T1 - Biological Molecules

Question 1

What element do carbohydrates contain?

Answer 1

C H O

Question 2

What are monosaccharides?

Answer 2

Simple sugar monomoers

Question 3

What is the function of monosaccarhides?

Answer 3

Rapid energy source

Question 4

What is a hexose sugar?

Answer 4

A monosaccrihde with 6 carbon atoms, formula c6h12o6

Question 5

Name three hexose sugars

Answer 5

Glucose, frucotose and galactose

Question 6

Name the two isomers of glucose

Answer 6

Alpha and Beta

Question 7

What is a pentose sugar?

Answer 7

A monosaccharide with 5 carbon atoms, Formula = c5h10o5

Question 8

Name a pentose sugar and where it is found

Answer 8

Ribose found in RNA and ATP

Question 9

Name and describe differences of an isomer of ribose

Answer 9

Deoxyribose lacks the OH group on the second carbon of the sugar ring, in DNA not in RNA

Question 10

Give two structural differences between glucose and ribose

Answer 10

Ribose is pentose, glucose is hexose
Ribose = C5H10O5
Glucose = C6H12O6

Question 11

What are disaccharides?

Answer 11

two monosaccharides linked together by glycosidic bonds (sucrose, lactose and maltose)

Question 12

What is the function of disaccharides?

Answer 12

Transport form

Question 13

What are polysaccharides?

Answer 13

Many monomers linked together by glycosidic bonds (starch glycogen cellulose)

Question 14

What reaction forms a bond and releases water?

Answer 14

Condesnation

Question 15

How are two monosaccharides joined together to form a disaccharide?

Answer 15

By a glycosidic bond during a condensation reaction, releasing water

Question 16

How is maltose formed?

Answer 16

By a condesation reaction forming a 1.4 glycosidic bond between two glucose molecules

Question 17

What two monomers form sucrose?

Answer 17

Glucose & fructose

Question 18

How is sucrose formed?

Answer 18

Condensation reaction forming a 1,4 glycosidic bond between glucose and fructose

Question 19

What two monosaccharides form lactose?

Answer 19

Glucose & galactose

Question 20

Describe the structure of glycogen

Answer 20

Polysaccharide. Straight, highly branched chain of α-glucose monomers joined together by α-1,4 and α-1,6-glycosidic bonds.

Question 21

Describe the structure of cellulose

Answer 21

Polysaccharide. Straight, unbranched, chain of β-glucose monomers joined by β-1,4-glycosidic bonds.

Question 22

Describe the structure of starch

Answer 22

Mixture of two polysaccharides of α-glucose monomers:
Amylose (80%) – coiled, unbranched chain of α-glucose molecules joined by α-1,4-glycosidic bonds.
Amylopectin (20%) - long branched chain of α-glucose molecules joined by α-1,4 and 1,6 glycosidic bonds.

Question 23

What type of reaction splits a glycosidic bond using a molecule of water?

Answer 23

hydrolysis

Question 24

Explain how the structure of glucose relates to its function

Answer 24

Glucose is the immediate energy source for cells.
Small and highly soluble - so is easily transported around body in solution and diffuses into and out of cells for respiration. Can be easily broken down into 2 3C molecules (pyruvate) for entry into Kreb’s cycle to form ATP.

Question 25

Explain how the structure of starch relates to its function

Answer 25

Starch is used for energy storage in plants.
Amylopectin is highly branched due to the α-1,6-glycosidic bonds between glucose monomers - this means there are many free ends for enzyme activity so it is easily and quickly hydrolysed to glucose or easily added to for energy storage.
Compact due to branching of amylopectin and coiling of amylose - storage molecule as more can be packed into a smaller space.
Insoluble in water - so does not affect water potential
Large - so cannot diffuse

Question 26

Explain how the structure of glycogen relates to its function

Answer 26

used for energy storage in animals and plants.
it is made of glucose monomers joined by α-1,4 and 1,6 glycosidic bonds:
α-1,6-glycosidic bonds between glucose monomers make it highly branched - this means there are many free ends for enzyme activity so it is easily and quickly hydrolysed to glucose or easily added to for energy storage.
Compact due to branching - storage molecule as more can be packed into a smaller space.
Insoluble in water - so does not affect water potential
Large - so cannot diffuse out

Question 27

Explain why glycogen releases energy more slowly than glucose

Answer 27

Glycogen is a polysaccharide, therefore the glycosidic bonds between glucose monomers need to be hydrolysed before glucose can be used for respiration.

Question 28

Explain how the structure of cellulose relates to its function

Answer 28

Structural polsaccharide in plant cell walls
Cellulose molecules are straight, with many hydrogen bonds holding cellulose molecules together; this makes the cell wall strong, preventing cell lysis and resisting turgor pressure.
The polar nature of glucose monomers allows water and minerals to diffuse through it.