COMPLETE BIOLOGY WITH MOST IMPORTANT QUESTIONS.pdf

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CHAPTERS
1-LIFE PROCESSES
2-CONTROL AND COORDINATION
3-HOW DO ORGANISMS REPRODUCE
4-HEREDITY
5-OUR ENVIRONMENT

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LIFE PROCESSES

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LIFE PROCESSES
NUTRITION
NUTRITION

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LIFE PROCESSES
NUTRITION

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LIFE PROCESSES
ZARA YE SOLVE KARKE DIKHAO -
Green plants use:
a. Heterotrophic
b. Autotrophic
c. Holozoic
d. Parasitic mode of nutrition.

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LIFE PROCESSES
PHOTOSYNTHESIS:
Photosynthesis can be defined as the synthesis of organic
compounds (carbohydrates) from C02 and H20 using radiant energy
or solar energy by chlorophyll molecules.
The process of photosynthesis involves two phases: Light Reaction
and Dark Reaction.
The following events occur during the process of photosynthesis:
• Absorption of light energy by chlorophyll.
• Conversion of light energy to chemical energy as well as splitting of
water molecules into hydrogen and oxygen.
• Reduction of carbon dioxide to carbohydrates.

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LIFE PROCESSES
PHOTOSYNTHESIS:

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LIFE PROCESSES
STOMATA:

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LIFE PROCESSES
NUTRITION IN ANIMALS:
(i) Ingestion: Taking in complex organic
food through the mouth opening.
(ii) Digestion: Change of complex food
into simple diffusible form by the action of
enzymes.
(iii) Absorption: Passing of simple,
soluble nutrients into blood or lymph.
(iv) Assimilation: Utilization of absorbed
food for various metabolic processes.
(v) Egestion: Expelling out the undigested
food.

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LIFE PROCESSES
NUTRITION IN ANIMALS:
Here is an overview of the key components
and functions of the human digestive
system:
1-Mouth or Buccal cavity
2-Oesophagus
3-Stomach
4-Small intestine
5-Large Intestine
Associated Glands:
1-Salivary Glands
2-Liver
3-Pancreas

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LIFE PROCESSES
YE QUES KAR LOGE?
Where does the complete digestion of
carbohydrates, fats, and protienstakes
plaacein a human body?
a. Large intenstine
b. Stomach
c. Liver
d. Small intestine

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LIFE PROCESSES

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LIFE PROCESSES
Ye to Easy Peasyhai!
What is the primary function of villi in the
small intestine?
a. Secretion of digestive enzymes
b. Absorption of digested food
c. Breaking down large food particles
d. Excretion of waste products

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LIFE PROCESSES
NUTRITION IN AMOEBA:
The process of nutrition in Amoeba is known as holozoic nutrition,
which involves five main steps:
• Ingestion: Amoeba captures its food by extending its cell membrane
and forming pseudopodia, which engulf the food particle.
• Digestion: Once the food is enclosed within a food vacuole, digestive
enzymes are secreted into the vacuole. These enzymes help break
down the food into simpler substances.
• Absorption: After digestion, the digested nutrients are absorbed from
the food vacuole into the cytoplasm of the Amoeba.

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LIFE PROCESSES
NUTRITION IN AMOEBA:
• Assimilation: The absorbed nutrients are then utilized by Amoeba for
various life processes, such as growth and repair.
• Egestion: Any undigested or indigestible material is expelled from
the cell through the cell membrane.
This process allows Amoeba to obtain its nutrition and energy by
consuming other microorganisms or organic particles in its
environment.

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LIFE PROCESSES
NUTRITION IN AMOEBA:

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LIFE PROCESSES
Abhito padhaye-
Try yourself: In amoeba, food is digested in the:
a. Food vacuole
b. Mitochondria
c. Pseudopodia
d. Chloroplast

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LIFE PROCESSES
WHAT IS METABLISM?
Metabolism refers to a series of chemical reactions that occur in a
living organism to sustain life.
Metabolism is a word used to describe the sum total of all the
chemical and physical changes that are constantly taking place in
living matter and are necessary for life.
Types of Metabolic Process
There are two types of metabolic processes:
1. Catabolism
2. Anabolism

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LIFE PROCESSES
WHAT IS METABLISM?

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LIFE PROCESSES
RESPIRATION
Respiration is the process in which living organisms, like humans
and animals, convert oxygen and glucose into energy (ATP) while
releasing carbon dioxide as a waste product. It's the fundamental
way our cells generate the energy needed for life.

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LIFE PROCESSES
Types of Respiration:
1.Aerobic respiration: Occurs in the presence of oxygen,
converting pyruvic acid into carbon dioxide. Energy is released,
and water is formed.
2.Anaerobic respiration: Occurs in the absence of oxygen, with
pyruvic acid being converted into either ethyl alcohol or lactic
acid.

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LIFE PROCESSES
Exchange of Gases:
• Organisms require a continuous supply of
oxygen for aerobic respiration and must remove
carbon dioxide produced during the process.
• Exchange of gases can occur through
diffusion in unicellular organisms, simple
organisms, and plants.
• Complex animals have a dedicated respiratory
system for gas exchange.
• Fishes use gills to extract dissolved oxygen
from water, while insects have spiracles and
tracheae.
• Terrestrial organisms, including humans, have
developed lungs for gas exchange.

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LIFE PROCESSES
HUMAN RESPIRATORY SYSTEM
1. Nostrils
2. Pharynx
3. Larynx
4. Trachea
5. Bronchi
6. Bronchioles
7. Alveoli

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LIFE PROCESSES
HUMAN RESPIRATORY SYSTEM
Breathing Mechanism
• The breathing mechanism of lungs is
controlled by the diaphragm and the
intercostalismuscles.
• The diaphragm is a membrane which
separates the thoracic chamber from the
abdominal cavity.
• When the diaphragm moves down, the lungs
expand and the air is inhaled.
• When the diaphragm moves up, the lungs
contract and air are exhaled.

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LIFE PROCESSES
TRANSPORTATION
Transportation refers to the movement of
substances like nutrients, oxygen, and waste
products within an organism's body to nourish
cells and remove waste. It ensures the proper
functioning and survival of living organisms.

