QUESTIONS

ANSWERS [MARKING SCHEMES]

QUESTIONS

ANSWERS [MARKING SCHEMES]

QUESTIONS

ANSWERS

QUESTIONS

MARKING SCHEMES & ANSWERS

GROWTH AND DEVELOPMENT

EXCRETION AND HOMEOSTASIS

1.1990 Q7 P1

(a) Explain why the body temperature of a healthy human being must rise up to 390C on a humid day.

(b) In an experiment a piece of brain was removed from a rat. It was found that the rat had large fluctuations of body temperature. Suggest the part of the brain that had been removed.

2. 1991 Q16 P1

(a) Explain how urea is formed in the human body

(b) Describe the path taken by urea from the organ where it is formed until it leaves the human body

3. 1992 Q4 P1

(a) Explain why sweat accumulates on a person’s skin in a hot humid environment.

(b) Name the specific part of the brain that triggers sweating

4. 1992 Q10 P1

Explain why some desert animals excrete uric acid rather than ammonia.

5. 1992 Q19 P1

Explain the part played by each of the following in homeostasis

(a) Insulin and Glucagon

(b) Antidiuretic hormone

(c) Fibrinogen

6. 1993 Q2 P1

State the role of the following hormones in the body:

a. Insulin

b. Antidiuretic hormone

7. 1993 Q10 P1

What osmoregulatory changes would take place in a marine amoeba if it was transferred to a fresh water environment?

8. 1994 Q2 P1

Name two components of blood that are not present in the glomerular filtrate.

9. 1994 Q3 P1

How would one find out from a sample of urine whether a person is suffering from diabetes mellitus?

10. 1995 Q17 P1

Describe how excretion takes place in

(i) Mammalian Kidneys

(ii) Green plants (5 marks)

11. 1996 Q3 P1

When is glycogen which is stored in the liver converted into glucose and released into the blood   (1 mark)

12. 1996 Q21 P1

Explain how the mammalian skin is adapted to perform its functions  (20 marks)

13. 1997 Q8 P1

A person was found to pass out large volumes of dilute urine frequently.

(a) Name the disease the person was suffering from

(b) Hormone that was deficient

14. 1997 Q15 P1

The equation below represent a metabolic that occurs in the mammalian liver

                Amino acids →Organic compounds + urea

(a) Name the process.

(b) What is the importance of the process to the mammal?

(c) What is the source of amino acids  in this process

(d) What is the difference between essential and nonessential amino acids?

15. 1999 Q11 P1

Give reasons for each of the following:

a) Constant body temperature is maintained in mammals.

b) Low blood sugar level is harmful to the body.

16.  2000 Q5 P1

State the importance of osmo-regulation in organisms

17. 2000 Q13 P1

The temperature of a person was taken before, during and after taking a cold bath. The results are shown in the graph below

(a) Explain why the temperature  fell during bath

(b) What changes occurred in the skin that enabled the body temperature to return to normal?

18. 2001 Q6 P1

Adult elephants flap their ears twice as much as their calves in order to cool their bodies when it is hot. Explain.

19. 2001 Q11 P1

The diagram below represents  a mammalian nephron

(a) Name the

(i) Structure labeled P

(ii) Portion of the nephron between point X and Y

(b) Name the process that takes place at point Q

(c) Name one substance present at point R but absent at point S in a healthy mammal

(d) The appearance of the substance you have mentioned in (c) above is a

symptom of a certain disease caused by a hormone deficiency. Name the

(i) Disease_________

(ii) Hormone_________

(e) State the structural modifications of nephrons found in the desert mammals

20. 2003 Q14 P1

a) Explain how marine fish regulate their osmotic pressure.

b) Explain the role of antidiuretic hormone when there is excess water in the human body.

21. Some students used a model to demonstrate the effect of sweating on human body temperature. Two boiling tubes A and B were filled with hot water. The temperature of water in the tubes was taken at the start of the experiment and then at 5 minutes interval.

