Karteikarten
A level biology Revision I
Karten in diesem Stapel (20)
- 1What is unsaturated fatty acid?Double bond between carbon atoms
- 2Describe how you would test a sample of food for starch?Add Iodine solution to the food sample.
Blue/Black/Purple indicates the presence of starch - 3Biuret test to distinguish between Lactase and Lactose?Add biuret to both solution.
Lactase will give purple solution.
As it is an enzyme.
Lactose will remain blue. - 4Emulsion TestCrush
With ethanol
Then add water
Form a white emulsion - 5Difference between a triglyceride and Phospholipid.Fatty acid removed
Replaced with a phosphate group - 6Describe how glucose is absorbed from the ilium into the bloodActive transport of Na to the blood
Creates conc. gradient
Na & Glucose(against conc. gradient) enter by facilitated diffusion
Glucose moves into the cell by facilitated diffusion - 7Competitive InhibitorSimilar shape to the substrate
Binds to the active site
Fewer ES Complexes
Less product - 8Non-Competitive InhibitorNot a similar shape
Binds to allosteric site
Changes shape of active site
Less ES Complex
Less product formed - 9Induced fit model of enzyme actionActive site not complementary
Active site changes shape as the substrate binds as enzyme substrate complex forms
Stressing Bonds - 10Explain why anti-bodies are only effective against a specific pathogen?Antigens are specific shape
Antibody binds to tis complementary antigen so anti-body -antigen complex forms - 11Describe the structure of protiens?Polymer of amino acids
Joined by peptide bonds
Formed by condensation
Primary structure is order of amino acids
Secondary structure is folding of polypeptide chain due to hydrogen bonding
Tertiary structure is the 3D folding due to hydrogen, ionic and dissulphide bonding
Quaternary structure is two or more polypeptide chain - 12Explain how the structure of cellulose is related to its function of cell wall?Long, unbranched chains f glucose
joined by hydrogen bonds
Forms microfibrils
Needs to be strong to form cell walls
Microfibrils provide strength, rigidity and support - 13Describe how to show reducing sugar is present in a solution?Add equal volumes of benedict's solution
Heat to 95C
Red/Orange/Yellow/Green precipitate shows reducing sugar present - 14Explain why hydrogen bonds are important in cellulose?Holds cellulose molecules together and forms microfibrils
Providing strength and rigidity to cell wall
Hydrogen bonds are strong as they are large in numbers - 15Describe how the student would show that a non reducing sugar was present in the solution?Add dilute HCl to sugar solution
Boil the sugar solution
Add equal volumes of Benedict's solution to the sugar solution
Heat to 95C
Coloured Precipitate shows reducing sugar present - 16Adaption of starch molecules for their functions.Insoluble-Does not affect the water potential/Osmotically Inactive
Helical - Compact
Large Molecule - Cannot leave cell, does not diffuse out of cells - 17Sucrose does not hydrolyse lactose, Explain why?Active site of sucrase has a specific shape
Lactose has a different shape so not complementary - 18Why does an enzyme only catalyse one reactionSpecific active site with a specific shape
Only one substrate can bind to the active site. - 19Suggest why insulin cannot be taken orally?It will be broken down by stomach enzymes
No longer will befunctional - 20What is the effect of substrate conc. on the rate of an enzyme controlled reaction?Increases then plateaus
Plateaus when all active site occupied
Maximum number of ES Complexes formed.
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- A level biology yaer 1 summary
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- Irene Binil
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