Online NCERT Notes on Chapter=7 (Control and Coordination) Part 2

This is Online NCERT Notes on Chapter=7 (Control and Coordination)  Part 2 for preparation of CBSE BOARD Examination, NTSE etc.

COORDINATION IN PLANTS:

Movements in plants :

(i) Independent of growth

(ii) Dependent on growth

(i) Independent of growth : Immediate response to stimulus.

• Plants use electrical-chemical means to convey information from cell to cell.

• For movement to happen, cells change their shape by changing the amount of water in them, resulting in swelling or shrinking of cells.

E.g., Drooping of leaves of ‘Touch-me-not’ plant on touching it.

(ii) Dependent on growth : These movements are tropic movements i.e., directional movements in response to stimulus.

• Tendrils : The part of tendril away from the object grows more rapidly as compared to the part near the object. This causes circulating of tendril around the object.

• Phototropism : Movement towards light.

• Geotropism : Movement towards/away from gravity.

• Chemotropism : Growth of pollen tube towards ovule.

• Hydrotropism : Movement towards water.

Plant Hormones : Are chemical compounds which help to coordinate growth, development and responses to the environment.

Main plant hormones are :

(a) Auxin :

• Synthesized at shoot tip

• Helps the cells to grow longer

• Involved in phototropism

(b) Gibberellin :

• Helps in the growth of the stem

(c) Cytokinins :

• Promotes cell division

• Present in greater concentration in fruits and seeds

(d) Abscisic Acid : 

• Inhibits growth

• Cause wilting of leaves

• Stress hormone

Hormones in Animals :

Hormones : Hormones are the chemical substances which coordinate the activities of living organisms and also their growth.

Endocrine glands : These glands secrete their product (hormone) into the blood. Endocrine Gland, Hormones and their Functions

Endocrine Gland, Hormones and their Functions

Iodised salt is necessary because iodine mineral is essential part of thyroxine hormone secreted by thyroid gland.

Thyroxine regulates metabolism of carbohydrates, fats and proteins.

So, we must consume iodised salt which is necessary for proper working of thyroid gland. It’s deficiency causes a disease called goiter (Swollen neck).

Diabetes:

Disease in which blood sugar level increase.

Cause : Due to the deficiency of insulin hormone secreted by pancreas that is responsible to control blood sugar levels.

Treatment : Injections of insulin hormone.

Feedback Mechanism:

The excess or deficiency of hormones has a harmful effect on our body.
Feedback mechanism makes sure that hormones should be secreted in precise quantity and at right time.

E.g., Feedback mechanism to control the sugar level in blood is as follows :

Sugar level in the blood rises.

Practice Questions on Chapter=7 (Control and Coordination)

These are Online Practice Questions on NCERT  Chapter =  7 (Control and Coordination)  for preparation of CBSE BOARD Examination, NTSE etc.

QUESTIONS:

VERY SHORT QUESTIONS (1 Mark)

1. Where is auxin synthesized in plants ?
2. Which gland is known as master gland ?
3. Name the hormone that regulates blood sugar level.
4. What is synapse ?
5. What are tropic movements ?
6. Which part of the brain is responsible for maintaining posture and balance of our
body ?
7. Which hormone has inhibiting effects on growth of plants ?

8. What is phototropism ?
9. What are the components of central nervous system ?
10. What happens at synapse between two neurons ?

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. Draw a labelled diagram of neuron.
2. What is reflex arc ? Explain with the help of flow chart.
3. What is the cause of diabetes ? How it can be controlled ?
4. Why is it advisable to use iodised salt ?
5. What are sensory and motor neurons ? Write their functions.
6. Why is Abscisic acid called as stress hormone ?
7. What is the need for a system of control and coordination in an organization ?

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. What are plant hormones ? Name a plant hormone that promotes growth in plants.
2. What is the significance of tropic movements in plants ? Explain any two types of
tropic movements.
3. Which hormone is known as emergency hormone in our body ? How it helps in coping
during emergency ?
4. Where are different receptors present in our body ? What are their functions ?

