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1.1 Check and Reflect answers Key Concept Review 1. The life processes that cells perform are: intake of nutrients, movement, growth, respond to stimuli, exchange of gases, waste removal, and reproduction. 2. The five organelles and their functions that are common to plant and animal cells are the nucleus (control centre of cell), Golgi apparatus (modifies, sorts, and packages proteins for delivery throughout cell or out of cell), endoplasmic reticulum (carries materials through the cell), cytoskeleton (maintains the cell’s shape), and mitochondrion (supplies energy to the cell). 3. Three differences between plant and animal cells are: • that plant cells have cell walls while animal cells have cell membranes only • that plant cells have chloroplasts (animal cells do not have chloroplasts) • that animal cells have centrioles that are involved in cell division while plant cells do not 4. Granum and thylakoid structures can be described as solar collectors because they collect the light energy from the Sun, which is used in photosynthesis. 5. TABLE 1.1 Structures and Organelles in Cells Cell Structure or Organelle Animal or Plant Cell cell membrane animal and plant cells cytoplasm animal and plant cells nucleus animal and plant cells cell wall plant cells chloroplast plant cells vacuole animal and plant cells vesicle animal and plant cells rough endoplasmic reticulum animal and plant cells ribosome animal and plant cells smooth endoplasmic reticulum animal and plant cells lysosome animal and plant cells Golgi apparatus animal and plant cells mitochondrion animal and plant cells cytoskeleton animal and plant cells 6. Fluorescence microscopy works using a special fluorescent substance that is added to the cells. When the stained cell is placed in ultraviolet light, the fluorescent substance glows. 7. Students’ answers may vary but could include the transmission electron microscope and scanning electron microscope. 8. An electron micrograph is created by an electron microscope. 9. The cell is the building block of life because all living things are made of cells, which perform all the basic functions of life (take in nutrients, exchange gases, reproduce, grow, move, and remove wastes). 10. Sometimes it is difficult to see the cell parts because both the cell and the background may be transparent or blend into each other. Contrast makes it possible to differentiate the cell parts from the background. 11. Students’ answers may vary but could include adding a stain, such as methylene blue or iodine, changing the light levels, or adding a fluorescent substance and using ultraviolet light. Connect Your Understanding 12. Students’ answers may vary but could include the following: A cell biologist may use an electron microscope to get a greater magnification (300 000 to 1 500 000× magnification) or to create a three-dimensional image of the cells. A light microscope would be better for looking at living samples. 13. To determine the total magnification, you need to know the magnification of the ocular lens and the magnification of the objective lens. 14. You would expect the cells of a desert plant to have thick cell walls to reduce the amount of water the plant loses. Plants that live in the desert need to conserve water. 15. Students’ answers may vary but could include the following: We would expect to see more mitochondria in the cells taken from the athlete’s leg muscle because those cells would need more energy due to active use (muscles need a great deal of energy during activity). The cells from the skin of an elderly person would have fewer mitochondria because skin cells do not need as much energy. 16. Students’ answers may vary but could include the following: A microscope can be used to check the health of the cells, to check the number of different cells (e.g., red and white blood cells), and the appearance of the cells. 17. Students’ answers may vary but could include the following: • plant cells have cell walls while animal cells have cell membranes only • plant cells have chloroplasts (animal cells do not have chloroplasts) 36 Unit A: Tissues, Organs, and Systems of Living Things • plant cells have a large central vacuole • animal cells have centrioles, which function in cell division • plant cells store energy in the form of starch or oils • animal cells store energy in the form of glycogen or in the form of fats • some animal cells have specialized compounds; for example, red blood cells contain hemoglobin 18. Students’ answers may vary but could include the fact that microscope technology has allowed scientists to see cells and their internal structures. These observations have helped scientists understand how cells work. Reflection 19. Students’ answers may vary but could include the differences between plant and animal cells, the different