Chemistry of Life DQs

Which of the following is true about protein molecules?

• Protein molecules are made up of strands of DNA joined together by amino acid sequences

• The shape and folded structure of a protein molecule are important in determining its function

• The sequence of amino acids that make up a protein molecule do not affect its function

• Protein molecules have many functions in the body, including the storage of genetic information

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

• as a pentose

• as a monosaccharide

• as a hexose

• as a disaccharide

Which of the following best describes a carbohydrate?

• A. Carbohydrates are organic macromolecules that are insoluble in water and have the ability to store energy for extended periods of time

• B. Carbohydrates always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups and are used to store genetic information

• C. Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms and are used for energy storage or as structural molecules

• D. Carbohydrates are composed of amino acid monomers and are involved in cell signaling, cell transport, immune responses, and the cell cycle

Polymers of the carbohydrate monomer glucose are used as the major form of energy storage for many plants. What are these glucose polymers called?

• Starch

• table sugar

• maltose

• glycogen

Carbohydrates, such as glucose, are excellent sources of immediate energy for living organisms. More complex carbohydrates, such as glycogen and starch, can also be used for the long term storage of energy. However, carbohydrates play other vital roles, too. Which of the following describes another common use for carbohydrates?

• A. Keratin provides support in hair, nails, feathers, hooves, and some animal shells.

• B. Cellulose is used as a structural component in plant cell walls.

• C. Collagen is a major component in cartilage and tendons.

• D. Enzymes help speed up metabolic reactions.

Cellular processes are carried out by many different types of molecules, mostly proteins. The function of each protein molecule depends on its shape which, in turn, is determined by the protein's specific sequence of

• monosaccharide

• triglycerides

• nucleotides

• Amino Acids

Nucleic acids are one of the four major macromolecules. The main functions of nucleic acids are to…..

• A. carry genetic information and create structures inside the cell.

• B. store and transport energy and structural components in the cell.

• C. Act as enzymes, cell signals, and structural support for the cell.

• D. Aid in development, the immune system and blood clotting.

Compared to carbohydrates:

• A. lipids contain less energy per unit of weight.

• B. lipids contain more carbon–hydrogen bonds per unit of weight.

• C. lipids contain more polar covalent bonds per unit of weight.

• D. lipids are more hydrophilic than the carbohydrate.

There are four types of macromolecules in living things. Which type of macromolecule is made without repeating subunits?

• A lipids

• B. proteins

• C. nucleic acids

• D. polysaccharides

To form a tristearin molecule, three fatty acids are joined to a glycerol. What is removed in each joining reaction?

• An O₂ molecule

• B. A water molecule

• C. CO₂ molecule

• D. A glucose Molecule