B1.1 Carbohydrates And Lipids

Question 1

Why is carbon so structurally important in biological molecules?

Answer 1

• Carbon atoms has unique properties that allow it to form up to 4 covalent bonds.
• It can bond with itself to form strong substances like diamond and graphite.
• Can form many different shapes.

Question 2

What is an organic molecule?

Answer 2

Organic refers to molecules containing carbon and hydrogen, such as CH4 and C6H12O6.

Question 3

What is an inorganic molecule?

Answer 3

Inorganic refers to molecules with carbon and hydrogen (both can’t be present with each other). Examples are CO2 and H2O.

Question 4

What are the functional groups?

Answer 4

Hydroxyl -OH

Carboxyl - C is double bonded to O and single bonded to OH group

Amine N attached to 2H

Phosphate bonded to 4 O

Must know all of these

Question 5

What is a hydrocarbon?

Answer 5

Combination of C & H

Question 6

Glucose

Answer 6

Exists as alpha and beta glucose

Question 7

Structural isomer

Answer 7

Are molecules that have the same molecular formula but have a different arrangement of the atoms in space.

Question 8

Fructose

Answer 8

Formed in plants, very sweet. Used to sweeten fruits to lure animals to eat the fruit to disperse seeds. Also the main sugar in honey.

Question 9

Galactose

Answer 9

Combines with glucose to form lactose, the disaccharide found in mammal milk.

Question 10

Condensation reaction

Answer 10

Where water is formed

Question 11

What are polysaccharides?

Answer 11

Are polymers containing many monosaccharides linked by glycosidic bonds. Like disaccharides, polysaccharides are formed by condensation reactions.

Mainly used as an energy store and as a structural component in cells.

Examples are starch and cellulose as well as glycogen.

Question 12

What are the functions of cellulose, starch and glycogen

Answer 12

Starch - storage form of carbohydrates in plants.

Glycogen - storage form of carbohydrates in humans and other vertebrates.

Cellulose - cell wall mostly made of cellulose as it provides structural support.

Question 13

What are lipids?

Answer 13

Composed of hydrogen and carbon atoms.

They are non polar

Lipids are therefore hydrophobic and water insoluble

Question 14

What are the four types of lipids?

Answer 14

Steroids
Triglycerides
Waxes
Phospholipids

Question 15

Function of triglycerides

Answer 15

Used for long term energy storage

Question 16

Role of lipids

Answer 16

Their main role is to be an energy source as they provide more than twice the energy in comparison to carbohydrates.

Lipids are also stored in adipose tissue which has several important roles including:
Heat insulation: adipose tissue helps reduce heat loss.

Protection: adipose tissue around delicate organs such as the kidneys and acts as a cushion against impacts.

Question 17

Carbohydrates vs lipids

Answer 17

Storage - lipids has a long term energy storage. Opposite for carbohydrates.

Osmolality - lipids have less of an effect osmotic pressure. Carbohydrates have more effect.

Less easily digested - can only be used for aerobic respiration. While carbohydrates can be used for aerobic and anaerobic respiration.

ATP yield - lipids store twice as much ATP per gram than carbohydrates.

Solubility - lipids aren’t water soluble meaning they are harder to transport while carbohydrates are.

Question 18

Saturated vs unsaturated

Answer 18

Saturated - all single c-c bonds

Unsaturated - at least one c=c bond

Poly unsaturated - many double bonds

Question 19

As chain length increases why does melting point increase?

Answer 19

The longer the chain, the more bonds needed to be broken.

Question 20

Unsaturated fatty acids can be either:

Answer 20

Cis-unsaturated:
Naturally occurring
Causes a kink in the fatty acid chain
Hydrogen atoms are on the same side of the c=c bond.

Trans-unsaturated:
Are not found in nature and are the result of human food processing such as butter.
Hydrogen atoms are on opposite sides of the c=c bond.
Causes a straighter fatty acid chain.