Biology Paper 1 Questions and Answers - Pavement Mock Exams 2021/2022

INSTRUCTIONS TO CANDIDATES 

• This paper consists of TWO sections: A and B.
• Answer ALL the questions in section A.
• In Section B, answer question 6 (compulsory) and either question 7 or 8.
• Answers must be written in English only.

1. State the branch of Biology that would be used in solving the problem of disputed parentage.   (1mark)
2. A young scientist observed a bird laying her eggs in a nest and later the eggs hatched into chicks. Name two characteristics shown by the chicks that show a chick is a living thing but an egg is not. (2marks)
3. Study the diagram below and answer questions that follow
   
   1. What is the name given to the apparatus shown above (1 mark)
   2. What is its use in Biological studies? (2 marks)
4. A form two student observed the leaf shown below.
   
   
   1. Name the process shown by the leaf. (1mark)
   2. Differentiate between the process shown above and transpiration (2marks)
5. A certain species of flowering plant relies entirely on sexual reproduction for propagation. The Chromosome number of the cell in the ovarian wall is 16.
   1. The pollen tube nucleus. (1mark)
   2. A cell of the endosperm. (1mark)
6.  
   1. What are fossils? (1mark)
   2. State two limitations of the use of fossils as an evidence of evolution. (2marks)
7. Name the disease of the blood characterized by,
   1. Abnormally large number of white blood cells (1mark)
   2. Crescent –shaped hemoglobin (1mark)
8.  
   1. State two roles of hydrochloric acid secreted by the stomach wall. (2marks)
   2. Name the cells that secrete the above component. (1mark)
9. Name the organisms that cause each of the following diseases.
   1. Amoebic dysentery. (1mark)
   2. Bilharzia (1mark)
10. Explain how marine fish regulate their osmotic pressure. (3marks)
11. A rhinoceros in a national park was found to be infected with ticks. State the trophic level occupied by the :
    1. Rhinoceros. (1mark)
    2. Ticks (1mark)
12. Study the flow chart below of a process that takes place in both plants and animals.
    
    
    1. Name the above process. (1mark)
    2. In the above process name the chemical reaction represented by X. (1mark)
13. The diagram below shows a gaseous exchange structure in the stems of angiosperms.
    
    Name;
    1. Part labelled A. (1 mark)
    2. Apparatus X. (1 mark)
    3. Substances represented by arrows B and C. (2 marks)
14. When blood is flowing through a vena cava, which main blood vessel will it flow through next?   (1mark)
15. Below is an image of a biological vector. Use it to answer questions that follow.
    
    1. Identify the parasite transmitted into human blood by the organism. (1 mark)
    2. Name the blood cells that are destroyed by the parasite in (a) above. (1 mark)
    3. State one biological method used to eradicate the larvae of these organisms. (1 mark)
16. Give the structural adaptations of the following in an insect pollinated plant.
    1. Pollen grain. (1 mark)
    2. Stigma. (2 mark)
17. Use the illustration below to answer questions that follow.
    
    
    1. Identify the type of pollution that has such an effect. (1 mark)
    2. State two effects of the type of pollution identified in (a) above to the organism. (2 marks)
18. Identify the following types of responses:
    1. Pollen tube growing towards the ovary (1 mark)
    2. Maggots moving away from light. (1 mark)
19. State two activities of the cell that are controlled by the nucleus. (2 marks)
20. The field of view of a light microscope appeared as shown below in diagram A and the diameter in A was occupied by cells as shown in B.
    
    Calculate the length of one cell. (3 marks)
21. State two importance of water in germination of seeds. (2 marks)
22. Why is sexual reproduction advantageous in flowering in plants? (2 marks)
23. Below is an illustration of an organism captured by students during a practical lesson.
    
    1.  Identify three features that enable the organism to be placed in the phylum Arthropoda. (3marks)
    2. Explain why the organism will die when Vaseline is applied on its thorax. (1 mark)
24. State the significance of natural selection. (2 marks)
25. Explain why a plant shoot develops lateral branches when its tip is removed. (2 marks)
26. The diagram below shows the structure of a neurone.
    
    1.  Identify the neurone and state its function (2 marks)
    2. Name the part of the brain that is involved in learning and memory. (1 mark)
27. Explain what happens to the structures of the human eye when a student reading a white printed paper on a bright sunny day enters a dark room for examinations. (3 marks)
28. The experiment below was carried out by form four students. The result was recorded below:
    
    Explain why the shoot doesn’t bend towards the light. (3marks)
29. In an investigation, a group of students came across animals living in the following habitats. What was the likely main nitrogenous waste product of each in its habitat? (3marks)
    

    Habitat	Nitrogenous waste
    Terrestrial
    Fresh water
    Marine

30. State the functions of each of the following parts of male reproductive system. (3marks)
    1. Sertoli cells ……………………………………………………………………………...................
    2. Epidydimis……………………………………………………………………………………………
    3. Seminiferous tubules ………………………………………………………………………………..
31. The diagram below shows various types of gene mutations.
    
