Answer the following question given this paragraph: about how that occurs, in terms of membrane structure. If the influx of water continued unopposed, the membrane would eventually burst like an over-inflated balloon, killing the cell. One strategy to avoid this lethal outcome, adopted by a range of organisms, is to build a semi-rigid "cell wall" exterior to the plasma membrane (). The synthesis of this cell wall is based on the controlled assembly of macromolecules secreted by the cell through the process of exocytosis (see above). As water passes through the plasma membrane and into the cell (driven by osmosis), the plasma membrane is pressed up against the cell wall. The force exerted by the rigid cell wall on the membrane balances the force of water entering the cell. When the two forces are equal, the net influx of water into the cell stops. Conversely, if the [H2O]outside decreases, this pressure is reduced, the membrane moves away from the cell wall and, because they are only semi-rigid, the walls flex. It is this behavior that causes plants to wilt when they do not get enough water. These are passive behaviors, based on the structure of the cell wall; they are built into the wall as it is assembled. Once the cell wall has been built, a cell with a cell wall does not need to expend energy to resist osmotic effects. Plants, fungi, bacteria and archaea all have cell walls. A number of antibiotics work by disrupting the assembly of bacterial cell walls. This leaves the bacteria osmotically sensitive, water enters these cells until they burst and die. Questions to answer & to ponder: Make a graph of the water concentration across a typical cellular membrane for an organism living in fresh water; explain what factors influenced your drawing. Look at this video: https://www. youtube. com/watch?v=VctALENHyyI&feature=youtu. How could you use reverse osmosis to purify water? Where does the energy involved in moving molecules come from? Plants and animals are both eukaryotes; how would you decide whether the common ancestor of the eukaryotes had a cell... Q: Plants, fungi, bacteria and archaea cells all have what feature that keeps them rigid that animal cells do not have? Choices: - cytoplasm - cell membrane - plastids - cell walls A:
cell walls
(Question)
Answer the following question given this paragraph: Most tunicates live a sessile existence in shallow ocean waters and are suspension feeders. The primary foods of tunicates are plankton and detritus. Seawater enters the tunicate's body through its incurrent siphon. Suspended material is filtered out of this water by a mucus net (pharyngeal slits) and is passed into the intestine through the action of cilia. The anus empties into the excurrent siphon, which expels wastes and water. Lancelets possess a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail in the adult stage (Figure 15.35). The notochord extends into the head, which gives the subphylum its name (Cephalochordata). Extinct fossils of this subphylum date to the middle of the Cambrian period (540488 mya). The living forms, the lancelets, are named for their blade-like shape. Lancelets are only a few centimeters long and are usually found buried in sand at the bottom of warm temperate and tropical seas. Like tunicates, they are suspension feeders. Q: Most tunicates live a sessile existence in shallow ocean waters and are suspension feeders. the primary foods of tunicates are plankton and this? Choices: - bacteria - crustaceans - debris - detritus A:
(Answer)
detritus
Ques: Answer the following question given this paragraph: A binary molecular compound is a molecular compound that is composed of two elements. The elements that combine to form binary molecular compounds are both nonmetal atoms. This contrasts with ionic compounds, which were formed from a metal ion and a nonmetal ion. Therefore, binary molecular compounds are different because ionic charges cannot be used to name them or to write their formulas. Another difference is that two nonmetal atoms will frequently combine with one another in a variety of ratios. Consider the elements nitrogen and oxygen. They combine to make several compounds including NO, NO 2 , and N 2 O. They all can't be called nitrogen oxide. How would someone know which one you were talking about? Each of the three compounds has very different properties and reactivity. A system to distinguish between compounds such as these is necessary. Q: A binary molecular compound is made up of two of what? Choices: - compounds - cells - wafers - elements A:
Ans: elements
(Q).
Answer the following question given this paragraph: At each level of a food chain, a lot of energy is lost. Only about 10 percent of the energy passes to the next level. Where does that energy go? Some energy is given off as heat. Some energy goes into animal wastes. Energy also goes into growing things that another consumer can't eat, like fur. It's because so much energy is lost that most food chains have just a few levels. There's not enough energy left for higher levels. Q: In a food chain, only about 10 percent of what passes to the next level? Choices: - mineral - vitamins - hydrogen - energy A:
(A).
energy
Ques:Answer the following question given this paragraph: Drip irrigation uses much less water than other methods. Q: Which kind of irrigation uses much less water than other methods? Choices: - constant - mist - solar - drip A:

Ans:drip
Answer the following question given this paragraph: Neurons are the structural and functional units of the nervous system. They consist of a cell body, dendrites, and axon. Neurons transmit nerve impulses to other cells. Types of neurons include sensory neurons, motor neurons, and interneurons. Q: What are the structural and functional units of the nervous system, which transmit nerve impulses to other cells? Choices: - axions - ions - electrons - neurons A:
neurons