General Chemical Reactions

Question 1

Define primary alcohols.

Answer 1

Primary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to one other carbon atom (or alkyl group).

Question 2

Describe secondary alcohols.

Answer 2

Secondary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to two other carbon atoms (or alkyl groups).

Question 3

Explain tertiary alcohols.

Answer 3

Tertiary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to three other carbon atoms (or alkyl groups).

Question 4

How are aldehydes characterized in terms of their functional group?

Answer 4

Aldehydes have the carbonyl functional group (C=O) at the end of the carbon chain and always have at least one hydrogen atom attached to the carbonyl carbon.

Question 5

What distinguishes ketones from aldehydes?

Answer 5

Ketones have the carbonyl functional group (C=O) in the middle of the carbon chain and are attached to two R groups, while aldehydes have it at the end of the chain.

Question 6

Describe the oxidation process of aldehydes.

Answer 6

Aldehydes can be further oxidized to form carboxylic acids.

Question 7

What are carboxylic acids and how do they behave in water?

Answer 7

Carboxylic acids are weak acids that dissociate in water, forming low concentrations of hydronium ions and alkanoate ions (carboxylate ions).

Question 8

How do water molecules interact with carboxylic acids?

Answer 8

Water molecules can hydrogen-bond with the functional group of carboxylic acids, which contributes to their weak acidity.

Question 9

Define esters and their relationship to carboxylic acids.

Answer 9

Esters are derivatives of carboxylic acids that contain the ester group (-COO) and are named after the parent carboxylic acid from which they are derived.

Question 10

Explain the nomenclature of esters.

Answer 10

The nomenclature of esters involves removing the ‘-oic acid’ suffix from the parent carboxylic acid and replacing it with ‘-oate’, while the alkyl chain attached to the oxygen atom is added as the first word in the name.

Question 11

What is the significance of the alkyl chain in ester naming?

Answer 11

The alkyl chain attached to the oxygen atom of the ester group is derived from the alcohol and is included as the first part of the ester name.

Question 12

Describe the process of forming a dipeptide from amino acids.

Answer 12

A dipeptide is formed when the -NH group of one amino acid reacts with the -COOH group of another amino acid in a condensation reaction, resulting in the elimination of a small molecule, typically water (H2O).

Question 13

Define triglycerides and their role in the human body.

Answer 13

Triglycerides are a type of fat stored in adipose tissues that serve as a source of energy for the human body. They can be hydrolyzed to release energy when needed, such as during fasting or between meals.

Question 14

How are amines classified based on their structure?

Answer 14

Amines are classified based on the number of hydrogen atoms replaced by alkyl or aryl groups. The classification includes primary, secondary, and tertiary amines.

Question 15

Explain the common naming convention for amines.

Answer 15

Amines are commonly named by using the alkyl (or aryl) prefix followed by the suffix -amine.

Question 16

What is the significance of the primary structure of proteins?

Answer 16

The primary structure of a protein refers to the specific sequence of amino acids bonded by covalent peptide bonds. This sequence is crucial as even a single alteration can affect the protein’s function.

Question 17

Describe the secondary structure of proteins.

Answer 17

The secondary structure of a protein arises from interactions between weakly charged nitrogen and oxygen atoms, leading to formations such as alpha helices and beta sheets.

Question 18

How do naturally occurring esters function in the human body?

Answer 18

Naturally occurring esters, such as triglycerides, serve as a source of energy stored in adipose tissues and are hydrolyzed to release energy when needed.

Question 19

What is the relationship between amino acids and proteins?

Answer 19

Amino acids are the building blocks of proteins, and they bond together through peptide links to form polypeptide chains, which fold into functional proteins.

Question 20

Define the term ‘peptide bond’.

Answer 20

A peptide bond is the amide bond formed between the -NH group of one amino acid and the -COOH group of another amino acid during a condensation reaction.

Question 21

How does the structure of proteins relate to their function?

Answer 21

The structure of proteins, including primary, secondary, tertiary, and quaternary levels, is directly related to their function, as specific arrangements of amino acids determine how proteins interact with other molecules.

Question 22

Describe the role of hydrogen bonds in protein structure.

Answer 22

Hydrogen bonds contribute to the formation of secondary structures in proteins, such as α-helix and β-pleated sheets.

Question 23

How does the α-helix structure form in proteins?

Answer 23

The α-helix structure forms when hydrogen bonds occur between every fourth peptide bond, specifically between the oxygen of the carboxyl group and the hydrogen of the amine group.

