Homeworks

HOLIDAYS ASSIGNMENTS

Subject: BIOLOGY

CLASS: S2

1. Name two largest groups into which all animals are classified? What is the difference between these two groups?
2. Plants and animals are both living things. show how they differ in terms of: Growth; Movement and Nutrition
3. Name the carbohydrates that is:
     a) Found in abundance in mammalian blood?
     b) Stored in mammalian liver?
     c) Transported in plants?
     d) Stored in plant seeds?
     e) Found in plant cell wall?
4. Explain why:
   a) Red blood cells burst when placed in distilled water while plant cells remain intact?
   b) Fresh water protozoa like amoeba do not burst when placed in distilled water?
   c) Addition of large amounts of salt to soil in which plants are growing kill the plants?
5. Explain why plants respond to light?
6. Complete the table below to summarizes the characteristics of each class of arthropods
characteristics Insecta Arachnida crustacea diplopoda chilopoda
Number of body parts          
Number of limbs          
Gaseous exchange structure          
Number of antennae          
7. Which of the following has an active site:
  i) Product; substrate     iii)enzyme     iv)enzyme substrate complex

8. Select the correct statement from the following: i) The release of an ovum from ovary and the preparation of uterus to receive a fertilized egg to develop into a zygote is called fertilization ii) The process of passing out dead unfertilized ovum and uterine lining in women is called menstruation iii) The embryo receives blood from placenta. iv) After fertilization, the ovum dies and is released during fertilization

9. Give the products of digestion after the following food substance are broken down letely: i) carbohydrates  ii) proteins  iii) lipids

10. A substance X was heated with dilute hydrochloric acid (HCl) and cooled. The same amount of sodium hydroxide (NaOH) was added to neutralize the acid .the mixture was heated with benedict’s solution. An orange red brown color was formed.

  1. What is substance X? 
  2. Outline how colors changed from the original color to orange or red?
  3. Why was temperature kept at 370c?
  4. What is the role of HCl in this experiment?
  5. Why was neutralization necessary before the addition of benedict’s solution
  1. Name the physiological process by which each of the following occurs: /3marks
  2. Carbon oxide moves from the body cell to the blood capillaries
  3. Water is absorbed from the soil by root hairs
  4. Root hair cells in plant absorb mineral salts and ions from the soil
  5. An investigation was carried out into the effect of PH on the action of the enzyme amylase on starch. Eight test tubes were set up at different PHs and incubated in a water bath at 300C for one hour. The amount of reducing sugar (product) was then estimated. The result are shown in the table below:
PH

4.0

 5.0  6.0  6.5 7.0   8.0 9.0  10
Amount of reducing sugar product 1 12 26 32 33 27 13 5
  1. Plot the graph to show these results
  2. Explain the effect of PHfor enzyme amylase in this investigation
  3. What is the most suitable PHfor enzyme amylase in this investigation
  4. Suggest other factors( not in this investigation ) that affect the action of an enzyme such as amylase                                                   15.  Slices of  onion epidermis were placed in different concentration of sucrose solution. The percentage of plasmolysed cells was determined after thirty minutes and the result were as follows:
Concentration of sucrose solution 0.55 0.6 0.65 0.7 0.75
% of plasmolysed cell 0 5 20 80 100
  1. What does the word plasmolysis mean? 
  2. What causes plasmolysis of cells? 
  3. Does plasmolysis occur to animal cell? Explain
  4. Explain the result of 0.55 molar sucrose solution
  5. What description or term would be used on a plant where 100% of its cell were plasmolysed?                                                                 16. which vitamin is deficient when a person has: i) Scurvy? ii) Rickets? 

b) Classify the following disease by placing them in the table below:

Cancer, Malaria, Diabetes, Typhoid, Ebola, Albinism, Tuberculosis and Marasmus

Communicable disease Non – communicable disease
   
   
   
   
   
  1. Study the equation given below

6CO2 +...……     C6H12O6 + …………..

  1. Complete the equation /2 marks
  2. What is the source of energy for this reaction? 1 Mark
  3. Name the pigment needed for this reaction to occur / 1 Mark
  4. What is the role of this pigment in photosynthesis?/ 1 Mark
  5. State the mineral ion required for the synthesis of this pigment 1Mark

18. Construct a dichotomous key that you can use to identify the following animals and place them into their taxonomic classes: Rabbit, Millipede, and Honey bee, Centipede, Tilapia Fish and Crocodile /10 Marks

Key:

       2) a) Animals body is covered with fur………………. Mammalia

             b) Animals body is covered with scales …………… go to 4

     3)   a) Animals body is divided into two parts ………….. go to 5

             b) Animals body is divided into three parts ……………insect

     4) a) Animals has fins ………………………….. ……….. pisces

           b) Animals has no fins …………………………………. reptilian

5) a) Animals body is elongated and cylindrical …………………. diplopoda

         b) Animal body is elongated and not cylindrical ………………….. Chilopoda

19) During an ecological tours ofLake MUHAZI a group of students from KIMANA Secondary school recorded the following observations.

              i)       Tilapia feed on mosquitoes larvae                                                                          

               ii)       Mosquito larval feed on planktonic algae

  1. Planktonic crustaceans feed on planktonic algae
  2. Hawks feed on tilapia, worms and planktonic crustaceans
  3. From this record of observations, construct a food web /3marks
  4. From the food web you have constructed in (a) above, isolate & write down a food chain that end with:
  5. Hawk as secondary consumer /2 Marks
  6. Hawk as a tertiary consumer /2marks
  7. Using the food web you constructed in (a),name:
  8. Two organisms that compete for food in the lake?/2marks
  9. The source of food the organisms in (d)(i) above compete for./1mark
  10. State way by which human beings may interfere with this lake in ecosystem./1mark

All the best!!!!!!!!!!!!!!!!!!!!!!!

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