Across
- 2. A cellular signaling mechanism in which the product of a particular process inhibits the process itself.
- 5. An organism consisting of two or more cells and whose cells may not live independently apart from the organism.
- 8. An organism consisting of only one cell.
- 9. The genetic material of eukaryotic cells consisting of DNA and associated proteins.
- 12. A cellular organelle found in plant cells that contains the pigment chlorophyll and is the site where photosynthesis takes place.
- 14. An organelle in plant cells that holds materials and helps maintain the cell’s shape through turgor pressure.
- 15. A nonpigmented cellular organelle found in plant cells whose functions include storing starches, lipids, and proteins.
- 16. A cellular organelle that functions in the organization of icrotubules.
- 18. (1) The membranebound region of a eukaryotic cell that contains the genetic material. (2) The central portion of an atom where protons and neutrons are located.
- 19. Describes cells lacking a true nucleus and membranetbound organelles.
- 21. A spherical structure within a eukaryotic cell’s nucleus where ribosomes are manufactured.
- 22. The structure within cells that helps define their shape, maintains internal organization, and aids in division and movement.
- 25. Describes cells having a true nucleus as well as membranetbound organelles.
- 30. A group of two or more organs that work together to perform a particular function.
- 32. The thick fluid inside cells that contains the organelles. Also called the cytosol.
- 34. The movement of substances across a cell membrane from regions of low concentration to regions of high concentration by any means that requires the use of energy.
- 37. The internal balance within the systems of living organisms that must be kept stable in order to maintain life. Processes that maintain homeostasis include getting nutrition, expelling wastes, and responding to the environment.
- 38. A protective coating found outside the cell walls of many bacteria.
- 39. A cellular signaling mechanism in which the product of a particular process enhances the process itself.
- 40. Describes a solution whose solute concentration is greater than the solute concentration of the cytoplasm in a cell.
Down
- 1. The diffusion of water molecules through a semipermeable membrane.
- 3. The cellular organelle that processes and packages proteins in preparation for secreting them from a cell.
- 4. A whiptlike cellular organelle similar in structure to a cilium but longer and used primarily for movement in many bacteria.
- 6. Structures found within the cytoplasm of cells that perform the various functions cells need to stay alive.
- 7. The cellular organelle in which aerobic respiration takes place to release energy from food.
- 10. Describes a solution whose solute concentration is less than the solute concentration of the cytoplasm in a cell.
- 11. (1) Individual organisms of the same species living closely together. (2) A group of cells that live and work together. Unlike in a multicellular organism, cells in a colony may break away and survive on their own.
- 13. The movement of substances across a cell membrane without the need for energy.
- 16. A thin layer of phospholipids and proteins that defines the boundary of a cell.
- 17. Describes a solution whose solute concentration is equal to the solute concentration of the cytoplasm in a cell.
- 20. A structure made of two or more tissues that work together to perform a particular function.
- 23. The two layers of phospholipids that make up a cell membrane.
- 24. A rigid structure made by cells of plants, fungi, and most bacteria to surround the cell membrane.
- 26. One of the fundamental models of biology that states that cells are the smallest form of life, come from preexisting cells, are the basic building block of all life forms, and carry out life processes to maintain homeostasis.
- 27. The pressure exerted by water in a full central vacuole upon the cytoplasm and cell membrane of a plant cell; maintains plant rigidity.
- 28. The non membranerbound region in prokaryotic cells that contains most of the genetic material.
- 29. A stack of diskushaped thylakoids within a chloroplast.
- 31. A type of passive transport in which substances can move across a cell membrane through special protein channels embedded in the membrane.
- 33. A cellular organelle that contains digestive enzymes.
- 35. The cellular organelle that directs the proteinbuilding process.
- 36. A group of cells that are specialized to perform a particular function.