Seed Germination

Sexual Reproduction in Flowering Plants

How do Organism Reproduce : CBSE Class 10 X Science (Biology)

                         Why do we fall ill?

Health: State of complete physical, social and mental well being and not only the absence of diseases.

Personal and community health:

           Personal health is directly linked to community health. Health of a person influenced by the environment and community. Community health involves

i) Provision of safe and clean drinking water

ii) Health care facilities

iii) Health education and IV) provision for sanitation

Diseases: Any deviation from normal body functioning resulting in disturbed state or stare of discomfort.

Indication of diseases:

Symptoms: General visible changes in the body during the diseased state include fever, headache, vomiting general weakness etc. they don’t point towards specific diseases. Signs- specific indications which point towards a specific diseases. E.g. specific fever pattern in malarias, rashes on skin in chicken pox etc. on the basis of signs doctor performs diagnostic tests and confirms the diseases.

  The signs and symptoms of the disease depend upon tissue or organs, the infectious agent or microbe agent.

               

TISSUE SPECIFIC MANIFESTATIONS-
Organ or tissue target                     Tissues specific symptoms            

1.     Lungs                                            Cough, breathless

2.     Liver                                             Yellowing of body ,digestion problems(jaundice)

3.     Brain                                             Headache, vomiting, fits     

4.     Intestine                                        Diarrhea

Classification of diseases:

·         On the basis of duration  : Acute & chronic

·         On the basis of  infection: communicable & non- communicable

 Acute                                                                 Chronic

1.      Last for short duration.                                1. Last for long duration.

                                                                                        (May be months or years) 

    2.  Do not affect general health for                     2. General health is affected badly.

          a long time.  

    3.  Vital organs of body are not affected.           3. Vital organs are affected.

E.g. influenza, malaria                                         E.g. leprosy, T.B

Communicable                                               Non communicable

1. Spread from diseases to healthy person.      1. Do not spread.

2. Spread by means of air water food,              2. Do not spread by these means.

     insects bite etc.

3. Caused by microbes.                                    3. Caused by genetic disorder   metabolic problems, food deficiency, pollution etc.

e.g.  T.B, chickenpox                                            e.g.  Marasmus, hemophilia

Causes and spread:

Causes or factor are of two types:

1.   External (extrinsic)causes or factors

                    I.            Diseases causing microorganisms commonly called pathogens

                  II.            Inadequate diet

                III.            Environmental pollutants

                IV.            Tobacco, alcohol and narcotic drugs

2.   Internal (intrinsic) causes or factors.

                    I.            Malfunctioning or improper functioning of body parts

                  II.            Genetic disorders

                III.            Hypo or hyper secretion of hormones

                IV.            Malfunctioning of body’s immune system

                      Level of caused – first level – refers to immediate cause of causative organisms of diseases (virus, bacteria).etc.

  

                                                       Second level- why the infection occurred to that     

                                                       Person (whether the person is weak has insured

                                                   Inhibitory cause                         something wrong or has genetic problems etc.

                                                                       Third level- deals with public health and public services           

                                                                       That a person is exposed to e.g. whether the

                                                                       Surrounding is clean there is provision of safe water.

Causes of infectious diseases:

  Virus –influenza, Dengue, AIDS

Bacteria – typhoid, cholera. T.B, anthrax

Fungi- skin infectious, athletics foot

Protozoa- malaria, worms- elephantiasis

      Category of microbe is important to know as it helps in deciding the kind of treatment.

·         Virus lives inside host cell. Bacteria rarely.

·         Worms multiply slowly. The others very fast.

·         Bacteria are closely related to each other and not to viruses or other categories.

·          

Mode of spread:

·         Direct contact: by touching using attires of diseased e.g. chicken pox.

·         Airborne or droplet infection: for the diseases that spread through air tiny droplets containing microbes are released in air when the infected person cough or sneezes. When a healthy person inhales these droplets he can also suffer from the disease. This is called droplet infection e.g. pneumonia, T.B, common cold.