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. Draw a labelled diagram of human brain and state the functions of its different parts.
2. What are hormones ? Give the name of associated gland and functions of different
animal hormones.
3. What is feedback mechanism ? Explain its working with the help of one example.
4. (a) How brain and spinal cord are protected ?
(b) What are the different parts of human nervous system ?
(c) What are the limitations of nervous system ?

VALUE BASED QUESTION

Rahul’s aunt is obese. She is very fond of eating sweets and junk food. She feels very
thirsty and passes excess of urine. She got herself examined by the doctor. Doctor told

her not to eat sweet things and exercise regularly. He prescribed some medicines also.
9. What are the components of central nervous system ?
10. What happens at synapse between two neurons ?

Online Notes on Chapter=7 (Control and Coordination) Part 1

This is Online Notes on Chapter=7 (Control and Coordination)  Part 1 for preparation of CBSE BOARD Examination, NTSE etc.




• All the living organisms respond and react to changes in the environment around them.

• The changes in the environment to which the organisms respond and react are called Stimuli such as light, heat, cold, sound, smell, touch etc.

• Both plants and animals respond to stimuli but in a different manner. Control and Coordination in Animals

It is brought about in all animals with the help of two main systems:

(a) Nervous system

(b) Endocrine system

NERVOUS SYSTEM:

• Control and coordination are provided by nervous and muscular tissues.
• Nervous tissue is made up of an organized network of nerve cells or neurons, and is specialized for conducting information via electrical impulses from one part of the body to another.

Receptors : Are specialized tips of some nerve cells that detect the information from the environment. These receptors are located in our sense organs.

(a) Ear : 
• Phonoreceptors

• Hearing

• Balance of the body

(b) Eyes :

• Photoreceptors

• Seeing

(c) Skin :

• Thermoreceptors

• Heat or cold

• Touch

(d) Nose :

• Olfactory receptors

• Smell detection

(e) Tongue :

• Gustatory receptors

• Taste detection

Neuron : It is the structural and functional unit of nervous system.

Parts of Neuron :

(a) Dendrite : Acquires information.

(b) Cell body : Acquired information travels as an electrical impulse.

(c) Axon : Longest fibre on the cell body is called axon. It transmits electrical impulse from cell body to dendrite of next neuron.

Synapse : It is the gap between the nerve ending of one neuron and dendrite of the other neuron. Here electrical signal is converted into chemical signal for onward transmission.

REFLEX ACTION:

Reflex action is quick, sudden and immediate response of

Reflex arc : The pathway through which nerve impulses pass during reflex action is called Reflex Arc.

Response : Responses are of three main types :

(a) Voluntary : Controlled by fore brain. E.g., talking, writing.

(b) Involuntary : Controlled by mid and hind brain. E.g., heart beat, vomiting, respiration.

(c) Reflex action : Controlled by spinal cord. E.g., withdrawal of hand on touching a hot object.

Need of Reflex Actions : In some situations such as touching a hot object, pinching etc. 
we need to act quickly, otherwise our body would be harmed. Here response is generated from spinal cord instead of brain.

HUMAN BRAIN:

Brain is the main coordinating centre of the body. It has three major parts :

(a) Fore-brain (b) Mid-brain (c) Hind-brain

(a) Fore-brain : It is the most complex or specialized part of the brain. It consists of cerebrum.

Functions :

(i) Thinking part of the brain.

(ii) Control the voluntary actions.

(iii)Store information (Memory).

(iv) Receives sensory impulses from various parts of the body and integrate it.

(v) Centre associated with hunger.

(b) Mid-brain : Controls involuntary actions such as :

• Change in pupil size.

• Reflex movements of head, neck and trunk.

(c) Hind-brain : It has three parts :

 (i) Cerebellum : Controls posture and balance. Precision of              voluntary actions e.g., picking pen.

 (ii) Medulla : Controls involuntary actions e.g., blood pressure,        salivation, vomiting.

(iii) Pons : Involuntary actions, regulation of respiration.

Protection of Brain and Spinal Cord:

(a) Brain : Brain is protected by a fluid filled balloon which acts as shock absorber and is enclosed in cranium (skull or brain box).


(b) Spinal Cord : Spinal cord is enclosed in vertebral column.

