High School Biology : Macromolecules
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Example Questions
Example Question #4 : Understanding Proteins And Nucleic Acids
Which of the following does not contribute to amino acid structure?
Amino group
Alpha carbon
R-side group
Glycerol
Carboxyl group
Glycerol
The structure of a given amino acid consists of an alpha carbon, amino group, carboxyl group, hydrogen, and a R-side group. R-side groups can have a variety of characteristics. They can be non-polar, polar, acidic, or basic. Amino acids can bond together through a peptide bond via dehydration synthesis—the loss of a single oxygen from one amino acid’s carboxyl group and two hydrogens from the other amino acid’s amine group.
Polypeptides are polymers of amino acids formed by this process. Glycerol is a component of a phospholipid.
Example Question #31 : Introductory Topics
A disulfide bridge between two cysteine molecules is an example of which structural level of peptide bonds?
Tertiary
Secondary
Quaternary
Primary
Tertiary
The cysteine-cysteine disulfide bond is an example of a tertiary bond. Tertiary bonds are bonds between R-side groups. Other examples include non-polar associated bonds, polar associations with a polar aqueous environment, and ionic bonds. Primary level bonds are described as the sequence of amino acids. Secondary bonds consist of local folding due to bonds between an oxygen on a carboxyl group with a hydrogen from an amino group. This bonding includes alpha helixes and beta sheets. Quaternary bonds are defined as the association between polypeptides.
Example Question #32 : Introductory Topics
Alpha helices and beta pleated sheets are examples of what level of structure in proteins?
Tertiary
Secondary
Quaternary
Auxiliary
Primary
Secondary
All proteins have at least a primary, secondary, and tertiary structure, but only some, such as hemoglobin, have a quaternary structure. Secondary structures are determined by hydrogen bonding between different amino acids in the polypeptide chain that form the primary structure. There may be multiple and different secondary structures in a single protein.
Example Question #33 : Introductory Topics
What is the basic subunit of a protein?
Monosaccharides
Nucleotides
Fatty acids
Glucose
Amino acids
Amino acids
Amino acids link together by peptide bonds to form proteins. Nucleotides link together to form nucleic acids like DNA and RNA. Monosaccharides are sugars that form links to form carbohydrates. Fatty acids attach to a glycerol backbone to form lipids, except those that are derived from cholesterol.
Example Question #34 : Introductory Topics
Which of the following elements is not found in amino acids?
Sulfur
Nitrogen
Phosphorous
Carbon
Oxygen
Phosphorous
Phosphorous is found in nucleotides, but not amino acids. In certain reactions, proteins can be modified by kinases to contain phosphate groups. Kinases are enzymes that catalyze the transfer of phosphate groups onto substrates. They function in signal transduction pathways.
There are only a few residues (amino acids in proteins) which can be phosphorylated: Serine, threonine, tyrosine, histidine, arginine, and lysine.
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