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LIFE PROCESSES
TRANSPORTATION
Transportation in Human Beings
The circulatory system is responsible for transporting various
substances in human beings. It consists of several key components,
including:
1. Heart: The heart is a muscular organ that pumps blood
throughout the body. It has four chambers: right atrium, right
ventricle, left atrium, and left ventricle. The heart contracts
during systole and relaxes during diastole.
2.Arteries: Arteries are thick-walled blood vessels that carry
oxygenated blood from the heart to various organs and
tissues. The pulmonary arteries are exceptions as they carry
deoxygenated blood from the heart to the lungs for
oxygenation.

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LIFE PROCESSES
TRANSPORTATION
Transportation in Human Beings
3. Veins: Veins are thin-walled blood vessels that transport
deoxygenated blood from different organs back to the heart. Pulmonary
veins are exceptions as they carry oxygenated blood from the lungs to
the heart. Veins are equipped with valves to prevent the backflow of
blood.
4.CapiIIaries: Capillaries are tiny, single-celled wall blood vessels that
facilitate the exchange of oxygen, nutrients, and waste products
between the bloodstream and the body's tissues.

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TRANSPORTATION
Blood: Blood is a connective tissue which plays the role of the
carrier for various substances in the body.
Blood is composed of:
1. Plasma
2. Blood cells
3. Platelets.

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LIFE PROCESSES
TRANSPORTATION
Lymph:
• Lymph is a fluid similar to blood but lacks red
blood cells (RBCs).
• It is formed from fluid that leaks from blood
capillaries into the intercellular spaces within
tissues.
• This lymphatic fluid is collected by lymph
vessels and eventually returns to the blood
capillaries.
• Lymph also plays a crucial role in the immune
system, assisting in the transportation of immune
cells and helping to destroy harmful
pathogens.

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LIFE PROCESSES
TRANSPORTATION IN HUMAN BEINGS
Double Circulation:
• In the human heart, blood completes two cycles in one cardiac
cycle, a phenomenon known as double circulation.
• A cardiac cycle consists of one complete heartbeat, during which
all chambers of the heart contract and relax once.
• In a normal adult, the heart beats approximately 72 times per
minute, pumping out about 70 mL of blood with each heartbeat,
resulting in about 4900 mL of blood being pumped per minute.
• Double circulation ensures the separation of oxygenated and
deoxygenated blood, which is essential for optimal energy
production in warm-blooded animals.

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LIFE PROCESSES
TRANSPORTATION IN HUMAN BEINGS
Double Circulation:

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LIFE PROCESSES
TRANSPORTATION IN PLANTS
• Plants have specialized vascular tissues for the transportation of
substances.
• There are two main types of vascular tissues in plants:
1. Xylem
2. Phloem

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LIFE PROCESSES
TRANSPORTATION IN PLANTS
1.Xylem:
• Function: Xylem is responsible for the transportation of water and
minerals in plants.
• Components: Xylem is composed of tracheids, xylem vessels,
xylem parenchyma, and xylem fibers. Tracheidsand xylem vessels
are the conducting elements.
• Route: Xylem forms a continuous tube in plants, running from the
roots, through the stem, and extending to the veins of leaves.
• Transport: Xylem carries water and minerals from the
roots to other parts of the plant.

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LIFE PROCESSES
TRANSPORTATION IN PLANTS
2.PhIoem:
• Function: Phloem is responsible for the transportation of food and
other substances in plants.
• Components: Phloem is composed of sieve tubes, companion
cells, phloem parenchyma, and bastfibers.
Sieve tubes are the conducting elements.
• Transport: Phloem carries the products of photosynthesis from
leaves to other parts of the plant.
• Two-Way Traffic: Unlike xylem, the flow of substances through
phloem occurs in both directions, making it a two-way
transportation system for food and nutrients.

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LIFE PROCESSES
TRANSPORTATION IN PLANTS
Mechanisms of Water Transport:
• Root Pressure: Water enters root hairs from the soil through
osmosis. The pressure created by this process, known as root
pressure, is responsible for moving water up to the base of the
stem.
• Transpiration Pull: Transpiration is the loss of water vapor
through stomata and lenticels on plant surfaces. Transpiration
creates a vacuum, leading to a suction force called transpiration
pull. This pull draws the water column from the xylem tubes,
enabling water to rise to great heights even in tall plants.

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TRANSPORTATION IN PLANTS
Transport of Food:
• Food transport in plants involves active processes and utilizes
energy.
• Unlike the passive flow of water through xylem, the transport of
substances through phloem is an active process.
• Phloem facilitates the movement of food in both directions within
the plant.
• Transpiration, which is the loss of water vapor from aerial plant
parts, plays a role in this process.

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LIFE PROCESSES
EXCRETION
Excretion in Human Beings:
• Excretion is the biological process involved in the removal of
harmful metabolic waste from the body.
• Various metabolic activities generate nitrogenous waste and other
harmful substances that must be removed promptly to prevent
harm to the organism.

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LIFE PROCESSES
EXCRETION
Human Excretory System Components:
• Kidneys: Human beings have a pair of bean-shaped
kidneys located near the vertebral column in the
abdominal cavity.
• Ureters: A tube called the ureter extends from each
kidney and leads to the urinary bladder.
• Urinary Bladder: Urine is collected in the urinary
bladder and expelled from the body through the
urethra as needed.

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LIFE PROCESSES
EXCRETION
• Nephron: The functional unit of the kidney,
composed of a complex network of tubes
and a filtering part known as the glomerulus.
Key components of the nephron include the
renal artery, afferent arteriole, efferent
arteriole, Bowman's capsule, and the
collecting duct.

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EXCRETION
Urine Formation in the Kidney:
• Glomerular Filtration: Nitrogenous wastes,
glucose, water, and amino acids filter from
the blood into Bowman's capsule of the
nephron.
• Tubular Reabsorption: Useful substances
from the filtrate are reabsorbed back into
capillaries surrounding the nephron.
• Secretion: Extra water and salts are secreted
into the tubule, which then opens into the
collecting duct and eventually the ureter.

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EXCRETION
• Urine Storage and Elimination: Urine
produced in the kidneys passes through the
ureters into the urinary bladder, where it is
stored until it is expelled from the body
through the urethra.
• Purpose of Urine Formation: The main
purpose of urine formation is to filter out waste
products from the blood, particularly urea,
which is produced in the liver.
• Haemodialysis: A medical procedure for
purifying blood by using an artificial kidney. It
is typically used for patients with kidney failure.

