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Showing posts with the label Life Science

Classification of Plant Kingdom - Cryptogamae & Bryophyta

Depending upon the presence or absence of flowers and seeds entire plant kingdom is divided into two types. They are Cryptogamae and Phanerogamae. 1. Cryptogamae: Cryptogams include all non-flowering plants such as algae, fungi, lichens, mosses and fern (Kryptos: concealed; gamus: marriage). Cryptogamae is further subdivided into three parts: Thallophyta, Bryophyta and Pteridophyta. 1.1 Thallophyta: Both Algae and Fungi are considered in Thallophyta, but nutrition in autotropic in algae, whereas fungi exhibit heterotropic nutrition. Algae usually sustain itself in a variety of habitats such as wetland as well as on other plants and even animals. Some grow in marine water and are called seaweeds. A variety of pigments in algae provide different colours. The green algae have mainly chlorophyll-a and chlorophyll-b along with carotenoids as photosynthetic pigments. Algae reproduce vegetatively by fragmentation, budding or tuber formation. Based on pigment colour, n

Female Reproductive System

Female reproductive system consists of the two ovaries, two oviducts (fallopian tubes), the uterus, cervix, a vagina, accessory genital glands, mammary glands, etc. In females, paired ovaries are located in the abdominal cavity near the kidney. The ovaries perform dual function of (i) production of female gamete (ovum) and (ii) secretion of female hormones (estrogen and progesterone). Each ovary is compared of ovarian follicles. At puberty, these follicles undergo maturation to produce ova. Near the posterior end of ovary, a funnel like structure leads into a long convoluted tube called fallopian tube. The fallopian tube from both sides open into a muscular structure, the uterus. Uterus opens into the vagina. Vagina is a tubular structure. it is also called birth canal. In female, urinary opening (urethra) and vaginal openings are separate. The ovaries start producing ovum (female gamete) at a definite age puberty (10-12 years). The ovarian follicles grow into mature follicle. U

Photosyntheisis - Equation of the Overall Process

Photosynthesis means synthesis of food with the help of sunlight. The overall equation of photosynthesis is Photosynthesis process takes place only in green parts of the plant, mostly in leaves and to lesser extent in green stems or floral parts of the plants. Leaves of the plant are known as light powered food factories. A green substance called chlorophyll in the leaves catches the energy from sunlight, water from soil, CO 2 from air and completes the chemical form. This process is called photosynthesis. Chlorophyll pigments are mainly present in cell organelles called plastids (chloroplast). There are different kinds of chlorophyll molecules present in photosynthesis organisms. In plants mostly there are two kinds viz. chlorophyll a and chlorophyll b . Both chlorophyll a and chlorophyll b are very similar in molecular structure, except that the CH 3 group in chlorophyll a is replaced by CHO group in chlorophyll b . The CO 2 for photosynthesis comes from air. It see

Vitamin - Function, Deficiency and Sources

Vitamin Function Deficiency Sources A-Retinol For normal growth in children. To maintain conjunctiva aids in night vision. To maintain skin and mucous membrane. Roughness and dry skin. Inability to see in dim light. Xerophthalmia leading to blindness (cornea becomes rough and dry). Nyctalopia (Night blindness). Fish, liver, oil, butter, milk, egg B1-Thiamine 1st vitamin to be discovered by Eijkman in 1897. Essential for healthy nerves & mucous membrane. (Destroyed by high temperature & banking soda) Causes Beri-Beri Checks growth in children Yeast, bacon, vegetables B2-Riboflavine To obtain steady and continuous release of energy Checks growth Skin becomes rough and red. Diarrhoea and digestive upsets. Milk, cereals, vegetables, yeast, meat B3-Niacin or Nictonic Acid Essential for healthy digestive function. Helps to control cholesterol

Respiratory System

 Important Respiratory Organs: The human respiratory system consists of external nares or nistrils, nasal cavity, nasopharnyx, larynx, trachea, bronchi, bronchiole and lungs. The air enters into the nasal cavity through the nostrils. Larynx is a small box and it forms the connection between pharynx and the windpipe or trachea. Larynx is also known as voice box. Larynx is covered by pieces of cartilage forming a box. In males, the adam's apple is the protuding cartilage of the voice box. Trachea is a tubular structure of about 12 cm in length and 2.5 cm in diameter. Lungs are paired structure present in the thoracic or pleural cavity. During inhalation, diaphragm contracts and lungs increases while during exhalation, the diaphragm relaxes and the lungs are compressed. The cycle of breathing (ventilation of lungs) consists of three phases: Inspiration Expiration and Pause Inspiration is an active process. It is the result of muscle contraction. Expiration is an passive process. It is