Class 10 Science Chapter 6 MCQ

Junction between two neurons is called synapse. Cell Junction is a junction between neighboring cells. Neuromuscular Junction which connects nervous system to “Muscular System”.

There are two adrenal glands in our body one on top of each kidney. The adrenal glands make adrenaline hormones when we are faced with any dangerous situation, then our nervous system stimulates the adrenal glands to secrete more adrenaline hormone into our blood, then we can react according to the situation.

The person having high sugar level in blood is called a “Diabetic”. Such persons are advised to take less sugar in diet, reduce weight, exercise regularly. Persons with severe diabetes (high sugar level in blood) are treated by giving injections of insulin. Pancreas secrete the hormone insulin. Its function is to regulate blood sugar level. Deficiency of insulin causes a disease known as diabetes that is characterized by large quantities of sugar in blood and even urine. Growth hormone secreted by the pituitary gland regulates growth and development of the body.

Pituitary gland is present just below the brain. The gland secretes a number of hormones. One of the hormone secreted by pituitary gland is growth hormone. The growth hormone controls the growth of the human body.

Testes are paired glands present in males, secretes male sex hormone (testosterone) which control the development of male sex organs and male features as deep voice etc. i.e. changes associated with puberty. Ovaries are paired glands present in females, secretes female sex hormone (oestrogen and progesterone). Oestrogen which control the development of female sex organs and female features as soft skin etc. And progesterone controls uterus changes during menstrual cycle and helps in maintenance of pregnancy.

Deficiency of growth hormone in childhood cause dwarfism while excessive secretion causes gigantism. Deficiency of thyroxine cause goitre. Adrenaline is secreted in small amounts all the time but is secreted in large amount to prepare our body for action during fight or flight.

Iodine is necessary for the synthesis of thyroxine hormone, deficiency of it in the diet of a person produces less thyroxine hormone and causes a disease known as goitre. The main symptom of goitre is that the neck of the person appears to be swollen (due to the enlargement of thyroid gland situated in the neck).

Pituitary gland is known as “master gland” and adrenal glands are often called “glands of emergency”

During cold, mucus in nasal passage becomes too thick, so that order molecules can’t reach the olfactory receptor cells. Thus, brain receives no signal identifying the odour, and so the smell of a perfume cannot be differentiating from that of an “Agarbatti”.

Here, all these statements are correct. Hence, your answer will be option [D].

Abscisic acid is responsible for the formation of layer of abscission. This layer disconnects the living tissue of leaf from the other parts.

The movement of a plant part in response to light is called phototropism.

The pathway or route taken by nerve impulse in a reflex action is called reflex arc. Reflex arcs allowed “Rapid response”.

Tendrils are the thin thread-like groups on the stem or leaves of climbing plants. These are sensitive to touch of other parts objects (i.e. thigmotropic). When a tendril touches an object, then the site in contact with object grows slowly than its other side, (i.e. rapid cell divisions in cells that are away from the support). This causes the tendril to bend towards the object by growing towards it, wind around object and cling to it.

Here, all these statements are correct. Hence, your answer will be option [D].

Adrenaline is secreted by the adrenal glands, located on top of kidneys. Growth hormone is secreted by the pituitary gland.

Abscisic acid is a plant hormone which functions mainly as a growth inhibitor. Abscisic acid promotes the dormancy in seeds and buds. It also promotes the closing of stomata. Abscisic Acid promotes the wilting and falling of leaves which is called “abscission”.

A receptor is a cell (or a group of cells) in a sense organ which is sensitive to a particular type of stimulus such as light, sound, etc. The common type of receptors are: i) Photoreceptors which are present in eyes detect light. ii) Gustatory receptors which are present in tongue detect taste. Iii) Olfactory receptors which are present in nose detect smell. iv) Thermo receptors which are present in skin detect heat or cold.

Spinal cord is a cylindrical structure enclosed in a bony cage called vertebral column. It begins in continuation with medulla and extends downwards.

Auxin hormone increases the rate of growth in a stem but it decreases the rate of growth in a root.