Topics
Reproduction in Lower and Higher Plants
- Reproduction
- Asexual Reproduction
- Asexual Reproduction in Unicellular Organisms > Binary Fission
- Binary Fission > Simple Binary Fission
- Binary Fission > Transverse Binary Fission
- Binary Fission > Longitudinal Binary Fission
- Asexual Reproduction in Unicellular Organisms > Multiple Fission
- Asexual Reproduction in Unicellular Organisms > Budding
- Asexual Reproduction in Multicellular Organisms > Fragmentation
- Asexual Reproduction in Multicellular Organisms > Spore Formation
- Vegetative Reproduction or Vegetative Propagation
- Natural Vegetative Propagation
- Artificial Vegetative Propagation
- Sexual Reproduction
- Flower - a Fascinating Organ of Angiosperms
- Structure and Development of Anther
- Microsporogenesis
- Structure and Development of Male Gametophyte
- Structure and Development of Ovule
- Types of Ovules (Based on Orientation)
- Types of Ovules (Based on Integuments)
- Megasporogenesis
- Development of Female Gametophyte or Embryo Sac
- Pollination
- Autogamy
- Cross-pollination
- Geitonogamy
- Agents and Types of Cross-pollination
- Anemophily
- Hydrophily
- Entomophily
- Ornithophily
- Cheiropteriphily
- Malacophily
- Outbreeding Devices
- Fertilization
- Pollen Pistil Interaction
- Artificial Hybridization or Artificial Fertilization
- Double Fertilization and Triple Fusion
- Endosperm
- Embryo
- Seed and Fruit Development
- Dormancy
- Apomixis
- Parthenocarpy
- Polyembryony
- Overview of Reproduction in Lower and Higher Plants
Reproduction in Lower and Higher Animals
- Reproduction
- Asexual Reproduction
- Asexual Reproduction in Multicellular Organisms > Gemmule Formation
- Asexual Reproduction in Multicellular Organisms > Budding
- Asexual Reproduction in Multicellular Organisms > Regeneration
- Sexual Reproduction
- Human Reproduction
- The Male Reproductive System
- Basic Concept of Testes
- Duct system of Male Reproductive Tract
- Accessory Glands of Male Reproductive System
- Semen (Seminal fluid)
- External Genitalia: Penis
- The Female Reproductive System
- Ovaries
- Female Reproductive Duct System
- External Genitalia: Vulva
- Mammary Glands
- Puberty
- Menstrual Cycle (Ovarian Cycle)
- Major Events of Menstrual Cycle
- Gametogenesis
- Spermatogenesis
- Phases of Spermatogenesis
- Structure of Sperms
- Oogenesis
- Phases of Oogenesis
- Structure of Secondary Oocyte
- Fertilization
- Fertilization in Human
- Embryonic Development in Human
- Pregnancy in Humans
- Placenta (Growth) in Human
- Parturition (Birth) in Human
- Lactation in Human
- Concept of Reproductive Health
- Methods of Birth Control and Contraceptive Devices
- Natural Contraceptive Methods
- Artificial Contraceptive Methods
- Sexually Transmitted Diseases (STD) or Sexually Transmitted Infections (STI)
- Infertility
- Assisted Reproductive Technology (ART)
- Overview of Reproduction in Lower and Higher Animals
Inheritance and Variation
- Heredity
- Genes and Genetic
- Back Cross and Test Cross
- Deviations from Mendel’s Findings
- Chromosomal Theory of Inheritance
- Chromosomes - The Carriers of Heredity
