CBSE Class 10 Biology Control And Coordination Set E

Question. Which of the following endocrine glands is unpaired?
(a) Adrenal
(b) Testes
(c) Pituitary
(d) Ovary
Answer : C

Question. In a synapse, chemical signal is transmitted from
(a) dendritic end of one neuron to axonal end of another neuron
(b) axon to cell body of the same neuron
(c) cell body to axonal end of the same neuron
(d) axonal end of one neuron to dendritic end of another neuron
Answer : D

Question. An example of a sex hormone is _________________.
(a) testosterone
(b) Insulin
(c) Thyroxin
(d) thymosin
Answer : A

Question. Which of the following statements is correct about receptors?
(a) Gustatory receptors detect taste while olfactory receptors detect smell
(b) Both gustatory and olfactory receptors detect smell
(c) Auditory receptors detect smell and olfactory receptors detect taste
(d) Olfactory receptors detect taste and gustatory receptors smell
Answer : A

Question. Chemical messengers secreted by ductless glands are called___________
(a) Lymph
(b) Platelets
(c) Plasma
(d) Hormones
Answer : D

Question. Dwarfism results due to _____.
(a) Excess secretion of thyroxin
(b) Less secretion of growth hormone
(c) Less secretion of adrenaline
(d) Excess secretion of growth hormone
Answer : B

Question. A doctor advised a person to take an injection of insulin because——-.
(a) His blood pressure was low
(b) His heart was beating slowly
(c) He was suffering from goitre
(d) His sugar level in blood was high
Answer : D

Question. Unconditioned reflex is controlled by the ______________.
(a) Brain
(b) spinal cord
(c) both a and b
(d) the autonomic nervous system
Answer : B

Question. Spinal cord originates from
(a) cerebrum
(b) medulla
(c) pons
(d) cerebellum
Answer : B

Question. The gland that plays a role in fight or flight response is _________________.
(a) pancreas
(b) pituitary
(c) adrenal
(d) thyroid
Answer : C

Question. Damage of cerebellum will mostly affect the career of :
(a) architect
(b) teacher
(c) librarian
(d) athlete
Answer : D

Question. Iodine is necessary for the synthesis of which hormone?
(a) Adrenaline
(b) Thyroxin
(c) Auxin
(d) Insulin
Answer : B

AR TYPE QUESTIONS
Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Question. Assertion(A) : Animals can react to stimuli in different ways.
Reason (R) : All animals have a nervous system and an endocrine system involving hormones.
Answer : A

Question. Assertion(A) : Phototropism is a directional growth movement.
Reason (R) : It occurs in the direction of light
Answer : A

Question. Assertion(A): A neuron transmit messages in both the direction.
Reason (R) : The response is slow and produced by all cells of target tissue.
Answer : D

Question. Assertion(A): impulse travels from dendrite to cell body and then along the axon to its end.
Reason (R) :information acquired at the end of the dendrite tip of a nerve cell sets of an electric impulse.
Answer : A

Question. Assertion(A) : The use of iodised salt prevents risk of goitre.
Reason (R) : Iodised salt provides iodine needed by thyroid gland to make sufficient thyroxin for our body.
Answer : A

Very Short Answers Type Questions

Question. List two different functions performed by pancreas in our body.
Answer :
(a) Pancreas makes two hormones i.e., insulin and glycogen that regulates blood sugar level.
(b) It secretes pancreatic juice that aids in the digestion of food. 

Question. Which part of the brain maintains posture and equilibrium of the body ?
Answer : Cerebellum of the hind brain maintains posture and equilibrium of the body.

Question. Which signals will get disrupted in case of a spinal cord injury ? 
Answer : Spinal cord controls mainly the reflex actions. So reflex actions and involuntary actions will get disrupted.

Question. What do you mean by reflex action ?
Answer : Reflex action is an automatic, quick and involuntary action in the body brought about by a stimulus.

Question. Pancreas and gonads perform dual functions. Give reasons to justify the statement.
Answer : Pancreas secretes hormones as well as various digestive enzymes i.e., they are associated with both digestive and endocrine system. Similarly, gonads produce male and female gametes along with male and female sex hormones i.e., they are associated with both reproductive and endocrine system. Hence, we can say pancreas and gonads perform dual functions.

