Carbohydrates And Lipdis Flashcards
Monomer definition
Small identical or similar molecules which can be condensed to make larger molecules called polymers
Polymers definition
Large molecules made from joining three or more identical or similar molecules together
What is the ration of C:H:O
1:2:1
C6H12O6
How are disaccharides formed and give examples
Condensation reaction between monosaccharides
Glucose-galactose and fructose
How to form maltose
Condensation reaction between two alpha glucose molecules, forming glycosidic bonds, catalysed by Maltase
How to form lactose
Condensation reaction between alpha glucose and galactose, joined by condensation reaction, catalysed by lactase
How to form sucrose
Condensation reaction between alpha glucose and fructose, joined by glycosidic bond and catalysed by sucrase
Which two monomers does starch break down to
Amylose and amylopectin
Describe the structure of amylose
Carbon 1:4 glycosidic bonds so long and straight chains of alpha glucose which coil into a helix
Compact so is good for storage
Insoluble so doesn’t affect water potential
Large so cannot diffuse out of cells
Describe the structure of amylopectin
Branched chain of alpha glucose molecules
Carbon 1:4 and 1:6 glycosidic bonds
This provides a large surface area for rapid hydrolysis by enzymes to release glucose for respiration
Insoluble so does not affect water potential
Large so cannot diffuse out of cells
Describe the structure of glycogen
Only found in animal cells
Shorter chains- glycogen being more rapidly hydrolysed into glucose used in respiration
More highly branched
Larger surface area
Stored in muscles and liver
Insoluble so doesn’t affect water potential or diffuse out of cells
Explain why this shape is important to its function in cells(spiral)
Helical so compact
Explain one way in which starch molecules are adapted for their function in plant cells
- Insoluble so doesn’t affect water potential
- Helical so compact
- Large so cannot leave cells
Explains the structure of cellulose
Long straight, unbranched chains of beta glucose, joined together by many weak hydrogen bonds to form microfibrils
Every other beta glucose molecule rotates horizontally 180 to form a 1-4 glycosidic bonds
Hydrogen bonds are important in cellulose molecules- explain why
Hydrogen bonds hold chains together, providing strength and rigidity, weak hydrogen bonds provide strength in large number
Describe the test for a reducing sugar
- Add equal volumes of Benedict’s solution
2.heat to 95
3.red/orange/yellow/green precipitate
Describe how the
student would show
that a non-reducing
sugar was present in
a solution.
- Complete Benedicts test and observe a negative result/stays
blue - Add acid (HCl) to sugar solution AND Heat to 95 ⁰C;
- Then neutralise with alkali (sodium hydrogen carbonate
(NaHCO₃); - Add equal volumes of Benedict’s solution to the sugar solution;
- Heat again to 95 ⁰C;
- Red/orange/yellow/green precipitate;
What type of test is using a colorimeter
Quantitive
How to standardise the method
- samples should always be shaken before testing
- zero the colorimeter before use
- use the same filter throughout
- use the same volume for each reading
Describe how you would produce a calibration curve
- Make up different known concentrated solutions of named sugar
- Carry out test on each sample
- Take absorbance readings using a colorimeter
- Plot a calibration curve- known conc on X axis and absorbance on Y
- Find the concentration of the unknown sample using the calibration curve
Test for starch
Add potassium iodide
Turns blue black in the presence of starch
Properties and functions of triglycerides and phospholipids
Triglycerides are commonly found in food, phospholipids help form the cell membrane of a cell
Conduct heat slowly so good thermal and electrical insulators, stored around delicate organs such as the kidneys to protect them
Emulsion test
Crush grind
Mix with ethanol and shake
Add water and shake
Forms a milky white emulsion
What are the differences between a triglyceride and a phospholipid
Fatty acid removed and replaced with phosphate group