Coordination between Nervous and Muscular Tissue:

Limitations of Electric communication/Nervous system :

(a) Electric impulse will reach only to those cells that are connected by nervous tissue.

(b) After generation and transmission of an electrical impulse, the cell takes some time to reset its mechanism before transmitting another impulse. So cells cannot continually create and transmit impulse.

(c) Plants do not have any nervous system.

Chemical communication: To overcome the limitations of electric communication.

Online Practice Q_ANS on CHAPTER => 6 (life processes )

This is Online Practice Q_ANS on CHAPTER => 6 (life processes ) for
preparation of CBSE BOARD Examination, NTSE etc.

VERY SHORT QUESTIONS (1 Mark)

1. State one difference between autotrophic and hetrotrophic mode of nutrition.
2. Define peristaltic movement.
3. What is the role of saliva in the digestion of food ?

4. Name the tissue that transports water and minerals in plants.
5. What is the role of acid in our stomach ?
6. What is emulsification ?

7. Name the cell organelle in which photosynthesis occur.
8. Name the largest artery in the human body.

9. Define transpiration.
10. What is the structural and functional unit of kidney called ?

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. How is small intestine designed to absorb digested food ?
2. What are stomata ? Draw a labeled diagram of stomata.
3. Write the equation for the process of breakdown of glucose in a cell :
(a) in the presence of oxygen.
(b) in the absence of oxygen.

4. Write the differences between inhalation and exhalation.
5. List the three events which occur during photosynthesis.
6. How does transpiration help in upward transport of substances.

7. Write the functions of the components of blood.
8. Why is small intestine longer in herbivores than in carnivores ?
9. Explain the cause of cramps after excessive physical exercise.

10. Why is the rate of breathing in aquatic organisms much faster than that seen in terrestrial organisms.

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. Describe the process of double circulation in human beings.
2. What are the methods used by plants to get rid of their waste products ?

3. Give reason for the following :
(a) Arteries are thick walled blood vessels.
(b) Veins are thin walled blood vessels.
(c) Veins have valves in them.

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. If you chew chapatti for long, after some time it taste sweet ? Why is this so ?
2. What is the benefit of residual volume of air in the respiratory process ?
3. Why is the energy needs in plants is very less as compared to animals ? Explain.

4. Draw a well-labelled diagram of Nephron. Explain the process of formation of urine in the human kidney.
5. Draw a diagram showing Human Respiratory System. Label the following parts :
(a) Alveolus (b) Trachea
(c) Bronchus (d) Lungs

Hints to Long Answer Type Questions

1. Chapati will taste sweet as saliva breaks down starch which is a complex molecule to give sugar.
2. The lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
3. Plant gets most of energy during photosynthesis.

4. See the given diagram.
5. See the given diagram.

Online Notes on Chapter = 6 ( life processes) Part 3

This is Online Notes on Chapter = 6 ( life processes)  Part 3 for 
preparation of CBSE BOARD Examination, NTSE etc.



Blood:

Lymph : A yellowish fluid escapes from the blood capillaries into the intercellular spaces contain less proteins than blood. Lymph flows from the tissues to the heart assisting in transportation and destroying germs.

Blood Vessels:

Function :

(a) Absorption and upward movement of water and minerals by creating PULL.

(b) Helps in temperature regulation in plant.

Transport of food from leaves (food factory) to different part of the plant is called Translocation.

EXCRETORY SYSTEM IN MAN

Excretory/urinary system consists of :

(1) The kidneys : The excretory organ

(2) The ureters : The ducts which drain out urine from the kidneys

(3) The urinary bladder : The urinary reservoir

(4) The urethra : The channel to the exterior

                   The human excretory system

EXCRETION

1. The metabolic activities in the body generates many kinds of wastes including

nitrogenous wastes which are harmful for the body and hence needed to be removed.

Excretion is a process by which these wastes are removed from our body.

2. Unicellular organisms remove these wastes by simple diffusion.

Human Excretory System

Formation of Urine:

• Each kidney contains many filtration units called as nephrons.

• Nephrons are made up of a cluster of thin walled capillaries called glomerulus

which is associated with a cup like structure called as Bowman’s capsule and the

long tube which terminates through this capsule.

