CHAPTER 4 WHY DO WE FALL ILL?
 

• Health is a state of physical, mental and social well-being.

 

• The health of an individual depends on his/her surroundings.

 

• Diseases are classified as acute or chronic depending on the duration for which they last.

 

• Diseases that last for a very short time are called acute. The diseases that last for a very long time are called chronic.

 

• Diseases may be due to infectious or non-infectious causes.

 

• Infectious agents belong to different categories or organisms. These may be unicellular or multicellular.

 

• The treatment for a disease depends on the type of the disease causing organism.

 

• Infectious agents spread through air, water and even physical contact. It is better to stay away from contaminated air and water.

 

• Preventing a disease is more important and necessary. Prevention is better than cure.

CHAPTER 6 IMPROVEMENT IN FOOD RESOURCES
 

• MACRO-NUTRIENTS: The nutrients required in large quantities are known as macro-nutrients.

 

• MICRO-NUTRIENTS: The nutrients required in small quantities are known as micro-nutrients.

 

• Manure and fertilizers are the main sources of nutrient supply to crops. Organic farming is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides, etc. and with a maximum input of organic manures, recycled farm wastes, and bio-agents.

 

• Mixed farming is a system of farming on a particular farm which includes crop production.

 

• Mixed cropping is growing two or more crops in simultaneously on the same piece of land.

 

• Growing two or more crops in definite row patterns is known as inter-cropping.

 

• CROP ROTATION: The growth of different crops on a piece of land in pre-planned succession is called crop rotation.

 

• Farm animals require proper care and management such shelter, feeding, breeding and disease control. This is called animal husbandry.

 

• Poultry farming is done to raise domestic fowls. Poultry production includes egg production. To enhance poultry production, cross breeding is done.

 

• Marine fish capture is done by fishing nets guided by echo-sounders and satellites. Composite fish culture system is commonly used for fish farming.

 

• Bee-keeping is done to get honey and wax.

CHAPTER 5 NATURAL RESOURCES
 
AIR
Air is a mixture of many gases like nitrogen, oxygen, carbon dioxide and water vapour. These gases are required for cellular respiration.
WINDS
Winds blow due to difference in pressure due to uneven heating of land and water. We’ve already studied this phenomenon as land breeze and sea breeze.
 
RAIN
Rain is the part of the water cycle. When water from various water bodies evaporates and rises up in the atmosphere, it cools down. The cooling causes condensation of the water vapour and forms tiny water droplets. Once these droplets become heavy, they fall down on the earth’s surface as rain drops.
 
AIR POLLUTION
Degradation of air quality caused due to unwanted particles present in the atmosphere.
Burning of fossil fuels, toxic smoke from industries all contribute to air pollution and cause harmful respiratory diseases. Such activities must be avoided as much as possible.
 
WATER POLLUTION
Water pollution is caused by industrial and domestic waste that is dumped in the water bodies. It causes harmful diseases and endangers the aquatic life.
 
 
 
Waste should be handled carefully and should be treated before being dumped in the water bodies.
 
These natural resources are essential to us and should be conserved to make sure that the balance of nature remains intact.

                CHAPTER 3 DIVERSITY IN LIVING ORGANISMS
 
HIERACRCHY OF CLASSIFICATION- GROUPS
There are five groups/ kingdoms: Monera, Protista, Fungi, Plantae, Animalia
Monera

• No defined nucleus or organelles.
• Mode of nutrition: Autotrophic or heterotrophic
• Includes bacteria, blue green algae, etc.

 
Protista

• Unicellular eukaryotic organisms
• Some organisms use appendages like cilia or flagella for moving around.
• Mode of nutrition: Autotrophic or heterotrophic
• Examples: Unicellular algae, protozoans

 
Fungi

• Heterotrophic eukaryotic organisms
• Use decaying organic material as food and therefore called saprophytes.
• Some fungal species have symbiotic relationship with other life forms  such as algae.

