Do our bodies store nutrients (vitamins and minerals) and water like they do with fat?
It varies with substance how much we store.We can store enough energy (mostly in the form of fat) to survive for several weeks without eating.Water, on the other hand, we don't have a lot stored, our performance will degrade after only one day without drinking, and depending on climate and other factors you'll probably die in less than a week if you don't drink anything.The body does try to conserve nutrients that it is low on. You will notice very quickly for example that if you don't drink enough, then your body starts to produce a lot less, and darker-colored urine. The same is true for energy. If you don't eat (or eat very little) for several days, then your metabolism will slow down and your body will use less energy. The difference is not huge, but your body can save 10 or 20% of the energy in the so-called "starvation mode".Vitamins and minerals vary. Some you could eat 5 times the dosis of every 5 days and you'd be okay, while others it's really best to get a little bit of every day.
How do trees carry water from their roots to the leaves at the top? Do the mechanics change for large trees like giant redwoods? Could this be imitated for carrying water without pumps?
Upward water transport in trees occurs in cells known collectively as xylem. These include tubelike cells called tracheids and vessel elements. These join together to form vertically oriented tubes reaching from the roots to the leaves. Two forces combine to move water upward in these tubes: root pressure and transpiration. Root pressure occurs when water flows into the roots through osmosis due to differences in the concentration of solutes between the soil and roots. This higher pressure in the roots exerts a slight upward force on the fluid column. Transpiration occurs when water evaporates from leaf surfaces, causing a lower pressure in the leaves. This also exerts a slight upward force on the fluid column. The xylem conduits are small diameter and act as capillaries; the adhesion of liquid to the inner capillary walls counteracts gravity and keeps the water column from falling. The slight upward forces of root pressure and transpirational pull are enough to move the fluid upward.There are minor variations on this among the vascular plants, and the physical limits to capillary action and the magnitude of the various forces are what limit potential height growth of trees. If anything causes a gap in the water column (cavitation), the system can break down and the flow stops.Pressure from below is already used in many places to move water for human use. Natural springs or wells drilled into aquifers under pressure are quite common in rural areas for moving water without pumps. Suction from above is the basis for most pumping systems. Creating a pump that relied on negative pressure created by evaporation is certainly possible, but wildly inefficient. Trees use the water for photosynthesis as it passes through the leaves, but evaporate far more molecules of water through their leaf stoma than they use in the photosynthetic process. Using evaporation to transport water for human use would mean that most of your water would be lost to the atmosphere. I like the concept of using capillary action by building well pipes as a collection of very small vessels. While the adherence of water to the vessel walls would reduce the upward force needed by a pump, it would also decrease the speed with which water could be drawn through the pipe.
Why do plants need water?
Plants have 3 basic parts: Roots, Stems, and Leaves.Roots are the part that are in charge of absorbing water for the plant. Different kinds of plants grow different types of roots, depending on the climate, the soil type, and its genes. For example, some weeds, like morning glories, can grow roots that can be 20 or more feet deep; which is one of the reasons why they are so hard to get rid of. Some Cacti have relatively short roots, but during very wet times, they develop deep and extensive “rain roots” to absorb as much water as they can. Once the water is gone, the roots are no longer needed, and are no longer maintained by the plant.All roots function roughly the same way. At root tips, tiny, thin roots develop- root hairs. The plant will then seek out water molecules in the soil.Root Development in Young CornThe plant will use water potential and chemicals to draw water and nutrients to the root tips, where water is drawn to.Water is drawn from higher concentrations to lower concentrations in any circumstance, and plants take advantage of that. They stock their roots with very high concentrations of ions, higher than that of the soil, so the water is drawn to the roots dilute it.Via Dictionary.com the definition of osmosisThe pull that these molecules have on the water, has to be stronger than the pull that molecules in the soil have on the water. Soil uses water to bunch it together. That’s partly why desert sand blows around so much, as there isn’t any water to hold it together. Very dry soil wants to hold onto water as tightly as it can, which makes it very difficult for many plants to fight against. Desert plants, and plants living in soils with high levels of salt have evolved to over come these tight pulls, called negative water and chemical potentials, that are exerted on dry or salty soils."Movement of Water and Minerals in the Xylem." https://www.boundless.com/biolog...Once the plant has obtained water from the soil, water is conducted upwards through the plant’s vascular system up through the stem to the leaves. Transpiration, or the evaporation of water from the leaves, causes water to be drawn upwards.
How is water digested?
Water is *not* digested by the body . Nevertheless it carries out many many important functions inside the body . Pure water is a basic compound of Hydrogen and Oxygen . It cannot be broken down further by the body . It is not processed any further. The water we drink gets mixed with food and stomach acids in the stomach . The mixture proceeds to the intestines where the mixture is absorbed in the linings of the intestines and mixed with blood . The part that is not absorbed passes on to the large intestine . This water here has a logistics function and eases the path of used food out of the body through the bowels . The earlier part of water that is absorbed in the intestines and goes to the blood is stored in blood cells as well as plasma . This water reduces the viscosity of blood , takes it to various organs , helps blood to take nutrients to all body parts and impurities from there back to the kidneys . In the kidneys the blood is filtered and water with the dissolved impurities ( remember the universal solvent ) is passed out of the body . We also sweat . That sweat is mostly water. That water is secreted by sweat glands and later replenished by blood . So the cycle here again is complete. In short pure water goes through the whole of the body dissolving , absorbing and distributing and gets thrown out of the body as it is . For information on the importance of water in our body have a look at this video here .
Why is it important for the central vacuole of a cell to always be full?
It's to maintain cell turgor. If the vacuole becomes empty (say, by not getting enough water), the plant will wilt...
Describe the difference between plant and animal cells?
The main difference between an animal cell and a plant cell is that, plant cells have a cell wall, which the animal cell lacks. The cell wall which is made up of cellulose gives the plant cell rigidity resulting in a fixed, rectangular shape. Animal cells lack the rigidity hence, they tend to have a round and irregular shape. Animal cells tend to vary greatly in appearance. The cell wall allows high pressure to build inside of the plant cell without bursting. Due to this, the plant cell is able to accept large amounts of liquid through osmosis without bursting. Animal cells, which only have a thin membrane restricting access to the cell, tend to burst if they absorb too much extra water. Both animal cells and plant cells have a defined nucleus, which contains chromosomes. The nucleus is protected and surrounded by cytoplasm, a watery or gel-like liquid that holds all the organelles in place. The cytoplasm, in turn is held in by the cell membrane. However, all animal cells have centrioles whereas only some lower plant forms have it. Also, plant cells tend to have one large central vacuole that can take up to 90% of cell volume. Animal cells tend to have one or more small vacuoles. Vacuoles contain waste materials, water, and nutrients that can be used or secreted as necessary. In plant cells, vacuoles store water and maintain turgidity of the cell. In animal cells, they store water, ions and waste. Another difference among them is that plant cells have chloroplasts for photosynthesis, which allows them to covert sunlight into food for the cell. Chloroplasts have its own DNA and tend to direct their own work. Animal cells lack chloroplasts and hence this ability, which is why we can’t live off of sunlight, sadly. :) :)
Which parts of the plant store food as starch?
Root tubers e.g in case of potatoes etc .Leaves small quantities are present in vacuoles , starch granules in a leave cells .Seeds and Fruits which are basically storage organs of plants .