Deck 3: The Biochemistry of Macromolecules

Question 1

Proteins, carbohydrates, lipids and nucleic acids are the four classes of macromolecules that compose all organisms. What characteristic(s) do these four groups share? (Select all that apply)

A) All have carbon atoms as a major portion of their backbone.
B) Each group has specific monomers that are joined together by polymer-specific covalent bonds.
C) Monomers are bonded to each other via hydrolysis reactions.
D) Each class of macromolecules functions similarly.

Answer 1

A,B

Question 2

________ are the most abundant class of macromolecule.

A) Proteins
B) Carbohydrates
C) Lipids
D) Nucleic acids

Answer 2

A

Question 3

Which of the following features characterize an amino acid? (Select all that apply)

A) They all contain a carboxyl group
B) The "R" group may be basic, acidic, nonpolar or uncharged polar
C) They all contain a hydroxyl group
D) The carboxyl group of one amino acid joins to the amino group of the adjacent amino acid

Answer 3

A,B,D

Question 4

If hydrolysis cleaves the second peptide bond in a pentapeptide, the two fragments can be described as ________.

A) dipeptides
B) an amino acid and a tetrapeptide
C) a dipeptide and a tripeptide
D) a hexapeptide

Question 5

The ________ level of protein structure is shown below.

A) primary
B) secondary
C) tertiary
D) quaternary

Question 6

This protein folding pattern is known as a(n) ________ and represents the ________ protein structure.

A) alpha-helix; primary
B) beta-sheet; secondary
C) peptide backbone; tertiary
D) zig-zig chain; quaternary

Question 7

Tertiary protein structure is maintained by________. (Select all that apply)

A) hydrogen bonds
B) ionic bonds
C) disulfide bridges
D) hydrophilic interactions

Question 8

This molecule demonstrates the ________ level of protein structure.

A) primary
B) secondary
C) tertiary
D) quaternary

Question 9

The overall structure of a protein is ultimately dependent upon ________.

A) the amino acid sequence of the polypeptide
B) the presence of beta-sheets
C) the interaction of alpha-helices
D) the non-covalent bonding of multiple polypeptides

Question 10

Denaturation of the secondary or tertiary structure of a protein may be caused by ________. (Select all that apply)

A) changes in environmental conditions such as temperature or pH
B) may be temporary as in the use of a curling iron on human hair
C) may be permanent as in the use of chemical solutions on human hair
D) usually involves ligands

Question 11

Hemoglobin is a protein that functions to ________.

A) facilitate glucose uptake by cells
B) provide host protection against infection
C) control gene expression
D) transport oxygen throughout the body

Question 12

Antibodies are proteins that function to ________.

A) facilitate glucose uptake by cells
B) provide host protection against infection
C) control gene expression
D) transport oxygen throughout the body

Question 13

The number of different types of proteins that are 250 amino acids long is equal to ________.

A) 10³⁰⁰
B) 10²⁵⁰
C) 20²⁵⁰
D) 250²⁰

Question 14

What is the correct sequence of steps in an enzyme-catalyzed biochemical reaction?
1) Induced fit distorts the substrate making it more reactive and lowering E_a
2) Substrate binds to active site of enzyme like a lock and key
3) Substrate converted to product because of change in shape, size and charge
4) Enzyme-substrate binding energy contributes to catalysis

A) 1, 2, 4, 3
B) 2, 1, 4, 3
C) 1, 2, 3, 4
D) apply an antiseptic

Question 15

Activation energy ________. (Select all that apply)

A) drives endergonic reactions
B) is the minimum amount of start-up energy necessary to initiate a chemical reaction
C) is increased by enzyme activity
D) is usually supplied in the form of heat

Question 16

________ is the enzyme that degrades peptidoglycan in bacterial cell walls.

A) amylase
B) catalase
C) β-galactosidase
D) lysozyme

Question 17

The slight conformational change in an enzyme following substrate binding to correctly orient the substrate and promote rapid conversion to product is known as ________.

A) enzyme-substrate complex formation
B) induced fit
C) product conversion
D) activation energy

Question 18

A prosthetic group is a ________. (Select all that apply)

A) cofactor
B) coenzyme
C) constitutive enzyme
D) non-protein component that enhances enzyme activity

Question 19

Which of the following are coenzymes? (Select all that apply)

A) Fe³⁺
B) Constitutive enzymes
C) NADH
D) Lysozyme

Question 20

The rate of an enzyme-mediated reaction will increase if the ________. (Select all that apply)

A) appropriate coenzyme is added
B) concentration of enzyme is doubled
C) concentration of competitive enzyme inhibitor is doubled
D) temperature is elevated slightly

Question 21

A non-competitive enzyme inhibitor ________.

