Biology Paper 1 Kenya High Post Mock Exams 2020 - Questions and Answers

INSTRUCTIONS TO CANDIDATES

• Write your name and Index Number in the spaces provided above.
• Sign and write date of examination in the spaces provided above.
• Answer ALL questions in the spaces provided.
• All workings MUST be clearly shown where necessary.

FOR EXAMINERS USE ONLY.

1. Name the reagent used for testing presence of (3 marks)
   1. Starch
      …………………………………………………………………………………………………………
   2. Reducing sugars
      …………………………………………………………………………………………………………
   3. Vitamin c
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2. State the processes which occur in each of the following organelles. (2 marks)
   
   1. Chloroplast
      ……………………………………………………………………………………….…………………
   2. Mitochondrion
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   3. Ribosomes
      ……………………………………………………………………………………………………….…
3. A student observed a specimen through a light microscope. He used the objective lens marked X40.If he indicated the magnification of the image as x 400, what was the eye - piece magnification?
   (Show your working). (3 marks) ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..
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4. State the function of the following in mammalian trachea. (3 marks)
   
   1. Rings of cartilage
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   2. Mucus
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   3. Cilia
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5.   
   1. What do you understand by the term biological control? (1 mark)
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   2. Explain why all the energy produced by producers does not flow to the tertiary consumers. (2marks)
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6. Name any three forces that maintain the transpiration stream (3 marks)
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7. Give the form in which the following gases are transported in blood. (3 marks)
   
   1. Oxygen
      ………………………………………………………………………………………….….……………
   2. Carbon (IV) oxide
      ……………………………………………………………………………………….…...……………..
   3. Carbon (II) oxide
      …………………………………………………………………………………………………..………
8.   
   1. Name the main group of organisms which comprise the Kingdom Monera. ( 1mark)
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   2. State any three ways in which the organisms named in 8 (a) above affect human lives. (3marks)
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   3. State the main characteristics of Monera which distinguish it from all other kingdoms. (1 mark)
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9. State ways in which the xylem tissue is adapted to carry out its function. ( 3marks)
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10. Why is it necessary for an athlete to breathe heavily after running? ( 2 marks)
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11. State ways in which the following diseases can be prevented
    1. Typhoid and amoebic dysentery (2 marks)
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    2. Malaria (2 marks)
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12. What are the three distinguishing features of phylum Arthropoda? (3marks)
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13.   
    1. Name the main product of the dark stage of photosynthesis. ( 1mark)
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    2. What is the role of chlorophyll during photosynthesis (2mark)
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14. Name three mechanisms that prevent self-pollination in flowers that have both male and female parts.
    (3 marks)
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15. State three applications of anaerobic respiration. (3 marks)
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16. What is the significance of highly folded inner membrane of a mitochondrion? (2 marks)
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17. Why is it necessary for blood from the gut to pass through the liver before joining general circulation?
    (2 marks)
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18. A person’s urine tested positive for reducing sugars.
    
    1. Name the type of sugar present in the urine. ( 1mark)
       …………………………………………………………………………………………………….
    2. Name the gland and the hormone which failed to control the above condition. ( 2marks)
       Gland
       ………………………………………………………………………………………………….
       Hormone
       ………………………………………………………………………………………………
    3. Which disease was the person suffering from? ( 1mark)
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19. State two roles played by the process of reproduction. ( 2marks)
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20. What is the habitat of the following plants? ( 3marks)
    
    1. Xerophytes
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    2. Hydrophytes
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    3. Halophytes
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21.   
    1. State ways in which molars are adapted to their functions. ( 2marks)
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    2. Name any two dental diseases. (2 marks)
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22. How is the sperm cell adapted to carry out its function? (3 marks)
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23. The following are diagrams of two pollen grains
    
    
    1. State one observable difference between K and L. (1 mark)
       …………………………………………………………………………………………………………………………………………………………………………………………………………………
    2. State the agent of pollination for each of them. (2 marks)
       K
       ………………………………………………………………………………………………………
       L
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24. How do sunken stomata reduce transpiration? ( 2marks)
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25. Give the classes to which the following animals belong. ( 3marks)
    
    1. Human being
       ………………………………………………………………………………………………………….
    2. House fly
       …………………………………………………………………………………………………………
    3. Spider
       …………………………………………………………………………………………………………
26.  
    1. State one event that occurs in prophase of meiosis I which does not occur in prophase of mitosis.(1 mark)
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    2. What are the results of the above phenomena? (2 marks)
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27. Explain why growing grass die a few days when salt is sprinkled on it. (3marks)
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MARKING SCHEME

