Watson and Crick DNA Model

Watson and Crick DNA Model

DNA stands for Deoxyribonucleic acid which is a molecule that contains the instructions an organism needs to develop, live and reproduce. It is a type of nucleic acid and is one of the four major types of macromolecules that are known to be essential for all forms of life. DNA Model The three-dimensional structure of DNA, first proposed by James D. Watson and Francis H. C. Crick in 1953, consists of two long helical strands that are coiled around a common … Read more

DNA- Structure, Properties, Types, Forms, Functions

DNA Structure

DNA stands for Deoxyribonucleic Acid which is a molecule that contains the instructions an organism needs to develop, live and reproduce. These instructions are found inside every cell and are passed down from parents to their children. It is a nucleic acid and is one of the four major types of macromolecules that are known to be essential for all forms of life. DNA is found in the nucleus, with a small amount of DNA also present in mitochondria in the … Read more

Zebrafish Development

Zebrafish Development The teleost fish Danio rerio is commonly known as the zebrafish. It is a common small‐bodied tropical, freshwater species originally from South Asia.  The fish is a part of the Cyprinidae family, which includes carps, true minnows, barbs and related genera. The Danio genus (formerly Brachydanio) contains more than 40 related species along with the zebrafish (Danio rerio). Zebrafish as a Vertebrate Development Model Organism In recent years, zebrafish has become a favorite organism of those who wish to study vertebrate development … Read more

Implantation- Process, Events, Significance

Implantation- Process, Events, Significance The term “implantation” is used to describe the process of attachment and invasion of the uterus endometrium by the blastocyst (conceptus) in placental animals. It begins at the end of the first week and is completed by the end of the second week of gestation. Implantation occurs in the endometrium of the uterus superior in the body region, slightly more often on the posterior than on the anterior wall. It involves a receptive endometrium and hormonal … Read more

Heart Embryology- Development of the Heart

Heart Embryology- Development of the Heart The heart is a muscular organ located in the middle mediastinum that pumps blood through the circulatory system. It is one of the earliest differentiating and functioning organs in the human body. In human embryos, the heart begins to beat at about 22-23 days, with blood flow beginning in the 4th week. It begins very early in mesoderm within the trilaminar embryonic disc. The heart forms initially in the embryonic disc as a simple paired tube … Read more

Developmental Biology

Developmental Biology

What is Developmental Biology? It is the field of biology that studies the processes by which multicellular organisms grow and develop, controlled by their genes.  It involves the study of mechanisms of development, differentiation, and growth in animals and plants at the molecular, cellular, genetic and evolutionary levels. It also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. The study of development has become essential for understanding any other area of biology. Image Source: Wikipedia and Researchgate … Read more

Stages of Childbirth

Stages of Childbirth

Stages of Childbirth Labor is a physiologic process during which the fetus, its associated membranes, the umbilical cord, and the placenta are expelled from the uterus. During most of the months of pregnancy, the uterus undergoes periodic episodes of weak and slow rhythmical contractions called Braxton Hicks contractions. Contractions become progressively stronger toward the end of pregnancy; that start stretching the cervix and later force the baby through the birth canal, thereby causing parturition. This process is called labor, and … Read more

Drosophila Development- Stages, Significance

Drosophila Development- Stages, Significance The fruit fly Drosophila melanogaster has been extensively studied for over a century as a model organism for genetic investigations. It also has many characteristics that make it an ideal organism for the study of animal development and behavior, neurobiology, and human genetic diseases and conditions. Image Source: biology.kenyon.edu Developmental Stages of Drosophila The development of Drosophila can be divided into the following stages: Embryogenesis 1. Fertilization Fertilization of Drosophila can only occur in the region of the oocyte … Read more

Development of Caenorhabditis elegans

The nematode worm Caenorhabditis elegans is a small (1 mm long), unsegmented, vermiform, free-living soil nematode. It is a relatively simple, and precisely structured organism, extensively used as a model organism for molecular and developmental biology. The body of an adult C. elegans hermaphrodite contains exactly 959 somatic cells, whose entire lineage has been traced through its transparent cuticle. Its genome has also been entirely sequenced, the first-ever for a multicellular organism. Reasons for Selection as Model Organism It has a rapid … Read more

Blastocyst- Stages, Significance

The preimplantation period of human embryo development is remarkable and characterized by successive changes in terms of genetic control, physiology, and morphology of the embryo. Blastocyst (Greek, blastos= sprout + cystos = cavity) is a distinctive stage of mammalian embryo development, characterized by a hollow cellular mass that forms in early development. It is an embryo that has developed for five to six days after fertilization. It is a form of blastula developing from a berrylike cluster of cells called the morula. When a cavity appears in … Read more