Biology Trial Exams Paper 2 Questions - Alliance Boys High School Mock December 2020

Instructions to Candidates

1. Write your Name, Admission number, class and house in the spaces provided above.
2. Answer ALL the questions in the spaces provided
3. Mathematical tables and electronic calculators may be used
4. All workings MUST be clearly shown where necessary.

FOR EXAMINER'S USE ONLY

QUESTIONS

1. The diagram below illustrates the structures of the female part of a flower
   
   
   1. Name the part labelled W 1 mark
   2. Describe what happens when the pollen tube enters the structure labelled V 5marks
   3. What do structures labeled R and T develop into after fertilization 2mks
      R.......................
      T.......................
2.                              
   1. What is meant by the term genetics 1mk
   2. State two examples of discontinuous variation 2mks
   3.                          
      1. A female with sickle cell trait marries a normal man. The allele for sickle cell is Hbs and the normal allele is Hba. Determine the probability that their first born will have the sickle cell trait. show your working. 5marks
      2. what is heterozygous advantage 1mark
      3. Using Darwin theory explain why Hbs Hbs is unfavorable trait in the individual offspring 1mark
3. The diagram below represent the human ear
   
   
   1. Name parts labelled E, F and G 3marks
      E.......................
      F.......................
      G.......................
   2. How is each of the following adapted to its function 2 marks
      1. External auditory meatus 2 marks
      2. Ear ossicles 2 marks
4. Below is a diagram showing internal structures of joint
   
   
   1. Name the bone s labelled 2marks
      U.......................
      V.......................
   2. State the functions of the following structures 2marks
      w.......................
      x.......................
   3.                      
      1. Name structure Y 1mark
      2. What effect would wearing off of the structure Y have on the joint? 1mark
   4. Name a vestigial structure b in the human that is made up of caudal vertebrae 1mark
   5. Name the compound responsible for making the bones hard 1 mark
5.                            
   1. Describe blood clotting process 5marks
   2. Briefly explain how gills are adapted as a respiratory surface 3mark

SECTION B 40 MARKS

• question 6 is compulsory
• choose one question between 7 and 8.
• Each question is 20 marks

6. An experiment was done to determine the uptake of nitrogen from the soil by broad. The experiment was done with one set of seedlings M grown in the atmosphere enriched with carbon (IV) oxide and another set up of seedlings N grown in the normal atmosphere. The amount of nitrogen in each seedling was measured in milligrams at intervals of ten days. The table below shows the results obtained
   

   Amount of Nitrogen in milligrams
   SETM	0	25	70	125	160	395	635	860	895	915
   SETn	0	15	35	50	65	105	120	125	135	140
   TIME(DAYS)	15	25	35	45	55	65	75	85	95	105

   1. Using the same axis draw line graphs of nitrogen uptake by the two (M and N) sets of broad bean seedlings against time 8 marks
      
   2. Determine the rate of uptake of nitrogen in set M between 65 and 85 days 2marks
   3.                                
      1. What is the relationship between carbon (iv) oxide concentration in the air and nitrogen? 1 mark
      2. Account for the relationship in (c) (i) above 3marks
   4.                      
      1. What would happen to the concentration of nitrogen in the seedlings in set M, if after 75 days the seedlings are transferred to a normal atmosphere 1mark
      2. Explain your answer in (d)(1) above 2marks
   5. State three ways in which nitrogen fixation occurs 3marks
7.                          
   1. Explain how the stomata opens using the photosynthetic theory 7marks
   2. Explain how the inhalation occurs in the mammalian until oxygen is transported in the blood stream 13marks
8.                        
   1. Explain light and dark stage of photosynthesis 10marks
   2. Briefly explain how the leaf is adapted for photosynthesis 10marks