IndietroGeneral Biology: Cell Structure, Membranes, and Metabolism
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Termini in questo insieme (35)
All living things are made of one or more cells. The cell is the basic unit of structure and function in living organisms. All cells come from pre-existing cells.
No nucleus, no membrane-bound organelles, smaller and simpler, includes Bacteria and Archaea.
Have a nucleus and membrane-bound organelles, larger and more complex, includes plants, animals, fungi, and protists.
As a cell grows, volume increases faster than surface area, limiting efficient exchange of materials. Cells remain small to maximize nutrient and waste transport.
Stores DNA and controls cell activities.
Sites of protein synthesis.
Modifies and transports proteins; studded with ribosomes.
Synthesizes lipids and detoxifies harmful substances.
Modifies, sorts, and packages proteins and lipids for transport.
Produce ATP through cellular respiration.
Digest waste and damaged organelles.
Provides support and protection.
Site of photosynthesis in plant cells.
Stores water and maintains turgor pressure in plant cells.
Movement of molecules from high to low concentration down a concentration gradient.
Allows some substances to pass while restricting others, maintaining homeostasis.
Small, nonpolar molecules like oxygen (O₂) and carbon dioxide (CO₂) cross membranes by simple diffusion.
Lower solute concentration outside the cell; water moves into the cell.
Equal solute concentration inside and outside; no net water movement.
Higher solute concentration outside the cell; water moves out of the cell.
Water enters, cell swells and may burst (lysis).
Water leaves, causing plasmolysis where the membrane pulls away from the cell wall.
Phospholipid bilayer, proteins, cholesterol, and carbohydrates; hydrophilic heads face water, hydrophobic tails face inward.
Movement of substances from high to low concentration without ATP, includes simple diffusion, facilitated diffusion, and osmosis.
Requires ATP to move substances from low to high concentration against the gradient.
Endocytosis brings materials into the cell; exocytosis releases materials out of the cell, both require ATP.
The capacity to do work or cause change.
Potential energy is stored energy; kinetic energy is energy of motion.
Energy cannot be created or destroyed, only transformed.
Every energy transfer increases entropy (disorder); organisms must use energy to maintain order.
The sum of all chemical reactions in an organism.
Anabolic builds molecules and requires energy; catabolic breaks down molecules and releases energy.
ATP consists of adenine, ribose sugar, and three phosphate groups; energy is released when the terminal phosphate bond is broken.
Biological catalysts that speed up reactions by lowering activation energy without being consumed.
Enzyme activity increases to an optimum temperature and pH; extremes denature enzymes and reduce activity.