Unit 1: Acid-Base Chemistry and Carbohydrates - Practice Quiz

BTY105 — Fundamentals Of Biochemistry 60 Questions
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1 Which substance donates a proton () in an acid-base reaction?

Acid, Base and Buffers Easy
A. A base
B. A buffer
C. An acid
D. A salt

2 Which substance accepts a proton ()?

Acid, Base and Buffers Easy
A. A solvent
B. A base
C. An acid
D. A buffer

3 Which property of water helps it dissolve many ionic and polar substances?

Properties of water Easy
A. High opacity
B. Low viscosity
C. High density
D. Polarity

4 What type of bond forms between neighboring water molecules?

Properties of water Easy
A. Peptide bond
B. Hydrogen bond
C. Glycosidic bond
D. Disulfide bond

5 A solution with a pH of 7 at room temperature is considered:

Concept of pH scale Easy
A. Weakly acidic
B. Strongly basic
C. Neutral
D. Strongly acidic

6 Which solution is more acidic?

Concept of pH scale Easy
A. A solution with pH 9
B. A solution with pH 7
C. A solution with pH 5
D. A solution with pH 2

7 What is the main function of a buffer?

Buffers and its mechanism of action Easy
A. To resist pH changes
B. To increase temperature
C. To remove all water
D. To produce oxygen

8 A buffer commonly contains:

Buffers and its mechanism of action Easy
A. A strong acid and water
B. A neutral sugar and lipid
C. A weak acid and its conjugate base
D. A strong base and salt only

9 Which equation is the Henderson–Hasselbalch equation for an acidic buffer?

Henderson Hasselbalch equation Easy
A.
B.
C.
D.

10 When the concentrations of a weak acid and its conjugate base are equal, the Henderson–Hasselbalch equation gives:

Henderson Hasselbalch equation Easy
A.
B.
C.
D.

11 Carbohydrates are primarily composed of:

Carbohydrates Easy
A. Carbon, nitrogen, and sulfur
B. Hydrogen, nitrogen, and calcium
C. Oxygen, sulfur, and phosphorus
D. Carbon, hydrogen, and oxygen

12 Which class of carbohydrate contains a single sugar unit?

Classification of carbohydrates Easy
A. Polysaccharide
B. Disaccharide
C. Monosaccharide
D. Oligosaccharide

13 Which of the following is a monosaccharide?

Monosaccharides Easy
A. Sucrose
B. Lactose
C. Glucose
D. Starch

14 A monosaccharide containing an aldehyde group is called a:

Monosaccharides Easy
A. Ketose
B. Pentose
C. Aldose
D. Hexose

15 What are stereoisomers?

Stereo isomerism of monosaccharides Easy
A. Compounds with the same formula but different spatial arrangements
B. Compounds with different formulas but identical structures
C. Compounds formed only from amino acids
D. Compounds containing only carbon atoms

16 D-glucose and L-glucose are examples of:

Stereo isomerism of monosaccharides Easy
A. Disaccharides
B. Peptides
C. Enantiomers
D. Anomers only

17 What is formed when the hydroxyl group of a sugar is replaced by a hydrogen atom?

Sugar derivatives Easy
A. Amino sugar
B. Deoxy sugar
C. Sugar phosphate
D. Sugar alcohol

18 An oligosaccharide usually contains:

Oligosaccharides Easy
A. Only one glucose unit
B. A few monosaccharide units
C. One amino acid unit
D. Thousands of lipid units

19 Which polysaccharide is the main storage carbohydrate in plants?

Polysaccharides (storage and structural) Easy
A. Cellulose
B. Chitin
C. Starch
D. Hyaluronic acid

20 Mucopolysaccharides are also commonly called:

Mucopolysaccharides Easy
A. Phospholipids
B. Nucleoproteins
C. Aminopeptidases
D. Glycosaminoglycans

21 A weak acid, , is mixed with its conjugate base, . Which change would most likely increase the buffer capacity of this solution?

