Cell Biology: Cellular Structure

Study Notes

Plasma Membrane: Semi-permeable membrane that surrounds the cell, regulating what enters and leaves.
Cytoplasm: Jelly-like substance inside the cell membrane, containing water, salts, sugars, and organelles.
Nucleus: Control center of the cell, containing most of the cell's genetic material (DNA).
Mitochondria: Organelles responsible for generating energy for the cell through cellular respiration.
Endoplasmic Reticulum (ER): Network of membranous tubules and cisternae, involved in protein synthesis, folding, and transport.
Ribosomes: Small organelles found throughout the cytoplasm, responsible for protein synthesis.
Lysosomes: Membrane-bound sacs containing digestive enzymes, breaking down and recycling cellular waste and foreign substances.
Golgi Apparatus: Complex of flattened sacs and tubules, involved in protein modification, sorting, and packaging.

Metabolism: Chemical reactions that occur within the cell, including energy production, protein synthesis, and cell growth.
Cell Signaling: Process by which cells communicate with each other, involving signal transduction pathways and response to stimuli.
Cell Division: Process of cell growth, DNA replication, and cell splitting, resulting in two daughter cells.
Cell Adhesion: Ability of cells to stick together, mediated by adhesion molecules, maintaining tissue structure and function.

Passive Transport: Movement of molecules from high to low concentration, without energy input (e.g., diffusion, osmosis).
Active Transport: Movement of molecules against their concentration gradient, requiring energy input (e.g., pumps, channels).

Mitosis: Process of cell division, resulting in two genetically identical daughter cells.
Meiosis: Process of gamete formation, involving reduction of chromosome number, resulting in genetically unique daughter cells.

Plasma Membrane: Selectively permeable, allowing certain substances to pass through while keeping others out.
Cytoplasm: Comprises 70-90% water, salts, sugars, and organelles, providing a medium for cellular activities.
Nucleus: Houses most of the cell's genetic material, with a double membrane called the nuclear envelope.
Mitochondria: Generate energy through cellular respiration, converting glucose into ATP.
Endoplasmic Reticulum (ER): Divided into Rough ER (with ribosomes) and Smooth ER (without ribosomes), responsible for protein synthesis and lipid metabolism.
Ribosomes: Found in both cytoplasm and ER, responsible for translating mRNA into amino acid sequences.
Lysosomes: Contain digestive enzymes, breaking down and recycling cellular waste, foreign substances, and damaged organelles.
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for transport to other cellular regions or secretion.

Metabolism: Encompasses anabolic (energy-storing) and catabolic (energy-releasing) reactions, maintaining cellular homeostasis.
Cell Signaling: Involves signal reception, transduction, and response, enabling cells to adapt to their environment.
Cell Division: Involves interphase (growth, replication, and preparation), mitosis (nuclear division), and cytokinesis (cytoplasmic division).
Cell Adhesion: Crucial for maintaining tissue structure and function, mediated by adhesion molecules such as integrins and cadherins.

Passive Transport: Includes diffusion (random movement), osmosis (water movement), and facilitated diffusion (protein-mediated transport).
Active Transport: Requires energy input, often through ATP hydrolysis, to pump molecules against their concentration gradient.

Mitosis: Results in two genetically identical daughter cells, with duplicated chromosomes separating equally.
Meiosis: Involves two successive cell divisions, resulting in four genetically unique daughter cells with reduced chromosome number.