Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
r hi! iii ‘ii Paramecium Animal-like Protists Animal—like protists cannot make their own food and must feed on things that are living or were once alive. They have all of the organdIes of an animal cell, and, like etiglena, they have a contractile vacuole. Amoeba As the amoeba moves, it changes shape (Figure 5). These bloblike organisms move by stretching out a branch of cytoplasm, called a pseudopod (false foot). The pseuclopod anchors to an object, and the rest of the cell is dragged toward it. This method of movement is also used by animal white blood cells, including the ones in your blood vessels. The Tb e param cci till) (plural /nna liter/a.), like the amoeba, uses structures designed for fllovei)lCnt to help it feed (Figure 6). Tiny hairlike structures, called cilia, beat together to create water currents that move the paramecium. There are also cilia around the paramecium’s oral groove. These cilia draw food into the groove. Bacteria and other smaller cells arc the main food source for paramecia. oerfo-ms. macronucleus contains genetic material that regulates cell function micronucleus contains genetic information that is exchanged between para’ec a dur ng reproduct:on food vacuole Where food is slowly digested 4;..;. I - “.ç I i.’ %%‘ iV -v’.’ i / i/i’? If) / II fl I\S gullet A cavity at the end of the oral groove. Hee :he food enters pseudopod contractile vacuole Pumps out excess water; prevents the paramecium from bursting oral groove Lined wirn cilia that sweep in food Fungus Ftingi (singtilarf’hngu.s) incltide many organisms th;tt are in ul ticel I tiiar. Bread mould, in ush rooms, and puff balls are well—known fungi. iiarmftil fungi incitide those that cause ringworm. Dutch elm disease, and athlete’s foot. l-lowever, there are some unicellular fungi. amoeba is a single O The armai cell. It feeds by wrappng itself around foco. food vacuole \t’ast is one of the few tinicelltilar ftingi (Figure 7). There are many different species of yeast. Like animal cells, yeast cells do not have chlorophyll and must rely on other organisms for their source of energy. s ow y engul’s food 0 Amoeba particles by extending its oseudopods. inside the vacuole. 44 Unit I . 8. What effect do chemicals such as caffeine have on unicellular organisms? State your hypothesis, and design an experiment to test it. With your teacher’s approval, conduct your experiment. j2sign Challenge Yeast, the Unicellular Fungus membrane around the food forms 0 The a food vacuole. Digestion takes place microorganisms with disease? 6. Using the information that you have gained about osmosis, indicate why euglena, paramecia, and amoebas need contractile vacuoles. 7. Penicillin is an antibiotic that weakens the cell wall of bacteria. The sugars and proteins in the cytoplasm of the bacteria are in higher concentration than they are in their environment. Draw a series of diagrams showing how penicillin kills bacteria. Exploring a fooc vacjoe. food ‘4 4 5. Why do many people associate 1 ‘1 i contra ctile vacuole 1. Why do you think bacteria are considered to be more primitive than other cells that you have studied? 2. Why are diatoms called plantlike protists? 3. Compare euglena to a plant cell. Make a list of similarities and differences. 4. Compare the process of feeding in the paramecium and amoeba. Making Connections ‘if’ / nucleus unct:ons that yo body anal pore Expels waste Hairlike structures V’at beat togetr.er to move water The amoeba crawls and feeds at the same time, Understanding Concepts singe amma cel! tnat must perform most of te ‘‘“ crawling motion of the amoeba is also used for feeding cilia bJ!ihi3.l The pwamecium is aiso a Using a microscope, it is difficult to tell that yeast are living, There are cells in the :ubes that lead to your lungs that have cilia much like those of paramecium. Human white blood cells, Pike amoeba, engulf and digest foreign particles. Examine the structures of the unicellular organisms carefully. Would any of these features be useful in your model cell? Consider looking to primitive cells for assistance with your Challenge. Cr’U. ?‘is ii,’s. (hrun s, and .S.clnns 45