Biology Paper 1 Questions and Answers - Form 3 End Term 3 Exams

INSTRUCTIONS

• Be keen on Spelling of Technical Terms

1.  
   1. Define the term Wilting (1mk)
   2. How is wilting important to a seedling (1mk)
2. Give the name of the enzymes that undertake the following (2mks)
   1. Digestion of sucrose
   2. Conversion of prothrombin to thrombin
3.  
   1. Explain why a person of blood group O can not receive blood from a donor of blood group B (2mks
   2. Give ONE precaution observed before blood transfusion (1mk)
4. Name the instruments used during the following activities in an ecological study
   1. Suction of small insects from the bark of trees (1mk)
   2. Determine the depth of penetration of light in a fish pond (1mk)
5. While studying onion cells under a light microscope, Susan observed 10 cells along the diameter of field of view with a radius of 3mm
   1. What is field of view? (1mk)
   2. Determine the diameter of one cell observed (2mks)
   3. If the actual diameter of one cell is 0.0003mm, determine the total magnification Susan used (2mks)
6. Explain how the following help in the process of photosynthesis
   1. Guard Cells         (1mk)
   2. Stomata     (1mk)
7. Differentiate between the following terms:
   1. Synecology and autecology (2mks)
   2. Innate immunity and acquired immunity (2mks)
8. The diagram shown below represents the human respiratory system
                                                   
   1. Name the structure found in region P that prevent entry of food bolus into region Q during swallowing?   (1mk)
   2. Give TWO adaptations of part Q to its function (2mks)
   3. Name the actual site of gaseous exchange found in the organ labelled R   (1mk)
9. The diagram shown below is a common organelle in cells
                                                          
   1. Name the organelle shown above  (1mk)
   2. Give TWO functions of the organelle  (2mks)
10. Consider the specimen provided below together with their family names
                                          
    1. Give a reason why the organisms shown above belong to Phylum Arthropoda        (1mk)
    2. Use the features shown above and in the same order to construct a dichotomus key to identify the families of the organisms shown above (2mks
       1. Antennae
       2. Wings
11.  
    1. Name the organisms that act as the following for Malaria disease (2mks)
       1. Cause: 
       2. Vector:
    2. Give TWO measures used to control Malaria by targeting the vector (2mks)
12. The photograph shown below represents one way of environmental pollution
                                                                  
    1. Give TWO ways by which the above affects life of fish in Lake Victoria (2mk
    2. Name TWO pollutants that cause acid rain (2mk
13. The sketch shown below represents a process in the mammalian body
                                                   
    1. Where does process X occur?   (1mk)
    2. State the significance of this process in digestion (1mk)
14. Explain the significance of the following:
    1. The testes are found hanging outside the body of males (1mk)
    2. It is advisable to use the fine adjustment knob to focus image when the high power objective lens is in position (1mk
15. How are the following prevented naturally in the human body
    1. Blood clotting in uninjured blood vessels (1mk)
    2. Corrosion of stomach lining by hydrochloric acid secreted by glands in the stomach (1mk)
    3. Ovulation during pregnancy (1mk)
16. James wrote the scientific name of human being as HOMO SAPIENS
    1. Name this system of naming organisms (1mk)
    2. Write the scientific name in the correct manner (1mk)
17. The following diagram represents the embryo sac of a flower
                                                                                
    1. Which letter represents parts that form the following after fertilization
       1. Zygote ……………………………(1mk)
       2. Endosperm………………………(1mk)
    2. Plants like banana and pineapples form fruits without fertilization. Which term describes this phenomenon?  (1mk)
18. Three potato strips each measuring 2.0mm were placed in three separate solutions and after 20minutes their lengths were as follows
    

    SOLUTION	LENGTH OF STRIP
    A	3.2mm
    B	1.8mm
    C	2.0mm

    
    
    1. Which of the solutions is:
       1. Isotonic…………………………………(1mk)
       2. Hypertonic……………………………(1mk)
    2. Account for the change in potato strip placed in solution B (2mk
19. An illustration of the mammalian heart is shown below
                                                    
