MACROMOLECULE INVESTIGATION
An unknown molecule contains carbon, hydrogen, oxygen, and nitrogen. It is made from repeating units, and each unit has a central carbon attached to an amino group, carboxyl group, hydrogen, and a variable group. Which additional observation would confirm the student's identification?
A. The units are connected by peptide bonds.
B. The molecule contains a sugar-phosphate backbone.
C. The molecule contains glycerol and fatty acids.
D. The molecule contains only sugar units.
A. The units are connected by peptide bonds.
A plant cell contains two different carbohydrate molecules. One is being used as a stored energy source, while the other is part of the cell wall. Which combination is most consistent with these roles?
A. Starch and cellulose
B. Cellulose and glycogen
C. Glycogen and sucrose
D. Glucose and fructose
A. Starch and cellulose
Two fatty acids are compared.
Fatty acid X has no carbon-carbon double bonds.
Fatty acid Y has one carbon-carbon double bond.
Which difference would most directly affect how closely their molecules can pack together?
A. The double bond in Y can create a bend in its chain.
B. The double bond in Y adds a phosphate group.
C. The absence of a double bond in X creates a bend.
D. The double bond in Y changes the fatty acid into a carbohydrate.
A. The double bond in Y can create a bend in its chain.
Two proteins contain the same number of amino acids, but their amino acid sequences are different. Which prediction is most reasonable?
A. Their shapes could differ because the sequence differs.
B. They must have identical functions because their lengths match.
C. One must automatically become a nucleic acid.
D. Neither protein can contain an R group.
A. Their shapes could differ because the sequence differs.
A student observes that two small molecules join and a water molecule is produced. Which change has most likely occurred?
A. A larger molecule was assembled.
B. A larger molecule was broken apart.
C. A nucleotide was converted into an amino acid.
D. A lipid was converted into a carbohydrate.
A. A larger molecule was assembled.
Four unknown molecules are described below.
Molecule 1 contains C, H, and O and is built from sugar units.
Molecule 2 contains C, H, O and is associated with glycerol and fatty acids.
Molecule 3 contains C, H, O, N and is built from amino acids.
Molecule 4 contains C, H, O, N, P and is built from nucleotides.
Which molecule would be most directly connected to storing genetic information?
Molecule 4
A carbohydrate composed of a long chain of sugar molecules is a __________.
Polysaccharide
A student predicts that a lipid with tightly packed fatty acid chains will tend to behave differently at room temperature from one whose chains cannot pack as closely. Which prediction is consistent with the material?
A. The more tightly packed lipid is more likely to be solid.
B. The more tightly packed lipid is more likely to be liquid.
C. Both must have identical physical properties.
D. Packing depends only on whether the molecule contains oxygen.
A. The more tightly packed lipid is more likely to be solid.
What portion of an amino acid varies between different amino acids?
R group
A student is given the following sequence:
Small units → larger molecule → water added → smaller units
Which interpretation best describes the two chemical processes?
A. Dehydration followed by hydrolysis
B. Hydrolysis followed by dehydration
C. Dehydration followed by saturation
D. Saturation followed by hydrolysis
A. Dehydration followed by hydrolysis
A researcher has identified the small units that can be repeatedly joined to construct a much larger molecule. Each small unit is a __________.
Monomer
A food contains a carbohydrate that can be broken down into glucose and fructose. Which carbohydrate was most likely present?
A. Lactose
B. Sucrose
C. Cellulose
D. Glycogen
B. Sucrose
A fatty acid containing at least one carbon-carbon double bond is __________.
Unsaturated
A protein is found as part of a body structure. Another protein helps protect against disease. Which pair of examples best matches those functions?
A. Collagen and antibodies
B. Hemoglobin and glycogen
C. Antibodies and cellulose
D. Collagen and starch
A. Collagen and antibodies
A researcher gives a student four sets of building materials:
Set 1: amino acids
Set 2: monosaccharides
Set 3: nucleotides
Set 4: glycerol and fatty acids
The student must predict the macromolecule that can be associated with each set.
Which arrangement is correct?
A. Protein, carbohydrate, nucleic acid, lipid
B. Carbohydrate, protein, lipid, nucleic acid
C. Nucleic acid, lipid, protein, carbohydrate
D. Lipid, nucleic acid, carbohydrate, protein
A. Protein, carbohydrate, nucleic acid, lipid
A molecule is found to contain phosphorus, but the scientist does not yet know its identity. Which conclusion is justified?
A. It must be a nucleic acid.
B. It could be a nucleic acid, but phosphorus alone is not enough to identify it.
C. It must be a carbohydrate.
D. It cannot be an organic molecule.
B. It could be a nucleic acid, but phosphorus alone is not enough to identify it.
What carbohydrate is associated with plant cell walls?
Cellulose
What lipid category includes cholesterol?
Steroid
What bond links amino acids together?
Peptide bond
A researcher finds a molecule containing C, H, O, N, and P. The molecule also contains a five-carbon sugar, a phosphate group, and a nitrogenous base. Which conclusion is best supported?
A. It is made of nucleotides.
B. It is made of amino acids.
C. It is made of fatty acids.
D. It is made of monosaccharides.
A. It is made of nucleotides
It contains C, H, O, N, and P.
Its smaller units contain a sugar, phosphate group, and nitrogenous base.
Its structure includes a sugar-phosphate backbone.
Its biological role involves information.
Which conclusion requires the fewest unsupported assumptions?
A. It is a protein involved in transport.
B. It is a carbohydrate used for energy.
C. It is a nucleic acid associated with genetic information.
D. It is a lipid involved in insulation.
C. It is a nucleic acid associated with genetic information.
A researcher compares four carbohydrate samples.
Sample A contains one sugar unit.
Sample B contains two sugar units.
Sample C contains many sugar units and is associated with plant energy storage.
Sample D contains many sugar units and provides plant structural support.
Which sequence correctly represents the samples?
A. Monosaccharide, disaccharide, starch, cellulose
B. Disaccharide, monosaccharide, glycogen, starch
C. Monosaccharide, polysaccharide, cellulose, starch
D. Disaccharide, polysaccharide, starch, glycogen
A. Monosaccharide, disaccharide, starch, cellulose
An unknown lipid has all of the following characteristics:
It contains a polar region.
It contains nonpolar fatty acid regions.
It is associated with cell membranes.
A second unknown lipid is associated with preventing water loss, and a third is associated with cholesterol.
Which sequence correctly identifies the three?
A. Phospholipid, wax, steroid
B. Wax, steroid, phospholipid
C. Steroid, phospholipid, wax
D. Phospholipid, steroid, wax
A. Phospholipid, wax, steroid
A protein normally has a shape that allows it to perform its role. A mutation changes several amino acids, and the altered protein has a different shape.
Which prediction is most scientifically reasonable based on the material?
A. The altered shape could affect the protein's function.
B. The altered protein must now be a carbohydrate.
C. The altered protein can no longer contain nitrogen.
D. The altered protein must have more nucleotides.
A. The altered shape could affect the protein's function.
How many phosphate groups are found in ATP?
Three