- You are provided with specimen labelled D which has been ground into flour. Make a solution of the flour provided by adding water and stirring properly. Sieve or decant to obtain a solution from the mixture.
-
- Using the reagents provided test for the presence of starch, proteins and lipids in the solution from specimen D. Record the procedures, observation, and conclusions in the table below. [9mks]
FOOD SUBSTANCE PROCEDURE OBSERVATION CONCLUSION Starch Proteins Lipids - From the conclusions made in (a) (i) above, suggest the regions of the alimentary canal where the digestion of specimen D would take place. (3mks)
- Using the reagents provided test for the presence of starch, proteins and lipids in the solution from specimen D. Record the procedures, observation, and conclusions in the table below. [9mks]
- State the one use of any two food types found in specimen D. (2 marks)
-
- You are provided with leaves of specimens A, B, C, D, and E.
- Use the following features in the order in which they are listed, to prepare a dichotomous key: (10 marks)
- Type of leaf
- Shape of the lamina
- Succulent or non-succulent
- Leaf margin
- Leaflet attachment.
-
- Name the likely habitat of specimen C. (1 mark)
- Give a reason for your answer in (b) (i) above. (1 mark)
- State the significance of the shiny upper surface of specimen A. (1 mark)
- Use the following features in the order in which they are listed, to prepare a dichotomous key: (10 marks)
- You are provided with small pieces of two tissues, labeled P and Q, obtained from an animal.
- Cut each specimen into two equal halves. From each specimen, crush one half and leave the other half as a solid piece. Place the solid half of specimen P into a test tube labeled K. Place the solid half of specimen Q into a test tube labeled L.
Put about 2cm3 hydrogen peroxide into each of the test tubes.- State the observations made in the two test tubes. (3mks)
- Place the crushed specimen P into test tube labeled M and also place the crushed specimen Q into test tube labeled N. Add 2cm3 hydrogen peroxide into test tube M and N. Record the observation for each test tubes M and N. (2mks)
- Write down an equation for the reaction that was responsible for your observations in the experiments above. (1mark)
- Name the process represented by the equation in (iii) above. (1 mark)
- Identify the substance that may be present in specimens P and Q that may have caused the observations made in the experiments. (1 marks)
- Explain how crushing affected the results of the experiments. (3 marks)
- What is the importance of the substance named in (b) above in a living organism? (3 marks)
- Cut each specimen into two equal halves. From each specimen, crush one half and leave the other half as a solid piece. Place the solid half of specimen P into a test tube labeled K. Place the solid half of specimen Q into a test tube labeled L.
MARKING SCHEME
-
-
-
FOOD SUBSTANCE PROCEDURE OBSERVATION CONCLUSION Starch To 1cm3 of solution D, add 3 drops of Iodine solution; Blue-black colour observed; Starch present; Proteins To 2cm3 of solution D, add equal amount of Sodium hydroxide then add copper sulphate dropwise; Purple colour observed; Proteins present; Lipids Rub a little solution D on a paper. Pass the paper over a flame. Hold the paper against light and observe; A translucent spot observed; Lipids present; -
- Starch – Mouth/Duodenum ;
- Proteins – Stomach;
- Lipids – Duodenum;
-
-
- Starch
- Produce energy;
- Protein
- Body building/Repair of worn out tissues/structural;
- Lipids
- Insulation against heat loss;
- Shock absorber/Cushions vital organs;
- Storage form;
- Release of energy;
- Release of metabolic water;
- Starch
-
-
-
-
- Simple leaf ------------------------------------------------------go to 2;
- Compound leaf -------------------------------------------------go to 5;
-
- Broad leaf lamina ----------------------------------------------go to 3;
- Leaf lamina long and slender --------------------------------B;
-
- Succulent leaf ------------------------------------------------- C;
- Non-succulent leaf ------------------------------------------- go to 4;
-
- Smooth leaf margin ------------------------------------------ A;
- Serrated leaf margin ----------------------------------------- D;
-
- Leaflets attached to main midrib --------------------------E;
- Leaflets attached to many smaller midribs ---------------;
-
-
- Dry/Semi-arid/Arid:
- Succulent to store water
-
- Has a cuticle to reflect away excess light;
- Prevent soaking water during rains;
-
-
-
-
- Test tube K - Bubbles/foam observed;
- Test tube L – More bubbles/foam than in test tube K;
-
- Test tube M – More bubbles/foam than in test tube K;
- Test tube N – Numerous bubbles/foam than in test tube L;
- 2H2O2 → 2H2O + O2;
Hydrogen peroxide → Water + Oxygen; - Detoxification
-
- Catalase enzyme
- Increases the surface area; that comes into contact with Hydrogen peroxide; exposing more catalase enzyme to react with hydrogen peroxide;
- Reacts with the toxic Hydrogen peroxide; produced in the body in metabolic processes; converting it into harmless substances, Water and Oxygen;
-
Join our whatsapp group for latest updates
Tap Here to Download for 50/-
Get on WhatsApp for 50/-
Download Biology Paper 3 Questions and Answers - Momaliche Pre Mock Exams 2023.
Tap Here to Download for 50/-
Get on WhatsApp for 50/-
Why download?
- ✔ To read offline at any time.
- ✔ To Print at your convenience
- ✔ Share Easily with Friends / Students