Biology Paper 1 Questions and Answers - Lanjet Joint Mock Exams 2023

Instruction To Candidates

• Answer all the questions in this question paper.
• Candidates should answer all the questions in english.

1. 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. (2mks)
2. In which two ways are the organelles chloroplast and mitochondria similar. (2mrks)
3. The illustration below shows a human eye that is defective.
                                                                
   1. Identify the eye defect. (1mrk)
   2. How would this defect be corrected? (1mrk)
4.  
   1. What is homeostasis? (1mrk)
   2. State three processes in humans in which homeostasis is involved. (3mrks)
5.  
   1. In which phase of photosynthesis are carbohydrates formed?  (1mrk)
   2. How is the dark stage of photosynthesis dependent to light stage? (2mrks).
6. Why are the cooling fans of value even in a closed room? (2mrks)
7. How can the colour of the skin affect the rate of heat loss or heat gain?  (3mrks)
8. List down three abiotic factors that would influence life in a lake. (3mrks)
9. Distinguish between the terms asexual and sexual reproduction    (2mrks)
10.  
    1. Define the term germination. (1mrk)
    2. State the two types of germination in plants. (2mrks)
    3. When does growth start in plants. (1mrk)
11.  
    1. What is polyploidy.  (1mrk)
    2. Mating a horse with a donkey produces an infertile animal, a mule. Explain.  (2mrks)
12. A part of DNA strand has the following base sequence: G-G-C-C-T-A-T-C.
    1. What is the sequence of the complimentary strand? (1mrk)
    2. What will be the sequence of m-RNA transcribed from this part of DNA? (1mtk)
    3. How does DNA differ from RNA? (3mrks)
       

       DNA	RNA

13. A student made a set up shown below to study a physiological process
                                                      
    1. In which beaker did the dialysis tubing reduce in size? (1mrk)
    2. Account for your answer in a) above. (2mrks)
14. Give two reasons why lumbar vertebrae have long and broad transverse processes.  (2mrks)
15. Give two ways in which seed dormancy benefit a plant. (2mrks)
16. State three precautions one should observe while conducting experiments in food test. (3mrks)
17. Use the diagram of the heart shown below to answer the questions that follow
                                                                 
    1. From the diagram, give a reason to show that X is the left ventricle. (1mrk)
    2. Name a class of organisms where all members have the heart structure above  (1mrk)
    3. Why are the muscles found in the heart above said to be myogenic? (1mrk)
18. State the role of the following in the nitrogen cycle. (2mrks)
    1. Thiobacillus denitrificans.
    2. Nitrococcus bacteria.
19. The diagram below shows the structure of germinating pollen grain
                                                                                
    1. Name the type of cell division that formed the parts labelled A. (1mrk)
    2. State the role of part labelled B? (1mrk)
20. The chart below is a summary of blood clotting mechanism in a man.
                                                      
    Name;
    1. The metal ion represented by Y. (1mk)
    2. The end product of the mechanism represented by Z. (1mk)
21. The following is part of a kidney nephron
                                                                      
    1.  
       1. Name the process represented by the arrows. (1mrk)
       2. Name the conditions necessary for the process named in (a) (i) above to take place.  (1mrk)
    2. Identify with a reason vessel A. (1mrk)
22. Name any two blood components that are present in vessel (A) but are absent in vessel B.  (2mrks)
23. State the function of the following during pregnancy. (3mrks)
    1. Amnion
    2. Amniotic fluid
    3. Umbilical cord
24. Below is a diagram of an organism.
                                                          
    1. Name the kingdom to which the organism belongs. (1mrk)
    2. Give a reason for your answer in (a) (i) above. (1mrk)
    3. Explain the process by which the food gets into the organism. (2mrks)
25. State two characteristics features of members of division bryophyte. (2mrks)
26.  
    1.  
       1. Name the cartilage between the bones of the vertebral column  (1mrk)
       2. State the function of the cartilage named in (a)(i) above. (1 mark)
27. Why do herbivores have large eyes on the side of their heads? (1mrk)
28. Suggest three measures that can be taken to control infection of man by protozoan parasites. (3mks)
29. In a family, all off springs have blood group AB. What are the possible blood groups of? the parents? (1mrk)
30. List the changes that take place during inhalation in the breathing cycle of a mammal in the following: (3mrks)
    1. Rib cage thoracic cavity
    2. Diaphragm
    3. External intercostal muscles
31. Evolution is an ongoing process, state two pieces of evidence which suggest that evolution is still taking place. (2mrks)