·         Food and water: contaminated water and food containing microbes which may enter water source through secretions (vomiting, excreta) of diseased may act as source of infection. E.g. jaundice , hepatitis , cholera

·         Sexual contact- e.g.- AIDS, Syphilis

·         Insect – insects may act as vectors / carrier of diseases

    Distinctions between healthy and disease- free

Healthy	Diseases-free
1.      It is a state of physical, mental and social well being. 2.      It refers not only to the individual but also its social and community environment. 3.      A ‘healthy ‘individual is one who is able to perform normal under given situation.	.       1.It is a state of absence of any discomfort or derangement of the functioning of the body. .         2. .It refers to the individual.         3.. A ‘disease-free’ individual may have good health or poor health.

                                                                                                                                         

Vector	Carrier
1.      Carries specific germs inside its body. 2.      Caused agent needs vector to complete its life cycle. E.g. female anopheles is a vector of plasmodium that causes malaria.	1.      Carries many germs upon its surface (wings, legs, etc.) 2.      Caused agent doesn’t need carriers to complete its life cycle. e.g. housefly is a carrier of many germs or diseases like cholera , typhoid etc.

     

Effects of diseases

Microbes enter the body through different body parts. The specific part affected depends upon the point of entry of microbe. (ORGAN SPECIFIC MANIFESTATIONS)

  Point of entry                   organ likely to be infected             Example

• ·            Nose                                      lungs and lymph nodes                         T.B
• ·          Mouth                                   alimentary canal , liver                    Japanese enuphatitis
• ·          Blood                                    Brain , liver cells, RBC                        Malaria
•       (Through mosquito
•         bite)
• 
  
•         Reproductive organs             reproductive organs                             Syphilis
•         (Sexual contact)                      immune system                                     AIDS

Common effect of diseases:

When infectious occurs in body immune system gets activated which results in a series of effects, together constituting inflammation.

Inflammation: the immediate response of the body towards an infection/ injury is called inflammation. Due to activation of immune system, there is increased blood supply in the affected area so that WBC can reach the place of infection and kill germs. This results in swelling and itching. These are the local effects produced during inflammation. While fever occurs as a general effect in body. (Hence mild fever is a protective mechanism. High fever destroys thermo-regulation.

  Treatment

Occurrence of diseases depends upon:

1.      Number of germs that enter body

2.      Whether the germs are virulent(strong)

3.      Strength of body’s immune system.

These are treatment of diseases

1.      Reduce the effect of diseases(Analgesics, Antipyretic , bed rest)

2.      Kill the cause of diseases (antibiotics to kill microbes)

 Antibiotics- medicines made from bacteria and fungi and used against them.

Broad spectrum antibiotics- An antibiotic may be effective against many strains of bacteria because these bacteria have similar biochemical pathways. E.g. penicillin blocks biochemical pathways that build cell wall. Hence bacteria are unable to make cell wall and die.

Q. why are antibiotics ineffective against viruses?

A. viruses do not have metabolic pathways as found in bacteria. Instead viruses make use of machinery and pathways of host cell. Hence antibiotics are not effective against viruses. For viruses, antiviral drugs are used.

Prevention is better than cure:

·      Once a person has a disease some of body functions may get damaged and do not recover treatment of or disease takes time and the person becomes incapable of normal routine.

·         Person may spread the disease to the others.

Prevention of diseases-

General ways-

·         By keeping environment clean

·         Providing clean drinking water ventilation

·         Providing proper, sufficient and clean food and balanced diet.

·         Exercise

Specific ways: by vaccination

Immunity:  ability of body to resist or diseases.

Immunization: method of imparting immunity to a specific disease by way of vaccination.

Principle of vaccination-

·         Dead or weakened germs are infected in body in the forms of vaccine.

·         These germs are not capable of providing a disease. But they act as antigens and body produces antibodies against them.

·         It also generated large number of memory cells which remains in body for long time. when the vaccinations person is attacked by the same pathogen the existing memory cells recognize antigen and produce large number of antibodies to combat the pathogen and the person does not suffer from the diseases.(this kind of immunity is also called active immunity).

