Multiple Choice Qs Redo Flashcards
Which elements make up approx 96% of living matter
C H N O
Van der walls interactions result when?
Electrons are not symmetrically distributed in a molecule
What bonding or interaction is most likely to occur among broad array of molecules of various types (polar, nonpolar, etc)
Van der waals
Ionic bonds form as a result of…
Attraction between ions that have opposite charges
A hydrogen bond is…
A weak chemical bond
When do h bonds occur
When partial opposite charges on molecules come close enough to attract each other
Many mammals control their body temp by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temp?
The absorption of heat by the breaking of hydrogen bonds
Why does evaporation of water from a surface cause cooling of the surface ?
The water molecules with the most heat energy evaporate the most readily
Which of the following occurs because molecules of water are farther apart in ice than in liquid water
Ice floats
Sweating has a cooling effect because of water’s high
Heat of vaporization
In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy . Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that….
Water is consumed by animal metabolism
13) Why are human sex hormones considered to be lipids?
a) They are essential components of cell membranes.
b) They are not soluble in water.
c) They are made of fatty acids.
d) They are hydrophilic compounds.
e) They contribute to atherosclerosis.
b) They are not soluble in water.
14) Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
a) creating cis double bonds to the fatty acids
b) adding hydrogens to the fatty acids
c) creating trans double bonds to the fatty acids
d) adding hydrogens and trans double bonds to the fatty acids
e) adding cis double bonds and trans double bonds to the fatty acids
d) adding hydrogens and trans double bonds to the fatty acids
18) Which of the following statements is true for triglycerols?
a) They are insoluble in water.
b) They are made from glycerol, fatty acids, and phosphate.
c) They contain less energy than proteins and carbohydrates.
d) They are made by dehydration reactions.
e) More than one answer is true.
e) More than one answer is true.
20) Which of the following statements concerning saturated fats is not true?
a) They are more common in animals than in plants.
b) They have multiple double bonds in the carbon chains of their fatty acids.
c) They generally solidify at room temperature.
d) They contain more hydrogen than unsaturated fats having the same number of carbon atoms.
e) They are one of several factors that contribute to atherosclerosis.
b)
23) What is a difference between saturated triacylglycerols and unsaturated triacylglycerols?
a) Saturated triacylglycerols have more double bonds than unsaturated triacylglycerols do.
b) Saturated triacylglycerols are fats; unsaturated triacylglycerols are steroids.
c) Saturated triacylglycerols are liquid at room temperature.
d) For carbon skeletons of equal length, saturated triacylglycerols have more hydrogen atoms
than unsaturated triacylglycerols do.
e) Saturated triacylglycerols are saturated with hydrogen atoms.
d)
30) Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by
__________.
a) ionic bonds
b) ester linkages
c) glycosidic linkages
d) peptide bonds
e) phosphodiester linkages
b)
) Explain what happens if even one amino acid is substituted for another in a polypeptide chain.
Provide two specific examples.
Amino acid substitution alters a protein’s primary structure. Since
different amino acids have differently shaped & sized functional groups, the new functional group will
highly likely affect the protein’s hydrogen bonding, which changes the formation of secondary structures
like helices and sheets. If the secondary structure changes, the tertiary structure will also change
(again because of changes in hydrogen bonds as well as changes in hydrophobic interactions, ionic bonds
& disulfide bonds). If the polypeptide is part of an oligomeric protein, the quaternary structure will also
change its conformation. Once the shape of a protein has been altered, the function will also be altered.
Specific examples include sickle cell anemia, misfolding of proteins caused by prions (like mad cow’s
disease), misfolding of proteins in Alzheimer’s Disease.
3) What is the function of actin and myosin?
Actin and myosin are contractile proteins. They are
abundant in muscles, facilitating contraction and elongation of these cells. Myosin proteins form
filaments that have “feet-like” structures that “walk” along the actin proteins (also filamentous) to
shorten or lengthen a muscle cell. They also facilitate the movement of cilia and flagella.
36) Upon chemical analysis, a particular polypeptide was found to contain n amino acids. How many
peptide bonds are present in this protein?
a) n + 1
b) n
c) n - 1
d) n – 2
e) none of the answers are correct
c)
39) Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
a) hydrophobic interactions
b) disulfide bonds
c) ionic bonds
d) hydrogen bonds
e) peptide bonds
d)
40) The R group or side chain of the amino acid serine is –CH₂–OH. The R group or side chain of the
amino acid leucine is –CH₂–CH–(CH₃)₂. Where would you expect to find these amino acids in a globular
protein in aqueous solution?
a) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
b) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
c) Both serine and leucine would be in the interior of the globular protein.
d) Both serine and leucine would be on the exterior of the globular protein.
e) Both serine and leucine would be in the interior and on the exterior of the globular protein.
b)
41) What aspects of protein structure are stabilized or assisted by hydrogen bonds?
a) primary structure
b) secondary structure
c) tertiary structure
d) quaternary structure
e) secondary, tertiary, and quaternary structures
e)
48) Which of the following lists ranks these molecules in the correct order by size from largest to
smallest?
a) water, protein, sucrose, glucose
b) water, glucose, sucrose, protein
c) glucose, water, sucrose, protein
d) protein, water, glucose, sucrose
e) water, sucrose, glucose, protein
b)