                                                                                MARKING SCHEME

1. (3mks)
   • Growth and development
   • Nutrition
   • Movement and locomotion
   • Excretion   
2. (2mrks)
   • Both contain enzymes
   • Both are oval in shape
   • Both have double membrane
3. 1.  (1mrk)
      • Short sightedness (myopia)
   2. (1mrk)
      • Concave (diverging) lens
4.  
   1. (1mrk)
      • Maintenance of a constant internal environment in living organisms.
   2. (3mrks)
      • Thermoregulation
      • Osmoregulation
      • Regulation of blood sugar level
5.  
   1. (1mrk)
      • Dark stage
   2. (2mrks).
      • Light stage generates hydrogen ions; and adenosine triphosphate used during carbon (IV) oxide fixation.
6. (2mrks)
   • Fans create air currents ; speeding up the loss of heat by radiation and evaporation.
7. (3mrks)
   • Dark surfaced bodies are the best heat absorbers;bright surfaces absorbs heat the least; good absorbers are also good emitters . In a hot surrounding dark skinned persons will gain heat faster than light skinned person;in cold environment,dark skinned persons lose heat faster.
8. (3mrks). (any three answers)
   • PH
   • Light intensity
   • Availability of mineral salts and trace elements
   • Temperature.
9. (2mrks)
   • Sexual;is a type of reproduction that involves fusion of male and female gametes;
   • Asexual reproduction is a type of reproduction in which offsprings are produced from mature organisms without fertilization.
10.  
    1. (1mrk)
       • The process bywhich a plant developes into a seedling.
    2. (2mrks)
       • Epigeal;Hypogeal
    3. (1mrk)
       • When a mature seed germinates.
11.  
    1. (1mrk)
       • Condition of the nucleus of a cell having more thanone set of chromosomes as per organisms belonging to that species
    2. (2mrks)
       • The chromosomes are from different species; thus are not homologous to pair up during meiosis
12.  
    1.  (1mrk)
       • C-C-G-G-A-T-A-G
    2. (1mtk)
       • C-C-G-G-A-U-A-G
    3. (3mrks)
       

       DNA	RNA
       Double stranded	Single stranded
       Has deoxyribose sugar	Has ribose sugar
       Confined in the nucleus	Found in nuclease and cytoplasm
       Has nitrogenous base;adenine guanine   cytosine and thymine	Has nitrogenous base adenine  ;guanine;cytosine and uracil

13.  
    1. (1mrk)
       • B
    2. (2mrks)
       • Sucrose solution is hypertonic; thus it gains water molecules by osmosis;
         Accept: Water is hypotonic; thus water molecules move out of the dialysis tubing by osmosis; hence dialysis tube decrease in size
14. (2mrks)
    • Increase surface area for attachment of abdominal muscles;
    • Provide support /withstand weight of the abdomen.
15. (3mrks)
    • Allows time for dispersal
    • Allows maturation of embryo
    • Enables plant to survive harsh environment
16. (3mrks)
    • Avoid contaminating the reagents;avoid burning filter paper;avoid spilling reagents;avoid misuse of food substance
17. Use the diagram of the heart shown below to answer the questions that follow
    1. (1mrk)
       • Thicker muscular wall
    2. (1mrk)
       • Mammalia; Aves; 
    3. (1mrk)
       • Contract without nervous stimulation/Initiate contraction on their own;
18. (2mrks)
    1. Thiobacillus denitrificans. Converts nitrates to nitrogen gas and ammonia
    2. Nitrococcus bacteria. Oxidise ammonia to nitrites.
19.  
    1. (1mrk)
       • mitosis
    2. (1mrk)
       • Regulate Growth of pollen tube;
20.  
    1. (1mk)
       • calcium ions 
    2. (1mk)
       • fibrin. 
21.  
    1.  
       1. (1mrk)
          • ultrafiltration process. 
       2. (1mrk)
          • High blood pressure
          • Selectively permeable membranes
    2. (1mrk)
       • Afferent arteriole:carries blood to the glomerulus for ultrafiltration process
22. (2mrks)
    • Nitrogenous waste;Glucose ;amino acids.
23. (3mrks)
    • Amnion ;forms amniotic cavity ;and encloses foetus and amniotic fluid.
    • Amniotic fluid ; provides aquatic media for the foetus ; absorb shock;prevents dessication of the foetus
    • Umblical cord ; connects placenta and the foetus ;supplying foetus with oxygen and the nutrients;Removes metabolic waste.
24.  
    1. (1mrk)
       • Protoctista / Protista
    2. (1mrk)
       • Single-celled eukaryotic organism.
    3. (2mrks)
       • Membrane forms pseudopodia which is extended to surround and engulf the food particles and then form a food vacuole.
25. (2mrks)
    • Presence of rhizoids
    • Absence of vascular tissues
    • Body parts not differentiated into roots, stem and leaves
26.  
    1. (1mrk)
       • Intervertebral disk.
    2. (1 mark)
       • Absorb shock ;reduce friction during movement; allows for certain degree of flexibility of vertebral column.
27. (1mrk)
    • To give them a wider field of view that enables them to track their enemies from far and therefore take precautions.
28. (3mks)
    • Proper disposal of human waste/faeces;
    • Destroy breeding sites of vectors
    • Proper cooking of food /boiling of drinking water;
    • Use of insecticide against vectors / drugs against pathogens
    • Use of protective dwelling /mosquito nets to prevent vector bites/ proper hygiene;
29. (1mrk)
    • AA and BB ;(must indicate the two genotypes to get one mark.)
30. Ribcage; thoracic cavity: Moves upwards and outwards Diaphragm- Flattens (due to contraction of muscles); External intercostals muscles-contract; (3mrks)
31. (2mrks)
    • Natural selection in action;industrial melanism; Resistance to drugs;pesticides; and acaricides;