2.5 Lipids

Question 1

What is common in all lipids?

Answer 1

They are all organic molecules, which are insoluble in water

Question 2

Most lipids are formed using

Answer 2

Fatty acids combined with alcohol

Question 3

Fats are_____ at room temperature

Answer 3

Solid

Question 4

Oils are______ in room temperature

Answer 4

Liquid

Question 5

Fatty acids contain the acidic group

Answer 5

-COOH Known as a carboxyl group

Question 6

The carboxyl group forms________ of the fatty acids

Answer 6

Acid head

Question 7

What do the common fatty acids have attached to their carboxyl group?

Answer 7

Long hydrocarbon tails

Question 8

How long is the chain of hydrocarbon in fatty acid is usually

Answer 8

15 or 17 carbon atoms

Question 9

Why are fatty acids which double bonds between carbon carbon bonds described as unsaturated

Answer 9

Because they do not contain the maximum possible amount of hydrogen

Question 10

What kind of fatty acids and lipids melt more easily

Answer 10

The one with more double bonds

Question 11

If there is more than one double bond, the fatty acid or lipid is described as

Answer 11

Polyunsaturated

Question 12

Animal lipids are often_______ while plant lipids are often________

Answer 12

Saturated, unsaturated

Question 13

Alcohols are a series of organic molecules, which contain

Answer 13

Hydroxyl group attached to a carbon atom

Question 14

What is glycerol?

Answer 14

An alcohol with three hydroxyl groups

Question 15

What is glycerol?

Answer 15

An alcohol with three hydroxyl groups

Question 16

The reaction between an acid and an alcohol produces a chemical known as

Answer 16

Ester

Question 17

The chemical link between the acid and the alcohol is called

Answer 17

An ester bond

Question 18

What is an ester bond/ ester linkage?

Answer 18

Chemical bond represented as -COO- formed when an acid reacts with an alcohol

Question 19

The most common lipids are

Answer 19

Triglycerides

Question 20

What is triglyceride?

Answer 20

A type of lipid performed when three fatty acid molecules combine with glycerol

Question 21

What is triglyceride?

Answer 21

A type of lipid performed when three fatty acid molecules combine with glycerol

Question 22

What is a glyceride?

Answer 22

An ester formed by a fatty acid, combining with alcohol glycerol

Question 23

Describe the solubility of triglycerides

Answer 23

They are in soluble in water, but are soluble in certain organic solvents such as ethanol

Question 24

Why are triglycerides not soluble in water?

Answer 24

This is because the hydrocarbon tails are nonpolar. They have no uneven distribution of electrical charge.

Question 25

Why do triglycerides make excellent energy stores?

Answer 25

Because they are even richer in carbon hydrogen bonds, than in carbohydrates

Question 26

What will yield more energy on oxidation (have higher calorific value) if they both have the same mass

Answer 26

Triglyceride compared to carbohydrate

Question 27

Where are triglycerides stored in a human body?

Answer 27

In a number of places, particularly just below the skin and around the kidneys

Question 28

What other role do triglyceride have apart from acting as energy store

Answer 28

They also act as an insulator below the skin against loss of heat
Blubber a triglyceride found in sea mammals, such as whales has a similar function, as well as providing buoyancy

Question 29

What is an unusual role for triglycerides?

Answer 29

A metabolic source of water

Question 30

What happens when triglycerides are oxidized in respiration?

Answer 30

Triglycerides are converted to carbon dioxide and water

Question 31

What is the structure of phospholipid?

Answer 31

The same as triglycerides, except one of the three fatty acid molecules is replaced by a phosphate group.

Question 32

Why does phospholipid have the unusual property of having one end which is soluble in water?

Answer 32

Phosphate group is polar and can therefore dissolve in water

Question 33

How does phospholipid form a cell surface membrane?

Answer 33

Two rows of phospholipids are arranged with hydrophilic heads in the watery solutions on either side of the membrane and their hydrophobic tails formal layer that is impermeable to hydrophilic substances