Chapter 7 Test Flashcards
Three Principles of Cell Theory
- All living organisms are composed of one or more cells.
- Cells are the basic unit of structure and organization of all living organisms.
- Cells arise only from previously existing cells, cells with passing copies of their genetic material on to their daughter cells.
Microscopes
Enlarge images by different magnifications. Reverse and flip the image shown through the microscope.
Eukaryotic Cells
Organelles are specialized structures that perform specific cell functions.
Nucleus is the distinct central organelle that contains the cell’s genetic material.
Eukaryotic are much larger than prokaryotic cells.
Prokaryotic Cells
Cells without a nucleus or other membrane-bound organelles.
Smaller and simpler compared to Eukaryotes.
Similar to the first organisms that lived on earth.
Selective Permeablility
Plasma membranes have selective permeability, meaning they allow some substances to pass through while keeping others out. The plasma membrane controls how, when, and how much of various substances enter and leave a cell.
Phospholipid Bilayer
A plasma membrane is composed of this which are two layers of phospholipids that are arranged to allow the membrane to exist in a watery environment.
Polar Heads
Face on the outside of the phospholipid bilayer and they are hydrophilic which means they love water.
Non-polar tails
Face the inside of the phospholipid bilayer and they are hydrophobic which means they don’t like water.
Cholesterol
Prevents the fatty acid tails of the phospholipid bilayer from sticking together.
Contributes to the fluidity of the membrane.
Carbohydrates
Define the cell’s characteristics.
Help cells identify chemical signals.
Fluid Mosaic Model
Describes the phospholipids in the bilayer as a “sea” in which other components can float and move around.
Different substances in the plasma membrane create a pattern or mosaic on the surface of the cell.
Diffusion
Particles in solids, liquids, and gases are in constant random motion.
Defined as the net movement of particles from an area of high concentration to an area of lower concentration.
Additional energy is not required for diffusion because the particles are already in motion.
Dynamic Equilibrium
When diffusion occurs over a long enough time, concentrations become uniform.
Molecules still move, but the concentration remains the same.
Facilitated Diffusion
Uses transport proteins to move ions and small molecules across the plasma membrane. Requires no additional energy.
Osmosis
Diffusion of Water through a selectively permeable membrane.
Isotonic Solution
Same concentration of water and solutes as the cytoplasm of the cell. Water moves through the membrane, but it enters and leaves at the same rate.
Hypotonic
Has a lower concentration of solutes compared to the cytoplasm. Water moves into the cell. Animal cells can burst in extreme situations.
Hypertonic
Higher concentration of solutes compared to the cytoplasm of the cell. Water moves out the cell. Not good for plant or animal cells because then cells shrivel.
Turgor pressure
Bacteria and plants have cell walls that prevent them from over-expanding. In plants the pressure exerted on the cell wall is called turgor pressure.
Passive Transport
No additional energy needed. Movement of molecules from a high concentration area to a low concentration area.
Active Transport
Energy required. Movement of molecules from a low concentration area to a high concentration area.
Na+/K+ ATPase Pumps
Found in the plasma membrane of animal cells. Maintain levels of sodium and potassium inside/outside the cell.
Coupled transport allows sugars to pair with Na+ ions and enter the cell through a membrane protein called a coupled channel.
Endocytosis
The process by which a cell surrounds an object in the outside in a portion of the plasma membrane.
Exocytosis
The excretion of materials at the plasma membrane
Phagocytosis
Cell Eating.
Pinocytosis
Cell Drinking.
Cells
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