High School Biology : Understanding Proteins and Nucleic Acids
Study concepts, example questions & explanations for High School Biology
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Example Questions
Example Question #11 : Understanding Proteins And Nucleic Acids
A disulfide bridge between two cysteine molecules is an example of which structural level of peptide bonds?
Quaternary
Secondary
Tertiary
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 #12 : Understanding Proteins And Nucleic Acids
Alpha helices and beta pleated sheets are examples of what level of structure in proteins?
Quaternary
Secondary
Tertiary
Primary
Auxiliary
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 #13 : Understanding Proteins And Nucleic Acids
What is the basic subunit of a protein?
Nucleotides
Glucose
Monosaccharides
Amino acids
Fatty 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 #14 : Understanding Proteins And Nucleic Acids
Which of the following elements is not found in amino acids?
Oxygen
Phosphorous
Carbon
Nitrogen
Sulfur
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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