzymes or their function is true?
A) Enzymes do not alter the overall change in free energy for a reaction
B) Enzymes are proteins whose three-dimensional form is key to their function
C) Enzymes speed up reactions by lowering activation energy
D) All of the above
46.
One of the following is considered as enzyme
A) DNA
B) Glucose
C) Dehydrogenase
D) Phosphate
47.
The action of sucrose on sucrose is called
A) Dehydration
B) Hydrolysis
C) Polymerization
D) Removing of Carbons
True or False ?
1.
The increasing in pH affect enzymes by increasing their catalytic role.
2.
Cofactors is an protein that help the enzyme in their catalytic action such as vitamins and some ions .
3.
Penicillin, is an antibiotic that attack the bacteria directly and kill it
4.
Enzymes could have more than one activation center
5.
Enzymes with one active site could bind to more than one substrate.
6.
Hormones acts as enzyme cofactors .
7.
All enzymes work best at a neutral pH.
8.
Adding more acid does not affect the rate of activity of an enzyme.
9.
Enzymes function only in a pH range of 4.0 to 5.5.
10.
Catalysts are substances that reduce the activation energy of a chemical reaction.
11.
Catalysts do not affect the speed of chemical reaction.
12.
Catalysts are consumed in the reactions they catalyze.
13.
Enzymes are highly specific to the reactions they catalyze. They are of vital importance
for life because most chemical reactions of the cells and tissues are catalyzed by
enzymes. Without enzymatic action those reactions would not occur or would not happen
in the required speed for the biological processes in which they participate.
14.
Substrates are reagent molecules upon which enzymes act.
15.
The substrate binds to the enzyme in the any place .
16.
The substance that binds to the enzyme is called cofactor.
17.
The enzymatic action is not specific because any substrates of one enzyme bind to
the activation center of that enzyme.
18.
When the substrate concentration increases, the speed of the reaction increases.
19.
Enzymes could be denatured by Heating and Changing pH.
20.
Competitive inhibition occurs when a resemble substrate molecule attach to the active
site.
21.
DDT and Penicillin are example of cofactor that help enzyme of attacking microbes.