Question

1. which property of carbon allows it to form diverse and complex molecules?

a. it can bond with a limitless amount of atoms
b. four valence electrons enable it to form strong bonds with four other atoms
c. it has a neutrally charged outer shell of four electrons
d. two valence electrons enable it to form strong bonds with four other atoms

1. what cell structure is composed of phospholipids?

a. cytoskeleton
b. cytoplasm
c. cell wall
d. cell membrane

1. which molecule is used in cellular respiration to produce atp?

a. cellulose
b. polysaccharide
c. glucose
d. glycogen

1. which elements are found in all macromolecules?

a. carbon, hydrogen, nitrogen, and oxygen
b. carbon and hydrogen
c. carbon, hydrogen, and oxygen
d. nitrogen, phosphorus, and carbon

1. what type of fats are typically solid at room temperature?

a. saturated fats
b. unsaturated fats
c. polyunsaturated fats
d. oily fats

1. what is the monomer of a protein?

a. nucleotide
b. nucleic acid
c. r - group
d. amino acid

1. which molecule functions as primary energy storage in plants?

a. starch
b. triglyceride
c. wax
d. cellulose

Explanation:

1. Carbon has four valence electrons. This allows it to form four covalent bonds with other atoms (including other carbon atoms), which is crucial for forming diverse and complex molecules. Option a is incorrect as carbon cannot bond with a limitless amount of atoms. Option c is wrong because the outer - shell electrons are not neutrally charged (they are negatively charged). Option d is incorrect as carbon has four valence electrons, not two.
2. The cell membrane is a phospholipid bilayer. The cytoskeleton is made of proteins. The cytoplasm is a gel - like substance with various dissolved molecules. The cell wall (in plant cells) is made of cellulose (in plants), chitin (in fungi), etc.
3. Glucose is the primary molecule used in cellular respiration (glycolysis is the first step where glucose is broken down) to produce ATP. Cellulose is a structural polysaccharide. Polysaccharides like glycogen (in animals) and starch (in plants) are storage molecules, but glucose is the immediate fuel. Glycogen is broken down to glucose for cellular respiration.
4. All macromolecules (carbohydrates, lipids, proteins, nucleic acids) contain carbon, hydrogen, and oxygen. Proteins and nucleic acids also contain nitrogen (and nucleic acids contain phosphorus), but the common elements in all are C, H, O.
5. Saturated fats have single bonds between carbon atoms in their fatty acid chains, which allows them to pack closely together and be solid at room temperature. Unsaturated (including polyunsaturated) fats have double bonds that cause kinks and make them liquid (oily) at room temperature.
6. Amino acids are the monomers of proteins. Nucleotides are the monomers of nucleic acids. Nucleic acids are polymers (like DNA and RNA). The R - group is a part of an amino acid.
7. Starch is the primary energy storage molecule in plants. Triglycerides are the main energy storage in animals (and also found in some plants but not the primary storage). Wax is a protective coating. Cellulose is for structure.

Answer:

1. B. four valence electrons enable it to form strong bonds with four other atoms
2. D. cell membrane
3. C. glucose
4. C. carbon, hydrogen, and oxygen
5. A. saturated fats
6. D. amino acid
7. A. starch