Question. What will happen if a ripened fruit is kept in a basket of raw fruits ?
Answer : If a ripened fruit is kept in a basket of raw fruits it will help in ripening of other raw fruits as the ripened fruit contains enthylene hormone which is responsible for
ripening of fruits.

Short Answers Type Questions

Question. What are plant hormones ? Name the plant hormones responsible for the following : 
(a) Growth of stem
(b) Promotion of cell division
(c) Inhibition of growth
(d) Elongation of cells
Answer : In plants, growth, development and response to the environment are controlled and co-ordinated by a special class of chemical substances known as phytohormones. They are synthesised in minute amounts.
(a) Gibberellins
(b) Cytokinins
(c) Abscisic acid
(d) Auxins

Question. What is feedback mechanism of hormonic regulation. Take the example of insulin to explain this phenomenon.
Answer : It is the mechanism by which the amount of any chemical increases or decreases resulting in secretion of the related hormone control of many cell activities, so they are very important for homeostasis most hormones are regulated by feedback mechanisms. A feedback mechanism is a loop in which a product feeds back to control its own production. Most hormone feedback mechanism involves negative feedback loops. Negative feedback keeps the concentration of a hormone within a narrow range.
For example,
The control of blood sugar by insulin is an example of a negative feedback mechanism. When blood sugar rises, receptors in a body sense a change. In turn the control center secretes insulin into the blood effectively lowering the blood sugar level.

Question. Nervous and hormonal systems together perform the function of control and coordination in human beings,Justify this statement with the help of an example.
Answer : The nervous system controls and coordinates all the functions in the body. It carries out its function in close coordination with hormonal system. Nerves don’t reach every hook and corner of body, hence needs assistance from hormones to control all the parts of body. Nervous control is faster. Hormonal control is slower. Hormonal control is based on feedback mechanism and tells body to pace up or slow down. Nervous control is on the other hand, a direct control.
Example : In situation of iodine deficiency hypothalamus releases hormones to stimulate pituitary gland it further sends stimulating hormone to thyroid gland to secrete thyroxine that regulates carbohydrate metabolism.

Question. What happens at the synapse between two neurons ?
Answer : Synapse is a point of contact between the axon terminals of one neuron with the dendrite of another neuron. The terminals of axon are swollen which contains a chemical called acetylcholine which is a neurotransmitter, which induces impulses in the dendrites of next neuron. Synapse acts as one way valve which prevents the back flow of impulses from axon terminals. So, impulse moves from dendrites through cyton to axon. It allows the nerve impulses in one direction.

Question. What is the need for a system of control and coordination in an organism ?
Answer : Multicellular organisms are highly complex. Every activity need to be regulated so that the activities can occur in proper time and correct sequence. Various organs and parts of the body should work together in a coordinate manner to perform a particular function. For proper control and coordination in higher organisms both nervous and endocrine system plays a major role. For example : While riding a bicycle there should be proper coordination between our hands and handle of our cycle.

Question. What is the role of brain in reflex action ?
Answer : Reflex actions are mainly controlled by spinal cord. For quick response to the stimulus spinal cord is generally involved but the information also reaches the brain where the thinking process occurs. Brain does not play any role for quick response to reflex action. But some reflex actions are only controlled by brain called cerebral reflexes like salivation at the sight of tempted food.

Question. When our finger gets pricked by a sharp nail, we immediately take away our finger. Explain the pathway from stimulus to response ?
Answer : When our finger gets pricked by the sharp iron nail the finger receives the stimuli. It acts as a receptor organ. The sensory neuron carries the impulse from finger to the spinal cord [Central nervous system]. The spinal cord interpretes these impulses and generates motor impulse. These impulses are carried by motor neuron to the effector organ. By receiving the motor impulses immediately we take away our finger from the nail. This whole phenomenon is called reflex action and the path of impulse from Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector is called reflex arc.