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EXCRETION
Excretion in Plants
• Other wastes may be stored in leaves,
bark etc. which fall off from the plant.
• Plants excrete some waste into the soil
around them.
• Gums, resin + In old xylem
• Some metabolic wastes in the form of
crystals of calcium oxalates in the
leaves of colocasiaand stem of
Zamikand.

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LIFE PROCESSES
QI: Following questions consists of two statements -Assertion (A)
and Reason (R). Answer these questions selecting the appropriate
option given below:
Assertion: Kidneys perform a dual function in our body.
Reason: Selective reabsorption occurs in the glomerulus.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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LIFE PROCESSES
Q2: Following questions consists of two statements -Assertion (A)
and Reason (R). Answer these questions selecting the appropriate
option given below:
Assertion: Tracheal cartilage is present in the throat.
Reason: The larynx plays an important role in human speech.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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Q3: Following questions consists of two statements -Assertion (A)
and Reason (R). Answer these questions selecting the appropriate
option given below:
Assertion: Veins have valves.
Reason: The pressure for the flow is far lesser compared to
arteries.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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Q4: Following questions consists of two statements -Assertion (A)
and Reason (R). Answer these questions selecting the appropriate
option given below:
Assertion: The opening and closing of the pore is a function of the
guard cells.
Reason: Stomatal pores are the site for exchange of gases by
diffusion.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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Q5: Following questions consists of two statements -Assertion (A)
and Reason (R). Answer these questions selecting the appropriate
option given below:
Assertion: Respiration is opposite of Photosynthesis.
Reason: In Photosynthesis food is made from energy and in
Respiration food is converted to energy.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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Q6:
Assertion: Kidneys purify blood.
Reason: Renal vein has more Oxygen than renal artery.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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Q7:
Assertion: In plants gaseous exchange takes place by the opening
and closing of guard cells.
Reason: The exchange of gases occurs across the surface of stem,
roots and leaves.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of the
Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.

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LIFE PROCESSES
Our body needs to remove the wastes that build up from cell
activities and from digestion. If these wastes are not removed, then
our cells can stop working and we can get very sick. The organs of
excretory system consist of a pair of kidneys, a pair of ureters, a
urinary bladder and a urethr(a) Each kidney is made up of nearly
one million complex tubular structures called nephrons. The
formation of urine involves various processes that take place in the
different parts of the nephrons. Each nephron consists of a cup-
shaped upper end called Bowman's capsule containing a bunch of
capillaries called glomerulus. Bowman's capsule leads to tubular
structure, proximal convoluted tubule, loop of Henle and distal
convoluted tubule which ultimately join the collecting tubule.

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QI: The following substances are the excretory products in animals.
Choose the least toxic form.
(a) Urea
(b) Uric acid
(c) Ammonia
(d) All of these
Q2: Glomerular filtrate is first collected by
(a) Distal convoluted tubule
(b) proximal convoluted tubule
(c) Bowman's capsule space
(d) loop of Henle

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LIFE PROCESSES
Q3: The outline of principal events of urination is given below in
random order.
I) stretch receptors on the wall of urinary bladder send signals to
the CNS.
II) The bladder fills with urine and become distended.
III) Micturition (voiding out urine)
IV) CNS passes on motor messages to initiate the contraction of
smooth muscles of bladder and simultaneous relaxation of urethral
sphincter.
The correct sequence of the events is
(a) I→II →III →IV
(b) IV→Ill →II →I
(c) II →I →IV →III
(d) III →II →I →IV

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Q4: Urine formation occurs through
(a) Ultrafiltration, reabsorption, secretion.
(b) Secretion, osmosis, ultrafiltration and reabsorption.
(c) Only filtration and absorption.
(d) Only osmosis and secretion.

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LIFE PROCESSES
QI: Name the respiratory pigments of human beings.

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LIFE PROCESSES
Q2: In which form is food stored in plants and in animals?

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LIFE PROCESSES
Q3: Why are heterotrophs called consumers?

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LIFE PROCESSES
Q4: Name the watery substance released in our mouth during
eating.

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LIFE PROCESSES
Q5: What does saliva contain?

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LIFE PROCESSES
Q6: Name the structure which prevents food from entering the
passage to the lungs.

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LIFE PROCESSES
Q7: Why and how does water enter continuously into the root
xylem of plants?

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LIFE PROCESSES
Q8: What is the role of following in human digestive system -
(a) mucous
(b) Bicarbonate
(c) Trypsin

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LIFE PROCESSES
Q9: (a)What is translocation? Why is it essential for plants?
(b)Where do the substances in plants reach as a result of
translocation?

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LIFE PROCESSES
QIO: What are outside raw materials used for by an organism?

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LIFE PROCESSES
Q11: What processes would you consider essential for maintaining
life?

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LIFE PROCESSES
Q12: Where do plants get each of the raw materials required for
photosynthesis?

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LIFE PROCESSES
Q13: In artificial kidney, which substance passes from the blood to
the dialysis fluid?
(a) Urea
(b) Heart
(c) Uric acid
(d) Creatinine

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LIFE PROCESSES
Q14: What is the role of the acids in our stomach?

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LIFE PROCESSES
Q15: How is small intestine deigned to absorb digested

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LIFE PROCESSES
Q16: What advantage over an aquatic organism does a terrestrial
organism have with regard to obtaining oxygen for respiration?

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LIFE PROCESSES
Q17: The breakdown of pyruvate to give carbon dioxide,waterand
energy takes place in
(a) cytoplasm
(b) mitochondria
(c) chloroplast
(d) nucleus

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LIFE PROCESSES
Q18: What are different ways in which glucose is oxidized to
provide energy in various organisms?

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LIFE PROCESSES
Q19: How is oxygen and carbon dioxide transported in human
beings?

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LIFE PROCESSES
Q20: (i) Draw a diagram of an excretory unit of a human kidney and
label the following:
Bowman's capsule, Glomerulus, Collecting duct, renal artery
(ii)Write the important function of the structural and functional unit
of kidney.
(iii)Write any one function of an artificial kidney.

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CONTROL AND COORDINATION
INTRODUCTION
• 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.

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CONTROL AND COORDINATION
INTRODUCTION
Control and Coordination in animals is done with the help of two
main systems:
(i) Nervous system
(ii) Endocrine system

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CONTROL AND COORDINATION
NERVOUS SYSTEM
• Control and coordination in organisms are provided by
nervous and muscular tissues.
• Nervous Tissue: This tissue is composed of an organized
network of nerve cells or neurons specialized for conducting
information via electrical impulses from one part of the body to
another.

