carbohydrates

Question 1

What is meant by monomers? (1)

Answer 1

Smaller units from which larger molecules are made

Question 2

What is meant by polymers? (1)

Answer 2

Molecules that are made from a large number of repeating units joined together

Question 3

What is a condensation reaction? (3)

Answer 3

A chemical reaction that joins up two molecules;

With the formation of a chemical bond;

And the loss of a water molecule

Question 4

What is a hydrolysis reaction? (2)

Answer 4

A chemical reaction that breaks up the chemical bond between two molecules;

And the addition of a water molecule

Question 5

What chemical elements do carbohydrates contain? (3)

Answer 5

Carbon (C), Hydrogen (H), Oxygen (O)

Question 6

What chemical elements do lipids contain? (3)

Answer 6

Carbon (C), Hydrogen (H), Oxygen (O)

Question 7

What chemical elements are found in all amino acids (and therefore all proteins)? (5)

Answer 7

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N);

Some also contain Sulphur (S)

Question 8

What are the monomers of carbohydrates? (1)

Answer 8

Monosaccharides

Question 9

What are three examples of monosaccharides? (3)

Answer 9

Glucose, Fructose, Galactose

Question 10

What type of monosaccharide is glucose? (2)

Answer 10

Hexose sugar

Which means it contains 6 carbon atoms

Question 11

What are the two forms of glucose? (2)

Answer 11

α-glucose
β-glucose

Question 12

How do you draw the two isomers of glucose? (2)

Answer 12

α-glucose: hydroxyl group above the ring on carbon 1

β-glucose: hydroxyl group below the ring on carbon 1

Question 13

What type of monosaccharide is ribose? (2)

Answer 13

Pentose sugar;
Because it has 5 carbons

Question 14

How is the structure of glucose related to its function as the main energy source in animals and plants? (2)

Answer 14

It is soluble, so it can be easily transported

Its chemical bonds contain a lot of energy.

Question 15

What type of bond joins monosaccharides together? (1)

Answer 15

Glycosidic bonds

Question 16

How is a disaccharide formed? (3)

Answer 16

When two monosaccharides are joined together;

By a glycosidic bond;

During a condensation reaction

Question 17

How is a polysaccharide formed? (3)

Answer 17

When more than two monosaccharides are joined together;

By a glycosidic bond;

During a condensation reaction

Question 18

What is maltose made of? (2)

Answer 18

Alpha glucose + Alpha glucose

Question 19

What is sucrose made of? (2)

Answer 19

α-glucose + fructose

Question 20

What is lactose made of? (2)

Answer 20

α-glucose or β-glucose + galactose

Question 21

What is the main energy store in plants? (2)

Answer 21

Starch;

Excess glucose is stored as starch

Question 22

Why is starch a good molecule for storage in plants? (3)

Answer 22

Insoluble so osmotically inert;-

Therefore, does not affect water potential;

So does not draw in water into plant cells

Question 23

What are the two polysaccharides that make up starch? (2)

Answer 23

Amylose
Amylopectin

Question 24

Describe the structure of amylose (3)

Answer 24

Long unbranched chain of α-glucose molecules;

Joined by 1-4 glycosidic bonds;

Which give it a coiled structure so compact

Question 25

Describe the structure of amylopectin? (3)

Answer 25

Long branched chain of α-glucose molecules; It has 1-4 glycosidic bonds and branches formed by 1-6 glycosidic bonds; Resulting in a branched rather than helical structure

Question 26

Why is the branched structure of amylopectin important? (2)

Answer 26

Allows enzymes to easily access the glycosidic bonds; Which enables quick release of glucose

Question 27

What is the main energy store in animals? (1)

Answer 27

Glycogen

Question 28

Describe the structure of glycogen (2)

Answer 28

Highly branched chain of α-glucose molecules; Which allows enzymes to access the glycosidic bonds easily and hydrolyse glucose quickly

Question 29

Why is glycogen a good storage molecule in animals? (3)

Answer 29

Compact; Has a high energy content for its mass; Insoluble, so it does not affect the cell's water potential

Question 30

What is the major component of cell walls in plants? (1)

Answer 30

Cellulose

Question 31

Describe the structure of cellulose (2)

Answer 31

Made up of long, straight, unbranched chains; Of β-glucose molecules inverted by 180 with each molecule

Question 32

How are cellulose chains held together, and what function does this serve? (3)

Answer 32

By hydrogen bonds to form microfibrils; Which are strong fibers; That provide structural support for plant cells