Science M.C.Q

Spinal cord begins in continuation with medulla and extends downwards.

Pituitary gland is unpaired gland.

Hormones of thyroid gland have iodine as their structural component.

Abscisic acid serves to form of layer of abscission.

Phototropism is the response of the plants towards light. Thus, sunflower moves in accordance with the path of sun.

Cerebellum controls posture and balance of the body.

Synapse is the junction between two neurons.

The actions that are not under our direct control are called as involuntary actions.

Testosterone is the male sex hormone necessary for sperm production.

Growth movements in response to touch are known as thigmotropism.

Testosterone and estrogen are male and female sex hormones respectively.

Abscisic acid (ABA) is a growth retardation hormone.

Cerebrum is the center for higher thought processes required for learning, memory, language and speech. Medulla is the center for regulation of involuntary actions.

It is an inhibitory hormone and hence is not associated with growth of plant.

The electric impulses travel from the axon to the dendrite of another neuron through a synaptic gap which consists of SYNAPSE.

Adrenaline is secreted by the adrenal gland.

Insulin has no role to play in growth and development of the body.

When a person is suffering from severe cold, his olfactory receptors are blocked. Due to this, sense of smell is compromised.

At the axonal end, electrical impulse sets off the release of some chemicals; called neurotransmitters. These chemicals enter the dendrite of another neuron to transmit the signal.

 Dendrite receives signals from sensory receptors or other neurons. Axon serves to conduct the nerve impulse away from the cell body.

 Medulla is a part of hind brain.

Chemicals are released from the axonal end and not from dendritic end.

It is iodine which is essential for the synthesis of thyroxin.

Excess amount of water results in guard cells becoming turgid, while lack of water results in flaccidity of guard cells.

Stigma serves as landing platform for pollens as well as secretes chemical substances that attract pollen tube through style towards ovary.

As the name suggests, growth hormone is responsible for proper growth in a person. Hence, lack of growth hormone would result in dwarfism.

A stimulus received by the receptors present on skin, is transmitted to the sensory neuron which carries it to the central nervous system (the spinal cord and brain). A motor neuron carries the message from the central nervous system to the effector which could be a muscle, a gland or both.

The term ‘phototropism’ is composed of two terms. ‘Photo’ means light and ‘tropism’ means growth.

Reproductive or respiratory systems have no role to play in control and coordination.

If a person is suffering from diabetes then his blood sugar level may become high. This disease is managed in some patients by administering insulin injection.

Gustatory receptors are the taste receptors which are present on the surface of tongue in the form of taste buds. Olfactory receptors help to sense the smell and are located over the roof of nasal cavity.