Monday, 4 April 2016

important questions of control and coordination

Which signals will get disrupted in case of a spinal cord injury?
Answer: The spinal nerves go to the organs which are below the head region. Moreover, the autonomous nervous system is also connected to the spinal cord. In case of spinal cord injury, communication between the spinal nerves and the brain would be disturbed. Similarly, the communication between the autonomous nervous system and brain would also be disturbed; in case of spinal cord injury.
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise? 
Answer: Receptors provide information about the external environment so that the brain can instruct a related to organ to take necessary action. Receptors play an important role in our survival. Let us take the example of a person with hearing impairment. Certain ordinary task would be very difficult for that person. For example; while walking on the road, the person needs to hear the sound of vehicles moving near him. Without hearing those sounds, he would not be in a position to move safely on the road.

  • Which of the following is a plant hormone?
    • Insulin
    • Thyroxin
    • Oestrogen
    • Cytokinin
      Answer: (d) Ctyokinin
  • The gap between two neurons is called a
    • Dendrite
    • Synapse
    • Axon
    • Impulse
      Answer: (b) Synapse
  • The brain is responsible for
    • Thinking
    • Regulating the heart beat
    • Balancing the body
    • All of the above
      Answer: (d) All of the above
  • Draw the structure of a neuron and explain its function.
    Answer: Function of Neuron: Neuron transmits the nerve impulses.
structure of neuron


  • How does phototropism occur in plants? 
    Answer: Concentration of auxin changes in a particular plant part, in response to the direction of light. For example; in a stem, concentration of auxin increases in those parts which are away from light. This increases cell division in that part and thus the stem bends towards light. That is how phototropism occurs in plants.
  • How does chemical coordination occur in plants?
    Answer: Plant hormones play their roles in chemical coordination. Most of the plant hormones promote growth in certain plant parts, e.g. auxin, gibberellins and cytokinin. Abscissic acid is a plant hormone which inhibits growth. Shedding of leaves or ripe fruits is facilitated by abscissic acid.
  • What is the need for a system of control and coordination in an organism?
    Answer: A living being does not live in isolation. It has to constantly interact with its external environment and has to respond properly for its survival. For example; when a hungry lion spots a deer, the lion has to quickly make a move so that it can have its food. On the other hand, the deer needs to quickly make a move to run for its life.
  • How are involuntary actions and reflex actions different from each other?
    Answer: Involuntary actions are part of routine activities, while reflex actions are in response to a sudden danger. Moreover, involuntary actions happen in involuntary organs, while reflex action happens in a voluntary organ.
  • Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
    Answer: Nervous control is fast, while hormonal control is slow. Nervous control is facilitated by neurotransmitters, while hormonal control is facilitated by hormones.
  • What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs? 
    Answer: The movement in a sensitive plant is facilitated by chemical control, while the movement in our legs is facilitated by nervous control.
    • Which of the following statements is correct about receptors?
      • Gustatory receptors detect taste while olfactory receptors detect smell
      • Both gustatory and olfactory receptors detect smell
      • Auditory receptors detect smell and olfactory receptors detect taste
      • Olfactory receptors detect taste and gustatory receptors smell
        Answer: (a) Gustatory receptors detect taste while olfactory receptors detect smell
    • Electrical impulse travels in a neuron from
      • Dendrite ⇨ axon ⇨ axonal end ⇨ cell body
      • Cell body ⇨ dendrite ⇨ axon ⇨ axonal end
      • Dendrite ⇨ cell body ⇨ axon ⇨ axonal end
      • Axonal end ⇨ axon ⇨ cell body ⇨ dendrite
        Answer: (c) Dendrite ⇨ Cell body ⇨ Axon ⇨ Axonal end

    • In a synapse, chemical signal is transmitted from
      • Dendritic end of one neuron to axonal end of another neuron
      • Axon to cell body of the same neuron
      • Cell body to axonal end of the same neuron
      • Axonal end of one neuron to dendritic end of another neuron
        Answer: (d) Axonal end of one neuron to dendritic end of another neuron
    • In a neuron, conversion of electrical signal to a chemical signal occurs at/in
      • Cell body
      • Axonal end
      • Dendritic end
      • Axon
        Answer: (b) Axonal end
    • Which is the correct sequence of the components of a reflex arc?
      • Receptors ⇨ Muscles ⇨ Sensory neuron ⇨ Motor neuron ⇨ Spinal cord
      • Receptors ⇨ Motor neuron ⇨ Spinal cord ⇨ Sensory neuron ⇨ Muscle
      • Receptors ⇨ Spinal cord ⇨ Sensory neuron ⇨ Motor neuron ⇨ Muscle
      • Receptors ⇨ Sensory neuron ⇨ Spinal cord ⇨ Motor neuron ⇨ Muscle
        Answer: (d) Receptors ⇨ Sensory neuron ⇨ Spinal cord ⇨ Motor neuron ⇨ Muscle
    • Which of the following statements are true?
      • Sudden action in response to something in the environment is called reflex action
      • Sensory neurons carry signals from spinal cord to muscles
      • Motor neurons carry signals from receptors to spinal cord
      • The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc
      • (i) and (ii)
      • (i) and (iii)
      • (i) and (iv)
      • (i), (ii) and (iii) 
        Answer: (c) (i) and (iv)


