✦ The cleavage furrow first appears during anaphase of mitosis.

✦ This furrow is the initial indentation in the cell membrane that signals the beginning of cytokinesis.

✦ It forms as the cytoskeleton contracts inward using actin microfilaments.

✦ While prophase, metaphase, and telophase involve chromosomal events, the physical separation of the cytoplasm starts in anaphase.

✦ This process ensures that the two daughter cells will eventually separate completely after the genetic material has divided.

🖊️ Proteins are made from amino acid building blocks, which join together through peptide bonds.

🖊️ Each amino acid has a specific R group (side chain) that determines the protein’s properties and folding.

🖊️ Proteins serve as enzymes, hormones, and structural molecules within the cell.

🖊️ Nucleotides form nucleic acids, monosaccharides form carbohydrates, and fatty acids form lipids—not proteins.

🖊️ Without amino acids, the cell could not perform vital processes like enzyme production and tissue repair.

❥ Keratin is a protein produced by specialized epidermal cells called keratinocytes.

❥ It provides the epidermis with strength, rigidity, and waterproofing properties, protecting against environmental damage.

❥ Keratin is a key structural protein in the skin, hair, and nails, making it essential for external protection.

❥ It forms a barrier that helps prevent pathogen entry and excessive water loss from the body.

❥ Unlike vitamin D, hemoglobin, or DNA, keratin is specifically a structural protein produced in the epidermis.

🔺 In mitosis, the goal is to create two daughter cells that are genetically identical to the parent cell.

🔺 Each daughter cell receives the exact same DNA sequence, ensuring consistency in the organism’s genetic makeup.

🔺 This process is critical for growth, repair, and replacement of damaged or dead cells in tissues.

🔺 Unlike meiosis, which introduces genetic variation, mitosis preserves genetic stability across generations of cells.

🔺 This fidelity guarantees that all body cells (except gametes) function correctly with the same genetic instructions.

🟤 Osmosis is the process in which water molecules move across a semipermeable membrane.

🟤 This movement occurs from an area of low solute concentration to an area of high solute concentration, driven purely by the concentration gradient.

🟤 Osmosis is a form of passive transport, meaning it requires no cellular energy input.

🟤 It plays a vital role in maintaining fluid balance within cells, preventing them from shrinking or swelling excessively.

🟤 While diffusion, facilitated diffusion, and active transport move solutes, only osmosis specifically refers to the movement of water.