A level biology Revision I

Pregunta	Respuesta
What is unsaturated fatty acid?	Double bond between carbon atoms
Describe 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
Biuret 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.
Emulsion Test	Crush With ethanol Then add water Form a white emulsion
Difference between a triglyceride and Phospholipid.	Fatty acid removed Replaced with a phosphate group
Describe how glucose is absorbed from the ilium into the blood	Active 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
Competitive Inhibitor	Similar shape to the substrate Binds to the active site Fewer ES Complexes Less product
Non-Competitive Inhibitor	Not a similar shape Binds to allosteric site Changes shape of active site Less ES Complex Less product formed
Induced fit model of enzyme action	Active site not complementary Active site changes shape as the substrate binds as enzyme substrate complex forms Stressing Bonds
Explain 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
Describe 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
Explain 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
Describe 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
Explain 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
Describe 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
Adaption 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
Sucrose does not hydrolyse lactose, Explain why?	Active site of sucrase has a specific shape Lactose has a different shape so not complementary
Why does an enzyme only catalyse one reaction	Specific active site with a specific shape Only one substrate can bind to the active site.
Suggest why insulin cannot be taken orally?	It will be broken down by stomach enzymes No longer will befunctional
What 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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	Creado por Irene Binil hace más de 6 años