GEN BIO

• A cell is the smallest unit capable of performing life functions

  
• Cell size is limited because as it increases, it takes longer for material to diffuse from the cell membrane to the interior of the cell
• Surface area-to-volume ratio: as a cell increases in size, the volume increases 10x faster than the surface area
• Examples of cells: Amoeba Proteus, Plant Stem, Bacteria, Nerve Cell, Red Blood Cell
• Two types of cells: Prokaryotic and Eukaryotic
• Prokaryotic cells does not have nucleus, have few internal structures, and are typically one-celled organisms like bacteria
• Prokaryotic cell walls are made of peptidoglycan, a polymer of sugars and amino acids
• Eukaryotic cells contains nucleus and are more complex than prokaryotic cells
• Eukaryotic cells possess a membrane-bound nucleus and compartmentalize many cellular functions within organelles and the endomembrane system
• Cell parts include organelles like the cell membrane, cell wall, nucleus, nuclear membrane, chromosomes, nucleolus, cytoplasm, endoplasmic reticulum, ribosomes, mitochondria, Golgi bodies, lysosome, and vacuoles
• The cell membrane is a thin, flexible, semipermeable barrier that surrounds a cell, composed of a lipid bilayer with embedded proteins, lipids, and carbohydrates

  
• Passive transport does not require energy, while active transport does; an example of passive transport is a swing moving back and forth without energy, while active transport is like pushing a child on a swing, requiring energy
• Osmosis is the movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration

  
• Cell membranes are selectively permeable barriers that regulate the passage of materials into and out of the cell, composed of a phospholipid bilayer with hydrophobic tails facing inward and hydrophilic heads facing outward
• Active transport is the movement of molecules from low to high concentration, requiring energy as molecules are pumped against the concentration gradient.
• Endocytosis and exocytosis are mechanisms by which large molecules enter and exit the cell; for example, white blood cells engulf bacteria by endocytosis
• Glycocalyx is an outer layer that provides protection. It protects disease-causing bacteria
• Cell wall confers rigidity and shape to the cell. Found outside of the plasma membrane and is compose of peptidoglycan
• Peptidoglycan holds up the walls of a bacteria and keeps it safe
• Plasmid holds genetic infos that helps bacterias do their job. A small, circular, extrachromosomal DNA molecule found in the cytoplasm
• Nucleoid is the region where DNA is concentrated
• Cytoplasm is where chromosomes, ribosomes, and other cellular inclusions are suspended
• Ribosome are protein creators
• Pilus or pili helps bacteria adhere to surfaces of host cells.
• Flagellum facilitates movement in bacteria
• Fimbriae used for bacterial attachment to tissue surfaces
• Proteins that work as pumps are called protein pumps