Biology Chapter 3 Test Part 1

A nucleotide subunit is a building block of nucleic acids, which include DNA and RNA. Nucleic acids are responsible for storing and transmitting genetic information in living organisms. They are composed of long chains of nucleotide subunits, each consisting of a sugar molecule, a phosphate group, and a nitrogenous base. Proteins, lipids, and carbohydrates are not made up of nucleotide subunits and do not play a direct role in genetic information storage and transmission. Therefore, the correct answer is nucleic acid.

Plants store glucose as starch. Starch is a polysaccharide made up of glucose molecules. It is the main storage form of glucose in plants, allowing them to store excess glucose for later use. Maltose is a disaccharide made up of two glucose molecules, while glycogen is the storage form of glucose in animals. None of these options are correct as plants primarily store glucose as starch.

Amino acids are the building blocks of proteins. Proteins are made up of long chains of amino acids that are linked together by peptide bonds. Each amino acid has a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a side chain. These side chains give each amino acid its unique properties. Therefore, the correct answer is protein.

A triglyceride is a type of lipid molecule that consists of a glycerol molecule bonded to three fatty acid molecules. This structure is formed through a process called esterification, where the hydroxyl groups of the glycerol molecule react with the carboxyl groups of the fatty acid molecules, resulting in the formation of ester bonds. Triglycerides are the main form of fat storage in the body and are an important source of energy.

A fatty acid is unsaturated if it contains carbon-carbon double bonds. This is because unsaturated fatty acids have one or more double bonds between carbon atoms in their hydrocarbon chain, which causes them to have fewer hydrogen atoms. In contrast, saturated fatty acids do not have any double bonds and have the maximum number of hydrogen atoms bonded to each carbon atom. Therefore, the presence of carbon-carbon double bonds is a characteristic feature of unsaturated fatty acids.

Carbon is known for its ability to form four covalent bonds, which allows it to bond with other carbon atoms and form long chains. It can also sometimes share two pairs of electrons with another atom. However, carbon is not typically ionic, meaning it does not readily gain or lose electrons to form ions.

Glycogen is a complex carbohydrate that serves as a form of energy storage in animals. It is made up of many glucose molecules linked together in a branched structure. Glycogen is primarily stored in the liver and muscles, where it can be broken down into glucose when the body needs energy. Therefore, the correct answer is carbohydrate.

Maltose is a disaccharide composed of two glucose molecules bonded together. It is formed when starch is broken down during digestion. Glucose, fructose, and ribose are all monosaccharides, meaning they consist of a single sugar molecule. Therefore, the correct answer is maltose.

In a dehydration reaction, a hydroxyl group from one monomer combines with a hydrogen atom from another monomer, resulting in the removal of a water molecule. This process allows the monomers to be attached together and form a polymer. Therefore, the correct answer is "removed, dehydration."

Glycerol is a component of lipids, specifically triglycerides, which are the main form of dietary fat. Lipids are organic compounds that are insoluble in water and play important roles in the body, such as energy storage and insulation. Glycerol is a three-carbon alcohol that combines with fatty acids to form triglycerides. Therefore, the correct answer is lipid.

C6H12O6 is an organic molecule because it consists of carbon (C), hydrogen (H), and oxygen (O) atoms bonded together. Organic molecules are compounds that contain carbon and are typically found in living organisms.

Organic molecules containing carboxyl groups are acidic because carboxyl groups can donate a proton (H+) to a solution, making them capable of releasing hydrogen ions. This donation of protons contributes to the acidity of the molecule.

The correct answer is the linkage between the glucose molecules. Cellulose is a polymer of glucose subunits, but the specific type of linkage between the glucose molecules in cellulose, called a beta-1,4-glycosidic linkage, cannot be broken down by the digestive enzymes in the human body. This is why cellulose is considered nondigestible in humans.