1.2 — carbohydrates: introduction

Question 1

what are carbohydrates?

Answer 1

carbohydrates are molecules that contain the elements carbon, hydrogen and oxygen

Question 2

what does the ‘carbo’ in carbohydrates show about a biological molecule?

Answer 2

that the molecule contains the element carbon

Question 3

what does the ‘hydrate’ in carbohydrates show about a biological molecule?

Answer 3

that it contains hydrogen and oxygen atoms in a ratio of 2:1 (like water — H₂O)

Question 4

what is the general formula for a carbohydrate?

Answer 4

C_x(H₂O)_Y

Question 5

what are the 5 roles of carbohydrates in living organisms?

Answer 5

1. energy supply for cells — the main role
2. energy storage — sugars can be stored as complex carbohydrates (e.g. starch of glycogen)
3. structural components — cellulose and chitin are used in cell walls
4. cellular recognition — glycoproteins help cells identify each other and communicate
5. building blocks for biological molecules — deoxyribose and ribose can be used to make nucleic acids

Question 6

how many subunits does a monosaccharide contain?

Answer 6

one

Question 7

give three examples of a monosaccharide:

Answer 7

glucose, fructose and galactose

Question 8

what is a monosaccharide’s main function?

Answer 8

energy source

Question 9

how many subunits does a disaccharide contain?

Answer 9

two

Question 10

give three examples of a disaccharide:

Answer 10

maltose, sucrose and lactose

Question 11

what is a disaccharide’s main function?

Answer 11

transport form

Question 12

how many subunits does a polysaccharide have?

Answer 12

many

Question 13

give three examples of a polysaccharide:

Answer 13

starch, glycogen, cellulose

Question 14

what is a polysaccharide’s main function?

Answer 14

storage form

Question 15

what is an example of carbohydrates being used for energy storage in living organisms?

Answer 15

sugars can be stored as complex carbohydrates, e.g. starch or glycogen

Question 16

what is an example of carbohydrates being used for structural components in living organisms?

Answer 16

cellulose and chitin are used in cell walls

Question 17

what is an example of carbohydrates being used for cellular recognition in living organisms?

Answer 17

glycoproteins help cells identify each other and communicate

Question 18

what is an example of carbohydrates being used for building blocks for biological molecules in living organisms?

Answer 18

deoxyribose and ribose sugars can be used to make nucleic acids