Acid, Base and Buffers Medium
A. Replacing with a neutral salt
B. Adding a strong acid only
C. Diluting the solution tenfold
D. Increasing the total concentration of and

22 Water has a relatively high boiling point compared with molecules of similar molecular mass primarily because of its:

Properties of water Medium
A. Covalent bonding between molecules
B. Hydrogen bonding between molecules
C. Van der Waals repulsion only
D. Ionic bonding between molecules

23 Why does ice float on liquid water?

Properties of water Medium
A. Ice contains fewer oxygen atoms
B. Ice molecules lose their polarity
C. Ice has stronger covalent bonds
D. Ice has a more open hydrogen-bonded structure

24 A solution has a hydrogen ion concentration of . What is its approximate pH?

Concept of pH scale Medium
A. 3
B. 7
C. 9
D. 5

25 Compared with a solution at pH 6, a solution at pH 4 has approximately:

Concept of pH scale Medium
A. 1,000 times greater hydrogen ion concentration
B. 100 times greater hydrogen ion concentration
C. 2 times greater hydrogen ion concentration
D. 20 times greater hydrogen ion concentration

26 In a bicarbonate buffer, what happens when a small amount of strong acid is added?

Buffers and its mechanism of action Medium
A. The acid permanently increases the buffer pH
B. Carbonic acid converts the acid into bicarbonate
C. Water converts the acid into hydroxide ions
D. Bicarbonate converts the acid into carbonic acid

27 A buffer works most effectively when:

Buffers and its mechanism of action Medium
A. The weak acid and conjugate base are present in comparable amounts
B. The solution contains a strong acid and strong base
C. Only the weak acid is present
D. Only the conjugate base is present

28 For a buffer with and equal concentrations of weak acid and conjugate base, the pH is approximately:

Henderson Hasselbalch equation Medium
A. 7.0
B. 2.4
C. 9.6
D. 4.8

29 A buffer has and a ratio . What is its approximate pH?

Henderson Hasselbalch equation Medium
A. 7.0
B. 6.0
C. 5.0
D. 16.0

30 Which feature best explains why many carbohydrates are soluble in water?

Carbohydrates Medium
A. They contain only carbon-carbon bonds
B. They contain many nonpolar hydrocarbon groups
C. They contain several hydroxyl groups
D. They lack hydrogen-bonding sites

31 A carbohydrate that cannot be hydrolyzed into a simpler carbohydrate is classified as a:

Classification of carbohydrates Medium
A. Polysaccharide
B. Monosaccharide
C. Disaccharide
D. Oligosaccharide

32 A sugar containing an aldehyde group and six carbon atoms is best classified as a:

Classification of carbohydrates Medium
A. Ketohexose
B. Aldohexose
C. Ketotriose
D. Aldopentose

33 When D-glucose forms a ring, the carbonyl carbon becomes a new chiral center called the:

Monosaccharides Medium
A. Terminal carbon
B. Anomeric carbon
C. Glycosidic carbon
D. Carboxyl carbon

34 Which monosaccharide is a ketose rather than an aldose?

Monosaccharides Medium
A. Ribose
B. Fructose
C. Glucose
D. Galactose

35 D-glucose and D-galactose differ in configuration at only one chiral carbon. They are:

Stereo isomerism of monosaccharides Medium
A. Constitutional isomers
B. Anomers
C. Epimers
D. Enantiomers

36 -D-glucose and -D-glucose are classified as:

Stereo isomerism of monosaccharides Medium
A. Anomers
B. Epimers at carbon 5
C. Constitutional isomers
D. Enantiomers

37 Replacement of the hydroxyl group at carbon 2 of glucose by hydrogen produces:

Sugar derivatives Medium
A. Deoxy sugar
B. Amino sugar
C. Sugar alcohol
D. Sugar acid

38 Glucosamine is formed by replacing a hydroxyl group of glucose with an amino group. It is therefore a(n):

Sugar derivatives Medium
A. Sugar alcohol
B. Aldonic acid
C. Amino sugar
D. Deoxy ketose

39 Lactose is composed of which two monosaccharides?

Oligosaccharides Medium
A. Glucose and galactose
B. Glucose and ribose
C. Glucose and fructose
D. Fructose and galactose

40 Which comparison between glycogen and cellulose is correct?

Polysaccharides (storage and structural) Medium
A. Glycogen is branched, whereas cellulose is linear
B. Glycogen is structural, whereas cellulose is storage
C. Both contain mainly linkages
D. Both are digested efficiently by human amylase

41 A weak acid has . Which statement best explains why its conjugate base is more abundant than the undissociated acid at physiological pH?

Acid, Base and Buffers Hard
A. The conjugate base is stabilized at higher pH
B. The acid becomes stronger when diluted
C. Water loses its buffering capacity near neutrality
D. The conjugate base always has a lower molecular mass

42 Why does water have an unusually high boiling point compared with molecules of similar molecular mass?

Properties of water Hard
A. Strong covalent bonds between separate molecules
B. Extensive hydrogen bonding between molecules
C. High concentration of dissolved ionic compounds
D. Permanent ionization of nearly all water molecules

43 Two solutions have pH values of 3 and 5, respectively. Assuming ideal behavior, how does the hydrogen-ion concentration of the first solution compare with that of the second?

