3.2 Carbohydrates, Lipids And Proteins

Question 1

Distinguish between organic and inorganic compounds

Answer 1

Organic compounds are compounds which are found in living organisms and contain carbon. Inorganic compounds are those which do not contain carbon.

Question 2

State three compounds which fit the definition of organic compounds, but are classified as inorganic

Answer 2

Carbonates, hydrogen carbonates and oxides of carbon.

Question 3

State three kinds of organic compounds

Answer 3

Carbohydrates, lipids, proteins.

Question 4

State three kinds of inorganic compounds

Answer 4

Minerals, metals, salts.

Question 5

Outline the structure of ribose

Answer 5

Pentose sugar. Five carbons, four in a ring.

Question 6

Outline the structure of glucose

Answer 6

Hexose sugar. Six carbons, five in a ring.

Question 7

Outline the structure of an amino acid

Answer 7

Central carbon + hydrogen + amino group + carboxyl group + variable ‘R’ group.

Question 8

Outline the structure of fatty acids

Answer 8

Carboxyl group + long hydrocarbon chain. Chain length ranges from 4-30 carbons.

Question 9

List three monosaccharides

Answer 9

Glucose, Galactose, Fructose.

Question 10

List three disaccharides

Answer 10

Lactose, Maltose, Sucrose.

Question 11

List three polysaccharides

Answer 11

Starch, Glycogen, Cellulose.

Question 12

Outline the function of glucose

Answer 12

Source of energy which can be broken down to form ATP via cell respiration.

Question 13

Outline the function of lactose

Answer 13

Sugar found in milk, provides energy for young mammals.

Question 14

Outline the function of glycogen

Answer 14

Used for short term energy storage (between meals), stored in muscles and liver.

Question 15

Outline the function of fructose

Answer 15

Make fruit sweet, attracts animals who eat fruit and spread seeds.

Question 16

Outline the function of sucrose

Answer 16

Transportable energy form for plants, transported in solution.

Question 17

Outline the function of cellulose

Answer 17

Main component of cell wall, makes plants strong.

Question 18

Outline condensation

Answer 18

Molecules are covalently joined together, water is formed as a by-product. In carbohydrates, the bonds is a glycosidic bond. The reaction is brought about by an enzyme.

Question 19

Outline hydrolysis

Answer 19

A water molecule splits the covalent bond between two molecule. Reverse of condensation; chains of carbohydrates broken down into their smaller components. Brought about by an enzyme (different from condensation).

Question 20

State three functions of lipids

Answer 20

Buoyancy
-Lipids are less dense than water, helping animals to float.
Insulation
-Fats in animals can serve as heat insulators.
Storage of energy
-Triglycerides can be used for long-term energy storage.

Question 21

Compare the energy storage of carbohydrates and lipids

Answer 21

Lipids have more energy per unit mass than from carbohydrates.

Question 22

Compare the solubility of carbohydrates and lipids

Answer 22

Lipids are insoluble, while sugars are highly soluble.

Question 23

Compare the ease of breakdown of carbohydrates and lipids

Answer 23

Lipids are not easily digested, while carbohydrates are quickly hydrolysed, and thus the transferring energy is quicker.