Biology Exams 4 U
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Biology Exams 4 U
1y ago
Nobel Prize in Chemistry 2022 was awarded to three scientists ?
Barry Sharpless, Scripps Research, USA,
Carolyn R. Bertozzi, Stanford University, USA and
Morten Meldal, University of Copenhagen, Denmark.
Barry Sharpless pioneered the concept of click chemistry, a form of simple and reliable chemistry, where reactions occur quickly, and unwanted by-products are avoided. He also presented the first click reaction copper catalysed azide-alkyne cycloaddition.
Carolyn Bertozzi developed click reactions that work inside living organisms. Her bioorthogonal reactions ta ..read more
Biology Exams 4 U
1y ago
Cell signaling can be divided into 3 stages
1. Stage 1 Reception: refers to the binding of the signaling molecule (ligand) to the cell surface receptor or receptor inside the cell. In the case of hydrophilic ligands such as insulin, has receptor on the cell surface as it cannot cross plasma membrane. Hydrophobic ligands such as steroid hormones can cross the plasma membrane therefore receptor may be either in the cytoplasm or nucleus.
2. Stage 2 Transduction: The binding of ligand to the receptor causes a conformational change in the receptor that ini ..read more
Biology Exams 4 U
1y ago
3 Types of Cell Surface Receptors
1. Ion Channel Linked Receptors
• Ionotropic receptors
• Ion channel gated receptor
• pore-forming membrane proteins that allow ions to pass through a channel pore
a) Ligand gated ion channels
Allow ions to flow into or out of the cell in response to the binding of a ligand to their respective receptors. Eg: Acetylcholine Receptors.
At the nerve muscle junction, the neurotransmitter acetylcholine binds to specific receptors that allows Na+ ions to flow into and K+ ions out of the target cell.
GABAA receptors: that allow chloride ions to flow into a cel ..read more
Biology Exams 4 U
1y ago
Awarded to: Swedish geneticist Svante Pääbo (Max Planck Institute for Evolutionary Anthropology)
Contribution: for contributions to paleogenomics in Human Evolution ..read more
Biology Exams 4 U
1y ago
Receptors in Cell Signaling
Cell surface receptors are transmembrane integral proteins that interact with ligands and initiates a cellular response.
The receptors may be present either on the cell surface or inside the cell depending on the chemical nature of ligand or signaling molecule.
1. Cell surface receptors: Hydrophilic (water soluble) molecules cannot pass through lipid membrane as lipid membrane is hydrophobic. Hydrophilic molecules include peptide hormones like insulin and glucagon binds to receptors in the plasma membrane.
2. Intracellular receptors: lipo ..read more
Biology Exams 4 U
1y ago
Enroll Now -
Free Online Certificate Course on Introduction to Recombinant DNA Technology
- Download Free E book ..read more
Biology Exams 4 U
1y ago
Cell Signaling (Cell Communication)
Definition: Cell signaling is the ability of a cell to receive, process, and transmit signals with its environment and with itself.
It is the basic property of all cells and is essential for survival, growth and development of an organism.
Cells primarily communicates through chemical signals or called ligands (signaling molecules).
Ligands are secreted by the sending cells and the target cell has a receptor specific for this ligand. Binding of ligand to the receptor causes some conformational changes that further activate some other proteins inside the cell ..read more
Biology Exams 4 U
1y ago
HORTICULTURE
· Grafting is not successful inmonocots compared to dicots due to Absence of cambium for secondary growth.
Objective of vegetative propagation:
· Multiplication of an elite variety
· Production of ‘true to the type’ plants
· Cost effective multiplication of plants
In pruning care should be taken to avoid
· Cutting at internodes
· &n ..read more
Biology Exams 4 U
1y ago
ANGIOSPERM MORPHOLOGY
· Some of them have xylem vessels in their wood
· Scutellum in Monocots: Scaly haustorial embryonic leaf
· Gynostegium relates to Fusion of stamens with gynoecium
· In Wheat and rice : Pericarp is fused with seed coat
· Leaf of Tamarindus indica is Paripinnate
· In Smilax tendrils a ..read more
Biology Exams 4 U
1y ago
BRYOLOGY
· Famous Indian Bryologist: DK Singh
· Hepaticae: Each cell in the thallus contains many chloroplasts; the chloroplasts are without pyrenoids.
· Anthocerotae: Each cell of the thallus possesses a single large chloroplast with a pyrenoid.
· In Moss, primary protonema is haploid and gametophytic
· diploid in moss plant- Spore mother cell
·   ..read more