(a) Name the hormone which is released into the blood when its sugar level rises. Explain the need of Chemical communication in multicellular organisms the organ which produces this hormone and its effect on blood sugar level. Also mention the digestive enzymes secreted by this organ with one function of each.
(b) Explain the need of Chemical communication in multicellular organisms.
(a) Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin is a hormone produced by the a-cells that regulates glucose levels in the blood.
In order for multicellular organisms to function properly, their cells must communicate. For instance, your muscles must contract when your brain sends a message to contract.
Pancreas produces insulin and p-cells which increase glucose in blood. It also – produces digestive enzyme (pancreatic amylase).
(b) Cell-to-cell signaling is a critical component of coordinating cellular activities. Through this communication, messages are carried from signaling cells to receiving cells, also known as target cells. This signaling occurs with proteins and other types of signaling molecules. Other things which happens in our body due to cell communication are – growth and development, cellular reproduction, tissue repair, sensing pain, etc.
What is the function of insulin hormone ? What type of patients are given insulin injections ?
(a) Which plant hormone is present in greater concentration in the areas of rapid cell division?
(b) Give one example of a plant growth promoter and a plant growth inhibitor.
(a) What does a plant root do in response to water ? What is this phenomenon known as ?
(b) What happens to the moonflower (i) during daytime, and (ii) at night ? What is this phenomenon known as ?
(a) Name the hormones secreted by the following endocrine glands :
(i) Thyroid gland (ii) Parathyroid glands (iii) Pancreas (iv) Adrenal glands
(b) Write the functions of testosterone and oestrogen hormones.
(a) What is a reflex action ? Explain with the help of an example.
(b) Define reflex arc. Give the flow chart of a spinal reflex arc.
(c) How are involuntary actions and reflex actions different from each other ?
(a) How is brain protected from injury and shock?
(b) Name two main parts of hind brain and state the functions of each.
Name and explain the function of the hormone secreted by the pituitary gland in humans.
What is the general name of chemical substances which bring about control and coordination in plants ?
Give the scientific terms used to represent the following :
(a) Bending of a shoot towards light.
(b) Growing of roots towards the earth.
(c) Growth of a pollen tube towards ovule.
(d) Bending of roots towards water.
(e) Winding of tendril around a support
Which of the following is a growth movement and which is not ?
(a) folding up of leaves of sensitive plant on touching with hand.
(b) folding up of petals of dandelion flower when light fades.
What is a tendril ? Name the two types of tendrils. What does a tendril do in response to the touch of a support ? What is this phenomenon known as ?
Which one term in each of the following includes the other three ?
(a) thyroid, ductless gland, thymus, pituitary, ovary
(b) adrenalin, insulin, hormone, thyroxine, estrogen
Mention one function for each of these hormones:
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.
State the structural and the functional unit of the nervous system. Draw its neat labelled diagram and write two functions.
Name, the two main organs of our central nervous system. Which one of them plays a major role in sending command to muscles to act without involving thinking process? Name the phenomenon involved.
Name one plant hormone that promotes growth and another plant hormone which inhibits growth.
(a) What does a stem (or shoot) do in response to gravity ? What is this phenomenon known as ?
(b) What does a root do in response to light ? What is this phenomenon known as ?
Define chemotropism. Give one example of chemotropism. State whether this example is of positive chemotropism or negative chemotropism.
a) What are the short fibres of a neuron known as ?
What is the long fibre of a neuron known as ?
What is the name of in-built ‘arrangement’ in our body which controls the timing and amount of hormones released by various endocrine glands in the body ?
(a) What is spinal cord ? What is its main function ?
(b) Give the functions of medulla.
(a) The human brain can be broadly divided into three regions. Name these three regions.
(b) What is cranium ? What is its function ?
State the functions of the following hormones :
(a) Thyroxine (b) Adrenaline (c) Growth hormone
Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands ?
Explain the difference between each of the following pairs of terms :
(a) receptor and effector (b) cerebrum and cerebellum
(a) Name the structural and functional unit of nervous system.
(b) Draw a flow chart to show the classification of nervous system into various parts.
(c) What is autonomic nervous system ? What is its function ?
(d) What is voluntary nervous system ? Explain the working of voluntary nervous system with an example.