Biological Molecules

Question 1

What is a monomer?

Answer 1

One of many small molecules that combine to form a larger one known as polymer

Question 2

What is a polymer?

Answer 2

Long chains of monomers.

Question 3

What is a monosaccharide?

Answer 3

Sweet tasting, soluble substances that have the general formula (CH2O)n.

Question 4

What is the test for reducing sugars?

Answer 4

Add Benedict’s reagent and heat.

It should turn from blue to brick red.

Question 5

What is a disaccharide?

Answer 5

pairs of monosaccharides can be combined.

Question 6

What do to glucose molecules form?

Answer 6

Maltose

Question 7

When glucose joins to fructose, what is formed?

Answer 7

Sucrose

Question 8

When glucose is joined to galactose, what is formed?

Answer 8

Lactose

Question 9

When monosaccharides join, what kind of reaction is it?

Answer 9

It is a condensation reaction because a water molecule is removed and the bond that is formed is glycosidic

Question 10

What bond is formed between carbohydrates?

Answer 10

A glycosidic bond is formed.

Question 11

When a water molecule is added to a disaccharide, what reaction is this?

Answer 11

Hydrolysis reaction

Question 12

What is a polysaccharide?

Answer 12

Polymers, by combining together many monosaccharides.

Question 13

What is the test for starch?

Answer 13

Add potassium iodide solution at room temperature.

The solution should go from yellow to blue-black if starch is present.

Question 14

What is starch?

Answer 14

A polysaccharide that is found in many part of a plant in the form of small grains.

Question 15

What type of glucose is found in starch?

Answer 15

Starch is made up of chains of alpha glucose monosaccharides linked by glycosidic bonds that are formed by condensation reactions.

Question 16

What is the main role of starch?

Answer 16

The main role of starch is energy storage.

Question 17

What makes starch effective at storing energy?

Answer 17

It’s insoluble so doesn’t affect water potential, so water isn’t draw. In by osmosis.
Large
Compact, so a lot can be stored in a small space.
When hydrolysed it form alpha glucose, which is both easily transported and readily used in respiration.

Question 18

Where is glycogen found?

Answer 18

Glycogen is found in animals and bacteria but never in plant cells.

Question 19

What makes glycogen different to starch?

Answer 19

Shorter chains and highly branched.

Question 20

Where is glycogen stored usually?

Answer 20

Glycogen is usually stored in muscled and the liver.

Question 21

What makes glycogen effective for storage?

Answer 21

• Insoluble
• Compact
• Highly branched so has a lot of ends that can be acted on simultaneously by enzymes

Question 22

What type of glucose is cellulose different to starch and glycogen?

Answer 22

It is made of monomers of beta glucose rather than alpha glucose.

Question 23

Describe the structure of cellulose.

Answer 23

Straight unbranched chains that run parallel to one another, allowing hydrogen bonds to form cross linkages between adjacent chains.

Question 24

Where is cellulose found?

Answer 24

In the cell wall

Question 25

What are the main groups of lipids?

Answer 25

Triglycerides and phospholipids.

Question 26

Are lipids soluble?

Answer 26

Not in water but they are soluble in alcohols and acetone.

Question 27

What are the main roles of lipids?

Answer 27

• Contribute to the flexibility of the cell membrane and help the transfer of lipid soluble substances across them.
• source of energy
• waterproofing
• insulation
• protection