Question 1

Which property of carbon most directly allows it to form a wide variety of molecular structures essential for life?

Accepted Answer

Its ability to form up to four covalent bonds due to four unpaired electrons in its valence shell

Question 2

Methanol (CH$$_3OH) $$and ethane (C$$_2H$_6) $$are mixed with water. Methanol dissolves, but ethane does not. Which statement best explains this observation?

Accepted Answer

Methanol is polar and forms hydrogen bonds with water, while ethane is nonpolar and hydrophobic

Question 3

Which of the following best describes the relationship between polarity and hydrophobicity?

Accepted Answer

Polar molecules are generally hydrophilic, while nonpolar molecules are hydrophobic

Question 4

A molecule with the formula C$$_6H$_{12}O$_6 is $$classified as a monosaccharide. What is its primary function in cells?

Accepted Answer

Immediate energy source and building block for larger carbohydrates

Question 5

Which feature of phospholipids enables them to form bilayers in water?

Accepted Answer

They have hydrophilic heads and hydrophobic tails

Question 6

Which of the following is NOT a function of lipids in biological systems?

Accepted Answer

Catalyzing chemical reactions

Question 7

Which chemical reaction is responsible for joining two monosaccharides to form a disaccharide?

Accepted Answer

Dehydration synthesis

Question 8

A fat molecule is composed of which components?

Accepted Answer

Three fatty acids and one glycerol

Question 9

Which of the following best explains why hydrocarbons are hydrophobic?

Accepted Answer

They lack significant charge separation and cannot form hydrogen bonds with water

Question 10

Cellulose and chitin are examples of polysaccharides. What is their primary biological role?

Accepted Answer

Structural support in cell walls and exoskeletons

Question 11

Which of the following statements about the molecular diversity of carbon skeletons is correct?

Accepted Answer

Carbon skeletons can vary in length, branching, double bond position, and presence of rings

Question 12

Which functional group is most likely to make a molecule hydrophilic?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 13

Which of the following best describes a polymer?

Accepted Answer

A molecule made of repeating monomer units joined by covalent bonds

Question 14

Which macromolecule is NOT a true polymer?

Accepted Answer

Lipid

Question 15

Which of the following is a correct balanced chemical equation for the formation of water from hydrogen and oxygen?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 16

Which of the following best explains why molecular shape is important in biological systems?

Accepted Answer

Molecular shape determines how molecules recognize and interact with specific receptors

Question 17

Which of the following is a correct statement about the bonding partners of carbon in biological molecules?

Accepted Answer

Carbon most frequently bonds with hydrogen, oxygen, and nitrogen

Question 18

Which of the following is a real-world example of how molecular shape affects biological function?

Accepted Answer

Morphine and endorphins have similar shapes and bind the same brain receptors, producing similar effects

Question 19

Which of the following statements about dehydration synthesis and hydrolysis is correct?

Accepted Answer

Dehydration synthesis joins monomers to form polymers by removing water, while hydrolysis breaks polymers into monomers by adding water

Question 20

Which of the following best describes the role of glycogen in animal cells?

Accepted Answer

It stores glucose for energy in liver and muscle cells

Carbon and Introduction to Macromolecules: Structure and Function in Biology

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