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CONTROL AND COORDINATION
Receptors
Receptors are specialized tips of some nerve cells that detect
information from the environment.
Receptors are located in various sense organs:
• Ear: Acts as phonoreceptors, responsible for receiving sound and
helping in hearing and maintaining body balance.
• Eyes: Acts as photoreceptors, receiving light and facilitating
vision.
• Skin: Acts as thermoreceptors, sensing temperature changes and
facilitating the perception of heat, cold, and touch.
• Nose: Acts as olfactory receptors, responsible for the sense of
smell.
• Tongue: Acts as gustatory receptors, facilitating the sense of
taste.

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CONTROL AND COORDINATION
NEURON
The neuron is the structural and functional unit of the nervous
system.
Functioning of Neuron:
•Information from receptors is acquired at the dendritic tip of a
nerve cell as a chemical reaction, creating an electrical impulse.
•This impulse travels from the dendrite to the cell body and then
along the axon.
•Chemicals are released at the end of the axon due to the
electrical impulse.
•These chemicals cross the synapse (gap) and initiate a similar
electrical impulse in the dendrite of the next neuron.
•Synapses allow the transmission of impulses from neurons to
other cells, such as muscle cells or glands.

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CONTROL AND COORDINATION
NEURON
Parts of Neuron:
• Dendrite: Acquires information.
• Cell Body: Receives and processes
information, transmitting it as an electrical
impulse.
• Axon: Transmits electrical impulses from the
cell body to the dendrite of the next neuron.
• Synapse: The gap between the nerve ending
of one neuron and the dendrite of another
neuron, where electrical signals are
converted into chemical signals for onward
transmission.

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CONTROL AND COORDINATION
REFLEX ACTION
Reflex action is a quick, sudden, and immediate response of the
body to a stimulus.
• Examples of reflex actions include the knee-jerk reflex and
withdrawing a hand upon touching a hot object.
• Stimulus: Observable or detectable changes in the external or
internal environment that trigger a reaction.
• Reflex Arc: The pathway through which nerve impulses pass
during a reflex action is called a reflex arc.
• Response: It is the final reaction after the reflex action.

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CONTROL AND COORDINATION
HUMAN NERVOUS SYSTEM
1.The human nervous system comprises two
parts: the Central Nervous System (CNS) and
the Peripheral Nervous
System (PNS).
2.The CNS includes the brain and spinal cord.
3. The PNS includes Cranial Nerves (arising
from the brain) and Spinal Nerves (arising
from the spinal cord).

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CONTROL AND COORDINATION
HUMAN BRAIN
The brain is the main coordinating center of the body, consisting
of three major parts:

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CONTROL AND COORDINATION
HUMAN BRAIN
Protection of Brain and Spinal Cord:
• The brain is protected by a fluid-
filled balloon that acts as a shock
absorber and is enclosed in the
cranium (skull).
• The spinal cord is enclosed in the
vertebral column (spinal column).

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CONTROL AND COORDINATION
HUMAN BRAIN
Coordination between Nervous and Muscular
Tissue:
• The brain sends messages to muscles to execute
voluntary actions.
• Communication between the central nervous
system and the body is facilitated by the peripheral
nervous system, which includes cranial and spinal
nerves.
• The brain integrates various inputs and outputs,
allowing us to think and act based on our
thoughts.

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CONTROL AND COORDINATION
COORDINATION IN PLANTS

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CONTROL AND COORDINATION
COORDINATION IN PLANTS
Plant Hormones: Plant hormones are chemical compounds
that coordinate growth, development, and responses to the
environment in plants.

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CONTROL AND COORDINATION
HORMONES IN ANIMALS
Hormones are chemical substances that coordinate the activities
and growth of living organisms.
• Endocrine glands secrete hormones into the bloodstream.
• Key endocrine glands and their hormones include:
o Thyroid gland secretes thyroxine, which regulates metabolism.
o Pituitary gland (master gland) secretes growth hormones,
regulating growth and development.
o Adrenal glands secrete adrenaline, which affects blood
pressure, heart rate, and carbohydrate metabolism.
o Pancreassecretes insulin, which regulates blood sugar levels.
o Testes(in males) secrete testosterone, associated with puberty.
o Ovaries(in females) secrete estrogen, associated with puberty.

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CONTROL AND COORDINATION
HORMONES IN ANIMALS

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CONTROL AND COORDINATION
HORMONES IN ANIMALS
Feedback Mechanism:
• Feedback mechanisms maintain the precise secretion of
hormones at the right time.
• For example, blood sugar levels are regulated through feedback
mechanisms.

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CONTROL AND COORDINATION
HORMONES IN ANIMALS
Feedback Mechanism:
• Feedback mechanisms maintain the precise secretion of
hormones at the right time.
• For example, blood sugar levels are regulated through feedback
mechanisms.

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CONTROL AND COORDINATION
QI: Grey matter is
(a) a fluid
(b) cluster of cytons
(c) a hormone
(d) a network of blood vessel

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CONTROL AND COORDINATION
Q2: Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin

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CONTROL AND COORDINATION
Q3: Secondary sexual characters are influenced by
(a) thyroxine
(b) adrenaline
(c) testosterone
(d) oestrogen

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CONTROL AND COORDINATION
Q4: The brain is responsible for:
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.

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CONTROL AND COORDINATION
Q5: Plant growth is/are promoted by
(a) cytokinin
(b) auxin
(c) gibberellin
(d) abscisicacid

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CONTROL AND COORDINATION
Q6: Which part of the brain is concerned with muscular
coordination in the body?
(a) Temporal toke
(b) Cerebellum
(c) Pons
(d) Parietal lobe

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CONTROL AND COORDINATION
Q7: Which centreregulates swallowing, coughing and vomiting?
(a) Pons
(b) cerebrum
(c) spinal cord
(d) medulla oblongata

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CONTROL AND COORDINATION
Q8: Which one of the endocrine glands is known as master
gland?
(a) Adrenal
(b) Pituitary gland
(c) Thyroid
(d) Parathyroid

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CONTROL AND COORDINATION
Q9: Which is the longest part of the neuron?
(a) Dendrites
(b) myelin sheath
(c) cell body
(d) Axon

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CONTROL AND COORDINATION
QIO: The hormone responsible for anger is
(a) adrenaline
(b) growth hormone
(c) oestrogen
(d) insulin

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CONTROL AND COORDINATION
Fill in the blanks
Q11: The cells of the islets of Langerhans produce
Q12: The thymus gland is _______in children.
Q13: _________ and _______ protect the brain of mammals.
Q14:______is plant's response to contact with hard surface.

