1.3 Functional Groups

Question 1

What makes carbon atoms essential to form the backbone of large diverse molecules?

Answer 1

Carbon has 4 valence electrons, which allows each carbon atom to form 4 covalent bonds with other atoms

Question 2

Which elements do carbon atoms most commonly form bonds with?

Answer 2

Oxygen, nitrogen, hydrogen, phosphorus, and sulfur

Question 3

What can carbon atoms form when bonding with each other?

Answer 3

Carbon atoms bonded to each other can form branch structures, long straight chains, and rings

Question 4

How are carbon atoms almost unlimited in size?

Answer 4

Because they can form many combinations of single, double, and triple bonds

Question 5

Carbon cannot readily dissolve in water. Why is this good?

Answer 5

Carbon is the backbone of important molecules such as DNA and proteins. If dissolved in water, the molecules would break down and effect their function.

Carbon-based compounds (ex. fats and proteins) stay intact in aqueous environments, which is needed to help cells function without falling apart.

Question 6

What are functional groups?

Answer 6

Functional groups are a small cluster of atoms within a larger molecule.

Question 7

What are functional groups responsible for?

Answer 7

Functional groups are responsible for how molecules behave in chemical reactions, and influence a molecule’s properties, determining how they interact with other substances.

Question 8

How do functional groups help molecules like carbohydrates, proteins, lipids, and nucleic acids build up or break down?

Answer 8

Functional groups help these molecules either build up through synthesis or break down through degradation by interacting with other molecules.

Question 9

What is an organic compound?

Answer 9

Organic compounds are compounds that contain carbon atoms bonded to other carbon atoms

Question 9

What is the chemical formula and major class of carboxyl?

Answer 9

-COOH, carboxylic acids

Question 10

What are inorganic compounds?

Answer 10

Inorganic compounds are compounds that don’t contain carbon, with a few exceptions like carbon dioxide

Question 10

What is the chemical formula and major class of hydroxyl?

Answer 10

-OH, alcohol

Question 11

What is the chemical formula and major class of carbonyl?

Answer 11

C=O, aldehydes and ketones

Question 12

What is the chemical formula and major class of amino?

Answer 12

-NH2, amines

Question 13

What is the chemical formula and major class of phosphate?

Answer 13

-PO4, organic phosphates

Question 14

What is the chemical formula and major class of sulfhydryl?

Answer 14

-SH, thiols

Question 15

What is a major characteristic of most functional groups?

Answer 15

Most functional groups are ionic or strongly polar, therefore soluble and hydrophilic

Question 16

Why do non-polar groups not attract other molecules?

Answer 16

Due to their even distribution of electrons, non-polar groups lack dipoles (charged ends). Therefore they do not attract other molecules and do not help initiate chemical reactions

Question 17

How can carboxyl (-COOH) become acidic?

Answer 17

Carboxyl (-COOH) can release a proton (H+) to become negatively charged: (-COO^-), which makes it acidic when H+ is released in H2O

Question 17

How can amino become a weak base?

Answer 17

Amino (-NH2) can attract a proton (H+), making it positively charged: (-NH3^+). This makes it a weak base when H+ bonds to NH2.

Question 18

What functional groups does amino acids have?

Answer 18

Amino acids have both an acid (carboxyl) and base (amino).

Question 19

How are phosphate groups acidic?

Answer 19

They are acidic since they lose their H⁺ ions and become negatively charged.
The ability to release H⁺ ions makes them acidic.

Question 20

What role does oxygen play in most functional groups?

Answer 20

Oxygen has a high electronegativity, which plays a key role when forming polar bonds. It creates partial charges which allows molecules to interact and form bonds with other molecules (ex. hydrogen bonds)

Question 21

What is a dehydration synthesis reaction?

Answer 21

When smaller molecules form a larger molecule by removing an H2O molecule

Question 22

What is a hydrolysis reaction?

Answer 22

It is the reverse/opposite of dehydration. Larger molecules are broken down into smaller groups by adding an H2O molecule

Question 23

What is an example of a dehydration synthesis reaction?

Answer 23

The formation of maltose, since it is made by removing H2O from two alpha-glucose molecules bonding to each other through a glycosidic linkage.

Question 24

What is an example of a hydrolysis reaction?

Answer 24

The breakdown of sucrose into fructose and glucose by adding H2O.

Sucrose + H2O –> glucose + fructose

Question 25

What is the primary purpose of functional groups that are found in organic molecules?

Answer 25

Functional groups determine the chemical reactivity and bonding of organic molecules, enabling the formation of macromolecules.

Question 26

How do functional groups influence solubility?

Answer 26

Most of the functional groups are ionic or strongly polar, therefore soluble and hydrophilic.

Question 27

How do functional groups influence the forces of attraction between molecules?

Answer 27

Functional groups create partial charges in molecules because of the different electronegativities of atoms. This affects their polarity and causes attractions between them. This leads to stronger forces like hydrogen bonds and dipole interactions.