Chemistry of Life: Master the Building Blocks of Life

Question 1

Which of these macromolecules consists mainly of amino acids joined by peptide bonds?

Accepted Answer

Proteins

Answer

Carbohydrates

Answer

Lipids

Answer

Nucleic acids

Question 2

Which of the following is **not** a biological molecule?

Accepted Answer

Electron

Answer

Carbohydrate

Answer

Lipid

Answer

Protein

Question 3

Which chemical reaction is crucial for breaking down nucleic acids?

Accepted Answer

Hydrolysis

Answer

Condensation

Answer

Oxidation-reduction

Question 4

Carbohydrates are complex molecules composed of smaller subunits. What is the name of the smallest and simplest subunit of a carbohydrate?

Accepted Answer

Monosaccharide

Answer

Amino acid

Answer

Nucleotide

Answer

Fatty acid

Question 5

How does genetic information in DNA lead to the production of proteins in cells?

Accepted Answer

Genetic information flows from DNA to RNA to proteins through transcription and translation.

Answer

DNA is directly converted into proteins.

Question 6

How do the structure and function of macromolecules, such as proteins and nucleic acids, contribute to the regulation of cellular respiration?

Accepted Answer

Proteins, acting as enzymes, facilitate metabolic reactions, while nucleic acids store and transmit genetic information.

Answer

Lipids, found in cell membranes, regulate substance movement, and carbohydrates provide energy.

Answer

Proteins synthesize new molecules, and lipids offer insulation.

Question 7

How do enzymes influence biochemical reactions in living organisms?

Accepted Answer

Enzymes exhibit high specificity, facilitating only specific reactions with precise molecular recognition.

Answer

Enzymes directly increase the energy of the reactants, lowering the activation energy.

Answer

Enzymes create a new pathway for the reaction, bypassing the original pathway.

Answer

Enzymes decrease the rate of a reaction by increasing the activation energy.

Question 8

DNA Replication and Enzyme Functions
What is the specific role of DNA polymerase III in DNA replication?

Accepted Answer

Synthesizes new DNA strands in the 5' to 3' direction using existing strands as templates.

Answer

Unwinds the DNA double helix ahead of the replication fork.

Answer

Proofreads newly synthesized DNA strands and corrects errors.

Answer

Separates the two DNA strands at the replication fork.

Question 9

Explain the process of photosynthesis, highlighting its purpose and the crucial role of light energy.

Accepted Answer

Photosynthesis utilizes light energy to transform carbon dioxide and water into glucose, releasing oxygen.

Answer

Photosynthesis employs chemical energy to convert glucose into carbon dioxide and water, releasing oxygen.

Answer

Photosynthesis harnesses heat energy to convert carbon dioxide and water into glucose, releasing oxygen.

Answer

Photosynthesis uses light energy to convert oxygen into carbon dioxide and water, releasing glucose.

Question 10

Explain enzyme specificity and describe how enzyme structure and substrate binding affinity contribute to it.

Accepted Answer

Enzyme specificity is influenced by both enzyme structure and substrate binding affinity.

Answer

Enzyme specificity is determined solely by enzyme structure and active site geometry.

Answer

Substrate binding affinity is the only factor that affects enzyme specificity.

Answer

Enzyme specificity is not affected by any factors.

Question 11

How does the amphipathic nature of lipids contribute to their role in forming cellular membranes?

Accepted Answer

Lipids have both hydrophilic and hydrophobic regions, allowing them to interact with both water and nonpolar molecules.

Answer

Lipids are highly branched, providing increased surface area for interactions with other molecules.

Answer

Lipids are highly polar, making them soluble in both water and nonpolar solvents.

Question 12

Which of the following is NOT a mechanism by which enzymes regulate metabolic pathways in cells?

Accepted Answer

Selective binding of enzymes to specific DNA sequences

Answer

Modulation of enzyme activity through allosteric effectors

Answer

Feedback inhibition of the pathway

Answer

Alteration of enzyme expression through genetic regulation

Question 13

How do cells regulate metabolic pathways to ensure efficient function?

Accepted Answer

Feedback inhibition, where the final product of a pathway blocks the first enzyme, is a key regulatory mechanism.

Accepted Answer

Hormones like insulin and glucagon act as signals to switch metabolic pathways on or off.

Accepted Answer

Allosteric regulators, proteins that bind to enzymes, can either activate or inhibit a pathway.

Answer

Metabolic pathways are solely determined by the availability of substrates.

Question 14

What is the main role of carbohydrates in living organisms?

Accepted Answer

Energy storage

Answer

Structural support

Answer

Enzyme catalysis

Answer

Genetic information storage

Question 15

What is the basic building block of proteins?

Accepted Answer

Amino acid

Answer

Nucleotide

Answer

Fatty acid

Answer

Monosaccharide

Question 16

What is the primary function of proteins in living organisms?

Accepted Answer

Catalytic activity (e.g., enzymes)

Answer

Energy storage

Answer

Cell signaling

Answer

Structural support

Question 17

Which of the following is a purine base found in nucleic acids?

