Test Bank Microbial Biochemistry Chapter.7

Chapter 7: Microbial Biochemistry

= Correct answer

Multiple Choice

1. Which of the following is the best definition of a macronutrient?

A. a trace element

B. a vitamin

C. an organic molecule necessary for life

D. the most abundant elements found in living cells

Difficulty: Easy

ASM Standard: N/A

1. Amino groups are an important component of which of the following macromolecules?

A. carbohydrates
B. lipids
C. nucleic acids

D. proteins

Difficulty: Easy

ASM Standard: N/A

1. The building blocks of polymers are called which of the following?

A. inorganic molecules

B. macromolecules

C. monomers

D. nucleic acids

Difficulty: Easy

ASM Standard: N/A

1. Which of the following is not one of the four major types of carbon-based macromolecules found in cells?

A. carbohydrates

B. lipids
C. macronutrients

D. nucleic acids

Difficulty: Easy

ASM Standard: N/A

1. Which of the following is the typical, stable shape of glucose in cells?

A. a branched chain

B. a double ring

C. a ring

D. a tetrahedron

Difficulty: Easy

ASM Standard: N/A

1. In which form do plants generally store sugar molecules?

A. cellulose

B. chitin

C. glycogen

D. starch

Difficulty: Easy

ASM Standard: N/A

1. Which term specifically describes fatty acids that do not have any double bonds, triple bonds, or rings?

A. esterified
B. polyunsaturated
C. saturated
D. unsaturated

Difficulty: Easy

ASM Standard: N/A

1. Which of the following best describes the difference between steroids and sterols?

A. Steroids are the most common type of sterol.
B. Steroids contain rings, whereas sterols do not.

C. Sterols are a type of steroid with an OH group.

D. Sterols are present in prokaryotes and steroids are not.

Difficulty: Moderate

ASM Standard: N/A

1. Which best describes oligopeptides?

A. a molecule consisting of two amino acids

B. long chains of amino acids
C. polymers of about 20 amino acids
D. polymers of about 50 amino acids

Difficulty: Easy

ASM Standard: N/A

1. Which of the following is not a lipid?
   A. a fatty acid
   B. a glyceraldehyde
   C. a wax
   D. an isoprenoid
   

Difficulty: Easy

ASM Standard: N/A

1. How many single covalent bonds can oxygen form?

A. one

B. two

C. three

D. four

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following molecules is an organic molecule?

A. CO₂

B. CaCO₃

C. CH₃OH

D. H₂O

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following is the best example of a micronutrient?

A. carbon

B. nitrogen

C. phosphorus

D. potassium

Difficulty: Easy

ASM Standard: N/A

1. Which of the following best describes glucose, fructose, and galactose?

A. achiral

B. enantiomers

C. stereoisomers

D. structural isomers

Difficulty: Moderate

ASM Standard: N/A

1. Why does it matter which enantiomer of a molecule is used for a medication?

A. Enantiomers can have different pharmacologic effects and only one may be effective.
B. It is usually easier to prepare one enantiomer than mixtures of both.

C. The d form is typically more effective than the l form.
D. The l form is typically more effective than the d form.

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following shows a ketone?

A. a carboxylic acid
B. an ester
C. an internal carbonyl group

D. an internal ether

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following types of bonds joins monosaccharides together to form a polysaccharide?

A. glycosidic bonds

B. hydrogen bonds

C. peptide bonds

D. phosphodiester bonds

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following best describes the molecule lactose?

A. disaccharide

B. monosaccharide

C. polysaccharide

D. trisaccharide

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following is an important component of insect exoskeletons?