(Ready made antibodies are given as vaccine in passive immunity but they are short lived)

                                      Tissue

                                      Class- IX

Plant tissues: Plant tissues are classified into two types:

·         Meristematic tissues

·         Permanent tissues

Meristematic tissues: it keeps on dividing 

   Features of meristematic tissues:

•          Cells of these tissues have thin elastic walls, made up of cellulose
•          Cytoplasm is dense with nucleus present in the centre of the cell
•          No vacuole or very few vacuoles are present
•          Cells are completely arranges without interference of spaces
•      It is further divide into three parts:

1.       Apical meristemtic:

·         Present at the root and shoot tips.

·         Helps in longitudinal growth of plant

2.       Intercalary meristematic:

·         Present at nodes (just above or below the node)

·         Help in longitudinal growth by increasing intermodal length

3.       Lateral meristematic:

·         Present parallel to the length of the plant. It is present just below bark.

·         Helps in increasing girth of the plant.

    

                             

                          shoot apex showing location and meristem .

  Permanent tissues:

•    It is formed by meristematic tissue
•   Meristematic tissues undergoe differentiation to form permanent tissue
•   Cell differentiation is a process by which cells acquire permanent shape and size to perform one special function.
•   Cells of permanent tissues do not divide further.
•   Permanent tissues can be classified as:

·         Simple permanent tissue

·         Complex permanent tissue

   Simple permanent tissue: (consists only one type of cells)

         It is of following types:

1.       Parenchyma

2.       Collenchyma

3.       Sclerenchyma

1.       Parenchyma:

•  It is basic permanent tissues made up of unspecialized cells.
• Cell wall is thin and made up of cellulose.
• Cell has large central vacuole and dense cytoplasm.
• Cells are closely packed and have inter cellular spaces.
• It is most abundant tissues and is found as packaging tissue in all plant organs such as fruit, root and seed.
• It acts as a storage tissue when present in stem and roots ( stores water and minerals)
• In leaf parenchyma cells contain chloroplast and help in photosynthesis. Such parenchyma is call Chlorenchyma.
• In aquatic plants, parenchyma cells are loosely arranged with large intercellular spaces. Such parenchyma is called Aerenchyma. It helps plant to float.    

2.       Collenchyma: (made up of living cells)

•   It has a cell structure similar to parenchyma tissue but cell wall has thickenings of pectin. These thickenings are more prominent at the corners that are why no intercellular spaces exist between the cells.

    Location:

    It is found just below epidermis in stem and leaves of dicot (absent in roots).

    It provides flexibility to these organs so that plant can stand against strong winds. It allows plant to bend without breaking.

    It also provides mechanical strength.

3.       Sclerenchyma : (made up of dead cells)

• Cells are long and narrow.
•  Cells have heavy deposits of lignin on their walls. Thickenings are so thick that there is no space inside the cell.
•  Lignin act like cement and harden these cell.  

    Location: Present in stem, in veins, around vascular bundles, covering of seeds and nuts, pulp of fruits (guava, apple), and husk of coconut.

   Function: provide mechanical strength.

    

Protective tissues:

•    It provide protection to plant it is combination of simple permanent tissue, specially for protection of plant.
•       Two type of protective tissues are formed:

1 Epidermal tissue:

•   It exists in the form of outer most layer in all plant organs called epidermis
•  Epidermis is a single layer in most of the plants byt in xerophytes (desert plants )it can be made up of many layers
•   Cells have structure similar to parenchyma nut cell walls are thicker. Cell is thicker in outer surface lateral walls than inner side.

Function:

•   It is a protective layer and forms a continuous layer (no inter cellular spaces)
•  In lower leaf epidermis small pores are present which help in the exchange of gasses of carbon dioxide and oxygen and transpiration. Stomata are guard by bean shaped guard cells.
•  Cells of epidermis tissue produce waxy coating called cuticle. Cuticle is thick xerophytes and prevents loss of water.
•  Epidermises of roots produce root hairs which help in absorption of water and minerals by increasing surface area for absorption.
•  Cuticle also provides protection against mechanical injury is parasitic infections.  

