2.1.2c and d- Carbohydrates

Question 1

What are carbohydrates?

Answer 1

a group of substances that are important in many biologial processes, provide energy and are used to build body structures

Question 2

What are the two structures of glucose?

Answer 2

chain or ring structure

Question 3

What is the difference between an alpha glucose and a beta glucose?

Answer 3

the OH group on the 1st carbon in the hexagonal structure is below the ring on an alpha glucose
WHEREAS
the OH group on the 1st carbon in the hexagonal structure is abouve the ring on a beta glucose

Question 4

What are isomers?

Answer 4

Isomers are different shaped forms of the same molecule

Question 5

What are the different types of carbohydrates?

Answer 5

• monosaccharides
• disaccharides
• polysaccharides

Question 6

What are the functions of carbohydrates?

Answer 6

• substrate for respiration- glucose is essential for cardiac tissues
• intermediate in respiration- glyceraldehydes
• energy stores- starch, glycogen
• structural- cellulose, chitin in arthropod exoskeletons and fungal walls
• transport- sucrose is transported in the phloem of a plant
• recognition of molecules outside a cell- attached to proteins or lipids on cell surface membrane

Question 7

Features of monosaccharides

Answer 7

• they are the simplest “simple sugars”
• same number of C as O atoms: Glucose is C6H12O6
• have the general formula (CH2O)n where n is any number between 3 and 7
• white crystalline solids
• dissolve in water to to form sweet tasting solution

Question 8

What are trioses?

Answer 8

glyceraldehydes, intermediates in respiration and photosynthesis

Question 9

What are tetroses?

Answer 9

rare

Question 10

What are pentoses

Answer 10

ribose, ribulose, used in the synthesis of nucleic acids (RNA and DNA), co-enzymes (NAD, NADP, FAD) and ATP

Question 11

What are hexoses?

Answer 11

glucose, fructose, used as a source of energy in respiration and as building blocks for larger molecules

Question 12

How are disaccharides formed from monosaccharides?

Answer 12

through condensation reaction, a 1-4 glycosidic bond is formed to join the two glucoses together

Question 13

What is required to break a glycosidic bond

Answer 13

reverse of condensation reaction, the formation of two monosaccharides from one disaccharide, is called a hydrolysis reaction and requires one water molecule to supply the H and OH to the sugars formed

Question 14

List 3 examples of disaccharides and their constituent monomers

Answer 14

SUCROSE- alpha glucose + fructose
MALTOSE- alpha glucose + alpha glucose
LACTOSE- glucose + galactose

Question 15

What is sucrose?

Answer 15

• one of the sweetest tasting sugars, main sugar found in plants
• plants transport sucrose for own carbohydrate (energy) intake
• sucrose used in many plants for transporting food reserves, often from leaves to other parts of the plant

Question 16

What is lactose?

Answer 16

sugar found in milk of mammals