A. cellulose

B. chitin
C. glycogen

D. starch

Difficulty: Moderate

ASM Standard: N/A

1. Which describes the hydrocarbon tails in the plasma membrane?

A. amphipathic
B. hydrophilic

C. hydrophobic

D. polar

Difficulty: Moderate

ASM Standard: N/A

1. In a protein, which type of chemical linkage joins the amino acids?

A. disulfide linkages

B. glycosidic linkages or bonds
C. hydrogen bonds

D. peptide bonds

Difficulty: Moderate

ASM Standard: N/A

1. Which is a common type of secondary structure of proteins?

A. the α helix
B. the β helix

C. the Δ helix

D. the ω helix

Difficulty: Moderate

ASM Standard: N/A

1. Disulfide bridges are most important in which of the following?

A. primary structure of proteins
B. secondary structure of proteins

C. structure of carbohydrates
D. tertiary structure of proteins

Difficulty: Moderate

ASM Standard: N/A

1. Which enantiomers rotate plane polarized light in a clockwise direction?

A. + or d

B. + or l

C. – or d

D. – or l

Difficulty: Moderate

ASM Standard: N/A

1. C₆H₁₂O₆ is an example of which type of molecule?

A. amino acid
B. fatty acid
C. monosaccharide

D. nucleotide

Difficulty: Moderate

ASM Standard: N/A

1. The phospholipid molecules in the plasma membrane are which of the following?

A. amphipathic

B. hydrophilic only

C. hydrophobic only

D. in the shape of micelles

Difficulty: Moderate

ASM Standard: N/A

1. Amylose is a component of which of the following?

A. cellulose
B. disaccharides
C. nucleotides

C. starch

Difficulty: Moderate

ASM Standard: N/A

1. Chitin is a polymer of which of the following?

A. amylase and amylopectin

B. glycosaminoglycan
B. N-acetyl glucosamine

C. N-acetyl muramic acid

Difficulty: Difficult

ASM Standard: N/A

1. Dextromethorphan and levomethorphan are best described as which of the following?
   A. achiral
   B. biologically identical

C. enantiomers

D. structural isomers

Difficulty: Difficult

ASM Standard: N/A

1. Which type of molecule is CH₃(CH₂)₁₄COOH?

A. amino acid
B. fatty acid
C. monosaccharide

D. nucleotide

Difficulty: Difficult

ASM Standard: N/A

1. A triglyceride contains which subcomponents?

A. a glycerol and two fatty acids

B. a glycerol and two sugars

C. a glycerol and three fatty acids

D. a glycerol and three sugars

Difficulty: Moderate

ASM Standard: N/A

1. The phospholipids of the plasma membrane contain which subcomponents?

A. a wax, a glycerol, and a phosphate group
B. two fatty acids, a glycerol, and a phosphate group

C. three fatty acids, a glycerol, and a phosphate group

D. four sphingolipids and a phosphate group

Difficulty: Difficult

ASM Standard: N/A

1. Which monomers make up lipids?

A. amino acids

B. fatty acids

C. lipids do not consist of monomers

D. monosaccharides

Difficulty: Difficult

ASM Standard: N/A

1. Which are the components found in starch?
   A. amylose and amylopectin
   B. amylose and glycogen

C. cellulose and glycogen
D. glucosamine and muramic acid

Difficulty: Difficult

ASM Standard: N/A

1. Which of the following is not true of triglycerides?

A. They are a type of phospholipid.

B. They are considered simple lipids.

C. They are hydrophobic.

D. They contain glycerol and three fatty acids.

Difficulty: Difficult

ASM Standard: N/A

1. FAME analysis involves which of the following?
   A. gas chromatography

B. high-pressure liquid chromatography

C. immunological testing

D. mass spectrometry

Difficulty: Difficult

ASM Standard: N/A

True/False

1. Polysaccharides generally have a sweet taste.

Difficulty: Easy

ASM Standard: N/A

1. Cellulose is an important structural component of plant cell walls.

Difficulty: Easy

ASM Standard: N/A

1. A denatured protein has lost its primary structure.

Difficulty: Moderate

ASM Standard: N/A

1. The MALDI-TOF method includes irradiation of the sample.

Difficulty: Moderate

ASM Standard: N/A

1. Proteins embedded within the plasma membrane are called integral proteins.

Difficulty: Moderate

ASM Standard: N/A

1. Disulfide bridges are a major component of the secondary structure of a protein.

Difficulty: Moderate

ASM Standard: N/A

1. The structure of β-pleated sheets is maintained by covalent bonds and ionic interactions.

Difficulty: Moderate

ASM Standard: N/A

1. The presence of poly-β-hydroxybutyrate granules is used in the classification of species of Pseudomonas bacteria.

Difficulty: Difficult

ASM Standard: N/A

1. Some plants use leghemoglobin to bind oxygen.

Difficulty: Difficult

ASM Standard: N/A

1. Xanthophylls are a type of isoprenoid.

Difficulty: Difficult

ASM Standard: N/A

Matching

1. Match each term with the best definition.

Answers: A. iv., B. i., C. iii., D. ii.

Difficulty: Easy

ASM Standard: N/A

1. Match each molecule with the best description.

Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Difficult
ASM Standard: N/A

1. Match each molecule with type of monomer it exemplifies.

Answers: A. iv., B. i., C. ii., D. iii.

Difficulty: Moderate

ASM Standard: N/A

1. Match each molecule with a type of functional group it contains.

Answers: A. iii., B. i., C. v., D. ii., E. iv.

Difficulty: Moderate

ASM Standard: N/A

1. Match each molecule with the class of macromolecules it exemplifies.

Answers: A. ii., B. iv., C. i., D. iii.