• The renal artery brings oxygenated blood to the kidneys along with the nitrogenous wastes like urea and uric acid and many other substances.

• The blood gets filtered through the glomerulus and this filtrate enters the tubular part of nephron.

• As this filtrate moves down the tubular part, glucose, amino acids, salts and excess of water gets selectively reabsorbed by the blood vessels surrounding these tubules.

• The amount of water reabsorbed depends upon :

* How much excess of water is there in the body and,

* How much nitrogenous wastes need to be excreted out.

• So the fluid now flowing in the tubular part is urine which gets collected in collecting ducts of nephrons.

• These collecting ducts together leave the kidney at a common point by forming the ureter.

• Each ureter drains the urine in the urinary bladder where it is stored until the

pressure of expanded bladder leads to an urge to pass it out through urethra.

• This bladder is a muscular structure which is under nervous control.

• 180 litres of filtrate is formed daily but only 2 litres is excreted out as urine so the rest is reabsorbed in the body.

Functions of Nephron:

• Excretion of nitrogenous wastes.

• To maintain the water and ionic balance (osmic regulation).

Excretion in Plants:

Plants use different strategies for excretion of different products :

• Oxygen and carbon dioxide is diffused through stomata.

• Excess water is removed by transpiration.

Plants can even loose some of their old parts like old leaves and bark of tree.

• Other waste products like raisins and gums especially in old xylem cells which canalso be lost by plants.

• Plants also secrete some waste substances into the soil around them

                                               Structure of a Nephron

The urine formation involves three steps :

1. Glomerular filtration : Nitrogenous wastes, glucose water, amino acid filter from the blood into Bowman Capsule of the nephron.

2. Tubular reabsorption : Now, useful substances from the filtrate are reabsorbed back by capillaries surrounding the nephron.

3. Secretion : Urea, extra water and salts are secreted into the tubule which open up into the collecting duct & then into the ureter.

Artificial Kidney:

Haemodialysis : The process of purifying blood by an artificial kidney. It is meant for kidney failure patients.

Online Notes on Chapter = 6 ( life processes) Part 2

This is Online Notes on Chapter = 6 ( life processes)  Part 2 for 
preparation of CBSE BOARD Examination, NTSE etc.



RESPIRATION:

Respiration involves :

(i) Gaseous exchange : 
Intake of oxygen from the atmosphere and release of CO2 → Breathing

(ii) Breakdown of simple food in order to release energy inside the cell → Cellular respiration


Breakdown of Glucose by Various Pathways:

Human Respiratory System:


Passage of air through the respiratory system :

Exchange of gases between alveolus, blood and tissues:

(i) Air (rich in O2) → Blood → Binds with haemoglobin in RBC → O2 is released in (in alveolus) (through blood vessels) tissues

(ii) CO2 → Released in blood → Dissolved in blood → Blood vessels → Released in alveolar sac → Sent out through nostrils (from tissue) (in alveoli)

Terrestial organisms : Use atmospheric oxygen for respiration

Aquatic organisms : Use dissolved oxygen for respiration

Respiration in plants:

Respiration in plants is simpler than the respiration in animals. Gaseous exchange occur through :

(a) Stomata in leaves

(b) Lenticels in stems

(c) General surface of the root Transportation

Human beings like other multicellular organism need regular supply of food, oxygen etc.

This function is performed by circulatory system.

Pulmonary Circulation : Blood moves from the heart to the lungs and back to the heart.

• Systemic Circulation : Blood moves from the heart to rest of the body and back to the heart.

Online Notes on Chapter = 6 ( life processes) Part 1

This is Online Notes on Chapter = 6 ( life processes)  Part 1 for 
preparation of CBSE BOARD Examination, NTSE etc.

All living things perform certain life processes like growth, excretion, respiration,
circulation etc.
All the processes like respiration, digestion, which together keep the living organisms
alive and perform the job of body maintenance are called life processes.