    1.  
       1. Identify the heart chamber labelled Z (1mk)
       2. Give a reason for your answer in ai) above (1mk)
    2. State the importance of part W (1mk)
    3. Name a class in Phylum Chordata where all members have the type of heart shown above (1mk)
20.  
    1. Describe the role of prothoracic gland in growth and development of insects  (2mks)
    2. Why is internal fertilization advantageous? (1mk)
21. During a field study, a group of students captured 500 cockroaches, labelled them with a dye and released them back to the building. 24 hours later, the students captured 600 cockroaches and realized 350 lacked the dye.
    1. Determine the population of cockroaches in the building (2mks
    2. Give TWO assumptions of this method of population estimation (2mk
22. The set up shown below was used to investigate a physiological process
                                                        
    1. State the aim of the experiment (1mk)
    2. Why is it advisable to boil the sugar solution before the experiment? (1mk)
    3. State the importance of the physiological process being investigated in agriculture (1mk
23.  
    1. What is Seed dormancy? (1mk)
    2. Explain the importance of Oxygen during seed germination (1mk)
24. The diagram below represents a cross-section of a leaf
                                                         
    1. Identify the habitat of the plant from which the leaf was obtained (1mk
    2. Identify a reason for your answer in a) above (1mk
    3. How does part F adapt the plant to its habitat? (1mk
25. The table below shows the composition of blood, glomerular filtrate and urine of a patient
    

    Component	Blood	Glomerular Filtrate	Urine
    Salts	1.60%	1.45%	1.40%
    Glucose	2.00%	0.70%	0.60%
    Urea	0.03%	0.04%	2.00%
    Ammonia	0.06%	0.04%	0.04%
    Proteins	1.80%	0.00%	0.00%
    Water	90.0%	88.0%	85.0%

    
    
    1. Account for the following
       1. Absence of proteins in the glomerular filtrate (1mk
       2. Increased concentration of Urea in the Urine (1mk
    2. Which disease is the patient likely to be suffering from? (1mk
    3. Give a reason for your answer in b) above (1mk
26. The equation for respiration of a certain substrate is shown below
      2C₅₁H₉₈0₆ + 145O₂ → 102CO₂ + 98H₂0
    1. Calculate the Respiratory Quotient (2mks
    2. Identify the type of respiration that took place (1mk

