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Bio 172 Week 4 Quiz

cellular biology
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H2O
A "mystery molecule" was isolated in a laboratory and scientists found that the molecule readily crossed artificial membranes. Which of the following molecules can be ruled out as the "mystery molecule"?
pentose
A monosaccharide that has the chemical formula C5 H10 O5 would be characterized as a _____
Form straight chains that bond with adjacent chains; built from alpha -glycosidic linkages.
Which statement best summarizes a key difference in the structure of polysaccharides that function in energy storage versus structural support (in that order)?
C-O
Which of the following types of chemical bonds are the most polar?
Despite their variety of structures, carbohydrates are less functionally complex than proteins.
In terms of their structure and how they are functioning in your body right now, which statement best explains how carbohydrates compare to DNA, RNA, or proteins?
Fats have more and bonds with high free energy, and fewer bonds with low free energy.
Both carbohydrates and fats are used as fuel in cells, but fats store twice as much energy per gram as carbohydrates. Which statement best explains why?
The sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both).
Which statement best explains why two four-sugar polysaccharides can be different, even if both consist of two glucose monomers and two galactose monomers?
Fats and phospholipids contain glycerol, steroids do not.
Which statement most accurately describes how the structures of fats, steroids, and phospholipids compare?
Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic.
Which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not?
Adding cholesterol reduces permeability because its steroid rings increase the density of the hydrophobic membrane interior.
Which statement best explains the effect on membrane permeability of cholesterol and/or temperature?
beta
The complex carbohydrates described in the table that are used for structural purposes (physical strength) have which of the following types of glycosidic linkages?
They are storing chemical energy, indicating cell identity, and serving as raw material for synthesizing other molecules.
Which statement most accurately describes how the carbohydrates you ate for breakfast are functioning in your body right now?
nucleic acids
Which of the following classes of macromolecules always contains a carbohydrate portion?
It changes the shape of the monosaccharide.
Which statement best explains why a relatively small difference in the location of a carbonyl or hydroxyl group can lead to dramatic changes in the properties and function of a monosaccharide?
less fluid bilayers
Decreasing the saturation of the fatty acid chains on a particular type of phospholipid would result in the formation of _____.
carbonyl
The _____ functional group can always be found in a carbohydrate molecule.
C-O bonds
Which of the following chemical bonds have the lowest free energy?
exterior
In a phospholipid bilayer, the polar heads are oriented toward the _____ of the bilayer.
They are found both inside and outside the cell.
Where are carbohydrates found in relationship to the cell?
Structural polysaccharides exist as sets of long, parallel strands that are linked to one another.
Carbohydrates that function as structural molecules withstand pulling and pushing forces well. Which structural feature best explains why?
monosaccharides
A glycosidic linkage is a covalent bond that links two _____.
In their linear forms, they all contain a carbonyl and several hydroxyl functional groups.
Which statement summarizes a feature shared by all monosaccharides?
lipids are largely hydrophobic
The physical property characteristic that distinguishes lipids from most other cellular macromolecules is that _____.
Structural polysaccharides exist as sets of long, parallel strands that are linked to one another.
Carbohydrates that function as structural molecules are extraordinarily resistant to degradation and decay. Which structural feature best explains why?
The individual phospholipid molecules form bonds with water and remain dispersed.
When a phospholipid bilayer in water is agitated by shaking, what is the result?
lipids
The plasma membranes of all known cells are largely composed of what class of macromolecules?