    • Which of the following statements are true about the brain?
      • The main thinking part of brain is hind brain
      • Centres of hearing, smell, memory, sight, etc. are located in forebrain.
      • Involuntary actions like salivation, vomiting, blood pressure are controlled by the medulla in the hind brain
      • Cerebellum does not control posture and balance of the body
      • (i) and (ii)
      • (i), (ii) and (iii)
      • (ii) and (iii)
      • (iii) and (iv) 
        Answer: (c) (ii) and (iii)
    • Posture and balance of the body is controlled by
      • Cerebrum
      • Cerebellum
      • Medulla
      • Pons
        Answer: (b) Cerebellum
    • Spinal cord originates from
      • Cerebrum
      • Medulla
      • Pons
      • Cerebellum
        Answer: (b) Medulla
    • The movement of shoot towards light is
      • Geotropism
      • Hydrotropism
      • Chemotropism
      • Phototropism
        Answer: (d) Phototropism
        • The main function of abscissic acid in plants is to
          • Increase the length of cells
          • Promote cell division
          • Inhibit growth
          • Promote growth of stem
            Answer: (c) Inhibit growth
        • The growth of tendril in pea plants is due to
          • Effect of light
          • Effect of gravity
          • Rapid cell divisions in tendrillar cells that are away from the support
          • Rapid cell divisions in tendrillar cells in contact with the support
            Answer: (c) Rapid cell divisions in tendrillar cells that are away from the support

        • The growth of pollen tubes towards ovules is due to
          • Hydrotropism
          • Chemotropism
          • Geotropism
          • Phototropism
            Answer: (b) Chemotropism
        • The movement of sunflower in accordance with the path of sun is due to
          • Phototropism
          • Geotropism
          • Chemotropism
          • Hydrotropism
            Answer: (a) Phototropism
        • The substance that triggers the fall of mature leaves and fruits from plants is due to
          • Auxin
          • Gibberellin
          • Abscissic acid
          • Cytokinin
            Answer: (c) Abscissic acid


        • Which of the following is not associated with growth of plant?
          • Auxin
          • Gibberellins
          • Cytokinins
          • Abscissic acid
            Answer: (d) Abscissic acid
        • Iodine is necessary for the synthesis of which hormone?
          • Adrenaline
          • Thyroxin
          • Auxin
          • Insulin
            Answer: (b) Thyroxine
        • Choose the incorrect statement about insulin
          • It is produced from pancreas
          • It regulates growth and development of the body
          • It regulates blood sugar level
          • Insufficient secretion of insulin will cause diabetes
            Answer: (b) It regulates growth and development of the body
        • Select the mis-matched pair
          • Adrenaline: Pituitary gland
          • Testosterone: Testes
          • Estrogen: Ovary
          • Thyroxin: Thyroid gland
            Answer: (a) Adrenaline: Pituitary gland
        • The shape of guard cells changes due to change in the
          • Protein composition of cells
          • Temperature of cells
          • Amount of water in cells
          • Position of nucleus in the cells
            Answer: (c) Amount of water in cells
              • Nerve impulse travels from dendritic end towards axonal end
              • At the dendritic end electrical impulses bring about the release of some chemicals which generate an electrical impulse at the axonal end of another neuron
              • The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron
              • A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells
                Answer: (c) The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron

            • Involuntary actions in the body are controlled by
              • Medulla in forebrain
              • Medulla in midbrain
              • Medulla in hindbrain
              • Medulla in spinal cord
                Answer: (c) Medulla in the hindbrain
            • Which of the following is not an involuntary action?
              • Vomiting
              • Salivation
              • Heart beat
              • Chewing
                Answer: (d) Chewing
            • When a person is suffering from severe cold, he or she cannot
              • Differentiate the taste of an apple from that of an ice cream
              • Differentiate the smell of a perfume from that of an agarbatti
              • Differentiate red light from green light
              • Differentiate a hot object from a cold object
                Answer: (b) Differentiate the smell of a perfume from that of an agarbatti
            • What is the correct direction of flow of electrical impulses?
            • exemplar question options
            • Which statement is not true about thyroxin?
              • Iron is essential for the synthesis of thyroxin
              • It regulates carbohydrates, protein and fat metabolism in the body
              • Thyroid gland requires iodine to synthesise thyroxin
              • Thyroxin is also called thyroid hormone
                Answer: (a) Iron is essential for the synthesis of thyroxine
            • Dwarfism results due to
              • Excess secretion of thyroxin
              • Less secretion of growth hormone
              • Less secretion of adrenaline
              • Excess secretion of growth hormone
                Answer: (b) Less secretion of growth hormone


            • Dramatic changes of body features associated with puberty are mainly because of secretion of
              • Oestrogen from testes and testosterone from ovary
              • Oestrogen from adrenal gland and testosterone from pituitary gland
              • Testosterone from testes and Oestrogen from ovary
              • Testosterone from thyroid gland and Oestrogen from pituitary gland
                Answer: Testosterone from testes and Oestrogen from ovary
            • A doctor advised a person to take an injection of insulin because
              • His blood pressure was low
              • His heart was beating slowly
              • He was suffering from goiter
              • His sugar level in blood was high
                Answer: (d) His sugar level in blood was high
            • The hormone which increases the fertility in males is called
              • Oestrogen
              • Testosterone
              • Insulin
              • Growth hormone
                Answer: (b) Testosterone
            • Which of the following endocrine glands is unpaired?
              • Adrenal
              • Testes
              • Pituitary
              • Ovary
                Answer: (c) Pituitary
            • Junction between two neurons is called
              • Cell junction
              • Neuro muscular junction
              • Neural joint
              • Synapse
                Answer: (d) Synapse
            • In humans, the life processes are controlled and regulated by
              • Reproductive and endocrine systems
              • Respiratory and nervous systems
              • Endocrine and digestive systems
              • Nervous and endocrine systems
                Answer: (d) Nervous and endocrine systems

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