lecture 6

Question 1

what is the polymerisation of biological molecules?

Answer 1

• polymer is a long molecule consisting fo many simila building blocks
• small building blocks called monomers
• carbohydrates
• proteins
• nucleic acids

Question 2

how are polymers formed?

Answer 2

• monomers connected by covalent bonds
• form through a loss of water molecules
• condensation/dehydration reaction
• facilitated by enzymes (specialised macromolecules that speed up chemical reactions in cells)

Question 3

what are carbohydrates?

Answer 3

• include sugars and polymers of sugars
• monosaccharides are simplist (single sugars)
• polysaccharides (many sugar building blocks)

Question 4

what are monosaccharides?

Answer 4

• CH2O
• glucose (C6 H12 O6)
• classified by location of carbonyl group (aldose/ketose); number of carbons in carbon skeleton
• serve as major fuel for cells
• link by glycosidic linkage (disaccharide)

Question 5

what are polysaccharides?

Answer 5

• polymers of sugars having storage/structural roles
• structure from sugar monomers and glycosidic linkages
• store as starch (stored in surplus as granules within chloroplasts/plastids)
• stored as glycogen (mainly in live and muscle cells)
• cellulose (major component in wall of plant cells)
• alpha/beta linkages
• chitin is another structural polysaccharide (exoskeleton of arthropods; support cell walls of fungi)

Question 6

how do linkages change polysaccharides?

Answer 6

• alpha are helical
• beta are straight
• parallel cellulose grouped in microfibrils (strong materials for plants)
• enzymes digest starch (hydrolising alpha linkages, but can’t beta linkages in cellulose)

Question 7

how does digestion of cellulose work?

Answer 7

• insoluble fibre
• some microbes use enzymes to digest cellulose
• many herbivores have symbiotic relationship with microbes