The surface of tube A was continuously wiped with a piece of cotton wool soaked in methylated spirit. The results obtained are shown in the table below.

a) On the same axes, plot graphs of temperature of water in the tubes against time.

b) At what rate was the water – cooling in tube A?

c) Why was tube B included in the set up?

d) Account for the rate of cooling in tube A.

e) State two processes of heat loss in tube b.

f) What would be the expected results if tube A was insulated?

g) What would the insulation be comparable to in:

i) Bird

ii) Mammals?

h) Name the structures in the human body that detect:

i) External temperature changes

ii) Internal temperature changes

22. 2004 Q18 P1

How is the mammalian skin adapted to its functions? (20 marks)

23. 2005 Q13 P1

The diagram below shows a section through the mammalian skin.

a) Name the parts labeled E, F and G. (3 marks)

E_____________

F_____________

G_____________

b) State two functions in each case of substance secreted by the structures labelled.

(i)  H    (2 marks)

(ii) I  (2 marks)

24. 2006 Q4 P1

a) Name the fluid that is produced by sebaceous glands. (1 mark)

b) What is the role of sweat in human skin? (2 marks)

25. 2006 Q7 P2

Describe how human kidney functions (20 marks)

26. 2007 Q14 P1

(a) What is the meaning of the terms

(i) Homeostatic    (1 mark)

(ii) Osmoregulation? (1 mark)

(b) Name the hormones involved in regulating glucose level in blood (2 marks)

27. 2007 Q2 P2

(a) Explain what happens to excess amino- acids  in the liver  of humans (3 marks)

(b) Which portion of the human nephron are only found in the cortex? (3 marks)

(c)(i) What would happen if a person produced less antidiuretic hormone? (1 mark)

(ii) What term is given to the condition described in (c) (i) above         (1 mark)

28. 2008 Q2 P1

State the importance of the following processes that take place in the nephrons of a human kidney

(a) Ultra filtration ( 1 mark)

(b) Selective reabsorption ( 1 mark)

29.  2008 Q11 P1

(a) What is homeostasis? (1 mark)

(b) Name three processes in the human body in which homeostasis is involved (3 marks)

30. 2009 Q17 P1

Explain why plants do not require specialized excretory organs          (4 marks)

31. 2009 Q21 P1

Explain what happens in humans when concentration of glucose in the blood decreases below the normal level ( 4 marks)

32. 2009 Q8 P2

Describe the role of the liver in homeostasis in the human body    (20 marks)

33. 2010 Q18 P1

Give two reasons why animals have specialized organ for excretion as compared to plants     (2 marks)

34. 2010 Q19 P1

State the changes that occur in arterioles in the human skin during thermoregulation.    (2 marks)

35. 2011 Q1 P1

Name two kidney diseases.(2 marks)

36.2011 Q25 P1

State one economic importance of each of the following plant excretory products.

a) Tannin

b) Quinine

c) Caffeine

37. 2011 Q7b P2

Explain how the human skin brings about cooling of the body on a hot day. (7 marks)

38. 2012 Q18, 19 P1

18. Why plants able to accumulate most of their waste products for long? (1 mark)

19. List four forms of diabetes mellitus. (4 marks)

39. 2012 Q2 P2

The diagram below illustrates the structure of the kidney nephron.    

(a)    Name the part labeled E.  (1 mark)

(b)    How the part is labeled F adapted to its function? (4 marks)

(c)    State three physiological mechanisms of controlling the human body temperature during a cold day. (3 marks)

THE CELL

1. 1995 Q2 P1

   Name the organelle that performs each of the following functions in a cell (2 marks)

   a) Proteins synthesis____

   b) Transport of cell secretions___

2. 1996 Q8 P1

   State two functions of cell sap  (2 marks)

