Anas Zoology

Nucleus: Nucleus is a membrane enclosed organelle that contains the chromosome. It is present inside the cell. The study of nuclei of cells is known as Karyology. Nucleus is present in all cells except mature RBC's and sieve cells of xylem. The shape of nucleus varies. It can be oval, disc shaped, lobular, irregular etc In prokaryotes the nucleus is not covered by well defined membranes. In prokaryotes it is called as prokaryon/genophore/nucleoid. Normally a cell contains one nucleus but their number varies in certain cells e.g. binucleate liver cells and cartilage, polynucleate in osteoblast and skeletal muscles etc. Nucleus is made up of four parts: Nuclear Membrane Nucleoplasm/Karyoplasm Chromatin Network Nucleolus Different parts of Nucleus 1) Nuclear Membrane: It is a perforated double membrane. The pores have pore complex to regulate the size of pore. It seems to separate the contents of nucleus from cytoplasm. The nuclear membrane is made up of phospholipid bilayer. 2) Nucl...

The specialized structures seen inside the living cells are called cell organelles. Different cell organelles present inside a cell are: Nucleus Ribosomes Endoplasmic Reticulum (Smooth and Rough) Cytoskeleton Golgi complex/apparatus Mitochondria Lysosomes Centriole Vacuoles

What are Lipids? A lipid is a class of organic compound which is a fatty acid or its derivative. They are insoluble in water but soluble in organic solvent. Major lipids in cell membrane are: Phospholipids  Cholesterol 1) Phospholipids: The lipid substances containing phosphorous and fatty acids are called phospholipids. There are different types of phospholipids present in cell membrane, they are as follows: Aminophospholipids Phosphatidylinositol Sphingomyelin Phosphatidylserine Phosphatidylcholine Phosphatidylglycerol Phosphatidylethanolamine The phospholipid molecules are arranged in two layers in cell membrane. A phospholipid molecule consist of two parts: head portion and tail portion. The head portion is made up of phosphate group and a glycerol atom and tail portion is made up of two fatty acid chains. Head portion is polar and hydrophilic (Strong affinity for water). The tail portion is non polar and hydrophobic (repelled by water/water fearing). Structure of Phospholipid ...

White-Eared Bulbul ( Pycnonotus leucotis ) The White-Eared Bulbul is a member of Pycnonotidae family. Distribution: It is found in south-western Asia from India to the Arabian Peninsula. Identification: It has a brownish-grey body. The tail is relatively long, starting off black and ending in white tips. The head is black, but the area around its cheeks is white. The vent is bright yellow. Conservation Status: Least Concern (LC) White-Eared Bulbul Realted Posts: Scarlet Skimmer:  https://anaszoology.blogspot.com/2022/08/scarlet-skimmer-blogpost-2.html

What is DNA Barcoding? It is a technique use to identify animals, plants and microbes. A short section of DNA from a gene is used to identify the species. The short section of DNA which is used is called DNA Barcode. Dr. Paul D.N. Hebert is the founder of DNA barcoding. The gene region which is used for animal groups is Cytochrome- C oxidase I gene abbreviated as CO-1. Procedure: Take the tissue from the specimen to extract the DNA. Isolate the barcode region. Multiply the isolated DNA using PCR. Then it is sequenced The sequence obtained is placed in BOLD database (Barcode of Life Data system). It is a reference library of DNA barcodes which can be used to identify unknown specimens. Advantages: Useful in identifying species where morphological techniques are not enough. Provide evidence in poaching cases.   Related Articles: DNA Fingerprinting:  https://anaszoology.blogspot.com/2022/08/dna-fingerprinting.html Applications of DNA Fingerprinting:  https://anaszoology.blog...

The stratified epithelium tissue consist of two or more layers of cells.  An epithelium tissue consist of cells that form membranes, which cover and line the body surfaces and glands.  The stratified epithelium tissue can be further classified in 4 types: Stratified Squamous Epithelium Stratified Cuboidal Epithelium Stratified Columnar Epithelium Transitional Epithelium 1) Stratified Squamous Epithelium: Description: There are several layers of cells which are cuboidal to columnar in shape. The apical cells are squamous and basal cells are cuboidal or columnar. Location: Forms superficial layer of skin (Keratinized form), lining of mouth, oesophagus, part of epiglottis and also covers the tongue. Function: Protection (against microorganisms and water loss) 2) Stratified Cuboidal Epithelium: Description: Several layer of cells in which the cells are cube shaped in both the apical surface and basal surface. Location: Pancreatic duct, Sweat glands. Function: Protection, absorptio...

What are Liverworts ? They are thought to be the simplest of all the existing groups of land plants. They are found mainly in damp shaded habitats. They come in two forms: flat and ribbon-like. They are traditionally classified with mosses and hornworts in a group of ancient plants known as bryophytes. Liverworts have some unique features that sets them apart from other two. Their rhizoids are single celled. Snakeskin Liverwort ( Conocephalum conicum ) The name C. conicum refers to the cone shaped archegoniophore, which bear sporangia. It is found worldwide on streamside rocks and in other moist places. It is the most common liverwort in northern hemisphere. It is also found in open woodlands. It grows upto 20 cm long. Snakeskin liverwort is ribbon-shaped liverwort. It has a glossy upper surface with minute translucent chambers.