Major biological activities of organisms

Investigate the main activities of living organisms.

Food is produced primarily in the green plants by a process called photosynthesis. There are four main factors needed for photosynthesis.

• Sun light

• Chlorophyll

• Carbondioxide

• Water

The main product of photosynthesis is glucose. The byproduct is oxygen.

Carbondioxide + Water + (Sun light + Chlorophyll)

> Glucose + Oxygen

Glucose is converted temporarily to starch and stored in chloroplasts. At night the starch is converted to a sucrose solution and transported to all other tissues of the plant.

Animal tissues

The varitions of animal tissues according to the structure and functions.

Some parts of an animal are very hard while others are soft or like a liquid. These variations are specialized to perform the animal's particular functions. Tissues are group of cells of one type or different types which are specialized to perform a particular function and have common origin. Animal bodies are comprised of several tissues.

BLOOD TISSUE

* Consists of blood plasma and blood cells.

* Red blood cells transport oxygen.

* White blood cells protect the body from diseases.

* Platelets are important in blood clotting.

MUSCLE TISSUE

* Composed of muscle fibers.

* Classified into three groups.

Skeletal muscle

* Participates in moving body parts.

* Attached to the skeleton by tendons.

* Fibers are striated.

* Muscles are voluntary.

Cardiac muscle

* Made up of branched and striated muscles.

* Uni-nucleated.

* Fibers have large number of mitochondria.

* Muscles are involuntary.

Smooth muscle

* Spindle shaped and unstriated muscles.

* Uni-nucleated.

* Muscles are involuntary.

* Can found in intestine, stomach, blood vessels, urinary system

etc.

EPITHELIAL TISSUE

* Functions as a lining tissue.

* Main functions are sensory, protection, absorption, and

secretion.

* Classified into three groups.

• Squamous epithelium

• Cuboidal epithelium

• Columnar epithelium

Plant tissues

The variations of plant tissues according to the structure and functions.

Some parts of a plant are very hard while others are soft or spongious. These variations are specialized to perform the plant's particular functions. Tissues are group of cells of one type or different types which are specialized to perform a paricular function and have common origin. Plant and animal bodies are comprised of several tissues.

PLANT TISSUES

Plant tissues are categorized into two main groups.

* Permanent tissues

* Meristamatic tisues

1. PERMANENT TISSUES

a. Simple permanent

* Parenchyma

* Collenchyma

* Sclerenchyma

b. Complex Permanent

* Phloem

* Xylem

SIMPLE PERMANENT TISSUES

PARENCHIMA TISSUE

* Consists of living cells.

* Cells are spherical or elongated in shape.

* Thin cell wall is made up of cellulse.

* There are intercellular spaces among these cells.

(Eg: pallisade parenchyma, spongy parenchyma, food stored

parts of the plant)

COLLENCHIMA TISSUE

* Consists of living cells.

* Cells are elongated in shape.

* Cell corners are thickend with cellulose.

* Intercellular spaces are not prominent.

(Eg: outer parts of stems, midrib of leaves, tender stems contain chloroplasts)

SCLERENCHIMA TISSUE

* When get matured cells become non living.

* Lignin deposited on the cell walls.

* Provides mechanical strenth to the plant.

* Absense of intercellular spaces.

(Eg: fibres, sclerids)

COMPLEX PEMANENT TISSUES

PHLOEM TISSUE

* Four types of cells can be seen in phloem tissue.( Sieve tube

elemants, Companion cells, Phloem parenchyma cells,

Phloem fibres)

* Phloem fibers are non living.

* Main function is translocation of food throughout the plant.

XYLEM TISSUE

* Four types of cells can be seen in xylem tissue.( Trcheids,

Vessel elemants, Xylem parenchyma cells, Xylem fibres)

* Xylem parenchima cells are only living cells in the tissue.

* Main function is conduction of water and mineral salts.

* Provide mechanical support.

2. MERISTEMATIC TISSUES

* Apical meristem

* Lateral meristem

* Inter calory meristem