Concept of pH scale Hard
A. It is 100 times higher
B. It is 1,000 times higher
C. It is 20 times higher
D. It is 2 times higher

44 A buffer contains equal concentrations of a weak acid and its conjugate base. If a small amount of strong acid is added, which event occurs first?

Buffers and its mechanism of action Hard
A. Water supplies enough hydroxide to neutralize the acid
B. The conjugate base consumes the added protons
C. The solution immediately reaches the acid's
D. The weak acid releases all of its protons

45 A buffer has . What ratio of conjugate base to weak acid is required to obtain pH 7.1?

Henderson Hasselbalch equation Hard
A.
B.
C.
D.

46 A buffer initially contains equal amounts of and . If one-half of the original amount of is converted into by added acid, what is the approximate pH change?

Henderson Hasselbalch equation Hard
A. It decreases by pH units
B. It increases by pH units
C. It remains exactly unchanged
D. It decreases by pH units

47 A weak acid buffer is most effective when the desired pH is close to which value?

Acid, Base and Buffers Hard
A. The acid's molecular mass
B. The acid's
C. The solution's ionic strength
D. The conjugate base's oxidation state

48 A carbohydrate yields two different monosaccharides on complete hydrolysis and contains a single glycosidic linkage. How should it be classified?

Classification of carbohydrates Hard
A. A heterodisaccharide
B. A monosaccharide
C. A homopolysaccharide
D. A branched mucopolysaccharide

49 Which structural feature distinguishes an aldose from a ketose in its open-chain form?

Monosaccharides Hard
A. An aldehyde group at a terminal carbon
B. A hydroxyl group on every carbon
C. A carboxyl group at the anomeric carbon
D. A ketone group at a terminal carbon

50 How many stereoisomers are theoretically possible for an aldohexose containing four asymmetric carbon atoms in its open-chain form?

Stereo isomerism of monosaccharides Hard
A. 16
B. 4
C. 32
D. 8

51 Two monosaccharides differ in configuration at only one chiral carbon that is not the anomeric carbon. What is their relationship?

Stereo isomerism of monosaccharides Hard
A. They are constitutional isomers
B. They are enantiomers
C. They are anomers
D. They are epimers

52 A cyclic D-sugar has its anomeric hydroxyl group trans to the terminal group. Which designation applies?

Stereo isomerism of monosaccharides Hard
A. The alpha anomer
B. The beta anomer
C. The L enantiomer
D. The D epimer

53 Oxidation of the terminal primary alcohol group of glucose, while retaining its aldehyde group, produces which derivative?

Sugar derivatives Hard
A. Glucuronic acid
B. Glucosamine
C. Gluconic acid
D. Glucaric acid

54 Replacement of the hydroxyl group on the second carbon of glucose by an amino group produces which compound?

Sugar derivatives Hard
A. Glucuronic acid
B. Gluconic acid
C. Sorbitol
D. Glucosamine

55 Why is sucrose classified as a nonreducing disaccharide?

Oligosaccharides Hard
A. It contains no oxygen atoms capable of hydrogen bonding
B. It contains only ketose monosaccharide units
C. Both anomeric carbons form the glycosidic bond
D. Its glucose unit cannot form a cyclic structure

56 Lactose is a reducing sugar because its glycosidic linkage leaves which structural feature available?

Oligosaccharides Hard
A. Both anomeric carbons simultaneously
B. The anomeric carbon of galactose
C. The anomeric carbon of glucose
D. Neither anomeric carbon in a free form

57 Which structural feature makes glycogen more rapidly mobilized than amylopectin?

Polysaccharides (storage and structural) Hard
A. Absence of terminal residues
B. More frequent branch points
C. Exclusive beta linkages
D. Longer unbranched chains only

58 Why can humans digest starch but not cellulose efficiently?

Polysaccharides (storage and structural) Hard
A. Starch cannot form hydrogen bonds between chains
B. Cellulose is composed only of ketose units
C. Starch contains nitrogen; cellulose lacks all oxygen
D. Starch has linkages; cellulose has linkages

59 Which combination is characteristic of glycosaminoglycans such as hyaluronic acid and chondroitin sulfate?

Mucopolysaccharides Hard
A. Nucleotides joined by phosphodiester bonds
B. Branched glucose polymers containing only alpha linkages
C. Repeating hydrophobic amino acids with no carbohydrate units
D. Repeating disaccharides with amino sugars and uronic acids

60 A heavily sulfated glycosaminoglycan attracts water and cations primarily because of its:

Mucopolysaccharides Hard
A. Abundance of neutral methyl groups
B. Large number of peptide bonds
C. Lack of polar functional groups
D. High density of negative charges