                                                                                        MARKING SCHEME 

1.  
   1. Drooping of a plant when water loss exceeds water intake;
   2. Prevents excess water loss/Drying up of plant
2.  
   1. Enzyme Sucrase; 
   2. Thrombokinase/Thromboplastin;
3.  
   1. Produce antibodies (against antigen B); leading to agglutination/Clumping of Erythrocytes/Red blood cells;
   2. Screening for pathogens; Check for Blood group compatibility; Check for compatibility of Rhesus antigen/factor/D;
4.  
   1. Pooter;
   2. Seechi disk;
5. 1. Cicular brightly illuminated area under a light microscope where images of specimen form;
   2. Diameter of 1 cell = (6mm/10cells);
                                   = 0.6mm;
   3. Magnification        = Image length/Actual length
                                   = (0.6mm/0.0003mm);
                                   = X 2000;
6.  
   1. Xylem-Supply photosynthetic cells with Water (that is a raw material for photosynthesis); Supply mineral ions (that are co-factors to activate enzymes used in photosynthesis);
   2. Stomata-Allow entry of Carbon (IV) Oxide (that is a raw material for photosynthesis);
7.  
   1. Synecology-Is the study of many species in an ecosystem; Autecology-Is the study of a single species in an ecosystem; Award 2 or 0
   2. Innate Immunity-Is Immunity which is Inherited or In-born; Acquired Immunity-Is Immunity that arise from interacting with pathogens in the environment; Award 2 or 0
8.  
   1. Epigllottis;
   2. Haas C-shaped rings of cartilage that prevent its collapse; Has Cells that secrete mucus which trap dust in inhaled air; Has ciliated epithelium with the cilia used to waft/move the mucus with trapped dust particles to the pharynx to be coughed out;
   3. Alveolus; reject plural
9.  
   1. Golgi apparatus/bodies;
   2. Formation of Lysosomes; Package Glycoproteins; Transport Glycoproteins; Secretion of Glycoproteins; Secretion of Synthesized materials/Enzymes; Formation of Enzymes; Secretion of synthesized proteins and carbohydrates; Mark 1^st 2
10.  
    1. Jointed appendages; Have Exoskeleton; Segmented Bodies;
    2. 1a) Have antennae…………………… Go to 2;
       1b) Lack antennae …………………… Ixodidae;
       2a) Has Wings ……………………….. Carbidae;
       2b) Lack Wings ……………………… Formicidae; Each Step earns a mark
11.  
    1.  
       1. Cause: Plasmodium falciparum; Plasmodium ovale; Plasmodium malariae; Plasmodium vivax; Plasmodium knowlesi;
          Follow the Rules of Binomial Nomenclature
       2. Infected Female Anopheles Mosquito; REJ Mosquito alone
    2. Spraying houses with insecticides; Sleeping inside (treated) net; Sterile male technique; Use of Repellants; Draining Swampy Places/Stagnant water; Clearing Bushes around the houses;
       REj Using Nets/Sleeping Under; Mark 1st 2
12.  
    1. Emit Hot Water that Kill fish directly; Emit Heavy metals that are metabolic poisons; Reduce concentration of Respiratory gases leading to suffocation of fish; Algal bloom that deprive fish of enough Oxygen;
    2. Nitrogen (IV) Oxide; Sulphur (IV) Oxide;
13.  
    1. Duodenum; b) Increase surface for efficient enzymatic/lipase action/digestion;
14.  
    1. Create a slightly lower temperature conducive/optimum for spermatogenesis/Sperm-formation;
    2. Prevent Breakage of Glass Slide; Avoid Contamination of Lenses/Specimen;
15.  
    1. Presence of Heparin/Anti-Clotting Factor; Release of Thrombin in its Inactive form/as Prothrombin;
    2. Secretion of Mucus that coats the inner stomach lining; Release of Pepsin in its inactive form/as Pepsinogen;
    3. High Concentration of Progesterone hormone that inhibit Secretion of Follicle Stimulating hormone (FSH) by Pituitary glands thus a new cycle can not commence;
16.  
    1. Binomial nomenclature; REJ Bionomial or Binomial system
    2. Homo sapiens; NB: Follow Rules of Binomial Nomenclature
17.  
    1. i. C; ii) B; REJ actual Names
    2. Parthenocarpy;
18.  
    1. i) C; ii) B;
    2. Solution B is hypertonic; thus gain water by osmosis from the potato cells; (This leads to reduction in length)
19.  
    1. i) Left ventricle; ii) Has thicker (muscular) wall;
    2. Prevent mixing of blood rich in Oxygen and the one that is of Low Oxygen Concentration;
       ACCEPT: Prevent mixing of blood rich in Carbon (IV) Oxide and that of Low Carbon (IV) Oxide concentration;
    3. Aves; Mammalia;
20.  
    1. Secrete Ecdysone/Moulting Hormone; that initiate moulting/shedding of larval cuticle;
    2. Higher chances of Fertilization; Higher chances of survival of the Embryo;
21.  
    1. First Marked X Second Capture = (500 X 600) ; = 1200 Cockroaches;
       Marked Recaptured                          (600−350)
    2. Have enough time to mix;  Dye does not alter the behavoiur of the cockroaches; They don't move in or out of the building; Those with dye mix freely with the rest; Population doesn't vary during study duration; Mark 1^st 2
22.  
    1. Find out the gas produced during anaerobic respiration;
    2. Drive away Oxygen;
    3. Improve soil fertility; Silage-making; Biogas; Food processing; Making Biofertilizers;
23.  
    1. Inability of seed to germinate even when all environmental conditions are favourable.
    2. Enable respiration/oxidation of food to supply energy (for cell division and growth);
24.  
    1. Desert/Arid/Semi-arid; REJ: Dry
    2. Sunken stomata; Stomata on the lower leaf surface only; Lack stomata on upper leaf surface;
    3. Accumulate water vapour thus reduce saturation deficit; Prevent direct exposure of sub-stomatal air space to wind/light/heat-factors that enhance vapourization;
25.  
    1.  
       1. Larger size thus failed to undergo ultrafiltration;
       2. Excreted by cells along the renal tubules;
    2. Diabetes mellitus;
    3. Presence of glucose in the urine;
26.  
    1. R.Q = Molecules of CO₂ produced = (102/145); = 0.704;
                    Molecules of O₂ Used
    2. Aerobic (respiration);