1.  
   1. iodine solution;
   2. Benedicts solution;
   3. DCPIP;
2. 1. photosynthesis;
   2. Respiration;
   3. Protein synthesis;
3. Total mg = eye piece magnification X objective lens magnification;
   400 = 40 X x;
   400/40 = x;
   10 = x
   Eye magnification is X10;
4.  
   1. Prevents collapsing of trachea;
   2. Traps dust / bacteria;
   3. Propels solid particles/dust towards pharynx;
5.  
   1. Using an organism to control other organisms;
   2. Because energy is lost between trophic levels; due to respiration; /excretion/urination; and defaecation;
      Some remains locked up indead bodies;
6.  
   • Cohesion and adhesion;
   • Transpiration pull;
   • Capillarity;
   • Root pressure;
     Rej cohesion, adhesion alone any 3x1 = 3 marks
7.  
   1. Oxyhaemoglobin;
   2. (Weak) carbonic acid/carbaminohaemoglobin/hydrosa carbonate; acc bicarbonate ions HCO _-3
   3. Carboxyhaemoglobin.
8.  
   1. bacteria;
   2.  
      • transmits diseases;
      • used in fermentation of milk;
      • add nitrogen to the soil through nitrogen fixation; e.g. Rhizobium
      • Help in decay hence circulate nutrients;
        Mark first three 3 x1 = 3 marks
   3. Nucleus /organelles are not membrane bound;
9.  
   • Lignified walls to prevent it from collapsing;
   • Narrow to facilitate upward movement of water by capillary action;
   • No cross walls to facilitate formation of continuous water column;
   • Have bordered pits for lateral movements of water;
     Mark first three 3x1= 3 marks
10. To increase oxygen supply; to tissues which oxidizes lactic acid;
    (Lactic acid is poisonous and must be removed)
11.  
    1.  
       • Maintaining proper personal hygiene
       • Boiling /treating water;
       • Depositing stools in deep latrine;
       • Treating sewage; mark any 2
    2. Clearing bushes; sleeping under mosquito nets; draining stagnant water; rearing fish in fish ponds; use of mosquito repellant jells/mosquito coil/insecticides; mark any 2
12. (Chitinous) exoskeleton; segmented bodies; jointed appendages mark first three
13.  
    1. Glucose; Rej. Starch1 mark
    2. Traps light; used in photolysis/to break water into oxygen gas and hydrogen ions; (2 marks)
14.   
    1. Protandry; OWTTE
    2.  
       1. Protogyny;
       2. Heterostyly mark first 3
15.  
    • manufacture of alcohol/wines/beer;
    • baking;
    • Fermentation of milk;
    • Manufacture of Ethanoic acid/vinegar;
    • Treatment of sewage; mark fist three
16. To increase surface area; for attachment of respiratory enzymes;
17. For storage of carbohydrates/glycogen;Rej glucose, detoxification; Deamination of excess amino acids;
18.  
    1. Glucose
    2. Gland - Pancrease;
       Hormone – Insulin;
    3. Diabetes mellitus; Rej diabetes inspidus and diabetes alone
19. Procreation;
    Improves the quality of a species;
20.  
    1. Desert /semi - desert/arid areas /semi arid areas;
    2. Fresh water;
    3. Marine /salty water;
21.  
    1. Have cusps; are ridged with flat surface; increased surface area; for chewing food; mark any two
    2. Dental carries; gingivitis; pyorrhea; mark first two
22.  
    • has a long tail that aids in locomotion;
    • Middle piece has many mitochondria to generate energy (for locomotion)
    • Acrosome has lytic enzymes to dissolve ovum wall for penetration of sperm;
    • Large nucleus preserves genetic material; mark any three
23.  
    1. K is smooth while L is rough;
    2. K – wind; L – Insect;
24. Water vapour accumulates in the depression of stomata; lowering water vapour concentration gradient ;( leading to reduced rate of transpiration)
25.  
    1. Mammalia; Rej mammal
    2. Insecta; Reg insect/ insector
    3. Arachnida; Reg arachnid Reg wrong spelling for all
26.  
    1. synapsis /pairing of homologous chromosomes;
    2. crossing over ;hence variation in offspring;
27. Salt exerts osmotic pressure on the cells of grass; Water is drawn from the cells by osmosis; the cells loose turgidity/become flaccid; further water loss dehydrates cells ;( hence kills the plant) (4 marks max 3 marks.)