3. 1997 Q1 P1

   State the functions of the following cell organelles

   a) Golgi  apparatus

   b) Ribosomes

4. 1998 Q3 P1

   Which organelle would be abundant in:

   a) Skeletal muscle cell

   b) Palisade cell

5. 2001 Q7 P1

   Name the organelle in which protein synthesis takes place

6. 2004 Q7 P1

   State the function of the organelles:

   a) Lysosomes    (1 marks)

   b) Golgi apparatus    (2 marks)

7. 2005 Q2 P1

   The diagram below represents a cell.

   a) Name the parts labelled X and Y         (2 marks)

   X____

   Y____

   b) Suggest why the structures labelled X would be more on one side than the other.     (1 mark)

8. 2006 Q1 P1

   a) State the functions of cristae in mitochondria.

   b) The diagram below represents a cell organelle.

   i) Name the part labelled Y.    (1 mark)

   ii)    State the functions of the part labelled X. (1 mark)

9. 2007 Q2 P1

   a) What is the formula for calculating linear magnification of a specimen when using a hand lens?

   b)     Give a reason why staining is necessary when preparing specimens for observation under the microscope (1 mark)

10.2007 Q4 P1

   State three functions of Golgi apparatus (3 marks)

11.2008 Q12 P1

   State two functions of the endoplasmic reticulum (2 marks)

12.2009 Q3 P1

   State the functions  of the following parts of a  light microscope (2 marks)

   a) Objective  lens _______

   b) Diaphragm _______

13.2009 Q7 P1

   State the function of the following cell organelles    

   a) Ribosome    (1 mark)

   b) Lysosomes    (1 mark)

14.2009 Q15 P1

   Name the type of movement that occurs within a plant cell (1 mark)

15.2009 Q26 P1

   How are the mitochondria adapted to their functions?    (2 marks)

16.2010 Q3 P1

   State the function of:

   a) Ribosomes    (1 mark)

   b) Lysosomes    (1 mark)

17.2010 Q9 P1

   State two ways in which chloroplasts are adapted to their functions.    (2 marks)

18.2011 Q11 P1

   State the functions of the following parts of a light microscope.

   i) Fine adjustment knob.

   ii) Stage  (2 marks)

19.2011 Q15 P1

   Give reasons for carrying out the following procedures when preparing temporary wet mounts of plant tissues.

   a) Making thin plant sections (1 mark)             

   b) Adding water on the plant section. (1 mark)

   c) Placing a cover slip over the plant section. (1 mark)

20.2012 Q3 P1

   The figure below is a fine structure of a generalised animal cell as seen under an electron microscope.

   a) Name the parts labelled A and B (2 marks)

    A______________

    B______________

   b) How is the structure labelled B adapted to its functions (2 marks)

21.2012 Q12 P1

   a) Name the part of a light microscope used to bring an image of a specimen into sharp focus. (1 mark)

   b) Why is it recommended to keep the stage of the microscope dry? (1mark)

22.2012 Q27, 30 P1

   27.What is the function of contractile vacuoles in amoeba? (1 mark)

   30.Name the organelle that is involved in each of the following:  (2 marks)

   a) Manufacture of lipids

   b) Formation of Lysosomes

TRANSPORTATION IN PLANTS AND ANIMALS

1.   1989 Q3 P1

     Explain how the red blood cells of mammals are adapted for efficient transport of oxygen.

2.   1989 Q11 P1

     In experiment, a leafy shoot was set-up in a perometer and kept in a dark room for two hours. The set up was then transferred to a well lit room for two hours.

     (a) What is the aim of the experiment?

     (b) Explain the result which would be expected in each of the two experimental conditions.

3.   1991 Q2 P1

     Give two reasons why the pressure of blood is greater in the arteries that in the veins of mammals.

4.   1992 Q6 P1

     Most carbon dioxide is transported from tissues to the lungs within the red blood cells and not in the blood plasma.

     Give two advantages of this mode of transport.

5.   1992 Q17 P1

     The amount of blood flow through various parts of a mammalian body was measured in cubic centimeters per minute at rest and also during physical activities.