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CONTROL AND COORDINATION
Mark the statements true(T) or false (F):
Q15: Sensory nerve connects the dorsal root of the spinal cord.
Q16: Testosterone produces femaleness.
Q17: Parathormoneis produced by adrenal gland.

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CONTROL AND COORDINATION
Q18: What is the function of gustatory receptors?

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CONTROL AND COORDINATION
Q19: Name the hormone which controls (i.e. reduces) the level of
sugar in blood, and the gland which secretes it.

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CONTROL AND COORDINATION
Q20: Name the structure that is responsible for reflex action.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION
Reproduction is the process by which living organisms produce new
individuals of the same species.
Reproduction is necessary for the survival and increase in the
population of a species. If organisms do not reproduce, their population
decreases and species will become extinct.

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HOW DO ORGANISMS REPRODUCE?
DO ORGANISMS CREATE CARBON COPIES OF THEMSELVES?
The DNA (Deoxyribonucleic acid) molecules in the chromosomes in the
nucleus is responsible for the transfer of characters from the parents to
the off springs.
During reproduction the reproductive cells produce two copies of the
DNA which separate into two cells.
The DNA copies will be similar but not identical to each other. So the
new individuals have slight variations from their parents.
This is the basis for variations and evolution of new species.

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HOW DO ORGANISMS REPRODUCE?
THE IMPORTANCE OF VARIATION
❖DNA copying during reproduction is important for maintaining the
body designs of different organisms to survive in the existing
environment. But the environment is constantly changing due to
changes in temperature, climate, water levels etc. If organisms cannot
adjust themselves to the changes in the environment then their
species will become extinct.
❖If there are variations in some individuals of a species they may be
able to survive the changes in the environment.
❖So variations in species is necessary for the survival of different
species and for the evolution of new species.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
❖There are two main types of reproduction in living organisms. They
are asexual reproduction and sexual reproduction.
❖Asexual reproduction :-is reproduction in which new individuals are
produced from a single parent.
❖Sexual reproduction :-is reproduction in which two individuals are
involved to produce a new individual.
❖Asexual reproduction is of different types. They are:-fission, budding,
regeneration, fragmentation, spore formation, vegetative propagation
etc.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Fission
❖Fission is an asexual reproduction by which a unicellular organism
divides and forms two or more new individuals.
❖Fission is of two types. They are binary fission and multiple fission.
i) Binary fission :-In this method an organism divides and forms two
individuals. First the nucleus divides and forms two nuclei. Then the
cytoplasm divides and forms two daughter cells. Eg:-Amoeba,
Paramaecium etc.
ii) Multiple fission :-In this method one organism divides into manv
daughter cells. Eg. PIasmodium(Malarial parasite).

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Budding
❖In this method a bud like projection is formed on the body of the
organism. The bud then develops into a new individual. It then
separates from the parent and forms an independent individual. Eg:-
Hydra, Yeast etc.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Regeneration
❖In this method a part of the body if the organism if cut or broken can
develop into a new individual. Eg:-Hydra, Planaria, Star fish etc.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Fragmentation
❖In this method the body of a simple multicellular organism breaks up
into smaller pieces on maturation and each fragment develops into
new individuals. Eg:-Spirogyra.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Spore formation
❖In this method structures called sporangia produce tiny cells called
spores. When the spores come in contact with a moist surface, it
develops into new individuals.
❖Eg:-Rhizopus, Mucor, Penicilliumetc.

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HOW DO ORGANISMS REPRODUCE?
TYPES OF REPRODUCTION
Vegetative propagation
❖In this method new plants are produced from the
vegetative parts of
❖the plant like root, stem or leaf. Eg:-from roots
—dhalia, sweet potato, from stem —potato,
ginger, from leaf —bryophyllum, begonia.
❖Plants produced by vegetative propagation
produce flowers and fruits earlier than those
produced from seeds. It also helps in the
propagation of plants which do not produce
seeds like rose, jasmine banana etc.
❖Vegetative propagation can also be done
artificially by cutting, layering, grafting etc.

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HOW DO ORGANISMS REPRODUCE?
SEXUAL REPRODUCTION IN FLOWERING PLANTS
Reproductive parts of a flower
❖The stamen and pistil are the reproductive parts of the flower. Stamen
is the male reproductive part.
❖It produces pollen grains in the anther which contains the male germ
cell (male gamete).
❖Pistil is the female reproductive part. It produces ovules in the ovary
which contain the female germ cell (female gamete).

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HOW DO ORGANISMS REPRODUCE?
SEXUAL REPRODUCTION IN FLOWERING PLANTS
Pollination
❖The transfer of pollen grains from the anther to the stigma of a flower
is called pollination. It takes place by wind, water or insects.
❖If the pollen grains are transferred from the anther to the stigma of the
same flower it is self pollination and if it is transferred from the anther
of one flower to the stigma of another flower it is cross pollination.
❖Pollination takes place by insects, wind, water etc.