     

2.       Cork tissue:

•        In old stems and roots epidermis tissue is replaced by a strip of meristematic tissue. This forms thick layers of barks (cork) of the tree.
•            Cells of cork are dead and compactly arranged without intercellular spaces. They have deposits of suberin as these cell walls make cork, impervious to form gases and water.

Complex permanent tissue

•  This tissue is made up of different types of cells which co-ordinate with each other to perform a common function.
•  Xylem and phloem (vascular tissue) are complex permanent tissue.
•  Both these tissues are present together in the form of patches called vascular tissues.
• They are conducting tissues are a distinguish feature of terrestrial plants. 

Xylem: (conducts water and minerals)

•  It consist of following component

·         Vessels

·         Tracheids

·         Xylem parenchyma

·         Xylem sclerenchyma

•  Tracheids and vessels are main conducting elements and water and minerals flow through them vertically upwards.
•  Xylem parenchyma stores food and also helps in vertically conduction.
•  Xylem fibers are supportive in function.

Phloem:(conducts food, hormones, amino acids, etc)

 It consists of following elements:

·         Sieve tubes

·          companion cells

·         Phloem parenchyma

·         Phloem sclerenchyma

All phloem elements are living except sclerenchyma.

·            Sieve tubes are tabular cells with sieve like perforated ends called sieve plate. When mature sieve tubes do not have nucleus.

·     Companion cells are living cells they are associated with sieve tubes and control their functioning.

·       Phloem parenchyma stores food and phloem sclerenchyma is supportive in function.

·        Conduction in phloem takes in both upward and downward direction in the leaf.

  

     Animal tissues:

     The animal tissues have been classified into four major types depending on the functions they perform.

1.       Epithelial tissue

Structure:

                    I.            The cell are closely packed and are without inter cellular spaces.

                  II.            The lower most layers of the cells rests on a non cellular basement membrane composed of collangenous fibers.

                III.            The free surface of cells may be modified into cilia and microvilli.

                IV.            Epithelial tissue could be simple i.e. made up of single layer so cells are compound i.e. made up of many layers of cells.

Location:

Epithelial tissue forms a continuous layer all over the external surface of the body, the skin surface layers of mouth, alimentary canal and lungs are made up of epithelial tissue.

Function:

1.       Protection: epithelial tissue covers the entire body surface; thereby it protects the underlying cells from drying, injury, bacteria or viral infections.

2.       Exchange of material being: extremely thin, simple epithelium allows diffusion of gases or materials.

3.       Absorption: cells help in absorption of water and other nutrients as in intestine

4.       Elimination of water products: epithelial tissue like those in nephron as sweat glands helps in removal of waste from the body.

5.       Secretion: number of epithelial cells is modified to produce secretion which could be in the form of mucous, enzymes or hormones.

Epithelial tissue can be classified into:

Type	Structure	Location	Function
Squamous epithelium	Thin flattened cells with a centrally placed nucleus. Irregular shaped cells, compactly arranged.	Form lining of mouth, oesophagus, and lungs. Inner lining of  blood vessels Cover the skin surface.	Diffusion of material or exchange of gases Protection from chemical injury entry of germs or from drying.
Cuboidal epithelium	Cube like cells with a central, spherical nucleus. Appear hexagonal in surface view.	Parts of nephron, lining of salivary pancreatic and sweat ducts.	Secretion, excretion and absorption.
Columnar epithelium	Tall pillar or column like cells with nucleus at the base. Generally have mucus cells in between.	Lining of stomach, intestine, and gall bladder.	Secretion, excretion and absorption. Mucous lubricates the passage.
Ciliated epithelium	Certain cuboidal and columnar epithelium have cilia at their free ends, cilia are thin, hair like projections that move to and fro.	Oviducts, trachea bronchioles and in parts of nephron in kidney.	Movement of cilia directs the flow of fluids in a particular one direction.
Glandular epithelium	Cuboidal and columnar epithelium and are modified into glands.	Salivary, gastric, intestinal, sweat gland adrenal thyroid glands.	Secrete enzymes, mucous or hormones

Nervous tissue:

Nervous tissue is made up of millions of nerve cells called neurons. The neurons are highly specialized cells. Brain, spinal cord, and nerves are all composed of neurons.