Raw Materials for Photosynthesis :
• Sunlight
• Chlorophyll → Sunlight absorbed by chlorophyll
• CO2 → Enters through stomata and oxygen (O2) is released as by-product through
stomata on leaf.
• Water → Water + dissolved minerals like nitrogen, phosphorus etc. are taken up by the
roots of the soil.
Site of Photosynthesis :
Chloroplast in the leaf, chloroplast contain chlorophyll (green pigment).
Main Events of Photosynthesis :
• Absorption of light energy by chlorophyll
• Conversion of light energy into chemical energy + splitting (breaking) of water into
hydrogen and oxygen
• Reduction of CO2 to carbohydrates
Stomata : Tiny pores present on the surface of the leaves.
Functions :
(a) Exchange of gases O2/CO2.
(b) Loses large amount of water (water vapour) during transpiration.

How do organisms obtain their food
Unicellular/Single celled organisms : Food is taken up through entire surface.
Example : (i) Amoeba
(ii) Paramaecium

Different organisms utilize different nutritional processes as it depends upon the source
of carbon from where the food is taken.

Online Practice Q_ANS on CHAPTER => 9 (Heredity and Evolution )

This is Online Practice Q_ANS on CHAPTER => 9 (Heredity and Evolution )for preparation of CBSE BOARD Examination, NTSE etc.


VERY SHORT ANSWER TYPE QUESTIONS (1 Mark):

1. Write the scientific name of men and garden pea.
2. Where are genes located ?
3. No two individuals are absolutely alike in a population. Why ?
4. What are the chromosomes XY and XX known as ?
5. Name five varieties of vegetables which have been produced from ‘wild
cabbage’ by the process of artificial selection.

SHORT ANSWER TYPE QUESTIONS (2 Marks):

1. Differentiate between homologous and analogous organs, with examples.

2. What are fossils ? How can the age of fossils be determined ?

SHORT ANSWER TYPE QUESTIONS (3 Marks):

1. Variation is beneficial to the species but not necessarily for the individual.
Give three reasons to justify it.

2. The human hand, cat paw and horse foot, when studied in detail show the
same structure of bones and point towards a common origin.
(a) What do you conclude from this ?
(b) What is the term given to such structures ?

LONG ANSWER TYPE QUESTIONS (5 Marks):

1. Which one is the edible part in kale, kohlrabi, broccoli, cabbage and
cauliflower ?
2. Name a recessive trait which is quiet common in human beings.

VALUE BASED QUESTION:

Raghu often taunts his wife for having only daughters and no son. As a
student of biology, how will you convince Raghu that his wife has no role in
giving birth to girls only ?

Hints to Long Answer Type Questions:

1. Kale - Large leaves
Kohl rabi - Swollen part
Broccoli - Arrested flower
Cauliflower - Sterile flower
Cabbage - Leaves with short distance between them

2. (a) Human height
(b) Skin colour
(c) Attachment of ear lobes
(d) Eye colour

Online Notes on Chapter = 9 ( Heredity and Evolution) Part 3

This is Online Notes on Chapter = 9 ( Heredity and Evolution)  Part 3 for
preparation of CBSE BOARD Examination, NTSE etc.





Evolution and Classification:

Both evolution and classification are interlinked =>

1. Classification of species is reflection of their evolutionary relationship.
2. The more characteristic two species have in common the more closely
they are related.
3. The more closely they are related, the more recently they have a common
ancestor.
4. Similarities among organisms allow us to group them together and to
     study their characteristic.

TRACING EVOLUTIONARY RELATIONSHIPS:

(Evidences of Evolution)

I. Homologous Organs: (Morphological and anatomical evidences). These
are the organs that have same basic structural plan and origin but different functions.

Homologous organs provides evidence for evolution by telling us that they
are derived from the same ancestor.

Evolution by Stages:

Evolution takes place in stages i.e., bit by bit generations.

I. Fitness Advantage:

Evolution of Eyes : Evolution of complex organs is not sudden. It occurs
due to minor changes in DNA, however takes place bit by bit over generations.

• Flat worm has rudimentary eyes. (Enough to give fitness advantage)
• Insects have compound eyes.
• Humans have binocular eyes.

II. Functional Advantage:
Evolution of Feathers : Feathers provide insulation in cold weather but later
they might become useful for flight.
Example, Dinosaurs had feathers, but could not fly using feathers. Birds
seem to have later adapted the feathers to flight.