 
Plantae

• Multicellular eukaryotes
• Have cell walls
• Mode of nutrition: Autotrophic
• Divided into 5 groups:
  • Thallophytes
  • Byrophytes
  • Pteridophytes
  • Gymnosperms
  • Anglosperms

 
Animalia

• Multicellular eukaryotes
• Do not have cell walls
• Mode of nutrition: Heterotrophic
• Divided into 10 groups:
  • Porifera
  • Coelenterata
  • Platyhelminthes
  • Nematoda
  • Annelida
  • Arthropoda
  • Mollusca
  • Echinodermata
  • Protochordata
  • Vertebrata

              CHAPTER 2 TISSUES
 
 
PLANT TISSUES

• Meristematic Tissue: This is the dividing tissue. The growth in plants occurs in certain specific regions because the meristematic tissues are present in these regions only. These tissues are classified into three types depending on where they are present:

 

• Apical: Apical meristem is present at the growing tips of stems and root. It increases the length.

 

• Lateral: The lateral meristem is responsible for the increase in the girth of the stem and root.

 

• Intercalary: The intercalary meristem is present at the base of the leaves or internodes on twigs.

 

• Permanent Tissue: When the cells lose their ability to divide, they form a permanent tissue. The following are the different types of permanent tissues:

 

• Simple permanent tissue: There are three types of simple tissues- Parenchyma, collenchyma and sclerenchyma.

 

• Complex permanent tissue: Tissues like xylem and phloem are complex tissues.

 
ANIMAL TISSUES

• Epithelial tissue: The covering or protective tissues in the animal body are called epithelial tissues.
• Connective tissues: The cells of the tissues are loosely spaced and embedded in an intercellular matrix. Example of connective tissues are blood, bone, cartilage, etc.
• Muscular tissues: Muscular tissues consist of elongated cells also called muscle fibres. These are the tissues responsible for movement in human body.
• Nervous tissue: These tissues are made of neurons that receive and conduct impulses.

  CHAPTER 1 THE FUNDAMENTAL UNIT OF LIFE
 
The basic building blocks of living organisms are called cells.
There are different types of organisms based on the number of cells that they are made up of. Unicellular organisms are the organisms which have only one cell. For e.g. Amoeba. Multicellular organisms are the organisms made up of more than one cell. For e.g. Humans
 
FEATURES OF THE CELL

• Plasma membrane: it is also called the cell membrane. It is the outermost covering of the cell that separates the contents of the cell from its external environment. It is selectively permeable as it allows certain substances like water, oxygen, carbon dioxide, etc. to pass through it.

 

• Cell wall: It is mostly found in plants and is mainly composed of cellulose. Because of these cell walls, plant cells can withstand greater changes in their surroundings ad compared to animal cells.

 

• Nucleus: The nucleus contains chromosomes which can be seen when the cell is about to divide. It has a double layered covering called nuclear membrane. Organisms whose cells lack nuclear membrane are called prokaryotes and organisms whose cells have a nuclear membrane are called eukaryotes.

 

• Cytoplasm: The fluid content inside the plasma membrane is called cytoplasm. It contains cell organelles.

 

• Cell organelles:

 

• Endoplasmic Reticulum(ER): It is a large network of membrane bound tubes and sheets. There are two types of ER- Rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). RER has ribosomes attached to it. These ribosomes are the sites of protein manufacture. The SER helps in the manufacture of fat molecules.
•  Golgi Apparatus: It consists of a system of membrane bound vessels arranged almost parallel to each other in stacks called cisterns. Its functions include storage, modification and packaging of the products synthesised near the ER in its vesicles.
• Lysosomes: These are the waste disposal system of the cell. Lysosomes help to keep the cell clean by digesting any foreign material as well as worn out cell organelles.
• Mitochondria: Mitochondria are the power house of the cell. The energy required by the cell for various chemical activities is released by mitochondria in the form of ATP (Adenosine Triphosphate).
• Plastids: Plastids are present in plant cells only. There are two types of plastids: chromoplasts and leucoplasts. Plastids containing the pigment chlorophyll are called chloroplasts. Leucoplasts are the white or colourless plastids which store materials like starch, oils and protein granules.
• Vacuoles: These are the storage sacs for solid or liquid contents. Animal cells have small vacuoles while plant cells have large vacuoles.