Chapter 8: Dynamic Cells Flashcards
What are Phospholids?
Cell membranes primarily made of a double layer.
What is a Hydrophilic (water loving)?
The phosphate head of the molecule.
What is a Hydrophobic (water fearing)?
The lipid tail of the molecule.
What is it called when head dissolves easily in water?
Hydrophilic
What is it called when tail does NOT dissolves easily in water?
Hydrophobic
What is a Phospholipid Bilayer?
2 layers of phospholipid molecules.
The bilayer gives the membrane flexibility and allows it to change shape.
What forms a biological mosaic?
Carbohydrates, lipids, proteins
What is the cell membrane function?
- Biological Barrier (prevents many substances from entering a cell, i.e., viruses, ions, bacteria, salts, etc.)
- Selective Filter (moves only certain substances across the membrane.)
How are your cells semi-permeable?
- Allows certain materials into the cell.
2. Moves wastes out of the cell.
What is Selective Transport?
Movement across membranes.
What is Brownian Motion?
It is when particles in a liquid or air are in constant, random motion.
What is Equilibrium?
A state of balance when all the particles are equally divided.
What is a Net Flow?
Overall division.
What is Passive Transport?
It is the movement across cell membranes without an input of energy.
What are the 2 reasons molecules move?
- Brownian Motion
2. Concentration Gradient
What are 3 Types of Passive Transport?
Diffusion, Osmosis, Facilitated Diffusion
What is Diffusion?
The net movement of particles from an area of high concentration to an area of low concentration.
Why does oxygen diffusing into the cell never reach equilibrium?
Your cells continually consuming oxygen for cellular respiration, therefore, making the concentration of oxygen inside the cell always lower than the concentration of oxygen outside the cell.
What is Osmosis?
The diffusion of water molecules across a membrane where they are more highly concentrated to where they are less concentrated.
What is a Hypotonic Solution?
Lower concentration of solute. Outside the cell (cell = hypertonic)
Water is more concentrated outside the cell and water will enter the cell (cell swells)
What is a Hypertonic Solution?
Higher concentration of solute compared to the inside of the cell (cell = hypotonic)
Water is less concentrated outside the cell and water will leave the cell (cell shrinks)
What is a Isotonic Solution?
Has the same solute concentration on both sides of the cell membrane. This means equilibrium has been reached. Equal amounts of water enters and leaves the cell. No net movement of water.
What happens when a cell is placed into distilled water?
The cell is hypertonic the water moves into the cell, the cell may burst.
What is turgor pressure?
Water pressure within plant cells that allows them to continue to be rigid.
What happens when a cell is placed into strong salt water?
The solution is hypertonic and the water leaves the cell. The cell shrinks and may die (plasmolysis).
What is plasmolysis?
When the cell membrane peels off the cell wall due to the loss of water which causes wilting.
Why would drinking saltwater pose a problem?
Hypertonic solution outside cells would cause cells to lose water, shrink and die (dehydration).
What is Facilitated Diffusion?
The use of transport proteins to help particles move across a cell membrane from an area of high concentration to an area of lower concentration.
When transport proteins have 3-D shapes what does it make them?
It makes them highly selective, recognizing atoms or molecules by shape, size or charge.
What is Active Transport?
When particles move up the concentration gradient from an area of low concentration to an high concentration. It needs an input of energy.
What is Bulk Transport?
The use of vesicles to facilitate movement of substances that are too large to enter or exit the cell which is via transport proteins.
What is Endocytosis?
When the cell membrane creates a pocket around the material to be transported, and then either pinches off as a vesicle or a vacuole.
What is the difference among a vacuole and vesicle?
- Vesicle transports contents.
- Vacuole stores or keeps ingested material.
What is Phagocytosis?
When cells “eat” by taking in large particles or other cells.
What is Pinocytosis?
When cells “drink” by taking in droplets of fluid.
What happens after a new vesicle enters the cytoplasm of a cell?
It fuses with a lysosome and the enzyme would digest the material.
What is Exocytosis?
It is when it allows the materials kept in vesicles and vacuoles to exit or leave the cell. Also, the membrane of the vesicle or vacuole fuses with the membrane, and the stored content are released.
What are the 3 examples of how semi-permeable membranes are utilized in technology and medical applications?
- Water Purification - Reverse Osmosis
- Kidney Dialysis
- Controlled Delivery of Medications
What are Liposomes?
Artificial vesicles which can safely move medications from one part of the body to another.
What is the Surface-area-to-volume ratio?
The surface area of the cell which relates to its volume.