Question 24

Explain the formation of the β-pleated sheet structure in proteins.

Answer 24

The β-pleated sheet structure forms when two parts of the polypeptide chain are parallel to each other, allowing hydrogen bonds to form between parallel peptide bonds.

Question 25

Identify types of proteins that commonly exhibit secondary structures.

Answer 25

Most fibrous proteins, such as collagen and keratin, exhibit secondary structures.

Question 26

Define the secondary structure of proteins.

Answer 26

The secondary structure of proteins refers to the specific arrangements formed by hydrogen bonds between the amino group and the carboxyl group in the protein backbone.

Question 27

What factors can disrupt hydrogen bonds in proteins?

Answer 27

High temperatures and changes in pH can break hydrogen bonds in proteins.

Question 28

Describe the tertiary structure of proteins.

Answer 28

The tertiary structure of proteins involves additional bonds forming between the R groups (side chains), including hydrogen bonds, disulfide bonds, ionic bonds, and weak hydrophobic interactions.

Question 29

What types of interactions contribute to the tertiary structure of proteins?

Answer 29

The tertiary structure is stabilized by hydrogen bonds, disulfide bonds (between cysteine amino acids), ionic bonds (between charged R groups), and weak hydrophobic interactions (between non-polar R groups).

Question 30

How do the properties of amino acid side chains influence protein structure?

Answer 30

The properties of amino acid side chains, such as being charged, polar, hydrophilic, or hydrophobic, and their order determine the folding and characteristic structure of each protein.

Question 31

Explain the significance of protein size and shape variation.

Answer 31

The enormous variation in protein sizes and shapes enables them to perform a wide range of biological roles.

Question 32

Describe the role of proteins in cells.

Answer 32

Proteins serve as structural components, enzymes that catalyze metabolic reactions, transport molecules that move materials across membranes, molecular motors for muscle contraction and cell movement, and protective antibodies that fight infections.

Question 33

Define enthalpy in the context of chemical reactions.

Answer 33

Enthalpy is the total heat energy of a system, denoted by the letter H.

Question 34

What is entropy and how does it relate to chemical reactions?

Answer 34

Entropy measures how ordered or random a system is, denoted by the letter S, and it influences the direction and extent of chemical reactions.

Question 35

Explain the concept of free energy in chemical reactions.

Answer 35

Free energy, also known as Gibbs’ free energy, is denoted by G and represents the energy available to do work during a reaction, influenced by changes in enthalpy and entropy.

Question 36

How is the change in Gibbs’ free energy related to enthalpy and entropy?

Answer 36

The change in Gibbs’ free energy during a reaction is related to the changes in both enthalpy and entropy, determining whether a reaction will proceed.

Question 37

What is the significance of temperature in biological systems?

Answer 37

Temperature in biological systems is measured in degrees Kelvin, which is calculated by adding 273 to the temperature in degrees Celsius, and it affects the change of free energy during reactions.

Question 38

Describe the importance of the change of free energy during a reaction.

Answer 38

The change of free energy is crucial as it determines whether a reaction can occur and the extent to which it can proceed under constant temperature and pressure.

Question 39

How does temperature affect enzyme-catalyzed reactions?

Answer 39

Temperature influences the rate and feasibility of enzyme-catalyzed reactions, as it affects the kinetic energy of molecules and the overall free energy change.

Question 40

Describe the significance of ΔG in chemical reactions.

Answer 40

ΔG, or Gibbs free energy change, indicates whether a reaction can occur spontaneously. A negative ΔG means the reaction is spontaneous, while a positive ΔG indicates that energy must be supplied for the reaction to take place.

Question 41

How does temperature affect the speed of spontaneous reactions?

Answer 41

The speed of spontaneous reactions can vary with temperature. For example, an ice cube melts faster in hot water than in cold water, but both melting processes are spontaneous.

Question 42

Define spontaneous reaction in terms of Gibbs free energy.

Answer 42

A spontaneous reaction is one that occurs without the net input of energy, characterized by a negative change in Gibbs free energy (ΔG).

Question 43

Do all spontaneous reactions occur at the same rate?

Answer 43

No, the rate of spontaneous reactions can vary. Factors such as temperature and the nature of the reactants influence how quickly a reaction occurs.

Question 44

Explain what a negative ΔG indicates about a reaction.

Answer 44

A negative ΔG indicates that the reaction can occur spontaneously, meaning it can proceed without the need for additional energy input.