A) binds in the active site, preventing substrate access
B) replaces a cofactor on an enzyme
C) binds an allosteric site causing a conformational change in the active site that prevents substrate binding
D) converts a regulated enzyme to a constitutive enzyme

Question 22

The negative feedback inhibition of a biochemical pathway ________.

A) helps a cell conserve valuable resources by preventing generation of excess product
B) uses competitive inhibitors
C) can use the final product as a non-competitive inhibitor of the initial enzyme
D) requires apoenzymes

Question 23

Carbohydrates ________. (Select all that apply)

A) are composed of carbon, hydrogen, and oxygen in the proportion of CH₂O
B) may be straight or branched chains of monosaccharides
C) are composed of monomers joined together by hydrolytic reactions
D) are composed of monomers linked together by peptide bonds

Question 24

This biological molecule can be described as a ________. (Select all that apply)

A) monomer
B) monosaccharide
C) hexose
D) carbohydrate

Question 25

Monosaccharides are joined together by ________ links to form polymers.

A) peptide
B) glycosidic
C) ester
D) phosophodiester

Question 26

Why are carbohydrates such excellent molecules for energy storage?

A) They are composed of three basic atoms: carbon, hydrogen and oxygen.
B) Hydrolysis of glycosidic links releases energy used in many parts of the cell.
C) Glycosidic links are very hard to break.
D) Carbon may form bonds with up to four different chemicals.

Question 27

________ is a carbohydrate commonly used as structural material. (Select all that apply)

A) Glycogen
B) Starch
C) Cellulose
D) Chitin

Question 28

What is the correct sequence of events in blood glucose level homeostasis?
1) low blood glucose levels stimulate glucagon production
2) insulin facilitates glucose uptake by body cells
3) glucagon makes liver and muscle cells release glucose
4) elevated blood glucose levels stimulate insulin production

A) 1, 2, 3, 4
B) 1, 3, 4, 2
C) 2, 1, 3, 4
D) 3, 4, 2, 1

Question 29

Emergency injection of ________ into a diabetic with severe hypoglycemia will revive the patient.

A) glucose
B) glycogen
C) insulin
D) glucagon

Question 30

The most important forms of lipids in living cells include ________.

A) steroids, triglycerides and phospholipids
B) steroids, phospholipids and waxes
C) phospholipids, triglycerides and waxes
D) triglycerides, steroids and waxes

Question 31

The covalent bond created by dehydration synthesis that links the three fatty acids with a glycerol molecule is called a(n) ________.

A) peptide bond
B) glycosidic link
C) ester bond
D) phosphodiester bond

Question 32

Examples of unsaturated fats include ________. (Select all that apply)

A) olive oil
B) corn oil
C) lard
D) cholesterol

Question 33

Saturated fats are not a healthy choice in human diets because ________.

A) they are solid at room temperature
B) every binding site on the carbons is occupied by hydrogens that result is a solid straight chain
C) they result in an increased chance of heart disease
D) they are usually found in animal fats

Question 34

Unsaturated fats ________.

A) contain at least one double bond
B) are straight chain fatty acids
C) have been implicated in heart disease
D) are at least 30 carbons long

Question 35

________ are amphipathic molecules.

A) Triglycerides
B) Waxes
C) Sterols
D) Phospholipids

Question 36

If Propionibacterium acnes on a teenager's skin hydrolyzes triglycerides in their sebum using lipase, what are the resulting products?

A) Fatty acids and phospholipids
B) Fatty acids and sterols
C) Fatty acids and glycerol
D) Phospholipids and sterols

Question 37

Phospholipids ________.

A) have a hydrophobic phosphate group and 2 hydrophilic fatty acids
B) contain three phosphodiester bonds
C) form a bilayer in an aqueous environment because they are amphipathic
D) are formed by alternating phosphate groups and fatty acids

Question 38

The androgen sex hormones produced in high amounts in adolescents belong to the ________ group of lipids

A) phospholipid
B) steroid
C) wax
D) triglyceride

Question 39

Cortisol, a steroid hormone, functions to________.

A) promote development of secondary sexual characteristics
B) prepare the body for conception and the maintenance of pregnancy
C) modulate the permeability of the plasma membrane
D) elevate blood glucose levels

Question 40

The fluidity of cell membranes is partially attributed to presence of ________.

A) unsaturated fatty acids
B) saturated fatty acids
C) phosphate groups
D) sterols

Question 41

One of the more common sterols is ________ that can be both beneficial to cells as a plasma membrane component but is also implicated in heart disease because of arterial plaque formations.