- Linkage and Crossing Over
- Autosomal Inheritance
- Sex Determination
- Sex Linked Inheritance
- Human Genetic Disorders
- Exceptions to Mendel's Principles > Multiple alleles
- Linkage
- Types of Linkage > Complete Linkage
- Types of Linkage > Incomplete Linkage
- Crossing Over
- Colour blindness
- Haemophilia
- Sex Determination in Birds
- Down's syndrome (Mongolian Idiocy)
- Turner's Syndrome
- Klinefelter's Syndrome
- Overview of Inheritance and Variation
Molecular Basis of Inheritance
- Deoxyribonucleic Acid (DNA)
- Griffith’s Experiment
- Packaging of DNA Helix
- DNA Replication
- Protein Synthesis
- Regulation of Gene Expression
- The Lac Operon
- Genomics
- Human Genome Project
- DNA Fingerprinting
- Genetic Code
- Mechanism of Translation
- Overview of Molecular Basis of Inheritance
Origin and Evolution of Life
- Origin and Evolution of Universe and Earth
- Theories of Origin of Life
- Chemical Evolution of Life (Self-assembly Theory of the Origin of Life)
- Darwin’s Theory of Natural Selection (Darwinism)
- Mutation Theory
- Modern Synthetic Theory of Evolution
- Organic Evolution
- Hardy Weinberg’s Principle
- Adaptive Radiation
- Evidence of Evolution > Morphological Evidences
- Speciation
- Geological Time Scale
- Theories of Biological Evolution
- Overview of Origin and Evolution of Life
Plant Water Relation
- Plant Water Relation
- Properties of Water
- Water Available to Roots for Absorption
- Imbibition
- Diffusion
- Osmosis
- Osmotic Pressure
- Turgidity and Flaccidity (Plasmolysis)
- Passive Transport
- Water Potential (ψ)
- Concept of Transpiration
- Path of Water Across the Root
- Kinds of Transpiration
- Forces Contributing to Ascent of Sap
- Transport of Mineral Ions
- Structure of Stomatal Apparatus
- Significance of Transpiration
- Transportation of Food and Other Substances
- Overview of Plant Water Relation
Plant Growth and Mineral Nutrition
- Plant Growth
- Phases of Plant Growth
- Conditions Necessary for Plant Growth
- Plant Growth Rate
- Plant Growth Curve
- Differentiation, De-differentiation, Re- Differentiation
- Plant Development
- Plant Plasticity
- Plant Hormones
- Auxins
- Gibberellins
- Cytokinins
- Ethylene
- Abscisic Acid (ABA)
- Photoperiodism
- Vernalization (Yarovization)
- Plant Mineral Nutrition
- Nitrogen Cycle
- Overview of Plant Growth and Mineral Nutrition
Respiration and Circulation
- Cellular Respiration
- Organs of Respiratory Exchange
- Human Respiratory System
- Mechanism of respiration-Breathing
- Regulation of Breathing / Respiration
- Modified Respiratory Movements
- Disorders of Respiratory System
- Transportation in Living Organisms
- Circulation in Animals
- Types of Closed Circulation
- Blood Circulatory System
- Composition of Blood > Plasma (The Liquid Portion of Blood)
- Composition of Blood > Cellular Elements: Red Blood Cells (Erythrocytes)
- Composition of Blood > Cellular Elements: White Blood Cells (Leukocytes)
- Composition of Blood > Cellular Elements: Blood Platelets (Thrombocytes)
- Human Heart
- Working mechanism of human heart
- Blood Vessels
- Blood Pressure (B.P.)
