Answer the following question given this paragraph: Enzyme Compartmentalization In eukaryotic cells, molecules such as enzymes are usually compartmentalized into different organelles. This allows for yet another level of regulation of enzyme activity. Enzymes required only for certain cellular processes can be housed separately along with their substrates, allowing for more efficient chemical reactions. Examples of this sort of enzyme regulation based on location and proximity include the enzymes involved in the latter stages of cellular respiration, which take place exclusively in the mitochondria, and the enzymes involved in the digestion of cellular debris and foreign materials, located within lysosomes. Feedback Inhibition in Metabolic Pathways Molecules can regulate enzyme function in many ways. A major question remains, however: What are these molecules and where do they come from? Some are cofactors and coenzymes, ions, and organic molecules, as you've learned. What other molecules in the cell provide enzymatic regulation, such as allosteric modulation, and competitive and noncompetitive inhibition? The answer is that a wide variety of molecules can perform these roles. Some of these molecules include pharmaceutical and non-pharmaceutical drugs, toxins, and poisons from the environment. Perhaps the most relevant sources of enzyme regulatory molecules, with respect to cellular metabolism, are the products of the cellular metabolic reactions themselves. In a most efficient and elegant way, cells have evolved to use the products of their own reactions for feedback inhibition of enzyme activity. Feedback inhibition involves the use of a reaction product to regulate its own further production (Figure 6.21). The cell responds to the abundance of specific products by slowing down production during anabolic or catabolic reactions. Such reaction products may inhibit the enzymes that catalyzed their production through the mechanisms described above. Q: In eukaryotic cells, molecules such as enzymes are usually compartmentalized into different what? Choices: - organisms - atoms - electrons - organelles A:
organelles
Answer the following question given this paragraph: Ecological pyramids can demonstrate the decrease in energy, biomass or numbers within an ecosystem. Energy pyramids are discussed at http://www. youtube. com/watch?v=8T2nEMzk6_E (1:44). Q: What can demonstrate the decrease in energy, biomass or numbers within an ecosystem? Choices: - biomes - spontaneous mutation - food chains - ecological pyramids A:
ecological pyramids
Q: Answer the following question given this paragraph: A person can live a normal, healthy life with just one kidney. However, at least one kidney must function properly to maintain life. Diseases that threaten the health and functioning of the kidneys include kidney stones, infections, and diabetes. Q: Stones, infections, and diabetes threaten the health and functioning of what paired organs? Choices: - tissues - lungs - arteries - kidneys A:
A: kidneys
Question: Answer the following question given this paragraph: Organisms that live in a hypotonic environment such as freshwater, need a way to prevent their cells from taking in too much water by osmosis. A contractile vacuole is a type of vacuole that removes excess water from a cell. Freshwater protists, such as the paramecia shown in Figure below , have a contractile vacuole. The vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm. After the canals fill with water, the water is pumped into the vacuole. When the vacuole is full, it pushes the water out of the cell through a pore. Other protists, such as members of the genus Amoeba , have contractile vacuoles that move to the surface of the cell when full and release the water into the environment. Q: Organisms that live in freshwater environments often possess a contractile vacuole that prevents cells from taking in too much water through what process? Choices: - electrolysis - glycolysis - hemostasis - osmosis A:
Answer: osmosis
*Question*
Answer the following question given this paragraph: Plant Parasites and Pathogens The production of sufficient good-quality crops is essential to human existence. Plant diseases have ruined crops, bringing widespread famine. Many plant pathogens are fungi that cause tissue decay and eventual death of the host (Figure 24.25). In addition to destroying plant tissue directly, some plant pathogens spoil crops by producing potent toxins. Fungi are also responsible for food spoilage and the rotting of stored crops. For example, the fungus Claviceps purpurea causes ergot, a disease of cereal crops (especially of rye). Although the fungus reduces the yield of cereals, the effects of the ergot's alkaloid toxins on humans and animals are of much greater significance. In animals, the disease is referred to as ergotism. The most common signs and symptoms are convulsions, hallucination, gangrene, and loss of milk in cattle. The active ingredient of ergot is lysergic acid, which is a precursor of the drug LSD. Smuts, rusts, and powdery or downy mildew are other examples of common fungal pathogens that affect crops. Q: Which is the active ingredient of cereal crop disease, ergot? Choices: - byblis acid - amino acid - pixelation acid - lysergic acid A:
**Answer**
lysergic acid
Answer the following question given this paragraph: Besides their strength, another pro of electromagnets is the ability to control them by controlling the electric current. Turning the current on or off turns the magnetic field on or off. The amount of current flowing through the coil can also be changed to control the strength of the electromagnet. Q: Electromagnets can be controlled by controlling what type of current? Choices: - magnetic - positive - negative - electric A:
electric