Cell Transport Study Guide, L4

Define homeostasis
Keeping a stable internal environment despite changes in the outside environment.
What is the function of the cell membrane?
Acts like a boundary for the cell
What is the cell membrane made from?
phospholipid bi-layer
Selectively/semi-permeable
Some materials can leave or enter through a membrane; some can’t
Is the cell membrane selectively permeable or not?
It is; it allows a small selection of molecules in and out.
What is diffusion?
The movement of molecules from an area of high concentration to an area of low concentration without the use of energy
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What does “reach a state of equilibrium” mean?
The number of a particular type or types of molecules is even on both sides.
When a cell reaches a state of equilibrium, does the movement of molecules through the cell membrane stop?
No, it continues.
What is osmosis?
The movement of WATER from an area of high water concentration to an area of low water concentration without the use of energy.
What does “passive” mean when used in cell transport?
The movement of molecules into and out of cells does NOT require energy.
What are two types of passive transport?
Osmosis and diffusion
What is something you can do to show the movement of molecules through a membrane?
Draw and label a container that contains a cell. Label the solute concentration in and out of the cell. Draw arrows to indicate movement of water.
True or false: Water surrounding or in the cell will always move towards the area of greater concentration of SOLUTE.
True
What happens when a cell with a low concentration of a a solute, example salt, enters an environment with a higher concentration of the solute?
Remember to draw the two concentrations. Water will leave the cell and move towards the area of higher concentration of solute. The cell will shrivel up.
What happens when a cell with a high concentration of a solute, example salt, enters an environment with a lower concentration of the solute?
Water will move through the cell membrane towards the cell’s high concentration of solute. The cell will swell.
What happens when the cell’s concentration of a solute equals the concentration of a solute in the environment?
Water doesn’t need to move. The cell is in a state of equilibrium with its environment.
hypertonic
more concentration ofsolute
hypotonic
less concentration of solute
isotonic
equal concentration of solute
What is active transport?
The movement of molecules from an area of low concentration to an area of high concentration with the use of energy.
Does active transport require energy?
Yes.
Does osmosis require energy?
No
Does diffusion require energy?
No
What are 3 types of active transport?
Cell membrane pumps
Endocytosis
Exocytosis
What is endocytosis?
Cell brings large molecules IN by pinching off part of the cell membrane allowing the molecules to enter. Molecules eNter.
What is exocytosis?
Cell forces large molecules OUT of the cell by putting the waste or unwanted molecule in a vesicle that can go through the cell membrane. Molecules (in a vesicle) EXit.
What are the 3 parts to the cell theory?
1. All cells come from other cells
2. The cell is the basic unit of structure and function
3. All living things are made of cells
What are the four things found in ALL cells?
Cytoplasm, ribosomes, cell membrane and genetic material such as DNA
What are the two major types of cells?
Eukaryotic and prokaryotic
What types of organisms belong to the two types of cells?
Eukaryotic – bacteria
Prokaryotic – plants, animals, protists and fungi