     The results are shown in the table below

     (a) Calculate the percentage changes in the blood flow through the skeletal muscle and the gut when the mammal was subjected to strenuous exercise from rest.

     (b) Account giving reasons for the differences in the amount of blood flow through the gut and skeletal muscles.

     (c)  How does the heart increase blood flow to some parts of the body during astrenuous exercise?

     (d) Explain the results obtained for the skin

     (e) Name three substances that are removed from the body by the Kidneys.

6.   1993 Q6 P1

     State two functions of mammalian blood other than transport of substances

7.   1994 Q1 P1

     Name a structure in veins which is not found in other blood vessels, that adapts them to their function.

8.   1995 Q11 P1

     The diagram below represents a transverse section of a young stem

     (a) Name the parts labelled  A and B (2 marks)

      A _________________________

      B _________________________

     b) State the functions of the parts labelled  C, D and E    (4 marks)

      C ____________________

      D ____________________

      E ____________________

     c) List three differences between the section shown  above and one that would  be obtained from the root of the same plant    (3 marks)

9.   1996 Q17 P1

     (a) How may excessive bleeding results in death? (4 marks)

     (b) Name the process by which the human body naturally stops bleeding? (1 mark)

     (c) How can low blood volume be brought back to normal (3 marks)

10.  1996 Q19 P1

     The diagram below represents then pathways of water from the soil into the plant.

     a) Name the structures labelled K and L. (2 marks)

      K ________________

      L ________________

     b) Explain how water from the soil reaches the structure labelled L.(5 marks)

     c)    Name the process by which mineral salts enter into  the plant (1 mark)

11.  1997 Q4 P1

     State two ways in which xylem vessels are adapted to their function

12.  1997 Q13 P1

     An experiment was carried out to determine the rate of transpiration in three plants A, B and C. Plants, A and B belonged to different species while plants B and C belonged to the same species. Plant C had all its leaves removed. The three plants were of similar size and were exposed to the same environment conditions.

     The results are as shown below in the graphs below

     (a) Suggest  possible environment  conditions  under  which the experiment was carried out between 30 and 60 minutes

     (b) Account for the results obtained for plant C

     (c) Suggest the habitat for plant A and B.  Give reasons for your answer.

13.  1998 Q1 P1

     Why are people with blood group O universal donors?

14.  1998 Q18 P1

     A hungry person had a meal, after which the concentration of glucose and amino acids in the blood were determined. This was measured hourly as the blood passed through the hepatic portal vein and the iliac vein in the leg. The results were as shown in the table below.

     (a) Using the same axes draw graphs of concentration  of glucose in the hepatic portal vein and the  iliac vein in the leg against time

     (b) Account for the  concentration of glucose in the hepatic vein from:

      (i) 0/1 hour

      (ii) 1-2 hour

      (iii) 2- 4 hours

      (iv) 5 – 7 hours

     (c) Account for the difference in the concentration of glucose in hepatic portal vein and the iliac vein between 2 and 4 hours.

     (d) Using the data provided in the table explain why the concentration of amino acids in the hepatic portal vein took longer to increase.

15.  1999 Q1 P1

     Name two processes that bring about the translocation of manufactured food

16.  1999 Q2 P1

     Give two reasons why accumulation of lactic acid during vigorous exercise leads to an increase in heartbeat.

17.  1999 Q14 P1

     The photograph below represents a blood smear obtained from a person suffering from a certain disease.

     //Diagram not availble now, check progress later

     a) Name the structure labelled  X.

     b) i)  Name the structure labelled  L

         ii) State the function of the source labelled M

     c) What disease was the person suffering from?

     d) List three ways by which micro-organisms enter the human body.

18.  2000 Q11ab P1

     The diagram below represents a section of a leaf.

     (a) Name the parts labelled X, and Y

      X _________________

      Y _________________

     (b) Using arrows indicate on the diagram the direction of flow of water during the transpiration stream

19.  2001 Q3 P1

     A person whose blood groups is AB requires a blood transfusion. Name the blood groups of the donors.