Accepted Answer

Adenine

Answer

Thymine

Answer

Cytosine

Answer

Uracil

Question 18

Which type of chemical bond connects amino acids in a protein?

Accepted Answer

Covalent bond

Answer

Hydrogen bond

Answer

Ionic bond

Answer

Van der Waals force

Question 19

What is the role of enzymes in biological reactions?

Accepted Answer

Lower the activation energy of the reaction

Answer

Increase the activation energy of the reaction

Answer

Provide the substrate for the reaction

Answer

Remove the products from the reaction

Question 20

Which of the following molecules plays a role in both energy storage and cell signaling?

Accepted Answer

Cyclic AMP (cAMP)

Answer

Glucose

Answer

Triglyceride

Answer

Protein

Question 21

Which of the following is the fundamental building block of carbohydrates?

Accepted Answer

Monosaccharide

Answer

Amino acid

Answer

Nucleotide

Answer

Fatty acid

Question 22

Which functional group distinguishes amino acids?

Accepted Answer

Amine and carboxyl groups

Answer

Hydroxyl and carbonyl groups

Answer

Phosphate and sugar groups

Answer

Methyl and ethyl groups

Question 23

In the structure of DNA, which base pairs with adenine?

Accepted Answer

Thymine

Answer

Cytosine

Answer

Guanine

Answer

Uracil

Question 24

In plants, the primary storage form of carbohydrates is:

Accepted Answer

Starch

Answer

Glucose

Answer

Cellulose

Answer

Glycogen

Question 25

Among the following, which amino acid is non-polar?

Accepted Answer

Alanine

Answer

Serine

Answer

Aspartic acid

Answer

Glutamic acid

Question 26

During cell division, DNA is duplicated through a process known as:

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Recombination

Question 27

Polypeptide chains are formed by linking amino acids through:

Accepted Answer

Covalent bonds

Answer

Ionic bonds

Answer

Hydrogen bonds

Answer

Van der Waals forces

Question 28

Enzymes facilitate biochemical reactions by:

Accepted Answer

Lowering the activation energy

Answer

Increasing the activation energy

Answer

Changing the equilibrium constant

Answer

Inhibiting the reaction

Question 29

Which of the following is the building block of a protein?

Accepted Answer

Amino acid

Answer

Nucleotide

Answer

Fatty acid

Answer

Monosaccharide

Question 30

Which of the following processes involves the breakdown of large molecules into smaller ones?

Accepted Answer

Catabolism

Answer

Anabolism

Answer

Metabolism

Answer

Respiration

Question 31

Which of the following is a buffer solution?

Accepted Answer

A solution that resists changes in pH when small amounts of acid or base are added

Answer

Pure water

Answer

A solution with a pH of 2

Answer

A solution with a high concentration of ions

Question 32

Which of the following is a key concept in green chemistry?

Accepted Answer

Preventing pollution

Answer

Using toxic chemicals

Answer

Producing large amounts of waste

Answer

Maximizing energy consumption

Question 33

Which of the following is a simple sugar (monosaccharide)?

Accepted Answer

Glucose

Answer

Starch

Answer

Cellulose

Answer

Glycogen

Question 34

Phospholipids are found in the cell membrane because they have:

Accepted Answer

One end hydrophobic and one end hydrophilic

Answer

Both ends hydrophilic

Answer

Both ends hydrophobic

Answer

One end hydrophilic and one end hydrophobic

Question 35

Which type of bond is responsible for the secondary structure of proteins?

Accepted Answer

Hydrogen bond

Answer

Covalent bond

Answer

Ionic bond

Answer

Van der Waals force

Question 36

The process of breaking down carbohydrates for energy is called:

Accepted Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Lipolysis

Answer

Proteolysis

Question 37

Which of the following is a saturated fatty acid?

Accepted Answer

Stearic acid

Answer

Linoleic acid

Answer

Oleic acid

Answer

Arachidonic acid

Question 38

The tertiary structure of a protein refers to:

Accepted Answer

The specific three-dimensional shape of the protein

Answer

The order of amino acids in the protein

Answer

The interactions between multiple protein chains

Answer

The chemical modifications of the protein

Question 39

Who discovered the double helix structure of DNA?

Accepted Answer

James Watson and Francis Crick

Answer

Rosalind Franklin and Maurice Wilkins

Answer

Erwin Chargaff and Alfred Hershey

Answer

Friedrich Miescher and Phoebus Levene

Question 40

Which technique is NOT commonly used to study protein-protein interactions?

Accepted Answer

Gel electrophoresis

Answer

Co-immunoprecipitation

Answer

Förster resonance energy transfer (FRET)

Answer

Protein microarrays

Question 41

Describe the structure and function of biological membranes:

Accepted Answer

A phospholipid bilayer with embedded proteins and cholesterol, selectively permeable and responsible for compartmentalization.

Answer

A single layer of fatty acids arranged randomly, forming a barrier.

Answer

A network of carbohydrates linked together, providing support.

Answer

A thin layer of proteins, controlling material movement.