Question.  Different parts of brain are associated with specific functions. Name the part of human brain which perform the following functions : 
(a) Sensation of feeling full
(b) Vomiting
(c) Picking up a pencil
(d) Riding a bicycle
Answer :
(a) Forebrain
(b) Medulla or Hind Brain
(c) Cerebellum or Hind Brain
(d) Cerebellum or Hind Brain

Long Answers Type Questions

Question. (a) Why is the use of iodised salt advisable ? Name the disease caused due to deficiency of iodine in our diet and state its one symptom.
(b) How do nerve impulses travel in the body ?
Explain. 
Answer :
(a) Iodised salt is advisable because iodine is necessary for the formation of thyroxine hormone by thyroid gland. Goitre is the disease caused due to its deficiency.
Symptom : The neck of the person appears to be swollen due to the enlargement of thyroid gland.
(b) Two neurons are not joined to one another completely. There is a small gap between a pair of neuron. This gap is called synapse. The nerve impulse are carried out to this gap by the help of neuro transmitter (chemical substance). The conduction of nerve impulse through the synapse takes place in the form of electrical nerve impulse. When a stimulus acts on the receptor, an electrical impulse is produced with the help of chemical reaction. This electrical impulse passes through the synapse and then to the other neuron. Thus, in this way nerve impulses travel in the body.

Question. What are the major parts of the brain ? Mention the function of different parts ?
Answer :
(a) Forebrain : It comprises of cerebrum and diencephalon.
(i) Cerebrum is the seat of intelligence, memory,will power, consciousness. It controls voluntary actions. It is the largest portion of the brain. It is divided into two halves called cerebral hemispheres which are connected by a sheet of fibres called corpus callosum.
(ii) Diencephalon consists of thalamus and hypothalamus. The centre of hunger, thirst is located in hypothalamus. Hypothalamus controls body temperature and pituitary gland. Thalamus relays pain and pressure impulses to the cerebrum.
(b) Midbrain is a small tubulare part which controls reflexes involving eyes and ears.
(c) Hindbrain comprises of cerebellum, pons, medulla oblongata.
(i) Cerebellum controls and coordinates muscluar activity and maintains the posture and balance of the body.
(ii) Pons regulate rate of respiration and body heat.
(iii) Medulla oblongata controls functioning of internal organs and involuntary actions like beating of heart, breathing movement, peristals movement etc. 

Creating Based Questions

Question. ‘Synapses act like one-way valves’ – Elaborate.
Answer : The chemical substance is present only on one side of the gap, so nerve impulse can go across only from one side ( which contains the chemical substance).

Question. Create a flow chart of neuron through which information travels as an electrical impulse by filling up ‘a’ and ‘b’.
Dendrite → a → b → end point of neuron.
Answer : (a) Cell body or cyton (b) Axon

Question. Using the following words below, construct a reflex arc. Sensory nerves, receptor, effector, stimulus, brain or spinal cord, response, motor neurons.
Answer :
Stimulus → Receptor → Sensory nerves → Brain or
spinal cord → Motor neurons → Effector → Response.

Question. Choose the incorrect word from the following and replace it with the correct word :
(a) Pancreas is called the master gland.
(b) Iron is needed for production of thyroxine.
Answer :
(a) Pancreas is the incorrect word replaced by pituitary gland.
(b) Iron is the incorrect word replaced by iodine.

Question. ‘An alcoholic person usually walks clumsily’— develop a better explanation for this statement.
Answer : Cerebellum is the part of the brain that maintains balance and posture. After consumption of alcohol the cerebellum gets affected by the alcohol for which it cannot maintain balance and posture properly and hence walk clumsily.

Case Study Based Questions

1. The brain directs our body’s internal functions. It also integrates sensory impulses and information to form perceptions, thoughts, and memories. The brain gives us self-awareness and the ability to speak and move in the world.

Question. The brain is divided into three major subclasses.Name these subclasses.
Answer : The brain is divided into three main subclasses: the forebrain, the midbrain, and the hindbrain. The structure present toward the lower back of the skull is the hindbrain. The narrow region that links the hindbrain with the forebrain is the midbrain. The structure in front of the brain is the forebrain.

