Carbs And Lipids Flashcards
Explain three ways in which starch molecules are adapted for their function in plant cells
•Insoluble so doesn’t affect water potential
•Helical/coiled so compact
•Large molecule so cannot leave cell
Describe how the structure of glycogen is related to its function
•Helical so compact
•Polymer of glucose so easily hydrolysed
•Branched so more ends for faster hydrolysis
•Glucose so provides respiratory substrates for energy
•Insoluble so doesn’t affect water potential
Explain how the structure of cellulose relates to its function
•Long straight unbranched chains of beta glucose
•Joined by hydrogen bonds
•Form micro fibrils
•Many weak hydrogen bonds are strong in large numbers
•Providing strength to cell wall
Compare and contrast the structure and properties of triglycerides and phospholipids
•Both contain ester bonds
•Both contain glycerol
•Fatty acids on both may be saturated or unsaturated
•Both are insoluble in water
•Both contain C,H and O whereas phospholipids also contain P
•Triglyceride has three fatty acids whereas phospholipids have two fatty acids plus phosphate group
•Triglycerides are hydrophobic/non-polar whereas phospholipids have hydrophilic and hydrophobic region
•Phospholipids form monolayer whereas triglycerides don’t
How do you make a calibration curve for a reducing sugar and use it to find an unknown concentration?
•Make several known concentrations of named reducing sugar
•Carry out Benedict’s test on each sample
•Use colorimeter to measure absorbance of light in each sample
•Plot calibration curve with concentration on X axis and absorbance on Y axis
•Find the concentration of unknown using the calibration curve
What is a monomer?
Monomers are small identical or similar molecules which can be condensed to make larger molecules called polymers
What is a polymer?
Polymers are large molecules made from condensing 3 or more identical or similar monomers together
What is a hydrolysis reaction?
Addition of H2O to break a named chemical bond catalysed by a named enzyme
What is a condensation reaction?
Loss of H2O to form a named chemical bond catalysed by a named enzyme
Name the bond between carbohydrate monomers
Glycosidic bond
What is an unsaturated fatty acid?
Double bonds between carbon
Describe how a triglyceride is formed
•one glycerol and three fatty acids
•three condensation reactions and the removal of three molecules of water
•creating 3 ester bonds
Why do phospholipids form a bilayer, but triglycerides do not?
•Phospholipid has two hydrophobic fatty acid tails and a hydrophilic phosphate head
•Triglycerides have three hydrophobic fatty acid tails only
•The hydrophilic phosphate group on phospholipids attracts water to either side of the bilayer
