chapter 4

Question 1

What are organic molecules based on?

Answer 1

Carbon

Organic molecules range from simple molecules to molecules with thousands of atoms and are typically found within living organisms.

Question 2

What are inorganic molecules?

Answer 2

Molecules not based on carbon

Exceptions include carbon oxides (CO, CO2), carbonates (H2CO3, HCO3-, CaCO3), and cyanides (HCN).

Question 3

Which group of molecules is considered hydrophobic?

Answer 3

Lipids

Question 4

Which functional groups are hydrophilic?

Answer 4

• Carboxyl (-COOH)
• Amino (-NH2)
• Phosphate (-PO4)
• Carbonyl (-C=O)

Charged groups are hydrophilic.

Question 5

What defines a single bond between atoms?

Answer 5

Atoms share 1 pair of electrons

Question 6

What defines a double bond between atoms?

Answer 6

Atoms share 2 pairs of electrons

Question 7

What defines a triple bond between atoms?

Answer 7

Atoms share 3 pairs of electrons

Question 8

What is the valence of hydrogen?

Answer 8

1

Question 9

What is the valence of oxygen?

Answer 9

6

Question 10

What is the valence of nitrogen?

Answer 10

5

Question 11

What is the valence of carbon?

Answer 11

4

Question 12

Define hydrocarbons.

Answer 12

Organic molecules consisting of ONLY carbon and hydrogen atoms

Hydrocarbons contain a carbon ‘backbone’ and many organic molecules have hydrocarbon components.

Question 13

How do you identify structural isomers?

Answer 13

• Different covalent arrangements of their atoms
• Same number and type of atoms but different connections
• Covalent bonds in different places
• Some atoms attached differently

Question 14

What are cis-trans isomers?

Answer 14

• Same covalent bonds but differ in spatial arrangements
• Atoms connected in the same way but differ in structural arrangements
• Atoms on different sides of a carbon-carbon double bond

Question 15

What are enantiomers?

Answer 15

Isomers that mirror each other

Having the correct enantiomer is important in medicine as the wrong one can be ineffective or dangerous.

Question 16

Identify the following functional group: -OH.

Answer 16

Hydroxyl

Question 17

Identify the following functional group: -NH2.

Answer 17

Amine

Question 18

Identify the following functional group: -COOH.

Answer 18

Carboxyl

Question 19

Identify the following functional group: -C=O.

Answer 19

Carbonyl

Question 20

Identify the following functional group: -CH3.

Answer 20

Methyl

Question 21

Identify the following functional group: -OPO32-.

Answer 21

Phosphate

Question 22

Identify the following functional group: -SH.

Answer 22

Sulfhydryl

Question 23

What is the property of hydroxyl functional groups?

Answer 23

• Made of an oxygen atom and a hydrogen atom
• O-H bond is polar and hydrophilic
• Forms hydrogen bonds with water
• Found in most biomolecules (also alcohols)

Question 24

What is the property of amine functional groups?

Answer 24

• Made of a nitrogen atom and 2 hydrogen atoms
• Functions as a base
• Nitrogen tends to pick up H+ from solutions

Question 25

What is the property of carboxyl functional groups?

Answer 25

* Made of a carbon atom, 2 oxygen atoms, and a hydrogen atom * Functions as acids * H+ tends to dissociate making O atom negatively charged * Found in amino acids

Question 26

What is the property of methyl functional groups?

Answer 26

* Made of one carbon and 3 hydrogen atoms * Not reactive and hydrophobic * Affects gene expression by binding DNA * Genes with –CH3 are usually 'turned off'