Answer

(a) Gustatory receptors detect taste while olfactory receptors detect smell

Explanation

A receptor is a cell which is sensitive for the external stimulus such as light,taste, smell. Ex: Photoreceptors detect light.Gustatory receptors detect taste. Olfactory receptors detects smell.

Answer

(c) Dendrite $\longrightarrow$ cell body $\longrightarrow$ axon $\longrightarrow$ axonal end

Explanation

Stimulus is received by dendrites which are transmitted to cyton through axon . Stimulus reaches the terminal branches called as axonal end from where they are transmitted to another neuron.

Answer

(d) axonal end of one neuron to dendritic end of another neuron

Explanation

Electric impulse travel from the axon to the dendrite of another neuron through a synaptic gap which consist of SYNAPSE.

Answer

(b) axonal end

Explanation

At axonal end electric impulse triggers the release of neurotransmitter. These chemicals eneter dendrite of another neuron to transmit the signal.

Answer

(d) Receptors $\longrightarrow$ Sensory neuron $\longrightarrow$ Spinal cord $\longrightarrow$ Motor neuron $\longrightarrow$ Muscle

Explanation

Sensory neurons receive signals from receptors. These signals are sent to spinal cord which reaches Muscles through motor neuron.

Answer

(c) (i) and (iv)

Explanation

Sensory neurons carry signals from muscles to spinal cord hence statement ii) and iv) are wrong statements.

Answer

(c) (ii) and (iii)

Explanation

Forebrain is the thinking part of brain hence statement i) is wrong. Cerebellum control posture and balance of the body hence statement iv) is wrong

Answer

(b) cerebellum

Explanation

Cerebrum is responsible for sensory processing. Medulla controls involuntary functions. Pons regulates respiration and controls involuntary actions sensations such as touch and pain.

Answer

(b) medulla

Answer

(d) phototropism

Explanation

Growth of plant roots towards or away from moisture is called hydrotropism. Plant growth in response to gravitational force is called as geotropism. Growth of plant in response to chemical stimulus is called chemotropism.

Answer

(c) inhibit growth

Explanation

Auxins increase the length of cells. Cytokinins promote cell division. Gibberlins promote growth of stem.

Answer

(d) Abscisic acid

Explanation

Abscisic acid inhibit the growth of plant hence it is not associated with growth of plant.

Answer

(b) Thyroxin

Answer

(b) It regulates growth and development of the body

Answer

(a) Adrenaline : Pituitary gland

Explanation

Adrenaline is secreted by Adrenal gland and Pitutary gland produces TSH, FSH and GSH hormones.

Answer

(c) amount of water in cells

Explanation

Excess of water will turn guard cells turgid and loss of water turn guard cells flaccid.

Answer

(c) rapid cell divisions in tendrillar cells that are away from the support

Answer

(b) chemotropism

Explanation

Chemicals released by ovules stimulate the growth of pollen tubes towards ovules.

Answer

(a) phototropism

Explanation

The movement of shoot towards light is called phototropism.

Plant growth in response to gravitational force is called as geotropism .

Growth of plant in response to chemical stimulus is called chemotropism.

Growth of plant roots towards or away from moisture is called hydrotropism.

Answer

(c) abscisic acid

Explanation

abscisic acid forms a layer of abscission. This layer disconnect the living tissue of leaf from the other parts.

Answer

(b) 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

Explanation

Chemicals or neurotransmitters are released at axonal end not on dendritic end. Hence statement b) is incorrect

Answer

(c) medulla in hind brain

Explanation

Medulla is present only in hind brain

Answer

(d) Chewing

Answer (b) differentiate the smell of a perfume from that of an agarbatti

Explanation

During cold olfactory receptors gets blocked hence we cannot differentiate smell.

Answer

c)

Explanation

Dendrites of a neuron receive electrical impulse from axonal end of another neuron. After that, electrical impulse travels through cell body, axon; to the axonal end.

Answer

(a) Iron is essential for the synthesis of thyroxin

Explanation

Iodine is essential for the synthesis of thyroxin but not iron hence statement a) is wrong

Answer

(b) Less secretion of growth hormone

Explanation

Growth hormones are responsible for the overall growth of an organism. When there will be no secretion of growth hormones it leads to dwarfism.

Answer

(c) testosterone from testes and estrogen from ovary

Explanation

These are the sex hormones responsible for the secondary character that appear after puberty. Males secrete testosterone and females secrete estrogen.

Answer

(d) his sugar level in blood was high

Explanation

Patient suffering from diabetes will have high blood glucose due to non-functioning or lack of insulin hormone. Such patients are administered with insulin injection to regulate blood glucose.

Answer

(b) testosterone

Answer

(c) Pituitary

Explanation

Adrenal glands are two which are present on top of each kidney. Testes is a paired gland in males which produces male sex hormones. Ovary is a paired gland in females which produces female sex hormones. Pitutary gland is an independent gland present below the brain. It is called as master gland as it secretes major of the hormones.

Answer

(d) synapse

Explanation

A synapse is a structure that allows a neuron to pass an electric signal to the next neuron or effector cell. Hence it is a junction between two neurons.

Answer

(d) nervous and endocrine systems

Explanation

Reproductive, respiratory and digestive systems have no role to play in control and regulation of life processes. It is the nervous system and the endocrine system that control and regulates all the processes including Reproductive, respiratory and digestive systems.

Answer

a) Sensory neuron

b) Spinal cord

c) Motor neuron

d) Muscle

Answer

a) Auxin

b) Gibberlin

c) Cytokinin

d) Abscisic acid

Answer

a) Pineal Gland

b) Pitutary gland

c) Thyroid gland

d) Thymus

Answer

Figure a) is more accurate because in figure a plant root shows positive geotrophism and shoot shows positive phototrophism.