20.  2001 Q8 P1

     (a) The type of circulatory system found in members of the class insecta is

     (b) Name the blood vessel that transports blood from:

      (i) Small intestines to the liver

      (ii) Lungs to the heart

21.  2002 Q6 P1

     In what form is oxygen transported from the lungs to the tissues?

22.  2002 Q16 P1

     The diagram below represents part of phloem tissue.

     a) Name the structures labelled R and S and the cell labelled T.

     b) State the function of the structure labelled S

     c)    Explain why xylem is a mechanical tissue

23.  2003 Q9 P1

     Name the:

     a) Material that strengthens xylem tissue.

     b)    Tissue that is removed when the bark of a dicotyledonous plant is ringed.

24.  2004 Q2 P1

     Distinguish between natural and acquired immunity    (2 marks)

25.  2004 Q13 P1

     The diagram below shows a vertical section through a mammalian heart.

     a)    Name the parts labelled A, B, E and F                (4 marks)

      A ________________

      B ________________

      E ________________

      F ________________

     b) Use arrows to show the direction in which blood flows in the heart. (2 marks)

     c)    Give a reason why the wall of chamber C is thicker than chamber D (2 marks)

26.  2005 Q3 P1

     What is the role of the vascular bundles in plant nutrition? (3 marks)

27.  2005 Q9 P1

     Why would carboxyhaemoglobin lead to death? (2 marks)

28.  2005 Q14 P1

     A set up that was used to investigate certain process in plants is shown in the diagram below.

     a) What process was being investigated? (1 mark)

     b) (i)  State two precautions that should be taken when setting up the experiment.    (2 marks)

    (ii) Give a reason for each precaution stated in b(i) above.        (2 marks)

     c) State three environmental factors that influence the process under investigation. (3 marks)

29.  2006 Q7 P1

     a) Name one defect of circulatory system in humans. (1 mark)

     b) State three functions of blood other than transport. (3 marks)

30.  2006 Q4 P2

     The diagram below represents a traverse section through a plant organ

      a). From which plant organ was the section obtained? (1 mark)

      b). Give two reasons for your answer in (a) above. (2 marks)

      c). Name the parts labelled J, K and L.    (3 marks)

      d). State two functions of the part labelled M. (2 marks)

31.  2006 Q8 P2

     Describe how water moves from the soil to the leaves in a tree. (20marks)

32.  2007 Q9 P1

     State two ways in which the root hairs are adapted to their function (2 marks)

33.  2007 Q10 P1

     The diagram below represents a plant tissue

     (a) Name the tissue (1 mark)

     (b) Name the cells labelled K and L. (2 marks)

     (c) What is the function of the companion cell? (1 mark)

34.  2007 Q11 P1

     (a) What prevents blood in veins from flowing backwards? (1 mark)

     (b) State two ways in which the blood cells are adapted to their function    (2 marks)

35.  2007 Q6 P2

     In the experiment to determine the effect of ringing on the concentration of sugar in phloem a ring of bark from the stem of a tree was cut and removed. The amount of sugar in grammes per 16cm3 piece of bark above the ring was measured over a 24 hour period. Sugar was also measured in the bark of a similar stem of a tree which was not ringed. The results are shown in the table below.

     (a) Using the same axes, plot a graph of the amount of sugar against time (6 marks)

     (b) At what time was the amount of sugar highest in the

      (i)  Ringed stem    (1 mark)

      (ii) Normal stem?    (1 mark)

     (c) How much sugar would be in the ringed stem if it was measured at 0345 hours?    (1 mark)

     (d) Give reasons why there was sugar in the stems of both trees at 06 45 hours (2 marks)

     (e) Account for the shape of  the graph for the tree with ringed stem between:

      (i) 06 45 hours and 15 45 hours    (3 marks)

      (ii) 15 45 hours and 00 45 hours    (2 marks)

     (f) Name the structures in phloem that are involved in the translocation of sugars        (2 marks)

     (g) Other than sugars name two compounds that are translocated in phloem (2 marks)

36.  2008 Q20 P1

     (a) What is a single circulatory system                               (1 mark)

     (b) Name an organism which has single circulatory system                     (1 mark)

     (c) Name the opening to the chamber of the heart of an insect              (1 mark)

37.  2008 Q6 P2

     An experiment was carried out to investigate transpiration and absorption of water in sunflower  plants in their natural environment  with  adequate  supply of water.  