- Electrocardiogram (ECG)
- Lymph and Lymphatic System
- Mechanism of respiration - Internal respiration
- Mechanism of respiration - External respiration
- Cellular Respiration
- Overview of Respiration and Circulation
Control and Co-ordination
- Control and Co-ordination
- Nervous System in Hydra
- Nervous System in Planaria (Flatworm)
- Neural Tissue
- Neuron (Or Nerve Cell)
- Neuroglial Cells (Or Glial Cells)
- Human Nervous System
- Central Nervous System (CNS)
- The Human Brain
- The Spinal Cord
- Peripheral Nervous System > Somatic Nervous System
- Sensory Receptors
- The Human Eye
- Human Ear
- Disorders of Nervous System
- Chemical Coordination
- Human Endocrine System
- The Hypothalamus
- Pituitary Gland or Hypophysis Gland
- The Pineal Gland
- Thyroid Gland
- Parathyroid Gland
- Thymus Gland
- Adrenal Gland (Suprarenal Gland)
- Pancreas (Islets of Langerhans)
- Reproductive Glands (Gonads)
- Synapse
- Types of Synapse
- Transmission of Nerve Impulse
- Generation of nerve impulse
- Reflex Action
- Peripheral Nervous System > Autonomic Nervous System
- Diffuse Endocrine Glands
- Overview of Control and Co-ordination
Human Health and Diseases
- Defence System in Our Body: Immune System
- Structure of Antibody
- Disease
- Protozoan Diseases
- Helminthic Diseases
- Bacterial Diseases
- Viral Diseases
- Fungal Diseases
- Vector Borne Diseases
- Cancer
- Drug Abuse
- Concept of Adolescence
- Addiction
- Vaccines and Vaccination
- Blood Transfusion and Blood Groups (ABO and Rh system)
Human Reproduction
Enhancement of Food Production
- Improvement in Food Production
- Plant Breeding
- Tissue Culture
- Single Cell Protein (SCP)
- Biofortification
- Animal Husbandry (Livestock)
- Animal Husbandry (Livestock) > Animal Breeding
- Dairy (Livestock) Farm Management
- Poultry Farm Management
- Animal Husbandry (Livestock) > Apiculture (Bee Farming)
- Animal Husbandry (Livestock) > Pisciculture (Fish Farming)
- Sericulture
- Lac Culture
- Microbes in Human Welfare
- Microbes in Industrial Products
- Microbes in Sewage Treatment
- Microbes in Energy Generation
- Microbes as Biocontrol Agents
- Microbes as Biofertilizers
- Microbial Role in Dairy Products
- Overview of Enhancement of Food Production
Biotechnology
- Biotechnology
- Principles of Biotechnology
- Methodology for rDNA Technology
- Crop Biotechnology > Hybrid Seeds
- Bioethics
- Effects of Biotechnology on the Environment
- Biopiracy
- Transgenic Plants
- Effects of Biotechnology on Human Health
- Tools and techniques for gene cloning/ rDNA technology
- Crop Biotechnology > Genetically Modified Organisms (GMOs)
- Overview of Biotechnology
Organisms and Populations
- Organisms and the Environment Around
- Habitat
- Niche
- Adaptations and Its Types
- Population
- Population Interactions
- Organisms and Populations
- Population Growth
- Positive Interactions > Mutualism (Symbiosis)
- Negative Interactions > Competition
- Negative Interactions > Parasitism
- Negative Interactions > Predation
- Positive Interactions > Commensalism
- Overview of Organisms and Populations
Ecosystems and Energy Flow
Biodiversity, Conservation and Environmental Issues
- Biodiversity
- Levels of Biodiversity
- Patterns of Biodiversity
- Biodiversity Current Scenario
- Loss of Biodiversity
- Conservation of Wildlife
- Biological Diversity Act, 2002
- Environmental Issues
- Noise Pollution
- Green House Effect
- Preventive Measures of Green House Effect
- Deforestation and Its Causes
- Global Warming
- Preventive Measures of Global Warming
- Mission Harit Maharashtra
- Conservation of Biodiversity
- Overview of Biodiversity, Conservation and Environmental Issues
- Definition: Microsporogenesis
- Primary Sporogenous Tissue
- Meiotic Division
- Types of Pollen Tetrads
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Definition: Microsporogenesis
The process of formation of microspores from the sporogenous tissue is said to be microsporogenesis.
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Definition: Compound Pollen Grains
When microspores of a tetrad do not separate and remain attached together in groups, they are called compound pollen grains.
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Definition: Pollinium
A compact mass formed when all microspores within a pollen sac remain united as a single structure is called a pollinium.
CBSE: Class 12
CISCE: Class 12
CISCE: Class 12
Key Points: Types of Pollen Tetrads
| Type of Pollen Tetrad | Arrangement of Microspores | Distinct Feature | Example |
|---|---|---|---|
| Tetrahedral | Four microspores at the corners of a tetrahedron | Only three microspores visible from one side | Rhododendron, Nicotiana |
| Isobilateral | All four microspores arranged in one plane | Microspores lie opposite each other | Cucurbita |
| Decussate | Microspores arranged in two crossed pairs | Cross-like arrangement | Magnolia |
| T-shaped | Three microspores in a row and one at right angle | Forms a T-shape | Aristolochia |
| Linear | Four microspores arranged in a straight line | All microspores in one row | Halophila |
