1. A) Distinguish Between Neurons and Nerves

KAIRI HIGH SCHOOL

FORM IV BIOLOGY

AUGUST 2017 ASSIGNMENT

1. a) Distinguish between neurons and nerves.

b) Name the three main types of neurons found in vertebrates and state their functions.

2. The diagram below shows the structure of a motor neuron.

a)  Name the parts labeled A – D.

b)  State three adaptations that enable the neurone to carry out its functions efficiently.

c)  State whether the axon of this neurone transmits impulses away from the cell body or towards the cell body.

d)  State two features that would distinguish a sensory neurone from this neurone.

3. a) What is a reflex action?

b) With the use of relevant examples, distinguish between a simple reflex and a conditioned reflex

c) Complete the following table with the words, response, stimulus, effector and receptor.

0lfactory cells
Salivary glands
Smell of food
Salivation

4. a) List the following in the order in which they are involved in a simple reflex:

Motor neurone, effector, stimulus, intermediate (relay) neurone, receptor, sensory neurone, impulse

b) Give three examples of reflex actions

c) If somebody accidentally puts a finger on a hot object, the hand is rapidly withdrawn away from the source of heat. Explain the process involved.

d) A hand is withdrawn from a hot object before one becomes consciously aware of the pain. Explain why this is so.

e) Differentiate between a monosynaptic and polysynaptic spinal reflex.

5. A person had a car accident that damaged one part of his brain but left the rest of it unaffected. Complete column B of the table below by filling in the part of the brain whose damage would correspond to the symptom shown in column A.

A / B
Inability to regulate body temperature
Loss o memory
Irregular heart beat and breathing movements
In ability to maintain proper boy balance and posture

6.

a) Where in the human body are relay neurons found

(b) The diagram below represents a neurone

(i)  Name the neurone

(ii) Name the parts labeled P and Q

(c) State a function of myelin sheath

7. A response exhibited by a certain plant tendril is illustrated below.

a) i) Name the type of response

ii) Explain how the response named in (a)(i) above occurs

b) What is the importance of tactic responses to microscopic plants?

c) State four applications of plant hormones in agriculture.

8. Distinguish between the fovea and blind spot of the eye

9. List in order, the structures through which light rays from an external object pass until they reach the retina.

10. Explain how the iris of the eye responds to light of varying intensity

b) What is the purpose of the response you have described in (a) above?

11. What is meant by accommodation of the eye?

b) Explain how light rays from (i) a distant object and (ii) a near object are focused on the retina.

12. Draw a table comparing the parts of a camera to those of the mammalian eye.

b) Give two important ways in which the mammalian eye differs from the camera.

13. Describe how the various parts of the eye are adapted for their functions

14. The figure below shows the path of light rays in a defective human eye.

a)  Name the defect

b)  0n the same diagram, draw the path of light rays after they have passed through a correcting lens until they reach the retina (use dotted lines)

c)  State in words how the correcting lens you have drawn in ( b) above correct the defect.

15. Explain why a faint star is seen more clearly at night by looking at it from the corner of the eye than by looking at it directly.

16. When you enter a dimly lit room from blight sunlight, it appears quite dark at first but gradually things become visible. Explain why this is so.

17. When reading a book, the words you look at directly are clear and sharp whereas the surrounding words are blurred. Explain this observation.

18. Explain why coloured objects appear black or grey in dim light

19. A girl could clearly read a book placed 10 cm away but could not identify her friend 10 metres away.

a) What eye defect was she suffering from?

b) Explain why she could not identify her friend but could read the book

c) Explain how the defect can be corrected.

20. Draw a table showing the differences between the rods and cones of the retina.

21. Explain how the various parts of the ear involved in hearing are adapted or their function

22. When a car descends rapidly down a hilly road, one feels an unpleasant sensation in the ears.

a) Explain how the unpleasant sensation comes about.

b) How can the unpleasant sensation be relieved?