Difficulty: Difficult

ASM Standard: N/A

Fill in the Blank

1. ________ tissue stores energy in the form of triglycerides.

Difficulty: Easy

ASM Standard: N/A

1. ________ fatty acids are usually liquid at room temperature.

Difficulty: Easy

ASM Standard: N/A

1. Another term for triglyceride is ________.

Difficulty: Moderate

ASM Standard: N/A

1. Sulfhydryl groups in amino acids join together to form ________.

Difficulty: Moderate

ASM Standard: N/A

1. Sebum contains wax esters, triacylglycerol, and ________.

Difficulty: Difficult

ASM Standard: N/A

1. ________ is a branched lipid that is a building block of β-carotene.

Difficulty: Moderate

ASM Standard: N/A

1. Fungi produce ________ in their cell membranes, which serves a similar function as cholesterol in animal cell membranes.

Difficulty: Moderate

ASM Standard: N/A

1. ________ is a hormone produced in response to stress; it is marketed in a synthetic form as hydrocortisone to reduce skin irritation and inflammation.

Difficulty: Moderate

ASM Standard: N/A

1. The presence or absence of the storage molecule ________ can be used to identify some species of Pseudomonas.

Difficulty: Difficult

ASM Standard: N/A

1. ________ is an important globular protein that has four subunits, including two α peptides and two β peptides.

Difficulty: Difficult

ASM Standard: N/A

Short Answer

1. Some lipid molecules have a distinctive four-ringed structure and often function as hormones. What is the name for this group of hormones, and what are two examples of molecules in this group?

Sample

Difficulty: Easy

ASM Standard: N/A

1. What is the difference between a steroid and a sterol?

Sample

Difficulty: Easy

ASM Standard: N/A

1. What is a unit membrane?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Draw an example of a type of dehydration reaction (a chemical reaction) important in living organisms.

Sample

Difficulty: Easy

ASM Standard: N/A

1. What is the function of cholesterol in cell membranes?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. How many glycosidic linkages are in the molecule below?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. What type of chemical reaction is needed to separate this molecule into three fatty acids and glycerol?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Indicate the α carbon on the amino acid below.

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Consider the molecule below. Of the four major types of important biological molecules, which type is this? How can you tell? Explain why it fits into that group and then explain why it does not fit into each of the other three groups.

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Identify the functional group or groups in this molecule: CH₃CH₂CHO

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Why is glucose usually found in nature as a ring rather than as a linear structure?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Compare the structures of starch, glycogen, and cellulose. Explain why humans cannot use cellulose as a major source of energy even though it contains glucose molecules.

Sample

Difficulty: Difficult

ASM Standard: N/A

1. What are micelles and why is it energetically favorable for them to form?

Sample

Difficulty: Difficult

ASM Standard: N/A

1. Is the α carbon of this molecule chiral? Explain.

Sample

Difficulty: Difficult

ASM Standard: N/A

Brief Essay

Essay Question Rubric

Assume rating/grading scale for the question ranges from 0 to 3 points.

1. When a plasma membrane is damaged, it reseals to keep the lipid bilayer intact. Explain how this process happens and why it is energetically favorable.

Difficulty: Moderate

ASM Standard: N/A

1. Explain how the structure of the plasma membrane affects what can pass through it.

Difficulty: Moderate

ASM Standard: N/A

1. Compare the types of interactions that are responsible for the four different levels of protein structure.

Difficulty: Moderate

ASM Standard: N/A

1. Look at the phospholipid molecule below. Compare the shape of saturated and unsaturated fatty acids and think about what would happen if you packed together many phospholipids with a saturated fatty acids compared with packing together many phospholipids with unsaturated fatty acids. How do you think the plasma membrane might act differently if it has a higher proportion of saturated fatty acids versus a higher proportion of unsaturated fatty acids?

Difficulty: Moderate

ASM Standard: N/A

1. Think about the structure of the plasma membrane and about how proteins form three-dimensional structures. How do you think hydrophobic interactions affect an integral membrane protein? Where would hydrophobic amino acids be located on the protein? How would this differ from the location of hydrophobic amino acids in a protein that is loose in the cytoplasm, such as an enzyme?

Difficulty: Difficult

ASM Standard: N/A

1. People often think of fats as unhealthy and something that they should avoid. What are some reasons that fats are important in the human diet? Give at least three reasons.

Difficulty: Difficult

ASM Standard: N/A

1. What are similarities between cholesterol and hopanoids? What types of organisms use them? What are some other molecules with similar functions?

Difficulty: Moderate

ASM Standard: N/A

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