Answer

a) Dendrite

b) Cellbody

c) Axon

d) Axon terminal

Answer

Answer

Directional growth movement of a plant due to external stimulus is called as tropic movement. Movement can be either toward the stimulus or away from stimulus. Ex: Roots shows positive geotropic movement and they grow with direction of gravity whereas shoots shows negative geotropic movement.

Answer

Iodine is essential for the synthesis of hormone thyroxin. If we take low iodine diet it leads to hypo thyroidism which results in a disease called as goiter.

Answer

At Synapse nerve impulse of a nerve cell gets converted to neurotransmitters which travels towards dendrites of next neuron leading to electric impulse.

Answer

a) Oestrogen hormone is responsible for the changes noticed in females at puberty

b) Dwarfism results due to deficiency of Growth Hormones.

c) Blood sugar level rises due to deficiency of Insulin Hormone

d) Iodine is necessary for the synthesis of Thyroxine Hormone

Answer

a) Pitutary gland is associated with brain

b) Pancreas secretes digestive enzymes as well as hormones

c) Adrenal gland is associated with kidneys

d) Testis is present in males but not in females

Answer

Neuron is highly specialized cell responsible for the transmission of nerve impulse.

STRUCTURE OF NEURON

Soma or cellbody is a star shaped hair like structure Hair like structures are called as dendrites. Dendrites receives nerve impulses.

Axon is the tail of the nucleus it ends in hair like structures which makes nerve endings. Nerve endings relay nerve impulses.

Mylein sheath acts as an insulator around the axon. It insulates axons from the electrical impulses from the surroundings.

Function of neuron is to process and transmit information from brain to all parts of the body.

Answer

Human brain

Functions of brain Parts

Forebrain:

The fore-brain is the main thinking part of the brain. It has regions which receive sensory impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight and so on.

Mid brain and Hind brain:

Involuntary actions are controlled by the mid-brain and hind-brain.

Cerebellum:

Responsible for voluntary actions and maintaining the posture and balance of the body.

Cerebrum:

Cerebrum is responsible for sensory processing.

Medulla:

Medulla controls involuntary functions.

Pons:

Pons regulates respiration and controls involuntary actions sensations such as touch and pain.

Hypothalamus:

Hypothalamus control sleep and wake cycle

Answer

Central nervous system comprises of brain and spinal cord. Peripheral nervous system is composed of nerves which are outside the spinal cord.

Central nervous system has a well-developed system for its protection. Brain is enclosed in a hard shell know as skull. Spinal cord is enclosed in vertebral column for its protection. Along with these there is cerebrospinal fluid which protects the brain from mechanical shocks.

Answer

Thyroxin:

Thyroxin regulates carbohydrate, protein and fat metabolism in the body so as to provide the best balance for growth.

Insulin:

Insulin regulates blood glucose levels. If insulin not secreted in an appropriate level it leads to rise in blood glucose level which results in many adverse effects on life processes.

Adrenaline:

Adrenaline prepares our body for emergency situations. Adrenaline is also called as fight and flight hormone.

Growth Hormone:

Growth hormone is responsible for the growth and regulation of growth.

Testosterone:

Testosterone is responsible for the expression of secondary sexual characters in the body.

Answer

a) Auxin- responsible for elongation of cells

b) Gibberlin- responsible for growth of stem and thereby increases girth of stem

c) Cytokinin promotes cell division in plants

d) Abscisic acid stops growth of the plant and it makes leaves and fruits fall from plant.

Answer

The sudden involuntary movement in a voluntary organ; in response to a stimulus; is called reflex action.

Examples of reflex action:

(a) Moving your hand away from a hot iron plate

(b) Blinking of eyes

Reflex Arc.

Reflex arc is a path of electrical impulse during a reflex action. It is composed of sensory neuron, spinal cord, motor neuron and muscle.

Steps of reflex arc

• The sensory neuron picks signals from the stimulus and carries the signals to the spinal cord.
• Spinal cord process the signals and sends message through the motor neuron.
• Motor neuron transmits the signals to the effector muscle so that the muscle can take immediate action.

Answer

Control and coordination in human beings is under the influence of nervous system . Brain control all the organelles and organ system. The control is obtained by network of neurons which carry signals through neurotransmitters in the form of electric impulses to the brain and from the brain.

Hormonal system consist of varieties of hormones secreted by various glands in our body. Hormonal system coordinates the function of nervous system. Hormones indirectly control the life processes by feedback mechanism. They can produce hormones when required and can stop production when not required.

Answer

Chemical coordination takes place in animals through hormones produced by glands present in animals. Hormones are directly released into blood stream to reach the target site. Hormones control the behavior of the target tissue.

Example:

Adrenal gland secretes Adrenalin which reaches the heart, lungs and Gastro intestinal tract. Heart speeds up its pumping action so that more blood could be supplied to the limbs and facial muscles. But activity of the GI tract is slowed down to ensure better blood supply in limbs. Thus, adrenalin prepares the body for a fight or flight situation.

Answer

Electrical impulse travels through a neuron. But to be transmitted to another neuron, it need to be passed in the form of neurotransmitters. Neurotransmitters are specialized chemicals. They can enter a neuron only through specialized channels. Such channels are present in dendrites but not in axon. On the other hand, a neurotransmitter can enter a dendrite. Due to this, the flow of signals in a synapse is from axonal end of one neuron to dendritic end of another neuron but not the reverse.