Topics
Heredity and Evolution
- Heredity
- Protein Synthesis
- Transcription, Translation and Translocation
- Protein synthesis - Transcription
- Protein synthesis – Translation
- Evolution
- Theories of Origin of Life
- Evolution and Classiffication
- Evidences for Biological Evolution
- Darwin’s Theory of Natural Selection
- Lamarck’s Theory of Evolution
- Speciation
- Origin and Evolution of Man
Life Processes in Living Organisms Part -1
- Living Organisms and Life Processes
- Living Organism and Energy Production
- Formation of ATP
- Energy Production in Living Organism
- Cell Division: an Essential Life Process
- Mitosis and Its Phases
- Phases of Mitosis: Karyokinesis (Division of Nucleus)
- Phases of Mitosis: Cytokinesis (Division of Cytoplasm)
- Significance of Mitosis
- Meiosis as a Reduction Division
- Stages of Meiosis: Meiosis I
- Stages of Meiosis: Meiosis II
- Significance of Meiosis
- Differences Between Mitosis and Meiosis
Life Processes in Living Organisms Part - 2
- Introduction to Life Processes in Living Organisms
- Asexual Reproduction in Animal
- Fission
- Fragmentation
- Regeneration
- Budding
- Sporulation (Sporogenesis)
- Asexual Reproduction in Plant
- Budding
- Vegetative Reproduction
- Reproduction in Plant
- Sexual Reproduction in Flowering Plants
- Sexual Reproduction in Animals
- Human Reproductive System
- The Male Reproductive System
- The Female Reproductive System
- Gametogenesis
- Fertilization in Human
- Embryonic Development in Human
- Implantation in Human
- Pregnancy in Humans
- Placenta (Growth) in Human
- Parturition (Birth) in Human
- Menstrual Cycle (Ovarian Cycle)
- Reproduction and Modern Technology
- Reproductive Health
Environmental Management
Towards Green Energy
Animal Classification
- Biological Classification
- Classification
- Taxonomic Hierarchy of Living Organisms: Unit of Classification
- New Criteria for Basis of Classification
- History of Animal Classification
- Traditional Method of Animal Classification
- Five Kingdom Classification
- Phylum: Porifera
- Phylum: Cnidaria/Coelenterata
- Phylum: Platyhelminthes
- Phylum: Aschelminthes
- Phylum: Annelida
- Phylum: Arthropoda
- Phylum: Mollusca
- Phylum: Echinodermata
- Phylum: Hemichordata
- Phylum: Chordata
- Chordata: Vertebrata
Introduction to Microbiology
Cell Biology and Biotechnology
Social Health
Disaster Management
Life's Internal Secrets
The Regulators of Life
The Life Cycle
Mapping Our Genes
Striving for Better Environment 2
Understanding Metals and Non-Metals
Amazing World of Carbon Compounds
- The Covalent Bond
- Saturated and Unsaturated Carbon Compounds
- Chains, Branches and Rings of Carbon Compound
- Homologous Series of Carbon Compound
- Nomenclature of Organic Compounds (IUPAC)
- Chemical Properties of Carbon Compound
- Chemical Properties of Carbon Compound
- Chemical Properties of Carbon Compound
- Ethanol
- Ethanoic Acid
- Soap
notes
Control and Coordination in plants:-
Coordination is the ability to use different parts of the plant together, smoothly and efficiently. In plants, coordination is due to the result of a chemical system, wherein plant hormones or phytohormones have a major role.
Movement in plants
Plants exhibit two types of movements.
- Growth-dependent movements called the Tropic Movements. ( towards or away from a stimulus)
- Non-growth dependent movements called the Nastic Movements. ( independent of stimulus)
Tropic movements
These can be classified again into 5 types. They are:
- Phototropism (light)
- Geotropism (gravity)
- Hydrotropism (water )
- Chemotropism (chemicals)
- Thigmotropism (touch)
- Phototropism – It is the movement of plants in response to light. The shoot system of a plant exhibits this characteristic. The shoot moves towards the light.
- Geotropism – It is the movement of a plant part towards the soil. This is a characteristic of the root system. The roots always move in the direction of the earth’s gravity.
- Hydrotropism– It is the movement of a plant towards the water. The stimulus here is water.
- Chemotropism – It is the movement of plants in response to a chemical stimulus. A classic example of this type of movement is the growth of the pollen tube towards the ovule, during fertilization, in a flower.
- Thigmotropism – It is a directional movement in plants in response to touch. For e.g. the plant tendrils climb around any support which they touch.
Nastic Movements
Nastic movements in plants are not directional movements. They are not dependent on stimulus and are growth independent. For example, the leaves of a touch me not plant (Mimosa pudica), fold up immediately when touched. These kinds of changes occur due to the changes in the amount of water in the leaves. Depending on the quantity, they either swell up or shrink.
notes
Control and Co-ordination in Plants:
Movements in plants and plant harmones. Co-ordination in Plants: Unlike animals, plants do not have a nervous system. Plants use chemical means for control and co-ordination. Many plant hormones are responsible for various kinds of movements in plants. Movements in plants can be divided into two main types:
-
Tropic movement
-
Nastic movement
1. Tropic Movement: The movements which are in a particular direction in relation to the stimulus are called tropic movements. Tropic movements happen as a result of growth of a plant part in a particular direction. There are four types of tropic movements.
(i) Geotropic movement: The growth in a plant part in response to the gravity is called geotropic movement. Roots usually show positive geotropic movement, i.e. they grow in the direction of the gravity. Stems usually show negative geotropic movement.
(ii) Phototropic Movement: The growth in a plant part in response to light is called phototropic movement. Stems usually show positive phototropic movement, while roots usually show negative phototropic movement. If a plant is kept in a container in which no sunlight reaches and a hole in the container allows some sunlight; the stem finally grows in the direction of the sunlight. This happens because of a higher rate of cell division in the part of stem which is away from the sunlight. As a result, the stem bends towards the light. The heightened rate of cell division is attained by increased secretion of the plant hormone auxin in the which is away from sunlight.
(iii) Hydrotropic Movement: When roots grow in the soil, they usually grow towards the nearest source of water. This shows a positive hydrotropic movement.
(iv) Thigmotropism Movement: The growth in a plant part in response to touch is called thigmotropism movement. Such movements are seen in tendrils of climbers. The tendril grows in a way so as it can coil around a support. The differential rate of cell division in different parts of the tendril happens due to action of auxin.
Plant hormones: Plant hormones are chemical which help to co-ordinate growth, development and responses to the environment.
Type of plant hormones: Main plant hormones are
-
Auxin: (Synthesized at shoot tip).
Function: Helps in growth.
Phototropism: more growth of cells towards the light. -
Gibberellin: Helps in the growth of the stem.
-
Cytokinins: Promotes cell division.
-
Abscisic acid: Inhibits growth, cause wilting of leaves. (Stress hormone)