Y3 Bio Topic 3

Question 1

What are the four main classes of macromolecules in living organisms?

Answer 1

Carbohydrates, lipids (fats), proteins, and nucleic acids.

Question 2

Which chemical elements make up carbohydrates?

Answer 2

Carbon (C), Hydrogen (H), and Oxygen (O), with a H:O ratio of 2:1.

Question 3

Which chemical elements make up fats?

Answer 3

Carbon (C), Hydrogen (H), and Oxygen (O), but the H:O ratio is not 2:1.

Question 4

Which chemical elements make up proteins?

Answer 4

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and sometimes Sulfur (S).

Question 5

Which chemical elements make up nucleic acids?

Answer 5

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and Phosphorus (P).

Question 6

What are the three types of carbohydrates?

Answer 6

Monosaccharides (single sugars), disaccharides (double sugars), and polysaccharides (complex carbohydrates).

Question 7

What is the general formula for carbohydrates?

Answer 7

CnH2mOm

Question 8

Give an example of a monosaccharide.

Answer 8

Glucose (C6H12O6) or fructose (C6H12O6).

Question 9

What is the function of glucose in living organisms?

Answer 9

Glucose is the main substrate for cellular respiration, releasing energy for cells.

Question 10

What is an example of a disaccharide and how is it formed?

Answer 10

Sucrose (table sugar) is formed by joining glucose and fructose.

Question 11

What is an example of a polysaccharide used for energy storage in plants?

Answer 11

Starch.

Question 12

What is an example of a polysaccharide used for energy storage in animals?

Answer 12

Glycogen.

Question 13

What is the structural polysaccharide found in plant cell walls?

Answer 13

Cellulose.

Question 14

What is the structural polysaccharide found in fungi and exoskeletons of arthropods?

Answer 14

Chitin.

Question 15

What are the functions of carbohydrates in living organisms?

Answer 15

Immediate energy source (glucose), storage (starch in plants, glycogen in animals), structural support (cellulose in plants), and synthesis of nucleic acids.

Question 16

What are the two components of a fat molecule?

Answer 16

Glycerol and fatty acids.

Question 17

How are triglycerides formed?

Answer 17

By the condensation of one glycerol molecule and three fatty acid molecules.

Question 18

What is the difference between saturated and unsaturated fatty acids?

Answer 18

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 19

Which type of fat is solid at room temperature?

Answer 19

Saturated fat (e.g. animal fat).

Question 20

Which type of fat is liquid at room temperature?

Answer 20

Unsaturated fat (e.g. plant and fish oils).

Question 21

Why are unsaturated fats liquid at room temperature?

Answer 21

The kinks in the fatty acid chains prevent tight packing, making them more fluid.

Question 22

What are the functions of fats in living organisms?

Answer 22

Long-term energy storage, insulation, protection of organs, structural components (cell membranes), and hormone production.

Question 23

What is the primary structural component of cell membranes?

Answer 23

Phospholipids.

Question 24

What is cholesterol and why is it important?

Answer 24

Cholesterol is a type of steroid important for maintaining membrane fluidity and synthesizing certain hormones.

Question 25

What is the basic unit of a protein?

Answer 25

Amino acids.

Question 26

How many different amino acids are found in proteins?

Answer 26

20.

Question 27

What type of bond forms between amino acids?

Answer 27

Peptide bond.

Question 28

What are the functions of proteins?

Answer 28

Growth and repair, enzyme production, hormone synthesis, immune defense (antibodies), structural support (keratin, collagen), and transport (hemoglobin).

Question 29

What is an enzyme?

Answer 29

A biological catalyst that speeds up chemical reactions in living organisms.

Question 30

What is hemoglobin?

Answer 30

A protein in red blood cells that transports oxygen.

Question 31

What are antibodies?

Answer 31

Proteins that help defend the body against pathogens.

Question 32

What are nucleic acids?

Answer 32

Macromolecules that store and transmit genetic information.

Question 33

What are the two types of nucleic acids?

Answer 33

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Question 34

What are the three components of a nucleotide?

Answer 34

A phosphate group, a pentose sugar, and a nitrogenous base.

Question 35

What is the function of DNA?

Answer 35

Stores genetic information and instructions for protein synthesis.

Question 36

What is the function of RNA?

Answer 36

Assists in protein synthesis by carrying genetic instructions from DNA to ribosomes.

Question 37

What is the iodine test used for?

Answer 37

Detecting starch.

Question 38

How is the iodine test performed?

Answer 38

Add iodine solution to a sample; a color change to blue-black indicates the presence of starch.

Question 39

What is the Benedict’s test used for?

Answer 39

Detecting reducing sugars (e.g., glucose, maltose).

Question 40

How is the Benedict’s test performed?

Answer 40

Add Benedict’s solution to a sample and heat in a boiling water bath; a color change to green, yellow, orange, or brick-red indicates the presence of reducing sugars.

Question 41

What is the Biuret test used for?

Answer 41

Detecting proteins.

Question 42

How is the Biuret test performed?

Answer 42

Add sodium hydroxide and copper sulfate solution; a purple or violet color indicates the presence of proteins.

Question 43

What is the ethanol emulsion test used for?

Answer 43

Detecting fats (lipids).

Question 44

How is the ethanol emulsion test performed?

Answer 44

Mix the sample with ethanol, then add water; the appearance of a white emulsion indicates the presence of fats.

Question 45

What is the importance of food tests?

Answer 45

They help identify the presence of specific nutrients in food samples.

Question 46

What is the difference between hydrolysis and condensation reactions?

Answer 46

Hydrolysis breaks down macromolecules by adding water, while condensation builds macromolecules by removing water.

Question 47

How are starch, glycogen, and cellulose formed?

Answer 47

They are all polysaccharides made from glucose monomers.

Question 48

How are proteins synthesized?

Answer 48

Proteins are synthesized by linking amino acids together in a specific sequence via peptide bonds.

Question 49

How are fats synthesized?

Answer 49

Fats are synthesized from glycerol and fatty acids through ester bonds.

Question 50

What is the main function of nucleic acids?

Answer 50

Storing and transmitting genetic information.

Question 51

What is an example of a storage protein?

Answer 51

Ovalbumin (egg white protein) or casein (milk protein).

Question 52

What is an example of a structural protein?

Answer 52

Collagen or keratin.

Question 53

What is an example of a transport protein?

Answer 53

Hemoglobin, which carries oxygen in the blood.

Question 54

What is an example of a hormonal protein?

Answer 54

Insulin, which regulates blood sugar levels.

Question 55

Why are macromolecules important in living organisms?

Answer 55

They are essential for energy storage, structure, genetic information, and biochemical functions in cells.