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HOW DO ORGANISMS REPRODUCE?
SEXUAL REPRODUCTION IN FLOWERING
PLANTS
Fertilisation
❖After the pollen grain is transferred to the
stigma it produces a pollen tube which passes
through the style and enters the ovary and
ovule.
❖In the ovule the male germ cell (male gamete)
fuses with the female germ cell (female
gamete) to form a zygote.
❖This process is called fertilisation.
❖After fertilisationthe zygote divides several
times and forms the embryo which then
develops into the seed and the ovary develops
into the fruit.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION IN HUMAN BEINGS
Male Reproductive System
❖The male reproductive system consists of a
pair of testes which produces the male
reproductive cells called sperms and the
hormone testosterone. It is contained in sac
like structures called scrotum. From each
testis arises a tube called vas deferens. It
joins into the urethra.
❖The urethra is enclosed in a muscular organ
called penis. It has an opening called genital
pore. The seminal vesicles and prostate
glands produce fluids which provide nutrition
and help in the movement of the sperms.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION IN HUMAN BEINGS
Female Reproductive System
❖The female reproductive system consists of a
pair of ovaries which produces the female
reproductive cells called ova or eggs and the
hormone oestrogen.
❖Above the ovaries are tubes called oviducts or
fallopian tubes.
❖The two oviducts unite into a bag like
structure called uterus. The uterus has
opening called vagina.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION IN HUMAN BEINGS
Fertilisationin Human beings
❖During sexual intercourse the sperms from the male enters into the vagina
of the female. The sperms reaches the oviduct. One sperm fuses with an
egg and forms a zygote.
❖The zygote then gets implanted in the uterus. The zygote then starts
dividing to form an embryo. The embryo gets nutrition from the mother's
blood through the placenta. The development of the child takes nine
months and then the child is born.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION IN HUMAN BEINGS
Menstruation
❖The ovary produces one egg every month and the uterus prepares to
receive the fertilisedegg.
❖Its wall becomes thick and spongy with blood vessels for nourishing the
embryo.
❖If fertilisationdoes not take place then the uterus wall breaks and comes
out of the vagina as blood and mucous.
❖This cycle takes place once every month and is called menstruation.

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HOW DO ORGANISMS REPRODUCE?
REPRODUCTION IN HUMAN BEINGS
Reproductive Health
a) Sexually transmitted diseases :-are diseases transmitted through sexual
contact. They may be bacterial infections like gonorrhoeaand syphillisetc. or
viral infections like warts and HIV-AIDS.
b) Prevention of pregnancy ( Contraception ) :-Pregnancy can be prevented
by three main methods. They are barrier methods chemical methods and
surgical methods.
i) Barrier methods consists of using condoms, diaphragm, cervical caps,
Copper T etc.
ii) Chemical methods consists of taking drugs like oral pills, vaginal pills etc.
iii) Surgical methods consists of removing or tying a small part of the vas
deferens in males (Vasectomy) or fallopian tube in female (Tubectomy).

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HOW DO ORGANISMS REPRODUCE?
QI: The two oviducts in a human female unite into an elastic bag like is known
as
(a) Vagina
(b) Uterus
(c) Fallopian tube
(d) Cervix

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HOW DO ORGANISMS REPRODUCE?
Q2: Which of the following disease is transmitted sexually?
(a) Kala azar
(b) Jaundice
(c) Cholera
(d) Syphilis

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HOW DO ORGANISMS REPRODUCE?
Q3: Which of the following is a contraceptive?
(a) Copper
(b) Condom
(c) Diaphragm
(d) All of these

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HOW DO ORGANISMS REPRODUCE?
Q4: When a animal is cut into pieces and each piece grows into a complex
organism. What is the process?
(a) Budding
(b) Fragmentation
(c) Spore formation
(d) Regeneration

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HOW DO ORGANISMS REPRODUCE?
Q5: Which is the portion on which grafting is done it provides the roots?
(a) Stock
(b) Scion
(c) Both a and b
(d) None of these

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HOW DO ORGANISMS REPRODUCE?
Q6: Where does fertilization occur in human females?
(a) Uterus
(b) Cervix
(c) Oviduct
(d) None of these

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HOW DO ORGANISMS REPRODUCE?
Q7: Growing fetus derive nutrition from mother's blood through
(a) Uterus
(b) Fallopian tube
(c) placenta
(d) cervix

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HOW DO ORGANISMS REPRODUCE?
Q8: What is the puberty age in human males?
(a) 8-10
(b) 10-12
(c) 12-14
(d) 14-16

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HOW DO ORGANISMS REPRODUCE?
Q9: Fruits are formed from
(a) Stamen
(b) Stigma
(c) Ovary
(d) Ovule

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HOW DO ORGANISMS REPRODUCE?
QIO: IUCD is for
(a) Vegetative propagation
(b) Contraception
(c) Increasing fertility
(d) Avoiding miscarriage

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HOW DO ORGANISMS REPRODUCE?
QI: Each of these questions contains an Assertion followed by
Reason. Read them carefully and answer the question on the basis
of following options. You have to select the one that best describes
the two statements.
Assertion (A): Spores are unicellular bodies.
Reason(R) : The parent body simply breaks up into smaller pieces on
maturation.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

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HOW DO ORGANISMS REPRODUCE?
Assertion(A) : Asexual reproduction is a primitive type of
reproduction.
Reason (R) : Asexual reproduction involves only mitotic cell division.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

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HOW DO ORGANISMS REPRODUCE?
Assertion(A) : The offspring produced by sexual reproduction is
likely to adjust better in environmental fluctuation.
Reason (R) : During the fusion of gametes there is mixing of genetic
material from Two parents.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

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HOW DO ORGANISMS REPRODUCE?
Assertion (A): Testes lie in penis outside the body
Reason (R): Sperms require temperature lower than the body
temperature for development
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

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HOW DO ORGANISMS REPRODUCE?
Assertion (A): Unisexual flowers have separate male and female
flowers whereas a typical monocot
embryo comprises an embryonal axis with single cotyledon.
Reason (R): Cucumber, pumpkin and water melon are example of
unisexual flowers.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

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HOW DO ORGANISMS REPRODUCE?
Read the following and answer the questions:
Preetiis very fond of gardening. She has different flowering plants in
her garden. One Day few naughty children entered her garden and
plucked many leaves of Bryophyllumplant And threw them here and
there in the garden. After few days, Preetiobserved that new
Bryophyllumplants were coming out from the leaves which fell on
the ground.
QI: What does the incidence sited in the paragraph indicate?
(a) Bryophyllumleaves have special buds that germinate to give rise
to new plant.
(b) Bryophyllumcan propagate vegetativelythrough leaves.
(c) Bryophyllumis a flowering plant that reproduces only asexually
(d) Both (a) and (b).

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HOW DO ORGANISMS REPRODUCE?
Q2: Which of the following plants can propagate vegetatively
through leaves like Bryophyllum?
(a) Guava
(b) Begonia
(c) Ginger
(d) Mint
Q3: Do you think any other vegetative part of Bryophyllumcan help
in propagation? If yes, then
which part?
(a) Roots
(b) Stems
(c) Flowers
(d) Fruits

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HOW DO ORGANISMS REPRODUCE?
Q4: Which of the following plant is artificially propagated
(vegetatively) by stem cuttings in horticultural practices?
(a) Potato
(b) Snake plant
(c) Rose
(d) Water hyacinth

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HEREDITY
HEREDITY AND VARIATION
• Genetics is the field of science that focuses on the study of heredity
and variation.
• Heredityrefers to the transmission of traits or characteristics from
one generation to the next.
• Variationrefers to the differences in traits between parents and
offspring.

