All High School Biology Resources
Example Question #1 : Understanding Proteins And Nucleic Acids
Which macromolecule is polymerized using peptide bonds?
Proteins are composed of amino acids linked together by peptide bonds. Nucleic acids are linked by phosphodiester bonds and polysaccharides are held together by glycosidic linkages. Lipid polymers are linked by simple covalent bonds.
Example Question #2 : Understanding Proteins And Nucleic Acids
Which of the following base pairs would never be seen in a healthy double helix of a nucleic acid?
In DNA, guanine will always pair with cytosine (C-G) and adenine will always pair with thymine (A-T). In RNA, thymine is replaced with the pyrimidine uracil, meaning that adenine will pair with uracil in RNA (A-U). Guanine and uracil will never be paired together.
Example Question #3 : Understanding Proteins And Nucleic Acids
Which of the following can be found in proteins?
Proteins are made up of a string of amino acids. Ribosomes are responsible for facilitating the formation of covalent peptide bonds between amino acids to build the polypeptide chain. Proteins called chaperones then help fold the protein into the proper shape.
Nucleotides are found in DNA and ribonucleotides are found in RNA. Nucleosomes are small regions of DNA that are tightly wound around histone proteins. Phosphates are functional groups made of one phosphorus atom and four oxygen atoms. Phosphates are found in numerous molecules, including DNA, RNA, and phospholipids in the cell membrane, but are not generally found in proteins.
Example Question #4 : Understanding Proteins And Nucleic Acids
A membrane pump transports ions against their concentration gradient. The pump most likely uses what type of cellular energy source?
The question states that the pump transports ions against their concentration gradient. This means that this pump must use active transport. Recall that active transport requires energy in the form of ATP. ATP, or adenine triphosphate, is a type of nucleotide because it contains a nitrogenous base, a pentose sugar, and phosphate groups.
Lipids and carbohydrates (such as glucose) are the energy source for the body; however, these macromolecules themselves do not provide energy for cellular processes. They undergo metabolism and generate ATP, the molecule used by cellular processes that require energy.
Example Question #5 : Understanding Proteins And Nucleic Acids
In which level of protein structure are the helices and pleated sheets found?
Primary protein structure is the sequence of the amino acids, linked by peptide bonds. Secondary protein structure involves helices and pleated sheets formed by hydrogen bonds between backbone amino and carboxyl groups. Tertiary protein structure involves electrostatic interactions between the R groups of the amino acids in the polypeptide. The tertiary structure of a protein may be globular or filamentous, and may include disulfide bonds and/or salt bridges. Quaternary protein structure involves interactions between two or more polypeptide chains.
Example Question #6 : Understanding Proteins And Nucleic Acids
Enzymes belong to which macromolecule-building block pair?
Nucleotides; nucleic acids
Enzymes are polypeptides. Polypeptides are created from proteins/amino acids. They contain a nitrogen, and have a nitrogen-carbon-carbon backbone.
Carbohydrates are referred to as polysaccharides when they form large molecules. They function as energy storage, and are responsible for the structure of plant cell walls. They are made of carbon, hydrogen, and oxygen.
Lipids in large molecules make up fats, oils, waxes, and phospholipids. They provide membrane structure, energy storage, and insulation. They are also made of carbon, hydrogen, and oxygen, and contain numerous carbon-hydrogen bonds.
Nucleic acids (DNA and RNA) are made of chains of nucleotides, bound together by phosphodiester bonds.
Example Question #7 : Understanding Proteins And Nucleic Acids
Which of the following is responsible for the unique chemical and physical properties of different amino acids?
All amino acids have a carboxyl end, and an amino end, both of which contain the same respective atoms. The main differences in amino acids come from the different side chains contained by each amino acid.
Example Question #8 : Understanding Proteins And Nucleic Acids
The __________ group is exposed at the N terminus end of a protein, while the __________ group is exposed at the C terminus.
nitrogen. . . carbonyl
nitrogen. . . carboxylic acid
amino. . . carbonyl
amine. . . carboxylic acid
amine. . . carboxylic acid
The N terminus is the end of the protein with the amino group——exposed, and the C terminus is the end of the protein with the carboxyl group——exposed.
Example Question #9 : Understanding Proteins And Nucleic Acids
Which of the following is not a function of a protein?
Proteins have six main functions: 1) movement (e.g. actin and myosin), 2) structure (e.g. keratin), 3) transport (e.g. hemoglobin), 4) protection (e.g. antibodies), 5) communication (e.g. hormones), 6) and catalyzation of chemical reactions (e.g. enzymes).
Example Question #31 : Introductory Topics
Which of the following does not contribute to amino acid structure?
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.