Sample questions with answers on biology

38. Which of the following is not a plant hormone?

(a) auxin (b) ascorbic acid

39. One of the following plant hormones is responsible for the phenomenon of phototropism in plants. This is

ADVERTISEMENTS:

(a) gibberellin (b) eltroxin

40. The movement of a plant part in response to the force of attraction exerted by the earth is called:

(a) hydrotropism (b) geotropism

ADVERTISEMENTS:

41. The movement of sunflower in accordance with the path of the sun is due to:

(a) photonasty (b) phototropism (c) hydrotropism (d) chemotropism

42. The plant part which exhibits negative geotropism is:

ADVERTISEMENTS:

(a) root (b) stem (c) branch (d) leaves

43. A big tree falls in a forest but its roots are still in contact with the soil. The branches of this fallen tree grow straight up (vertically). This happens in response to

(a)water and light

(b) water and minerals

ADVERTISEMENTS:

(c)gravity and water

(d)light and gravity

44. Which of the following is not caused by a growth movement?

(a) bending of the shoot of a plant in response to light

ADVERTISEMENTS:

(b) closing up of leaves of a sensitive plant on touching with an object

(d) movement of the root of a plant towards a source of water

45. The root of a plant is:

ADVERTISEMENTS:

(i) positively phototropic but negatively geotropic

(ii) positively geotropic but negatively phototropic

(iii) negatively phototropic but positively hydrotropic

(iv) negatively hydrotropic but positively phototropic

(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv)

46. The main function of the plant hormone called abscisic acid is to:

(a) increase the length of cells (b) promote cell division

47. The growth of tendrils in pea plants is due to the:

(a) effect of sunlight on the tendril cells facing the sun

(b) effect of gravity on the part of tendril hanging down towards the earth

(d)rapid cell division and elongation in tendril cells in contact with the support

48. Which of the following phytohormone is not associated with the promotion of growth in plants?

(a) auxin (b) abscisic acid

49. The plant hormone which triggers the fall of mature leaves and fruits from the plant body is:

(a) auxin (b) gibberellin

50. Which of the following terms denotes the movement of the root of a plant towards moisture in the soil?

(a) thigmotropism (b) chemotropism

51. The growth of a pollen tube towards the ovule caused by a sugary substance as stimulus is an example of:

(a) phototropism (b) chlorotropism

52. The bending of the shoot of a plant in response to light is called:

(a) geotropism (b) phototropism

53. The stimulus in the process of thigmotropism is:

(a) touch (b) gravity

54. A growing seedling is kept in a dark room. A burning candle is placed near it for a few days. The top part of seedling bends towards the burning candle. This is an example of:

(a) chemotropism (b) hydrotropism

55. Which of the following acts as a stimulus in the process of hydrotropism?

(a) hydrocarbon (b) hydrogen oxide

56. The growth movement of a plant part in response to the touch of an object is called:

(a) thigmonasty (b) hydrotropism

57. The climbing organs of plants like tendrils grow towards any support which they happen to touch and wind around the support. This is an example of:

(a) chemotropism (b) nastic movement

58. The rate of growth in roots is decreased by one of the following plant hormones. This plant hormone is:

(a) gibberellin (b) auxin

59. When the leaves of a Mimosa pudica plant are touched with a finger, they fold up quickly. This is an example of:

(ia) chemotropism (b) thigmonasty

60. Dandelion flowers open the petals in bright light during the daytime but close the petals in dark at night. This response of dandelion flowers to light is called:

(a) phototropism (b) thigmonasty

61. To which of the following directional stimulus roots of a plant do not respond?

(a) moisture (b) candle light

62. One of the following is not caused by the growth related movement of the concerned plant part. This is: a

(a) phototropism (b) photonasty

63. The bending of the root of a plant away from a source of light is caused by a plant hormone called:

(a) cytokinin (b) gibberellin

64. Most of the plant hormones promote plant growth. A plant hormone which inhibits growth is:

(a) abscisic acid (b) ethene

65. The movement of a shoot towards light is:

(a) geotropism (b) hydrotropism

66. The bending of the stem of a plant towards a source of light is caused by the action of a phytohormonel known as:

(a) abscisic acid (b) auxin

67. Which of the following plant part exhibits negative phototropism?

(a) root (b) branch

68. Which of the following are not tropisms?

(i) growing of pollen tube in response to a sugary substance

(ii) folding up of leaves of sensitive plant in response to touch

(iii) winding of tendril around a support in response to touch

(iv) opening up of the leaves of a daisy flower in response to light

(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv)

Answers:

38. (b) 39. (d) 40. (b) 41. (b) 42. (b) 43. (d) 44. (b) 45. (b) 46. (c) 47. (c) 48. (b) 49. (c) 50. (c) 51. (d) 52. (b) 53. (a) 54. (c) 55. (&) 56. (c) 57. (c) 58. (b) 59. (b) 60. (d) 61. (c) 62. (c) 63. (d) 64. (a) 65. (d) 66. (b) 67. (a) 68. (ii)