23 . In the experiment was set up to investigate the affect of unilateral light on the growth of oat coleoptiles. The diagram in the table represent the experimental set ups at the start, and the result at the end of the experiment,

Setup / Start of experiment
A / /
B / Aluminum
Foil cap. / Aluminum
Foil cap.
C / /
D / Plate of mica /
E / /

a) Account for the results in the experiment set up A

b) Explain the purpose of experiment set ups B and C

c) Explain the results in the experiment set ups D and E

24. Explain how the fight or flight response is triggered when one hears a sudden threatening sound.

25. Differentiate between a voluntary and a reflex action

26. Distinguish between nervous and endocrine systems of communication

27. Match the hormonal defect in column A with its associated disease condition in column B.

A / B
a) 0versecretion of growth hormone / 1. Diabetes insipidus
b) Deficiency of insulin / 2. Exopthalmic goiter
c) Under-secretion of thyroxin during infancy / 3. Dwarfism
d) under-secretion of growth hormone during infancy / 4. Diabetes mellitus
e) under-secretion of antidiuretic hormone / 5. Gigantism
f) 0ver-secretion of thyroxine / 6. cretinism

28. In most plants, the growing tip of the stem inhibits the development of lateral buds into branches.

a) What is the name given to this effect?

b) Explain how the effect comes about

c) Explain what happens when the stem tip is removed

d) How is this effect employed in agriculture?

29. In an investigation, the pancreatic duct of a rat was blocked by tying it with a string. Explain how this affected the following processes.

a) Digestion of food

b) Regulation of blood glucose level

30. The diagram below represents a nerve cell.

(a)  (i) Identify the nerve cell.

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

(b)  Name the structure labeled T

(c)  Using an arrow indicate on the diagram the direction of movement of an impulse in the cell.

a) Explain what you would expect to observe after 48 hours if the clinostat was not rotating

b) Explain what you would expect to observe after 48 hours if the clinostat was rotating slowly.

31. Explain the meaning of the term tropism or tropic response

b) Explain how tendrils of climbing plants coil around a support

c) The leaves of some insectivorous plants make very rapid movements when they are touched by an insect.

i) Give an example of such a plant

ii) How does the response come about?

iii) What is the importance of the response?

32. List five functions of bones in the mammalian body.

33. State five functions of an insect’s exoskeleton

34. State the major difference between the skeleton of an adult shark and that of an adult lion

35. Indicate which of the bones listed below belong to the axial skeleton and which belong to the appendicular skeleton:

Vertebrae, carpals, radius, skull, ribs, tibia, femur, humerus, sternum

36. Explain the terms localized movement and locomotion

b) What is the importance of locomotion in animals?

37. Explain what antagonistic muscles are and give an example

38. The diagram below shows two fused bones of a mammal

(a)  Identify the fused bone

(b)  Name the

(i)  Bone that articulates at the point labelled F

(ii)  The hole labelled G

39. The diagram below shows the structure of the human knee joint.

a)  Name the parts labeled X Z Y

b)  State two roles of the fluid present in the space labelled H.

c)  In what main way does this joint differ from: i) the hip joint (ii) sutures of the skull?

40. Give one example of each of the following types of joints:

a) Hinge joint b) fixed joint c) Ball and socket joint

41. In what ways do the following adaptations help a bony fish to swim?

a) streamlined body

b) swim bladder

c) Tail fin with a large surface area

d) Strong tail muscles and a flexible vertebral column

e) Median fins

f) Overlapping and backward pointing scales

42. Explain the importance of movement in animals

b) In what ways do plants compensate for their inability to move?

43. In what ways do the following adaptations help a bird to fly?

a) Streamlined body, b) large keel, c) flight feathers, do) Hollow bones, e) Rigid skeleton, f) High metabolic rate.

44. Explain why herbaceous plants droop in hot-dry weather while woody plants remain erect under similar conditions.

45. Distinguish between tendons and ligaments

46. a) Draw a table listing the main structural and functional differences between the biceps muscle and the muscles of the intestinal wall.

b) State one important functional difference between the muscles given in (a) above and the muscles of the heart.

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