Structure of a nerve cell or neuron:

1.       A neuron consists of two distinct parts: i) cell body or soma ii) cytoplasmic processes.

2.       The cell body contains the nucleus and granule cytoplasm.

3.       From the cell body extent out 2 kinds of cytoplasmic processes called dendrite and axon.

4.       Dendrites are small short, fine branched process, numerous in number impulses towards the cell body.

5.       Axon is a long cylindrical generally unbranched single process and ends in many branches called terminal end fibers. Axon conducts the nerve impulses away from cell body.

6.       The axon may be covered by a fatty myelin sheath.

             

Connective tissue

Structure: A composite tissue, it has following three basic components:

1.       Cells- living part, loosely spaced, embedded in the matrix

2.       Fibers- non living part scattered in between the cell.

3.       Matrix- basic ground tissue may be jelly like fluid or dense. Matrix decides the nature and function of a connective tissue.

	Have soft matrix. Cells are closely packed.	Fill the space inside organs like packaging tissue. Support internal organs. Helps in repair of tissues.	Between skin and muscles. Around blood vessels and nerves. In the bone marrow
Adipose	Has soft matrix. Cells are closely packed. Cells are filled with fat globules.	Stores fats and acts as an insulator. Acts as a source of energy reserve.	Below the skin. Between internal organ like kidney, heart, eyes, etc.
Ligament	Has soft the little matrix. Cells are densely packed. Loose network of yellow fibres.	Connects two bones at the joint. Highly elastic and considerable strength.
Tendons	Have soft little matrixes. Consist of white collagen fibers	Connect muscles to bone. Tissue has great strength but limited flexibility.
Bone	Matrix is solid and hard and made up of calcium and potassium salts. Bone cells called osteocytes are arranged around harvesian canal. Harvesian canal has blood vessel and nerve fibers.	Forms the frame work/ skeleton of the body. Anchors the muscles. Support and protects main organs of the body.	Skeleton
Cartilage	Solid matrix composed of protein and sugars. Widely spaced cells called chondrocytes. Hard but flexible tissue	Smoothens bone surfaces at joint. Forms some parts of skeleton	Present at the ends of bones. At the tip of nose. Ear penna Trachea Larynx
Blood Rbc Wbc Platelets	Fluid matrix called blood plasma. Blood cells called corpuscles float in matrix. They are of three types 1.       RBC(erthyocytes) 2.       WBC(leucocytes) 3.       Platelets (thromocytes)	RBC transport O2 and CO2 . WBC protects against diseases. Platelets help in blood clotting. Transport food hormones waste materials.

              

                 Muscular tissue:

Features-

1.       Muscular tissue consists of elongated cells called muscle fibers.

2.       This tissue has the capability to contract and relax causing movement due to presence of contractile proteins (actin, myosin).

Types of muscular tissue: 3 types of muscle tissue

Feature	Striated	Unstraited	Cardiac
Structure cell shape	Elongated , cyndrical, unbrached	Spindle shaped with tapering ends	Elongated, cylindrical branched
Nucleus	Multinucleated with peripheral nucleus	Uninucleated with centrally located nucleus
Striations(bands)	Has alternate light and dark striations	No striations	Faint regular striations
Interrelated dics	Absent	Absent	Present
Function	Voluntary muscles Undergo rapid contraction, tired easily	Involuntary muscles Undergoes slow and rhythmic contraction, do not get tired easily	Involuntary muscles Undergo continuous and rhythmic contractions and relaxation, without getting fatigue
Location	Called skeletal muscles, attached to bones	Called smooth muscles, present in organs like ureters stomach , intestine	In walls of heart