Although there is great diversity of human forms all over the world, yet all
humans are a single species.

GENETIC FOOTPRINTS OF HUMANS:

Hundreds/thousand of years ago

• They did not go in a single line.
• They went forward and backward.
• Moved in and out of Africa.
• Sometimes came back to mix with each other.

Genetic Terminology:

1. Gene : Mendel used the term factor for a gene. A gene is the unit of
DNA responsible for the inheritance of character.

2. Allele : A pair of genes that control the two alternatives of the same
character e.g., TT/tt.

3. Heterozygous : The organism in which both the genes of a character are
unlike e.g., Tt.

4. Homozygous : The organism in which both the genes of a character are
similar e.g., TT, tt.

5. Dominant : The gene which expresses itself in F1 generation is known
as dominant gene.

6. Recessive : The gene which is unable to express itself in presence of the
dominant gene.

7. Genotype : It is the genetic constitution of an organism which determines
the characters.

8. Phenotype : It is the appearance of an individual.

9. Micro-evolution : It is the evolution which is on a small scale.

10. Species : A group of similar individuals within a population that can
interbreed and produce fertile offspring.

11. Chromosome : Thread like structures present in the nucleus of a cell,
containing hereditary information of the cell.

12. DNA : Deoxyribose Nucleic Acid.
It is present in chromosomes which carries traits in a coded form, from one
generation to the next.

Online Notes on Chapter=9 ( Heredity and Evolution) Part 2

This is Online Notes on Chapter=9 ( Heredity and Evolution)  Part 2 for preparation of CBSE BOARD Examination, NTSE etc.





Dihybrid Cross:
A cross between two plants having two pairs of contrasting characters is

called dihybrid cross.

Conclusion:
No genetic change has occurred in the population of beetle. The population
gets affected for a short duration only due to environmental changes.

ACQUIRED AND INHERITED TRAITS:

Online Notes on Chapter=9 ( Heredity and Evolution) Part 1

This is Online Notes on Chapter=9 ( Heredity and Evolution)  Part 1 for preparation of CBSE BOARD Examination, NTSE etc.

Accumulation of Variation during Reproduction :

Importance of Variation :

(i) Depending upon the nature of variations different individuals would
have different kinds of advantage.
Example: Bacteria that can withstand heat will survive better in a heat
wave.

(ii) Main advantage of variation to species is that it increases the chances of
its survival in a changing environment.
Free ear lobes and attached ear lobes are two variants found in human
populations.

Mendel and His Work on Inheritance:
• Gregor Johann Mendel (1822 & 1884) : Started his experiments on
plant breeding and hybridisation. He proposed the laws of inheritance in
living organisms.

Mendel was known as Father of Genetics.
• Plant selected by Mendel : Pisum sativum (garden pea). Mendel used a
number of contrasting characters for garden pea.

Medel’s Experimental Material : He chose Garden Pea (Pisum sativum) as
his experiment material because of :

(i) Availability of detectable contrasting traits of several characters.
(ii) Short life span of the plant.
(iii) Normally allows self-fertilisation but cross-fertilisation can also be
carried out.
(iv) Large no. of seeds produced.

• Mendel’s Experiments : Mendel conducted a series of experiments in
which he crossed the pollinated plants to study one character (at a time).

Monohybrid Cross:
Cross between two pea plants with one pair of contrasting characters is called
a monohybrid cross.

Example : Cross between a tall and a dwarf plant (short).

Observations of Monohybrid Cross:

(i) All F1 progeny were tall, no medium height plant. (Half way
characteristic)

(ii) F2 progeny ¼ were short, ¾ were tall.

(iii) Phenotypic ratio F2 – 3 : 1 (3 tall : 1 short)

Genotypic ratio F2 – 1 : 2 : 1

TT : Tt : tt = 1 : 2 : 1

Conclusions:

1. TT and Tt both are tall plants while tt is a short plant.

2. A single copy of T is enough to make the plant tall, while both copies have
to be ‘t’ for the plant to be short.

3. Characters/traits like ‘T’ are called dominant trait (because it express
itself) and ‘t’ are recessive trait (because it remains suppressed).