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HEREDITY
VARIATION
Types of Variations: Variations can be categorized into two main
types:

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HEREDITY
HEREDITY
• Heredity involves the passing of traits from parents to offspring.
• Genes, which are functional units of heredity, carry these traits.
• Genes are short segments of DNA that encode specific proteins or
RNA.
• Genetics, a branch of biology, is the study of genes, heredity, and
variations.

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HEREDITY
HEREDITY
Heredity Process:
• Heredity is the mechanism through which
an organism's features are passed from
one generation to the next.
• Genes play a crucial role in defining an
organism's traits.

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HEREDITY
MENDEL’S WORK IN GENETICS
GregorJohann Mendel:
• GregorJohann Mendel, often referred to as the
‘Father of Genetics’, was an Austrian Monk.
• He conducted groundbreaking research on pea
plants to unravel the principles of heredity.
• Mendel's work laid the foundation for modern
genetics.
He formulated three fundamental laws of
inheritance:
• The Law of Dominance
• The Law of Segregation
• The Law of Independent Assortment.

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HEREDITY
MENDEL’S WORK IN GENETICS

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HEREDITY
MENDEL’S WORK IN GENETICS
Traits
Traits in heredity are characteristics or features passed from one
generation to another through genes, determining an individual's
physical and often behavioral attributes, such as eye color or
susceptibility to certain diseases.

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HEREDITY
MENDEL’S WORK IN GENETICS

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HEREDITY
MENDEL’S WORK IN GENETICS
Monohybrid Cross:
• In a monohybrid cross, only one
character is considered when
crossing two organisms.
• The resulting ratio of characters in
the F2 generation is called the
monohybrid ratio.
• For example, when a tall plant (T T)
is crossed with a dwarf plant (tt),
the monohybrid ratio in the F2
generation is 3 tall plants to 1 short
plant (3:1).

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HEREDITY
MENDEL’S WORK IN GENETICS
Dihybrid Cross:
• A dihybrid cross involves
considering two different characters
when crossing two organisms.
• The resulting ratio of characters in
the F2 generation is called the
dihybrid ratio.
• For instance, when a plant with
round and green peas is crossed
with a plant with wrinkled and
yellow peas, the dihybrid ratio in the
F2 generation is 9:3:3:1.

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HEREDITY
MENDEL’S WORK IN GENETICS
Inheritance
• Inheritance refers to the transfer of
traits from one generation to the next.
• It involves the passing of genetic
information (traits) from parents to
offspring.

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HEREDITY
LAWS OF MENDEL
1. Law of Dominance: States that a gene has two contrasting
alleles, and one always expresses itself in the organism as the
dominant gene.
2. Law of Segregation: Explains that traits segregate completely
during gamete formation, with no mixing of alleles.
3. Law of Independent Assortment: Indicates that different traits
can segregate independently during gamete formation, meaning
they are inherited independently of each other.

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HEREDITY
TYPES OF TRAITS
Acquired Characters:
• Acquired characters are traits that an organism develops during its
lifetime.
• These traits are not passed on to the DNA of germ cells and are not
transferred to the next generation.
• Examples include muscle loss and weight loss due to starvation,
limb loss due to injury, etc.
Inherited Characters:
• Inherited characters are traits passed from parents to offspring
through genes.
• These traits are always transferred to the next generation, but their
expression can be influenced by dominance or recessiveness.
• Examples include height, skin color, and eye color.

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HEREDITY
SEX DETERMINATION
The determination of an individual's sex can vary among species,
and different strategies are used. In the case of humans, sex is
largely genetically determined, and it depends on the inheritance
of specific genes from our parents.
In humans, the sex of an individual is determined by the presence
of sex chromosomes. While most human chromosomes are paired,
one pair, known as the sex chromosomes, is unique. Women have a
matched pair of sex chromosomes, both of which are X
chromosomes (XX). Men, on the other hand, have a mismatched
pair consisting of one X chromosome and one shorter Y
chromosome (XY).

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HEREDITY
SEX DETERMINATION
The inheritance pattern of X and Y chromosomes in humans
determines the sex of offspring. Here's how it works:
I. AII children inherit an X chromosome from their mother, as women
have two X chromosomes.
2. The sex of the children is determined by what they inherit from their
father.
3. If a child inherits an X chromosome from their father, they will be a
girl (XX).
4. If a child inherits a Y chromosome from their father, they will be a
boy (XY).
As a result, approximately half of the offspring will be boys (XY), and
the other half will be girls (XX). This pattern of inheritance is
responsible for the genetic determination of sex in humans.

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HEREDITY
SEX DETERMINATION

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HEREDITY
QI: If a trait A exists in 10% of a population of an asexually
reproducing species and a trait B exists in 60% of the same
population, which trait is likely to have arisen earlier?

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HEREDITY
Q2: How does the creation of variations in a species promote
survival?

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HEREDITY
Q3: How do Mendel's experiments show that traits may be dominant
or recessive?

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HEREDITY
Q4: How do Mendel's experiments show that traits are inherited
independently?

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HEREDITY
Q5: A man with blood group A marries a woman with blood group O
and their daughter has blood group O. Is this information enough to
tell you which of the traits -blood group A or O –is dominant? Why or
why not?

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HEREDITY
Q6: How is the sex of the child determined in human beings?

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HEREDITY
QI: A Mendelian experiment consisted of breeding tall pea plants
bearing violet flowers with short pea plants bearing white flowers. The
progeny all bore violet flowers, but almost half of them were short.
This suggests that the genetic make-up of the tall parent can be
depicted as
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw

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HEREDITY
Q2: A study found that children with light-colouredeyes are likely to
have parents with light colouredeyes. On this basis, can we say
anything about whether the light eye colouris dominant or
recessive? Why or why not?

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HEREDITY
Q3:How is the equal genetic contribution of male and female parents
ensured in the progeny?