     The account of water was determined in two hour intervals. The results are as shown  in the table below

     (a) Using the same axes, plot graphs to show transpiration and absorption  of water in grammes against time of the day    (7 marks)

     (b) At what time of the day was the amount of water the same for transpiration and absorption?    (1 mark)

     (c) Account for the shape of graph of:

     (i)  Transpiration    ( 3 marks)

     (ii) Absorption    ( 3 marks)

     (d) What would happen to transpiration and absorption of water if the experiment was continued till 05 00 hours?    (2 marks)

     (e) Name two factors that may  affect transpiration and absorption at any given time  (2 marks)

     (f) Explain how the factors you named in (e) above affect transpiration (2 marks)

38.  2009 Q6 P1

     The diagram below shows a section through a plant organ

     (a) (i)  Name the class of the plant which the section was obtained ( 1 mark)

         (ii) Give a reason for your answer in (a) (i) above

     (b) State the functions of the part labelled F (1 mark)

39.  2009 Q28 P1

     (a) State three structural differences between arteries and veins in mammals (3marks)   

     (b) Name a disease that causes thickening and hardening of arteries (1 mark)

40.  2009 Q29 P1

     Explain why the rate of transpiration is reduced when humidity is high

41.  2010 Q14 P1

     Explain why is not advisable to be in a poorly ventilated room with a burning charcoal. (3 marks)

42.  2010 Q23 P1

     Explain three ways in which red blood cells are adapted to their function.    (3 marks)

43.  2010 Q 28 P1

     State three structural differences between arteries and veins. (3 marks)

44.  2010 Q2 P2

     The diagram below shows blood circulation in a mammalian tissue.

     a)     Name the part labelled  P and Q (2 marks)

     b)     Name the substance that are:

     i)     Required for respiration that move out of capillaries; (2 marks)

     ii) Remove from tissue cells as a result of respiration (2 marks)

     c)     Explain how substances move from blood capillaries into the tissue cells. (2 marks)

     d)     Name one component of the blood that is not found in the part labelled  P (1mark)

45.  2011 Q16 P1

     a) Describe the condition known as varicose veins. (2 marks)

     b) What is the role of blood platelets in the blood clotting process? (2 marks)                                                                                                                   

46.  2011 Q20 P1

     The number of stomata on the lower and upper surfaces of two leaves from plant species X and Y were counted under the field of view of a light microscope. The results were as shown in the table below.

     a) Which of the two leaves would be expected to have a lower rate of transpiration? (1 mark)          

     b)  Give a reason for your answer in (a) above.                                 (1 mark)

47.  2011 Q7a P2

     a) Explain how the structural features in terrestrial plants affect their rate of transpiration.    (13 marks)

48.  2012 Q8 P2

     What is the probability of a couple with blood group AB getting a child with blood group AB? Show your working.  (4 marks)

49.  2012 Q11 (a) P1

     (a) State two ways in which heart muscles are special.  (2 marks)

50.  2012 Q23, 28 P1

     23.  Name the strengthening materials found in the following support tissues:

      (a) Collencyma;

      (b) Xylem  (2 marks)

28.  State two differences between open and closed circulatory systems  (2 marks)

51   2012 Q8 P2

     (a) Using a relevant example, describe how an allergic reaction occurs in a human being. (10 marks)

     (b) Describe how environmental factors increase the rate of transpiration in terrestrial plants. (10 marks)