P2 and p3 qtions chap 4

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P2 and p3 qtions chap 4

  1. 1. 1B Biology Exam format• 30 Obj. q’tions (30m)• 5 P2 Structure (Section A) (50m)• 1 P2 Essay (Section B) (10m)• 1 P3 Question 2 (10m)
  2. 2. P2 Section B1 a) Extracellular enzymes are enzymes that are used outside the cell they were synthesised. With the help of a diagram, explain the synthesis of extracellular enzymes. (10m) b) You intend to set up a food processing factory with meat and fish as the main ingredients. Suggest an enzyme that can be used in this industry and state your reasons. (4m) c) Protein can be classified based on their structure. Describe the four structures of protein. (6m)
  3. 3. Enzyme expelled Rough endoplasmic reticulum (5m)Nucleus Secretory vesicle Ribosomes Transport Protein vesicle Golgi apparatus
  4. 4. a)Answers Marks Diagram + Label 5m Transcription of DNA into mRNA in nucleus 1m mRNA is then transported out from nucleus 1m into ribosome to form protein via translation process Protein is packed into transport vesicle and 1m carried to Golgi apparatus In Golgi apparatus, protein is modified into 1m enzymes Enzymes is packed into secretory vesicle which 1m fuse with plasma membrane and enzyme is released
  5. 5. P2 Section B1 a) Extracellular enzymes are enzymes that are used outside the cell they were synthesised. With the help of a diagram, explain the synthesis of extracellular enzymes. (10m) b) You intend to set up a food processing factory with meat and fish as the main ingredients. Suggest an enzyme that can be used in this industry and state your reasons. (4m) c) Protein can be classified based on their structure. Describe the four structures of protein. (6m)
  6. 6. b)Answers Marks Enzyme protease 1m Protease can tenderise meat to make the meat 1m taste better Protease can remove animal hair / fur before 1m the meat is being processed Remove scales of fish 1m
  7. 7. P2 Section B1 a) Extracellular enzymes are enzymes that are used outside the cell they were synthesised. With the help of a diagram, explain the synthesis of extracellular enzymes. (10m) b) You intend to set up a food processing factory with meat and fish as the main ingredients. Suggest an enzyme that can be used in this industry and state your reasons. (4m) c) Protein can be classified based on their structure. Describe the four structures of protein. (6m)
  8. 8. c)Answers Marks Can start by writing a short, precise 0m introduction (eg: Protein can be divided into primary, secondary, tertiary and quaternary structure.) Primary structure:  Straight chain of amino acid sequence / 1m Straight chain of polypeptide chain Secondary structure:  Polypeptide chain coiled and folded to form 1m alpha-helix and beta-pleated respectively  Formed by hydrogen bond 1m
  9. 9. Answers Marks Tertiary structure:  Folded in various way to form globular 1m protein  Example are enzymes and hormones 1m  Formed by hydrogen bond, ionic bond and 1m disulphide bridges Quaternary structure:  Formed by several polypeptide chains joined 1m together  Example is haemoglobin 1mAll the four structures must be mentionedand explained!
  10. 10. P3 Question 2a) The rate of enzyme reaction is influenced by the pH value of the medium of reaction. Some enzymes are most active in an acidic medium while some are more active in an alkaline or neutral medium. Based on this statement, design an experiment to show the effect of pH values on the rate of pepsin reaction. The planning of your experiment should include:  Problem statement (3m)  Hypothesis (3m)  Variables (3m)  Materials and apparatus (3m)  Procedure (3m)  Presentation of data (2m) (17m)
  11. 11. Answers:Aspect Criteria MProblem  Able to state problem statement correctly.statement  Manipulated variable  Responding variable  Question form & have relationship  Without question mark, - score 2m  Sample answer: What is the pH value where enzyme pepsin is 3m most active?Variables  Able to state all 3 variables correctly.  Sample answer:  Manipulated: pH value of medium 3m  Responding: Changes in albumen solution at the end of experiment  Constant: Temperature of medium, [E], [S]
  12. 12. Hypothesis  Able to relate manipulated & responding variable correctly.  State manipulated variable  State responding variable  Show specific relationship  Sample answer: Enzyme pepsin is most active in acidic 3m medium / Enzyme pepsin is most active at pH3Materials  Able to list all the materials & apparatus&apparatus  Sample answer:  Materials: 0.1M hydrochloric acid, 0.1M 3m sodium hydroxide, distilled water, pepsin, albumen  Apparatus: Beaker, test tubes, Bunsen burner, wire gauze, tripod stand, thermometer, syringe
  13. 13. Procedure  Able to write all the steps and include diagram  In passive form  Sample answer: (Diagram) 3m 1. 4ml of albumen is poured into each of the test tube, labeled A, B and C 2. Each test tube is added with the following mixtures according to the table below. (Table) 3. pH paper is used to determine the pH value of each solution. The pH is recorded. 4. All the test tubes are placed in water bath at 370C for 20 minutes. 5. Change in each test tubes is observed and recorded.
  14. 14. Presentation  Able to draw a complete table to recordof data relevant data based on:  Aspects with correct units  Correct samples  Sample answer: 2m Test pH Observations after 20 minutes tube A 3 B 9 C 7
  15. 15. Homework (P2 Section B):2. An experiment was conducted to study the effect of temperature on enzyme reaction. The results of the experiment are shown in table below. Test tube Temperature (0C) Time (min.) P 5 16 Q 28 4 R 37 2 S 45 6 T 60 20
  16. 16. a) Based on the table, draw a graph showing rate of enzyme activities (1/time) against temperature. (4m)b) Explain why high temperature can affect the function of proteins (6m)c) Describe how the characteristics of enzymes influence their activity (10m)
  17. 17. Homework (P3 Question 2):b) One of the factors affecting rate of enzyme reaction is enzyme concentration. Amylase catalyses the hydrolysis of starch in mouth. Plan a laboratory experiment to study the relationship between concentration of amylase on rate of reaction of amylase. The planning of your experiment should include:  Problem statement  Hypothesis  Variables  Materials and apparatus  Procedure  Presentation of data (17m)

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