Question. Name the part of the brain that is responsible for maintaining body posture ?
Answer : The cerebellum is present in the hindbrain. It controls the body posture and coordinates motor activity for moving limbs. It is densely packed with neurons.

Question.Name the part of the brain that has the reflex centers for sneezing and vomiting ?
Answer : The medulla oblongata is the region which regulates the breathing, heart rate, and blood pressure, and also consists of reflex centers for sneezing, vomiting, defecating, coughing,hiccupping, and swallowing.

Question. The brain is the part of the central nervous system or peripheral nervous system ?
Answer : The nervous system present in vertebrates is divided into the peripheral nervous system and central nervous system. The brain and spinal cord are found in the central nervous system. Thus, the brain is part of the central nervous system.

2. Study the table given below and answer the questions.
Parts of brain Function
Cerebellum Balance and coordination
Frontal lobe Thinking, behavior, and movement
Motor cortex Movement
Occipital lobe Sight and vision

Question. Name the part of the brain where the cerebrum is located ?
Answer : The forebrain of the brain contains an area known as the cerebrum. This area is composed of the cerebral cortex.

Question. The cerebellum is located in the ____________ .
Answer : The cerebellum is located in the hindbrain. The structure present toward the lower back of the skull is the hindbrain.

Question. What is the main thinking part of the brain ?
Answer : The major part of the brain that is involved in thinking is the forebrain.

Question. Name the nerves that arise from the spinal cord.
Answer : The nerves that arise from the spinal cord are called spinal nerves.

3. A system of control and coordination is essential in living organism to maintain homeostasis as well as to respond to various stimuli. The working together of various organs in an organism, to produce a proper response to a stimulus is called coordination. In animals, control and coordination is done by the nervous system and endocrine system.
Hormones in animals conduct a variety of functions like growth, sexual development, vegetative development, cellular respiration, metabolism, thermal production etc. While the nervous system coordinates activities of animals like movement, hormones integrate the coordination. Larger complex animals like vertebrates have endocrine glands to produce hormones.

Question. Which of the following statement is incorrect regarding Thyroid gland?
(a) Present in the neck region.
(b) Produces thyroxin.
(c) Responsible for metabolic rate, healthy hair & skin.
(d) Regulates blood sugar level.
Answer : D

Question. Which endocrine gland controls Development of female sex organs, regulates menstrual cycle, etc?
(a) Pituitary
(b) Thyroid
(c) Ovaries
(d) Pancreas
Answer : C

Question. Deficiency of which hormone leads to dwarfism
(a) Adrenaline
(b) Thyroxin
(c) Growth Hormone
(d) Somatostatin
Answer : C

Question. _________ is a hormone produced by the beta cells of the pancreas
(a) Insulin
(b) Glucagon
(c) Glycogen
(d) Oxytocin
Answer : A

Question. Growth hormone is secreted by:
(a) Pituitary gland
(b) Thyroid gland
(c) Pancreas
(d) Testes
Answer : A

4. Plants do not show the type of movements that animals exhibit. Plants are anchored to a place, remain stationary and perform their duties. However, plants also show certain movements of their body or body parts in response to changes in the environment. Most of these movements are hard to see. The movements that plants exhibit come under two categories viz Growth movements and Turgour movements.

Question. The movement of a plant part in response to the force of attraction exerted by the earth is called:
(a) Hydrotropism
(b) Geotropism
(c) Chemotropism
(d) Phototropism
Answer : B

Question. The main function of the plant hormone called Abscisic acid is to:
(a) Increase the length of cells
(b) Promote cell division
(c) Inhibit growth
(d) Promote growth of stem and roots
Answer : C

Question. 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
(c) Rapid cell division and elongation in tendril cells that are away from the support
(d) Rapid cell division and elongation in tendril cells in contact with the support
Answer : C

Question. Twining of tendrils around a support is a good example of:
(a) Chemotropism
(b) Nastic movements
(c) Phototropism
(d) Thigmotropism
Answer : D

Question. A growing seedling is kept in a dark room. A burning lamp is placed near to it for a few days.The top part of seedling bends towards the burning candle. This is an example of:
(a) Chemotropism
(b) Hydrotropism
(c) Phototropism
(d) Geotropism
Answer : C