BIOLOGY PAPER 2 - KCSE 2019 MARANDA MOCK EXAMINATION

1. In a garden with plants of same species, 705 plants had red flowers while 224 had white flowers.
   1. Work out the ratio of red to white flowered plants. 1mk
   2.  
      1. Using letter r to represent the dominant gene, work out a cross between the heterozygous F1 offspring and a white flowered plant.  4mks
      2. What is the genotype ratio from the cross in b(i) above? 1mk

2. In a physiological experiment, starch, protein, diastase and sodium chloride were added to water and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a temperature between 35 – 40oc. The set uop was shown in the diagram below. The following observations were made after the procedure indicated.
   
   

   Contents in	At the start of experiment	After 1 hour
   Visking tubing	i) Solution tastes salty	Solution tastes salty
   	ii) Visking tubing is not firm	Visking tubing is firm
   	iii) After boiling with Benedicts solution, solution remains blue	After boiling with Benedicts solution the solution turns brown
   	iv) On addition of sodium hydroxide followed by copper sulphate solution to the solution, the colour changes to purple	On addition of sodium hydroxide followed by copper sulphate to the solution, the colour changes to purple.
   Beaker	i) Water is tasteless.	Solution tastes sweet/salty
   	ii) after boiling solution with benedicts solution, blue colour remains.	After boiling solution with Benedicts solution, colour turn to brown
   	iii) On addition to sodium hydroxide followed by copper sulphate solution, colour remains blue	On addition of sodium hydroxide followed by copper sulphate solution, colour remains blue

   
   
   1. Name the process by which salt is moved into the water in the beaker from the visking tubing. 1mk
      1. Name the food substance responsible for the brown colour observed after 1 hour both in the beaker and visking tubing when solutions are boiled with benedicts solution. 1mk
      2. Account f or the observation in b(i) above. 3mks
   2.  
      1. Name the food substances tested with sodium hydroxide followed by copper sulphate solution(s)         1mk
      2. Account for the absence of the food substance named in (c) (i) above in the beaker after 1 hour         1mk
   3. After one hour, the visking tubing was firm. State the term used to d escribe this state if it occurred in a plant cell. 1mk
3. The diagram below represents a feeding relationship in an ecosystem.
   
   
   1. Name the type of ecosystem represented by the above food web. 1mk
   2. Name the organism in the food web that:
      1. Are producers 1mk
      2. Occupies the highest trophic level 1mk
   3.  
      1. Write a food chain that ends with the hawk as quaternary consumer. 1mk
      2. State two short term effects on the above ecosystem if all the small fish were killed. 2mks
   4. State two ways in which oil spills lead to death of fish. 2mks
4. The diagram below represents a section of the human brain.
   
   
   1.  
      1. Name the structures labelled P And Q. 2mks
      2. State two functions of the part labelled R 2mks
   2.  
      1. Name two productive hormones secreted by t he pituitary gland in women. 2mks
      2. State one function of each of the hormone named in (b) (i) above. 2mks
5. The diagrams below represent the photographs of two bones labelled K and L obtained from the same mammal.
   
   
   1. Identify the bone labelled K. 1mk
   2.  
      1. Name the parts labelled P and Q. 2mks
      2. State the function of the part labelled Q. 1mk
   3.  
      1. Identify the bone that articulates with bone at the proximal end. 1mk
      2. Name the type of joint formed at the proximal end by bone L. 1m

SECTION B: (40 Marks)
Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8.

6. In an experiment to investigate certain processes in a given plant species, the rates of carbon(iv) oxide released and intake were measured over a long period of time. The results of the investigation were as shown below.
   

   Time of the day (hours)	6	8	10	12	14	16	18	20	22	24
   Volume of carbon (iv) oxide consumed (mm3/min)	10	43	69	91	91	50	18	0	0	0
   Volume of carbon (iv) oxide released (mm3/min)	38	22	10	3	3	6	31	48	48	48

   
   
   1. On the same axes, draw graphs of volume of carbon(iv) oxide consumed and released against time.       7mks
   2. Name the chemical process changes represented by:
      1. Carbon (iv) oxide consumsed. 1mk
      2. Carbon (iv) oxide released 1mk
   3. Account for the shape of the curve for:
      1. Carbon (iv) oxide consumed 3mks
      2. Carbon (iv) oxide released. 3mks
   4.  
      1. What is meant by compensation point. 1mk
      2. From the graph, find the time of day when the plants attained compensation point. 2mks
   5. Explain how temperature affects the rate of carbon (iv) oxide consumption in the plant. 2mks
7.  
   1. Describe the mechanism of urine formation in the kidney. 10mks
   2. Explain how the human skin brings about cooling of the body on a hot day. 10mks

8.  
   1. How are flowers adapted to pollination by insects. 10mks
   2. Describe the process of fertilization in flowering plants. 10mks