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40 Cards in this Set
- Front
- Back
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What is the cell membrane?
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the thin flexible barrier that surrounds all cells
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What is the cell wall?
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A string supporting layer around the membrane
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What does the cell membrane do?
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Regulates what enters and leaves the cell; provides protection and support
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What is the cell membrane made of?
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a double layered sheet called a lipid bilayer
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What is the purpose of the lipid bilayer?
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gives cells a flexible structure and forms a barrier between the cell and its surroundings
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What is the cell membrane?
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the thin flexible barrier that surrounds all cells
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What is the cell wall?
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A string supporting layer around the membrane
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What does the cell membrane do?
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Regulates what enters and leaves the cell; provides protection and support
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What is the cell membrane made of?
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a double layered sheet called a lipid bilayer
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What is the purpose of the lipid bilayer?
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gives cells a flexible structure and forms a barrier between the cell and its surroundings
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What is the cell membrane?
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the thin flexible barrier that surrounds all cells
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What is the cell wall?
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A string supporting layer around the membrane
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What does the cell membrane do?
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Regulates what enters and leaves the cell; provides protection and support
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What is the cell membrane made of?
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a double layered sheet called a lipid bilayer
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What is the purpose of the lipid bilayer?
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gives cells a flexible structure and forms a barrier between the cell and its surroundings
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What is the fluid mosaic model?
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Describes the plasma membrane of animal cells. The plasma membrane that surrounds these cells has two layers (a bilayer) of phospholipids (fats with phosphorous attached), which at body temperature are like vegetable oil (fluid).
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What are phospholipids?
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Compounds called proteins and phospholipids make up most of the cell membrane. The phospholipids make the basic bag.
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What are hyprophilic heads?
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Phospholipids are in a shape like a head and a tail. The heads like water (hydrophilic) and the tails do not like water (hydrophobic). The tails bump up against each other and the heads are out facing the watery area surrounding the cell.
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What are hydrophobic tails?
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Phospholipids are in a shape like a head and a tail. The heads like water (hydrophilic) and the tails do not like water (hydrophobic). The tails bump up against each other and the heads are out facing the watery area surrounding the cell.
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What do membrane proteins do?
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You will find thousands of proteins throughout the cell membrane. Some are just on the inside of the cell and some on the outside. A special few cross the cell membrane. Each type of protein has a specific purpose.
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What is a peripheral protein?
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Peripheral proteins are not bonded as strongly to the membrane. They may just sit on the surface of the membrane, anchored with a few hydrogen (H) bonds.
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What is an integral protein?
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Integral membrane proteins are permanently connected to the cell membrane. Some integral proteins cross the membrane and act as pathways for ions and molecules
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What is the finction of carbohydrates in the cell membrane?
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Carbohydrate chains attach to the outer surface of the plasma membrane on each cell. These carbohydrates are specific to every person, and they supply characteristics such as your blood type.
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Describe a plant cell wall.
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Cell walls are made of specialized sugars called cellulose. Cellulose provides a protected framework for a plant cell to survive. Cellulose is called a structural carbohydrate (complex sugar) because it is used in protection and support. Cell walls also help a plant keep its shape.
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Why are there holes in cell walls?
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There are small holes in the cell wall that let nutrients, waste, and ions pass through. Those holes are called plasmodesmata.
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What is the most important job of the cell membrane?
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to regulate the movement of dissolved molecules from the liquid onone side of the membrane to the liquid on the other side
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What does concentration mean?
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the concentration of a solution is the mass of the solute in a given volume of solution (mass/volume)
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What is passive transport?
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Easy movement of molecules. It could be as simple as molecules moving freely such as osmosis or diffusion. You may also see proteins in the cell membrane that act as channels to help the movement along.The cell is not required to use energy.
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What is diffusion?
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a process by which molecules move from an area of high concentration to an area where they are less concentrated
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What is osmosis?
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the diffusion of water through a selectively permeable membrane.
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What does isontonic mean?
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means same strength. Applied when concentrations are the same on both sides of a membrane.
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What does hypertonic mean?
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means above strength. appplied when comparing a more concentrated solution to a dilute solution.
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What does hypotonic mean?
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means below strength. Applied to a dilute solution.
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What is osmotic pressure?
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osmotioc pressure is exerted on ther hypertonic side of a selectively permeable membrane; it can casue a cell to increase in colume and then burst
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What is facilitated diffusion?
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When a cell membrane has protein channels that help diffuse molecules across the membrane. Different protein channels allow particuoar substances to cross different membranes.
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What is active transport?
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Active transport describes what happens when a cell uses energy to transport something. Active transport usually happens across the cell membrane. There are thousands of proteins embedded in the cell's lipid bilayer. Those proteins do much of the work in active transport.
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What is endocytosis (active transport)?
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The process of taking material into the cell by means of infoldings, or pockets, of the cell membrane. The pocket breaks loose from the outer portion of the cell membrane and forms a vacuole within the cytoplasm.
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What is phagocytosis (active transport)?
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Means "cell-eating". Extensions of cytoplams surround a particle and oackage it within a food vacuole. The cell than engulfs it.
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What is pinocytosis (active transport)?
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The process by which cells take up liquid from the surrounding environment. Pockets from along the cell membrane, fill with liquid, pinch off to form vacuoles within the cell.
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What is exocytosis (active transport)?
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When cells release large amounts of material from the cell. The membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.
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