VO 1 cell biology

• Ribosomes are particles made of ribosomal RNA and protein.
• Ribosomes are the cellular components that carry out protein synthesis.
• The nucleus contains most of the cell's genes, is the site of ribosomal RNA synthesis, and is enclosed by a double membrane called the nuclear envelope.
• Prokaryotic cells have no nucleus, DNA in an unbound region called the nucleoid, no membrane-bound organelles, and cytoplasm bound by the plasma membrane.
• Eukaryotic cells have membrane-enclosed organelles, including a nucleus, and internal membranes that partition the cell into organelles.
• The extracellular matrix is made up of glycoproteins such as collagen, proteoglycans, and fibronectin.
• Components that function in phagocytosis are the cytoskeleton, lysosomes, and plasma membrane.
• Extracellular matrix proteins bind to receptor proteins in the plasma membrane called integrins.
• Tight junctions prevent fluid from moving across a layer of cells.
• Extracellular components and connections between cells help coordinate cellular activities.
• Robert Hooke used a primitive microscope to observe that a plant cell wall is an elaborate extracellular matrix that encloses each cell in a plant.
• Hooke for the first time used the term "cell" to describe the boxlike cavities he observed in cork.
• The word "bacteria" was originally used to refer to prokaryotes in general but has been redefined to refer specifically to eubacteria.
• Hooke's discovery of plant cells led to the understanding of cells as the smallest units of life and the foundation of cell theory.
• The acidic internal pH of lysosomes is maintained by a proton pump in the lysosomal membrane, which imports protons from the cytosol coupled to ATP hydrolysis.
• Functions of the Golgi apparatus include modifying products of the ER, manufacturing certain macromolecules, and sorting and packaging materials into transport vesicles.
• The endomembrane system regulates protein traffic and performs metabolic functions in the cell.
• The Golgi apparatus consists of flattened membranous sacs called cisternae.
• Lysosomes contain acid hydrolases that are active at the acidic pH maintained within the lysosome.
• If the metabolic rate exceeds the rate of exchange of vital materials and wastes, the cell will eventually die.
• As a cell grows, volume increases faster than surface area, leading to a decreased SA:Vol ratio.
• Metabolic requirements set upper limits on the size of cells.
• Cells need to produce cellular components and chemical energy to survive.
• Growing cells tend to divide and remain small to maintain a high SurfaceArea:Volume ratio suitable for survival.
• The rate of metabolism of a cell is a function of its mass/volume.
• The rate of material exchange is a function of the cell's surface area.
• The molecules that form a membrane are amphiphilic, consisting of a hydrophilic head group and a hydrophobic tail.
• All cells contain and manipulate a similar collection of small molecules, including simple sugars, nucleotides, and amino acids.
• Phospholipids, the main components of cell membranes, arrange themselves as bilayers in water, with the hydrophilic heads facing the water and the hydrophobic tails facing each other.
• All cells are enclosed by a plasma membrane, which acts as a selective barrier and allows the cell to concentrate nutrients and retain synthesized products while excreting waste.
• All cells require ATP (adenosine triphosphate) as a building block for DNA and RNA synthesis and as a carrier of free energy for chemical reactions.
• Gap junction: Communicating junctions that provide cytoplasmic channels between adjacent cells.
• All cells transcribe portions of their hereditary information into the same intermediary form: RNA
• The ability of a macrophage to destroy bacteria involves the coordination of various components.
• Plasmodesmata: Channels that perforate plant cell walls, allowing the passage of water and small solutes between cells.
• Desmosome: Anchoring junctions that fasten cells together into strong sheets.
• Tight junction: Membranes of neighboring cells pressed together, preventing leakage of extracellular fluid.
• Cells rely on the integration of structures and organelles to function.
• Cell walls: Extracellular structures that protect plant cells, maintain shape, and prevent excessive uptake of water.
• All cells are enclosed in a plasma membrane across which nutrients and waste materials must pass