Carbohydrates

Question 1

Carbohydrates

Answer 1

• Organic molecules (contain carbon)
• Used as: source, storage of energy, sugars, and structural function
• Consist of only carbon, hydrogen and oxygen

Question 2

What are the 3 main groups of carcbohydrates?

Answer 2

• Monosaccharides
• Disaccharides
• Polysaccharides

Question 3

Monosaccharides

Answer 3

• These are the simplest form of carbohydrates
• Monomer- building blocks for more complex carbohydrates
• General formual: (CH₂O)n

Question 4

Examples of Monosaccharides:

Answer 4

• Glucose
• Fructose
• Galactose

Question 5

Glucose

Answer 5

• Hexose sugar (6 carbons)
• C₆H₁₂O₆
• Main source of energy in respiration, makes ATP
• Small and soluble so its easily transported around the blood
• 2 isomers: Beta glucose = (cellulose) hydroxyl group, -OH above ring
  Alpha glucose = (starch) hydroxyl group, -OH below ring

Question 6

Isomer

Answer 6

Molecules that have the same molecular formula but with a different arrangement of atoms in space
e.g. a-glucose and B-glucose

Question 7

Disaccharides

Answer 7

• Formed when 2 monosaccharides bond together
• Occurs due to a condensation reaction where water is rejected/released and covalent, glycosidic bond is formed

Question 8

Types of disaccharides:

Answer 8

1. Maltose = a-glucose + a-glucose
2. Sucrose = a-glucose + fructose
3. Lactose = a-glucose + galactose

Question 9

Polysaccharides

Answer 9

• Long, complex carbohydrate polymers
• Formed by joining monosaccharides in a condenstaion reaction
• Insoluble so they don’t draw water into cells by osmosis

Question 10

Types of polysaccharides:

Answer 10

1. Starch
2. Glycogen
3. Cellulose

Question 11

Starch

Answer 11

• Found in plants (energy storage + photosynthesis cells)
• Compacted and coiled into dense insoluable grains
• a-glucose
• Contains 2 types of polysaccharides:
  1. Amylose- long chain of a-glucose joined together by 1-4 glycosidic bonds, Coils up to create a helical structure with unbranched chains
  2. Amylopectin- long chain of a-glucose joined by 1-4 and 1-6 glycosidic bonds, Forms highly branchedchains

Question 12

Compare amylose and amylopectin:

Answer 12

• Both polysaccharides and make up starch
• Made up of a-glucose
• Bonded by glycosidic bonds from condensation reactions
• Amylose has only 1-4 glycosidic but amylopectin has 1-4 and 1-6 glycosidic bonds
• Amylose is a long, coiled structure but amylopectin is highly branched

Question 13

Glycogen

Answer 13

• Found in animals and bacteria (energy store)
• Found in cells with a high metabollic rate (small granules in liver + muscle cells)
• 1-4 and many 1-6 glycosidic bonds (similar to amylopectin)
• Very branched structure
• Less dense
• Broken down more rapidly (less insoluble)
• It’s compact, lots can be stored in a small place
• a-glucose

Question 14

Cellulose

Answer 14

• Found in plants (cell wall, structure + support)
• Long chain of β-glucose molecules
• joined by 1-4 glycosidic bonds
• β-glucose is inverted 180° from previous/adjacent molecule resulting in long, straight chains that run parallel to eachother
• H-bonds form links between chains to increase strength
• H-bonds cross link bundles to form microfibrils
• increased strength stops plant from bursting and keeps it turgid