    1.  Identify the type of gene mutation shown above. (2marks)
       
       1. Mutation 1 ……………………………………………
       2. Mutation 2 ……………………………………………
    2. Distinguish between gene and chromosomal mutations (2mark)

MARKING SCHEME

1. Genetics;
2. Reproduction, Movement and locomotion, Growth and development, Irritability
3.  
   1. Pit fall trap;
   2. Trap into which small crawling animals fall and get trapped;
4.  
   1. Guttation
   2. Guttation is the process by which plants loose water in form of droplets through hydathodes while transpiration is the loss of water in form of water vapour through stomata
5.  
   1. 8 chromosomes 
   2. 24 chromosomes
6.  
   1. Fossils are past materials/ remains of ancestral forms of organisms that were accidentally preserved in naturally occurring materials; (OWTTE)\
   2.  
      • Only partial preservation was possible due to soft parts decayed;
      • Distortion during sedimentation;
      • A subsequent geological activities (erosion, earthquakes, faulting) destroyed some fossils;
7.  
   1. Leukemia
   2. Sickle Cell Anaemia
8.  
   1.  
      • Provides acidic medium for enzyme pepsin;
      • Activates pepsinogen (inactive) to pepsin active);
      • Kills pathogenic micro – organism swallowed in food/ antiseptic;
   2. Oxyntic/Parietal cells;
9.  
   1. Entamoeba histolytica;
   2. Schistosoma spp; acc. Specific species
10.  
    • Swallow plenty of sea water to increase amount of water in the body
    • Have chloride secretory cells in their gills to remove excess salts;
    • Eliminates nitrogenous waste in form of trimethylamine oxide which requires little water for elimination;
    • Few/small glomeruli thus slow filtration rate in the kidneys; (any 3)
11.  
    1. Primary consumers; √ 
    2. Secondary consumers; √
12.  
    1. Respiration
    2. Glycolysis
13.  
    1. Lenticel
    2. Hand lens/Magnifying lens
    3.  
       • B - Oxygen
       • C - Carbon (IV) Oxide and water
14. Pulmonary artery
15.  
    1. Plasmodium species//Plasmodium vivax//Plasmodium malariae//Plasmodium ovale//Plasmodium falciparum
    2. Red blood cells//Erythrocytes.
    3. Fish feeding on the larvae;
16.  
    1. Rough //sticky to stick onto the body of the insect;
    2. Occur inside the flower ensuring that the insects brush against them as they look for nectar;// Sticky so that pollen grains from the body of an insect stick onto it; any 1
17.  
    1. Water pollution;
    2.  
       • Oil soaks the feathers hindering locomotion;
       • Birds remove oil using their beaks swallowing some of the oil causing poisoning;
18.  
    1. Positive Chemotropism;
    2. Negative Phototaxis;
19.  
    • Cell division;
    • Growth;
    • respiration
20. Length of one cell   =   Diameter of field of view in um ; 6000 um = 1000um;
      Number of cells                                                                6
21.  
    • Dissolve food substances
    • soften testa
    • hydrolyze food substances
    • activate enzyme any 2
22.  
    • Hybrid vigour;
    • Causes variations;
23.  
    1.  
       • Segmented body;
       • Jointed appendages;
       • Presence of exoskeleton;
    2. Blocks the spiracles and thus no inhalation;
24.  
    • Formation of new species;
    • Elimination of undesirable characteristics;
25. Tip has a higher concentration of auxins; when the tip of shoot is removed auxin concentration is lowered; less auxin concentration stimulates sprouting of lateral btranches;
26.  
    1. Motor neurone; transmit nerve impulses from central nervous system to the effectors;
    2. Cerebrum;
27. Radial muscles of the iris contract, circular muscles relax; and pupil enlarges this allows more light for perception of objects;
28. The auxins migrate to the dark side; and cannot diffuse downwards due to the blade; hence no curvature
29.  
    • Terrestrial - Uric acid
    • Fresh water - Ammonia;
    • Marine - Trimethylamine oxide
30.  
    1. Sertoli cells – nourishment of spermatids/ immature sperms/ sperm cell / spermatozoa;
    2. Epidydimis – site for temporary storage of sperm cells / contracts to allow ejaculation of sperms;
    3. Seminiferous tubule – site for spermatogenesis/ sperm synthesis/ sperm formation;
31.  
    1.  
       1. Mutation I – Deletion;
       2. Mutation II – Inversion;
    2.  
       • Gene mutation – changes in the sequence of nucleotide in a DNA sequence;
       • Chromosomal mutation – changes in chromosome structure or number;