A) wax
B) cortisol
C) cholesterol
D) triglycerides

Question 42

Waxes have many biologically important functions, including ________. (Select all that apply)

A) waterproof coatings on surfaces that inhibit water evaporation, such as plant cuticles
B) waterproof coatings on surfaces that inhibit water penetration, such as duck feathers
C) waterproof compounds that strengthen bacterial cell walls, such as mycolic acid
D) long-term energy storage products, such as glycogen

Question 43

The basic structure of steroids includes ________.

A) 2 fatty acid tails with a sterol hydrocarbon ring attached
B) 3 fatty acid tails with a sterol hydrocarbon ring attached
C) four fused hydrocarbon rings
D) three fused hydrocarbon rings

Question 44

Mycolic acid is a waxy cell wall material found in members of the Genus Mycobacterium. Because of the waterproof nature of mycolic acid, which staining technique must be used to identify these bacteria under the microscope?

A) Gram stain
B) Ziehl-Neelson Acid-fast stain
C) Endospore stain
D) Malachite green

Question 45

The secondary stain in Ziehl-Neelson acid-fast staining protocol is ________.

A) crystal violet
B) safranin
C) carbol fuschin
D) methylene blue

Question 46

DNA may be described as ________. Select all that apply)

A) a macromolecule made of monomers called nucleotides
B) the hereditary material of cells that is passed one generation to the next
C) a double helix composed of small packets of information called genes
D) a master blueprint for the production of all proteins needed by the cell

Question 47

The major differences between DNA and RNA are ________. (Select all that apply

A) DNA has a deoxyribose sugar while RNA has a ribose sugar.
B) The nucleotides used in DNA include adenine, uracil, guanine and cytosine, while those used in RNA include adenine, thymine, guanine and cytosine.
C) DNA is never used in protein synthesis while RNA is used to make proteins on the ribosomes.
D) DNA exists in a double helix while RNA exists either in a single strand or a double helix.

Question 48

Purines differ from pyrimidines in that ________. (Select all that apply)

A) purines have a double ring structure while pyrimidines have a single ring structure
B) in DNA the purines include cytosine and uracil
C) in RNA the purines include cytosine and thymine
D) in both DNA and RNA the purines are adenine and guanine

Question 49

The backbone of the DNA helix is composed of the alternating pentose sugars and phosphate groups that join the nucleotides with ________ bonds.

A) hydrogen
B) peptide
C) ester
D) phosphodiester

Question 50

Adenosine triphosphate ________. (Select all that apply)

A) is composed of an adenine nucleotide bonded with two more phosphate groups
B) is an unstable molecule because the three adjacent phosphate groups carry negative charges, leading to repulsion and the easy hydrolysis of the terminal phosphate group
C) the breaking of this bond releases 5 kcal/mol of energy that may be used for cellular "work"
D) is a nucleoside

Question 51

Identify the numbered items on this strand of DNA.

A) 1=deoxyribose; 2 =purine; 3= phosphodiester bonds; 4= 3' end
B) 1=deoxyribose; 2=purine; 3= ester bonds; 4=3' end
C) 1=deoxyribose; 2=pyrimidine; 3= ester bonds; 4= 5' end
D) 1=ribose; 2=pyrimidine; 3= phosphodiester bonds; 4=5' end

Question 52

DNA replication ________. (Select all that apply)

A) is semiconservative
B) uses each original strand as a template to make a complementary strand
C) provides two identical copies of the genetic material prior to cell division
D) requires reverse transcription.

Question 53

________ is the conversion of mRNA into a protein.

A) Transposon
B) Translation
C) Transcription
D) Transformation

Question 54

The specific sequence of DNA that provides the blueprint for making a given protein is a ________.

A) complement
B) gene
C) trait
D) transposon

Question 55

The three base sequences of mRNA that code for a specific amino acid are known as ________.

A) anticodons
B) codons
C) nucleosides
D) genes

Question 56

Transcription directly requires which of the following molecules? (Select all that apply)

A) DNA
B) mRNA
C) tRNA
D) enzymes

Question 57

Transcribe this "gene" into mRNA: TAG GAT TAT CAC

A) AUC CUA AUA GUG
B) ATC CTA ATA GTG
C) TAG GAT TAT CAC
D) ATC CTA ATA GTG

Question 58

Using semiconservative replication, write the complementary strand of DNA for this segment: TAT GCG GAG CAT

A) ATA CGC CTC GTA
B) AUA CGC CUC GUA
C) TAT GCG GAG CAT
D) TAG GAT TAT CAC

Question 59

Using the genetic code table provided, convert this mRNA sequence into a polypeptide. AUG CUA AUA GUG UAG

A) met-leu-ile-val-stop
B) ile-leu-val-met-stop
C) met-trp-ile-arg-phe
D) met-trp-ile-arg-stop