Question 42

Which type of lipid is the primary structural component of cell membranes?

Accepted Answer

Phospholipids

Answer

Steroids

Answer

Fatty acids

Answer

Triglycerides

Question 43

What is the primary function of nitrogenous bases in nucleic acids?

Accepted Answer

To store and transmit genetic information

Answer

To catalyze biochemical reactions

Answer

To transport molecules across cell membranes

Answer

To provide energy for cellular processes

Question 44

What type of chemical bond is responsible for linking amino acids in a protein?

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Hydrogen bond

Answer

Disulfide bond

Question 45

What is the key difference between saturated and unsaturated fats?

Accepted Answer

Saturated fats have only single bonds between carbon atoms, while unsaturated fats have one or more double bonds

Answer

Saturated fats are liquid at room temperature, while unsaturated fats are solid

Answer

Saturated fats are derived from animals, while unsaturated fats are derived from plants

Answer

Saturated fats are healthier than unsaturated fats

Question 46

Which of the following is NOT a type of nucleic acid?

Accepted Answer

Polypeptide

Answer

DNA

Answer

RNA

Answer

ATP

Question 47

In DNA, which base pairs with adenine (A) according to the complementary base pairing rule?

Accepted Answer

Thymine (T)

Answer

Cytosine (C)

Answer

Guanine (G)

Answer

Uracil (U)

Question 48

How are biological molecules utilized in the development of diagnostic tools and therapeutic agents?

Accepted Answer

As biomarkers for disease detection and monitoring

Accepted Answer

As targets for drug development

Answer

As indicators of overall health and well-being

Question 49

In eukaryotic cells, what is the order of metabolic pathways involved in cellular respiration?

Accepted Answer

Glycolysis → Krebs cycle → Electron transport chain

Answer

Glycolysis → Electron transport chain → Krebs cycle

Answer

Krebs cycle → Glycolysis → Electron transport chain

Question 50

Which of the following is NOT a type of biological molecule commonly studied in the unit 'Chemistry of Life'?

Accepted Answer

Mineral

Answer

Carbohydrate

Answer

Protein

Answer

Lipid

Question 51

What is the primary role of carbohydrates in living organisms?

Accepted Answer

Provide energy and structural support

Answer

Regulate cell division

Answer

Carry genetic information

Answer

Facilitate hormone production

Question 52

Which of the following fatty acids has a saturated structure?

Accepted Answer

Palmitic acid

Answer

Arachidonic acid

Answer

Oleic acid

Answer

Linoleic acid

Question 53

What is the basic building block of proteins?

Accepted Answer

Amino acid

Answer

Nucleotide

Answer

Monosaccharide

Answer

Fatty acid

Question 54

Which type of nucleic acid primarily stores genetic information?

Accepted Answer

DNA

Answer

ATP

Answer

RNA

Question 55

What is the main function of enzymes in biological systems?

Accepted Answer

Catalyze biochemical reactions

Answer

Alter the products of reactions

Answer

Provide energy for reactions

Answer

Initiate reactions

Question 56

Which of the following biological processes involves the removal of water molecules?

Accepted Answer

Dehydration synthesis

Answer

Hydrolysis of starch

Answer

Translation of mRNA

Answer

Replication of DNA

Question 57

What is the primary function of the cell membrane?

Accepted Answer

Regulates the passage of substances into and out of the cell

Answer

Synthesizes proteins

Answer

Controls cellular respiration

Question 58

Which metabolic process involves the breakdown of complex molecules into simpler ones?

Accepted Answer

Catabolism

Answer

Glycolysis

Answer

Metabolism

Answer

Anabolism

Question 59

What is the primary role of ATP in cellular processes?

Accepted Answer

Serves as the main energy currency of cells

Answer

Catalyzes biochemical reactions

Answer

Transports genetic information

Answer

Stores amino acids

Question 60

Which biological molecule serves as the primary source of immediate energy for living organisms?

Accepted Answer

Carbohydrates

Answer

Nucleic acids

Answer

Proteins

Answer

Lipids

Question 61

Which type of bond is responsible for connecting amino acids in a polypeptide chain?

Accepted Answer

Peptide bond

Answer

Ionic bond

Answer

Hydrogen bond

Answer

Covalent bond

Question 62

A researcher is examining the structure of a novel enzyme. Which level of protein organization is primarily influenced by the disruption of hydrogen bonds?

Accepted Answer

Secondary structure

Answer

Tertiary structure

Answer

Quaternary structure

Answer

Primary structure

Question 63

Which of the following is NOT a function of lipids in living organisms?

Accepted Answer

Transporting genetic information

Answer

Forming cell membranes

Answer

Providing insulation

Answer

Storing energy

Question 64

A scientist is studying the impact of varying temperatures on the activity of an enzyme. What is the most likely outcome of elevating the temperature beyond the enzyme's optimal range?

Accepted Answer

The enzyme's activity will decrease due to denaturation.

Answer

The enzyme's activity will remain stable.

Answer

The enzyme's activity will increase indefinitely.