Mid Term Review Essay
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1. For each pair of terms, explain the differences in their meanings. A. Diffusion, osmosis Diffusion is the process where molecules move from a region of high concentration to a region of low concentration. Osmosis is basically the same, but with water. B. cell division, mitosis Cell division is part of mitosis, when a cell splits into two. Mitosis has more steps than just cell division. C. facilitated diffusion, active transport Active transport is where a cell uses energy to move molecules.
Facilitated diffusion is the same as diffusion, just when they pass through integral proteins. D. endocytosis, exocytosis Endocytosis is when useful nutrients are put into a cell. Exocytosis is when useful materials are removed from the cell.
2. Voltage sensitive channels help cells communicate by
A. electrical signals
B chemical stimuli
C. binding to molecules
D. insulin molecules
3. Cells sense chemical signals by using:
B. receptor proteins
C. signaling messengers
D. surface markers
4. The process by which water moves into and out of the cell is: A.
C. active transport
5. A cell uses some of its energy to move molecules by
A. osmotic pressure
B. active transport
6. The sodium-potassium pump
A. requires no energy
B. moves potassium out of the cell.
C. enables sugars to enter cells.
D. works independently of channels.
7. Which is an example of active transport?
A. sodium-potassium pump
B. electron pump
D. facilitated diffusion
8. Particles too large to pass through protein channels in the cell membrane may enter the cell by:
B. selective transport
D. osmotic pressure
9. During mitosis:
A. chromosomes are copied
B. chromosomes move to opposite sides of the cell
C. cytoplasm divides in half
D. a new cell wall forms in the center of the cell.
10. If a cell has 8 chromosomes before cell division, how many chromosomes will each of the two new cells have at the end of cell division?
11. During cell division in bacteria
A. a circle of DNA is copied
B. chromosomes coil and move
C. the cell splits into 3 parts
D. two new nuclei are formed
12. After mitosis, the cytoplasm of cells is pinched in half. In cells of plants, cell walls are formed. 13. If placed in water, a cell would swell and possibly burst due to osmotic pressure being too high. 14. A type of active transport system that uses light or chemical energy to move molecules that are required for cell metabolism is called the proton pump Short Answer:
15. What two helpful jobs are performed by the surface markers on cells? Cell markers tell your cells what type of cells they are and where they are to go, plus what type of cells they can join with. 16. Explain why animal cells do not burst due to osmotic pressure. When the amount liquid in the animal cell rises, the difference between that pressure and the osmotic pressure decreases. When the pressure levels even out, the cell intake stops.
17. Describe the events that result in the formation of two complete nuclei in a eukaryotic cell. This process is called mitosis and it has four phases, prophase, metaphase, anaphase, and telophase. First, the cell breaks down and bound together at one point. Next, the chromosomes separate into two. Then, the plasma membrane of the cell pinches the middle of the cell so the entire cell can divide into two separate cells.