Mendelism – Principles of inheritance and variation Videos by Siddharth Sanghvi Sir
Mendelism – Principles of inheritance and variation Videos by Siddharth Sanghvi Sir Read More »
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R.H. Whittaker (1969) proposed a Five Kingdom Classification. The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, body organisation, mode of nutrition, phylogenetic relationships and reproduction
Kingdom Cell Type Cell Wall Nuclear Membrane Body Organization Mode of Nutrition Main Criteria Secondary Criteria Monera Prokaryotic Noncellulosic (Polysaccharide + amino acid) Absent Cellular Autotrophic (chemosynthetic and photosynthetic) and Heterotrophic (saprophytic/parasitic) Cell structure Body organization, Mode of nutrition Protista Eukaryotic Present in some Present Cellular Autotrophic (Photosynthetic) and Heterotrophic Cell structure, Nuclear membrane Mode
NCERT-NEET-The Golgi cisternae are concentrically arranged near the nucleus
Golgi Apparatus – Concentric Cisternae Near the Nucleus The Golgi apparatus is a key organelle in eukaryotic cells, made up of flat, membrane-bound sacs called cisternae. These cisternae are concentrically arranged near the nucleus. “Concentrically arranged” means the cisternae are organized in curved or ring-like layers, one around the other — much like ripples in
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Bacteria can be classified into two groups on the basis of the differences in the cell envelopes and the manner in which they respond to the staining procedure developed by Gram viz., those that take up the gram stain are Gram positive and the others that do not are called Gram negative bacteria.
Gram staining is a method used to classify bacteria into two groups based on the characteristics of their cell walls. Here’s a breakdown of the Gram staining process, which is best visualized with a flowchart: Fixation: Bacteria are fixed to a slide by heat. Primary Stain: Crystal violet stain is applied. Mordant: Iodine solution is
Structure of Cilia and Flagella – Why do cilia and flagella have singlet microtubules in the hub but not in the basal body?
Structure of Cilia and Flagella Structure of Cilia and Flagella Why do cilia and flagella have singlet microtubules in the hub but not in the basal body? Cilia and flagella are complex cellular structures responsible for motility and fluid movement. Their structural organization is key to their function, and the arrangement of microtubules within them
NCERT-Gregor Mendel, conducted hybridisation experiments on garden peas for seven years (1856-1863) and proposed the laws of inheritance in living organisms. Mendel published his work on inheritance of characters in 1865 butfor several reasons, it remained unrecognised till 1900.
Mendel’s Approach and Results Mendel’s Approach and Results Aspect of Mendel’s Approach Result Application of statistical analysis Novological – New way to address Biological Problems by using Maths Application of mathematical logic Increased reliability of inferences Large sampling size Greater credibility of collected data Experimentation on successive generations Confirmation of general rules of inheritance Investigation
NCERT-Emasculated flowers have to be covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen
Emasculated Flowers and Butter Paper Emasculated Flowers and Butter Paper Using butter paper to cover emasculated flowers serves a specific purpose in plant breeding and hybridization processes. Butter paper, also known as wax paper, is a semi-transparent paper that has been coated with a thin layer of wax. Here’s why it’s commonly used: Non-stick surface:
NEET-NCERT-Mitochondria (sing.: mitochondrion), unless specifically stained, are not easily visible under the microscope. The number of mitochondria per cell is variable depending on the physiological activity of the cells.Plastids are found in all plant cells and in euglenoides.
Mitochondria Line 1: Mitochondria (sing.: mitochondrion), unless specifically stained, are not easily visible under the microscope. Explanation: This line introduces mitochondria and highlights that they are challenging to see under a microscope without special staining techniques due to their small size and colorless nature. Line 2: The number of mitochondria per cell is variable depending
NEET-NCERT-Ribosomes are the granular structures first observed under the electronmicroscope as dense particles by George Palade (1953).
Ribosome Line 1: Ribosomes are the granular structures first observed under the electron microscope as dense particles by George Palade (1953). Explanation: This line introduces ribosomes and their key characteristics: They are granular structures (small, grain-like). They were first observed using an electron microscope, a powerful tool for viewing tiny structures within cells. They appeared
NCERT-NEET-Pollination-In the preceding sections you have learnt that the male and female gametesin flowering plants are produced in the pollen grain and embryo sac,respectively. As both types of gametes are non-motile, they have to be brought together for fertilisation to occur. How is this achieved?
The Pistil, Megasporangium (Ovule) and Embryo Sac Line 1: Pollination Explanation: This line sets the stage for the main topic: the process of pollination in flowering plants. Flowering plants rely on pollination for the transfer of pollen grains, containing male gametes, to the stigma, the receptive surface of the pistil, where fertilization occurs. Lines 2-4: