Name:______________
Date:__________
1. In 1665, ______ _____, an English scientist observed that cork was composed of small units which he called _____.
2. ____ ______ states that living things are composed of cells.
3. A ______ is a hypothesis that scientific investigations have shown to be true most of the time.
4. A ___ is a hypothesis that scientific investigations have shown to be true all of the time.
5. Life forms called _______, ______ and ______ are not composed of cells.
6. Many organisms such as ________, ______, some______, and _____ are composed of only a single cell.
7. Single celled organisms are described as being ___________.
8. Organisms which are composed of many cells are described as being _____________.
9. All cells live in a _____ environment.
10. The human body is about _ _% water.
11. The ____ ________ allows materials to come into or out of a cell.
12. _____________ means that the membrane only allows certain things to pass into or out of a cell.
13. Cell membranes are composed of ___ layers of molecules called ____________.
14. The phospholipid cell membrane is composed of atoms called a _______ group and ______ (fats) such as ___________.
15. The outside parts of the phospholipid bilayer are described as being ___________ (water loving) and the inside parts are described as being ___________ (water fearing).
16. _____ is the universal solvent.
17. Because the outside and inside of the phospholipid bilayer attracts water, things can dissolve to join with the membrane to enter or leave the cell.
18. Embedded in the cell membrane are ________.
19. Some proteins are bonded together to form _____ through which certain things can pass into or out of the cell.
20. A ______ is a work of art composed of bits and pieces of things inlaid into some uniform surface.
21. The model of the cell membrane is often described as being a _____ ______ _____.
22. ________ is the random movement of particles resulting in their movement from a region of greater concentration to one of lesser concentration.
23. Oxygen enters a cell and carbon dioxide leaves a cell by way of ________.
24. _______ is the diffusion of water through a semipermeable membrane.
25. _______ _______ exists when the amount of water which enters the cell is equal to the amount of water that leaves the cell.
26. If salt or sugar is added to the liquid environment of bacteria, the bacteria die from ___________.
27. Osmosis and diffusion allow things to enter cells through _______ transport.
28. Passive transport means that the cell does not have to use ______ to move these substances into or out of the cell.
29. In ___________ diffusion, proteins in the cell membrane form pores which allow certain substances to pass. Without the protein pore, these substances would be too _____ to pass directly into the cell.
30. The use of a protein to aid the passage of particles from a region of greater concentration to a region of lesser concentration is called ___________ _________.
31. The proteins involved in facilitated diffusion are called _________.
32. It is through facilitated diffusion that _______ and _______ enter cells.
33. Whether passive transport occurs by osmosis, simple diffusion or facilitated diffusion, it always involves a movement of particles from a region of _______ to ______ concentration.
34. If a cell must transport something from a region of lesser concentration to a region of greater concentration, the cell must use ______ to create this movement.
35. When cell energy is used to transport a particle from an area of lesser to greater concentration it is called _______ _________.
36. Active transport also involves ________ molecules, which are known as _____.
37. It is by ______ _________ that cells rid themselves of harmful particles which could poison and kill the cell.
38. Materials which are too large to enter or leave the cell by passive or active transport can enter or leave through ___________ or ___________.
39. ___________ is the process by which a cell uses energy to surround and take in large particles.
40. If a solid particle is taken through endocytosis, this process is referred to as being ____________, which means "____ ______."
41. It is through ____________ that white blood cells eat ________.
42. If liquid is taken in through endocytosis, this process is called ____________, which means "____ ________."
43. The reverse of endocytosis by which cells rid themselves of wastes or expel
useful substances needed elsewhere is called __________ (____ ________).