pre-class

NCERT-NEET-In the five kingdom classification of Whittaker there is no mention of lichens and some acellular organisms like viruses, viroids and prions. These are briefly introduced here.

NCERT-NEET-In the five kingdom classification of Whittaker there is no mention of lichens and some acellular organisms like viruses, viroids and prions. These are briefly introduced here.

Biological Classification, NCERT LINE BY LINE, pre-class /

Type Characteristics Viruses – Non-cellular organisms with inert crystalline structure outside the living cell. – Infect host cells and take over their machinery to replicate, killing the host. – Recognized by Dmitri Ivanowsky (1892) as causal organisms of tobacco mosaic disease. – Named “virus” by M.W. Beijerinek (1898). – W.M. Stanley (1935) showed viruses could […]

NCERT-NEET-In the five kingdom classification of Whittaker there is no mention of lichens and some acellular organisms like viruses, viroids and prions. These are briefly introduced here. Read More »

NCERT-NEET-Growth and reproduction are characteristics of cells,indeed of all living organisms. All cells reproduce by dividing into two,with each parental cell giving rise to two daughter cells each time they divide. These newly formed daughter cells can themselves grow and divide,giving rise to a new cell population that is formed by the growth anddivision of a single parental cell and its progeny. In other words, such cycles of growth and division allow a single cell to form a structure consisting of millions of cells

NCERT-NEET-Growth and reproduction are characteristics of cells,indeed of all living organisms. All cells reproduce by dividing into two,with each parental cell giving rise to two daughter cells each time they divide. These newly formed daughter cells can themselves grow and divide,giving rise to a new cell population that is formed by the growth anddivision of a single parental cell and its progeny. In other words, such cycles of growth and division allow a single cell to form a structure consisting of millions of cells

Cell Cycle and Division, NCERT LINE BY LINE, pre-class /

Stage Characteristics G1 Phase Interval between mitosis and DNA replication initiation. Cell grows and carries out normal metabolism. Organelles are duplicated. S Phase DNA synthesis or replication occurs. DNA content doubles from 2C to 4C, but chromosome number remains the same (2n). Centriole duplicates in the cytoplasm in animal cells. G2 Phase Preparation for mitosis.

NCERT-NEET-Growth and reproduction are characteristics of cells,indeed of all living organisms. All cells reproduce by dividing into two,with each parental cell giving rise to two daughter cells each time they divide. These newly formed daughter cells can themselves grow and divide,giving rise to a new cell population that is formed by the growth anddivision of a single parental cell and its progeny. In other words, such cycles of growth and division allow a single cell to form a structure consisting of millions of cells Read More »

NCERT-NEET-The morphology of the mycelium, mode of spore formation and fruiting bodies form the basis for the division of the kingdom into various classes.

NCERT-NEET-The morphology of the mycelium, mode of spore formation and fruiting bodies form the basis for the division of the kingdom into various classes.

Biological Classification, NCERT LINE BY LINE, pre-class /

Fungal Classes Comparison Characters Phycomycetes Ascomycetes Basidiomycetes Deuteromycetes Habitat Aquatic habitats, decaying wood in moist and damp places, obligate parasites on plants. Saprophytic, decomposers, parasitic, coprophilous (growing on dung). Soil, logs, tree stumps, living plant bodies as parasites (rusts, smuts). Saprophytes, parasites, decomposers of litter, help in mineral cycling. Mycelium Aseptate and coenocytic. Branched and

NCERT-NEET-The morphology of the mycelium, mode of spore formation and fruiting bodies form the basis for the division of the kingdom into various classes. Read More »

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

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

Biological Classification, NCERT LINE BY LINE, pre-class /

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

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 Read More »

NCERT-NEET-The Golgi cisternae are concentrically arranged near the nucleus

NCERT-NEET-The Golgi cisternae are concentrically arranged near the nucleus

CELL: THE UNIT OF LIFE, NCERT LINE BY LINE, pre-class /

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

NCERT-NEET-The Golgi cisternae are concentrically arranged near the nucleus Read More »

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.

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.

CELL: THE UNIT OF LIFE, NCERT LINE BY LINE, pre-class /

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

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. Read More »

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.

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.

NCERT LINE BY LINE, pre-class, PRINCIPLES OF INHERITANCE AND VARIATION /

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-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. Read More »

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

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

NCERT LINE BY LINE, pre-class /

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:

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 Read More »

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.

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.

CELL: THE UNIT OF LIFE, NCERT LINE BY LINE, pre-class /

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-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. Read More »

NEET-NCERT-Ribosomes are the granular structures first observed under the electronmicroscope as dense particles by George Palade (1953).

NEET-NCERT-Ribosomes are the granular structures first observed under the electronmicroscope as dense particles by George Palade (1953).

CELL: THE UNIT OF LIFE, NCERT LINE BY LINE, pre-class /

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

NEET-NCERT-Ribosomes are the granular structures first observed under the electronmicroscope as dense particles by George Palade (1953). Read More »