Chemistry Quizz

1. Which of the following molecules orient themselves into sandwichlike membranes because of hydrophobic components within the molecule?

Amylose

Glycogen

Cellulose

Phospholipid

Protein

Phospholipids are composed of glycerol molecules bonded to two fatty acids and one phosphate group. The
phosphate group is a hydrophilic “head” and the long hydrocarbon chains of fatty acids are hydrophobic “tails.”
In cell membranes, phospholipids orient themselves into two layers, with the hydrophobic tails pointing to the
inside of the “sandwich.”

Explanation

Phospholipids are composed of glycerol molecules bonded to two fatty acids and one phosphate group. The
phosphate group is a hydrophilic “head” and the long hydrocarbon chains of fatty acids are hydrophobic “tails.”
In cell membranes, phospholipids orient themselves into two layers, with the hydrophobic tails pointing to the
inside of the “sandwich.”

2. Each of the following molecules is a polymer EXCEPT:

Protein

Glucose

Cellulose

Starch

Glycogen

Glucose is a monomer consisting of a single glucose molecule. Starch, glycogen, and cellulose are polymers
consisting of repeating units of glucose. Protein is a polymer of amino acids.

Explanation

Glucose is a monomer consisting of a single glucose molecule. Starch, glycogen, and cellulose are polymers
consisting of repeating units of glucose. Protein is a polymer of amino acids.

3. All of the following are carbohydrates EXCEPT:

Polypeptide

Glycogen

Amylose

Glucose

Polysaccharide

A polypeptide is a protein. Amylose is a starch and, therefore, a carbohydrate

Explanation

A polypeptide is a protein. Amylose is a starch and, therefore, a carbohydrate

4. Hydrophilic properties are characteristic of all of the following EXCEPT:

Polar molecules

Molecules soluble in water

Molecules that readily ionize in water

The long hydrocarbon chain components of some molecules

The hydroxyl group

Long hydrocarbon chains are nonpolar and, therefore, hydrophobic. Any polar molecule (or polar group
of atoms like the hydroxyl group) is hydrophilic. When a substance ionizes in water, it dissolves; thus, it is
hydrophilic

Explanation

Long hydrocarbon chains are nonpolar and, therefore, hydrophobic. Any polar molecule (or polar group
of atoms like the hydroxyl group) is hydrophilic. When a substance ionizes in water, it dissolves; thus, it is
hydrophilic