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OUR ENVIRONMENT
EFFECT OF ADDING WASTE TO THE
ENVIRONMENT
Human activities produce a lot of waste materials
which are thrown away into the environment. These
wastes cause pollution of air, water and soil.
The waste materials produced are of two main
types. They are biodegradable wastes and non
biodegradable wastes.

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i) Biodegradable wastes :-are wastes which are
decomposed into harmless substances by microorganisms.
Eg:-vegetables, fruits, pulses, cereals, cotton, jute, wool,
wood, leather, paper, animal dung, animal bones etc.
ii) Non biodegradable wastes :-are wastes which are not
decomposed by microorganisms.
Eg:-polythene bags, plastics, synthetic fibres, glass,
metals, synthetic rubber, insecticides, pesticides etc.
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170. Learn Practically
Learn PracticallyECOSYSTEM AND IT COMPONENTS
a) Ecosystem-An ecosystem consists of all the living
organisms in an area along with the non living components
and their interaction.
There are different types of ecosystems. They are :-
i) Natural ecosystems :-like forests, deserts, grass lands,
mountains, ponds, lakes, rivers, oceans etc.
ii) Artificial ecosystems :-like gardens, parks, crop fields,
aquarium, zoo etc.
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b) Components of an ecosystem :-
An ecosystem consists of two main components. They are
biotic and abiotic components.
i) Biotic components :-are the living components like plants,
animals and microorganisms. They consist of producers,
consumers and decomposers.
Producers:-are green plants which produce food by
photosynthesis.
Consumers:-are herbivores which get their food directly from
plants, carnivores which get their food indirectly from plants
and omnivores which get their food directly or indirectly from
plants.
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Decomposers:-are microorganisms which decompose dead
plants and animals. They decompose complex organic
substances into simple inorganic substances in the soil which
are again used by plants.
ii) Abiotic components :-are the non living components like air,
water, soil, minerals, sunlight , temperature, wind etc.
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Food chain
A food chain is the flow of food energy from one organism to
the next and to the next and so on. They usually start with a
producer (plants) and end with a carnivore. In a food chain an
organism gets food from one group of organisms.
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Food web
Food web is a group of several interconnected food chains. In a
food web an organism gets food from more than one group of
organisms.
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Trophic Levels
➢Each step in a food chain where transfer of food energy takes
place is called trophic level.
➢The first trophic level consists of producers.
➢The second trophic level consists of primary consumers.
➢The third trophic level consists of secondary consumers.
➢The fourth trophic level consists of tertiary consumers.
➢Since the transfer of food energy decreases at every trophic
level, the number of trophic levels are limited and do not
exceed four or five.
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Energy flow in trophic levels :-
➢Green plants (producers) absorb about 1% of solar energy
falling on the leaves and stores it as food energy during
photosynthesis.
➢During the transfer of food energy from one trophic level to
the next, 90% of the energy is lost to the environment and
only 10% is transferred to the next trophic level.
➢So there is a decrease in the amount of food energy
transferred at every trophic level by 10%. This is known as
the 10% law.
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Biological Magnification
➢Harmful chemicals like insecticides and pesticides which are
used to protect crops from insects and pests are absorbed by
plants and enter the food chain. Since these chemicals are
non biodegradable, they get accumulated at every trophic
level and their concentration increases.
➢Since human beings occupy the highest trophic level, the
concentration of these harmful chemicals is maximum in our
bodies.
➢The increase in concentration of harmful chemicals in the
bodies of organisms at higher trophic levels is called
biological magnification.
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Depletion of ozone layer in the atmosphere
➢Ozone molecule contains three oxygen atoms (03). At higher
levels in the atmosphere the UV radiation splits some oxygen
molecules (02) into free oxygen atoms which combines with
oxygen molecules (02) to form ozone. It is highly poisonous.
➢The ozone layer present in the higher layer of the atmosphere
➢protects the earth from the harmful UV radiation from the
sun. UV radiation causes skin cancer in humans.
➢The ozone layer is being damaged by the use of chemicals
like chlorofluorocarbons (CFCs) used in refrigerators and
fire extinguishers. So the use of CFCs is now being reduced
to protect the ozone layer.
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Managing the garbage we produce-
➢The household waste is called garbage. Some of the garbage
is biodegradable and some are non biodegradable. Garbage
causes pollution of air, water and soil. So it should be
disposed properly.
Some of the methods of garbage disposal are :-
i) Land fills
ii) Recycling
iii) Production of biogas and manure
iv) Preparation of compost
v) Incineration
vi) Sewage treatment
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Fill in the blanks.
QI: Producers always contain_______pigments.
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Fill in the blanks:
Q2: A position in a food chain is called a______
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Fill in the blanks:
Q3. ________ constitute the first trophic level.
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Fill in the blanks:
Q4: A series of interconnected food chains representing the
feeding relationship of the organisms within an ecosystem is
called __________
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Fill in the blanks:
Q5: Autotrophs capture the energy present in sunlight and
convert it into _______
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Fill in the blanks:
Q6: In a grassland ecosystem a hawk represents the _______
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Mark the statements true (T) or false(F).
QI: The frog that eats the grasshopper is a secondary
consumer.
Q2: Sewage may be used to produce biogas.
Q3: Decomposers are also called saprotrophs.
Q4: All green plants and blue-green algae are producers.
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Assertion: Polythene bags and plastic containers are non-
biodegradable substances.
Reason: They can be broken down by microorganisms in
natural simple harmless substances.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of
the Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.
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Assertion: Ozone is formed in upper atmosphere by 02 in
presence of UV radiations.
Reason: Ozone depletion will lead to UV rays reaching earth
which may cause skin cancer.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of
the Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.
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Assertion: Tropical rain forests are disappearing fast from
developing countries such as India
Reason: No value is attached to these forests because these are
poor in biodiversity.
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of
the Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.
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Assertion: Aquarium needs regular cleaning
Reason: There are no microbes to clean water in aquarium,
therefore, it needs to be regularly cleaned
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of
the Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.
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Assertion: Biotic components of ecosystem continuously
require energy to carry on life processes.
Reason: Biotic components are the nonliving components of
the ecosystem
(a) Both 'A' and 'R' are true and 'R' is correct explanation of the
Assertion.
(b) Both 'A' and 'R' are true but 'R' is not correct explanation of
the Assertion.
(c) 'A' is true but 'R' is false.
(d) 'A' is false but 'R' is true.
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THANK YOU CHUNNU MUNNUS

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