Monthly archives: November, 2014

Mendel’s Laws of Inheritance – Terminology and Symbols

• Character is a well defined morphological or physiological feature of an organism. • Trait is the distinguishing feature of a character. • Gene is the inherited factor that determine the biological character of an organism. • A pair of contrasting characters is called allelomorph or allele. •  Term allele was given by W. Bateson …

Gregor Johann Mendel

Gregor Mendel Biography Gregor Johann Mendel (1822-84) was born to a peasant family in the Central European village of Heinzendorf. The poverty his family experienced meant that Mendel had to work to support himself in his studies from an early age. It placed a strain on his health throughout his schooling. From the age of …

Mendelian Genetics and Heredity

Genetics and Heredity It is the branch of biological sciences which  deals with the transmission of characteristics from  one generation to the next and also the action of  hereditary units called genes as they bring about the  . characteristics which they control. Modern genetics is concerned with the study of  genes. The term genetics was …

Kerala PMT Solved paper 2014

1. Match Column I with Column II and select the correct option Column -1                 Column – II A. Ascomycetes           (i) Ustilago B. Phycomycetes         (ii) Saccharomyces C. Basidiomycetes      (iii) Trichoderma D. Deuteromycetes    (iv) Albugo (a) A-(ii), B-(i), C-(iv), D-(iii) (b) A-(iv), B-(iii), C-(ii), D-(i) (c) A-(ii), B-(iv), C-(i), D-(iii) (d) A-(iii), B-(iv), C-(i), D-(ii) …

AIPMT – All India Premedical test solved paper 2014

Medical_entrance

1. Which one of the following shows isogamy with non- flagellated gametes? (a) Sargassum (b) Ectocarpus (c) Ulothrix (d) Spirogyra 2. Five kingdom system of classification suggested by R.H. Whittaker is not based on (a) presence or absence of a well defined nucleus (b) mode of reproduction (c) mode of nutrition (d) complexity of body …

Dense connective tissues

Dense connective tissue It contains tightly packed collagen fibres, making it stronger than loose connective tissue, and it is of two types : dense irregular tissue and dense regular tissue. You can find Connective Tissue Examples below. Dense irregular tissue has fibroblasts and many fibres (mostly collagen) that are oriented differently. This type of connective …

Muscular Tissue – Structure and Types

Muscular tissue It constitutes the muscles, made up of myocytes, (muscle cells) which are in the form of contractile fibres varying in lengths. Muscular tissue in general develops from the mesoderm of the embryo but the muscles of the iris of the eye and myoepithelial cells of the salivary, mammary and sweat glands arise form …

Lysosome – Ultrasturucture and Polymorphism

Christian de Duve first observed these organelles in animal cells in 1949, by cell fractionation studies and Novikoff (1960) suggested that they are derived from pinocytic vesicles. These are single membrane bound small vesicular structures of 0.2 – 0.5 mm in diameter or larger, rich in hydrolyzing enzymes (acid hydrolases) and you can find lysosomes …

Vesicular transport processes or transcytosis

Many substances are transported across the cell membrane by endocytosis and exocytosis. Endocytosis It involves intake of materials in the form of carrier vesicles formed by invagination of small regions of plasma membrane. Endocytosis It is of three types : (i) phagocytosis (ii) pinocytosis and (iii) receptor-mediated endocytosis. (i) Phagocytosis : It is the process …

Types of loose connective tissue

Areolar tissue Structure: It takes the form of fine threads crossing each other in every direction leaving small spaces called areolae. It consists of ground substance, the matrix, white and yellow fibres and cells like fibroblasts, mast cells, macrophages (= histocytes or clasmatocytes), lymphocytes, plasma cells, mesenchyme cells, chromatophores. Fat cells can be seen in …

Life’s Levels of Organization

  Nature is every substance and energy in the universe except what humans have manufactured. It includes flowers, water, animals, rocks, thunder, and so on. Biologists study the parts of nature that have to do with life, past and present. Through their work, we glimpse a great pattern of organization. The pattern starts with atoms, …