Compare and Contrast Xylem Tissue and Phloem Tissue, Including Their Respective Structures and Functions.

The cross-sections demonstrated the basic differences that distinguish a monocot plant for a dicot plant. When looking at the cross-section of the monocot stem you can see that the vascular bundles are scattered. These vascular bundles consist of only a phloem and xylem. The phloem is responsible for transporting soluble compounds (food) created by photosynthesis, to the rest of the plant, especially where they are needed. The xylem is important for the movement of water throughout the plant. Another difference that can be seen by looking at the cross-section of at stem is that the ground tissue (parenchyma) is not partitioned into pith and cortex. In the dicot stem cross-section the vascular bundles form a ring and they are made up of a phloem, xylem, and a cambium which divides the two. The ground tissue (parenchyma) for a dicot is separate into a pith (nutrient storage and distribution) and a cortex (conducting tissues). The Leaf cross-sections reveal the venation of each plant. For monocots, the veins appeared run parallel to each other, while the veins for the dicot plant had no clear pattern. The root cross-sections also displayed differences between the groups belonging to the phylum Anthophyta. The root cross-section of a monocot is formed by vascular bundles that are arrange in a ring. In the dicot root cross-section, the xylem is at the center in the form of an

Transpiration is said to be the loss of water vapor through the stomata of the leaves in a plant. Transpiration essentially serves to move water and other nutrients throughout a plant, to cool down plants and humans and to maintain turgor pressure in the cells of plants (sdhydroponics). The transpiration rate in a plant is affected by the wind, light and humidity. temperature and water. The wind serves to determine how dry the air is when transpiration occurs. Light can at times speed up the rate of transpiration in plants. Transpiration tends to occur faster in the light rather than when in the dark. Humidity serves to determine the rate of the diffusion of water in the plant. As

Diffusion, osmosis and active transport of substances in and out of the membrane is very important for all types of cells. One example is the root hair cell. These cells are the exchange surface in plants which are responsible for the absorption of water and mineral ions so without osmosis and active transport this would not be possible. The water is taken up by osmosis through the partially permeable membrane. The root hair cells are surrounded by a soil solution which contains small quantities of mineral ions but mainly water, so has a high water potential (slightly less than zero). The root hair cells themselves contain a high quantity of amino acids, mineral ions and sugars inside them (low water potential). Therefore water will move by osmosis from the soil solution and into the root hair cells, going down the water potential gradient.

Despite its importance osmosis may also damage cells by causing them to; a) shrink from water loss or b) burst from too much water gain. Plant cells [fig 3] have adapted themselves to ensure that these factors do not affect them, by forming a ridged wall, known as the cell wall, around their cells. The cell wall maintains the shape of the cell, and prevents the cell from bursting in a hypotonic medium by resisting water pressure. Plant cells have also adapted a larger vacuole, which occupies 80% or more of the cells cytoplasm (Davidson, 2004); allowing plants to store more water and nutrients per cell. Vacuoles also play a structural role in plant cells; by swelling when liquids contact them, plant vacuoles are able to control turgor pressure within the cell. This helps maintain the structural integrity of the cell as well as providing the plant with suitable amounts of water and nutrients; however the cell will never burst because the vacuole is contained within the cell wall. If plant cells are deprived of water their vacuole will begin to shrink, yet due to the cell the wall, the plant cell will be able to maintain its shape. [fig.4] Animal cells [fig 5] on the other hand do not have this

Water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane are equal. The diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called osmosis. The movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms. ("Diffusion And Osmosis - Difference And Comparison | Diffen"). A semi-permeable membrane known as the cell membrane surrounds the living cells of both plants and animals. Both solute concentration and membrane permeability are taken into account in the ability of a cell to gain or lose water. If there is a higher concentration of solutes in the surrounding solution, water will tend to leave the cell, and vice versa. The membrane forms a selective barrier between the cell and its environment and does not allow toxic substances from the surroundings to enter into the cell (Deena T Kochunni). The selective permeability allows the cell to regulate the flow of necessary substances into and out of the cell. In plants osmosis is also responsible for absorbing water and minerals from the soil by using the semipermeable membrane of the root (Deena T Kochunni). If the extracellular fluid has a lower osmolarity than the fluid inside the cell, it’s said to be

Capillary action uses both adhesion(water “holding” on to a surface) and cohesion (water holding on to water). The adhesion lets the water gradually grab onto the surface of the xylems and “pull” itself up the stalk of the celery, or any tube small enough for this. Cohesion lets the water molecule(s) hold onto other water molecule(s) and pull eachother up while they are using adhesion at the same time to climb up the xylem walls. Transpiration relates to both adhesion and cohesion because the water is able to connect to eachother while being pulled up by the water going out of the leaves. This relates to our experiment because when the first trial was run with the stalks without leaves, the water went up a very small amount, but did not go up nearly as much as when the leaves were left on the celery stalks.

The flow is driven by an osmotically generated pressure gradient between the source and the sink. The translocation pathway has cross walls that allow water to move between the xylem and phloem. At the source phloem loading causes high solute concentrations. Pressure decreases, so water flows into the cells increasing pressure. At the sink pressure is lower outside the cell due to unloading of sucrose. Osmotic loss of water releases hydrostatic pressure. Water movement is driven by pressure gradient and not osmosis.

ecently in Biological Sciences 150 Lab we have been learning about osmosis. Osmosis is the net movement of water from an area of high concentration to an area of low concentration through a selectively permeable membrane. A selectively permeable membrane is a membrane that only lets through smaller solutes and prohibits large solutes to pass through. You can measure the pressure of the water in a cell, the measurement is called tonicity. Tonicity is the measure of osmotic pressure, therefore relative tonicity is a cell at an isotonic stage.

All plants have tiny pore like structures called stomata (singular, stoma). When carbon dioxide enters a leaf, oxygen then escapes through the stomata. Each stoma is surrounded by guard cells in the leaf’s epidermis layer (Reece, et al. 109). Photosynthesis is the process in which plants gain their energy and nutrients. Solar energy is used to convert carbon dioxide and water into sugars. Oxygen is then released as a by-product of this process. When the time is right, the stomata open and allow carbon dioxide to enter the leaf and later the release of water and oxygen takes place. If the stomata are closed, this means that the plant is actively holding its water (Reece, et al. 109). As humans, we benefit greatly

This movement is called capillary action, which is one part of the plants transpiration system.

They tend to move to high solutes concentrations which is called hypertonic and the water is trying to equalize. There are three factors that will effect the osmosis and they are temperature, concentration gradient, diffusion distance, and the membrane will only allow some of the molecules to travel across. Glucose will not be able to move across the membrane; only the water molecules will be allowed to cross the membrane, so the osmosis is the same movement of high to low concentration, but only through the partially permeable

Osmosis is the movement of water molecules from high concentration to low concentration through semipermeable membranes, caused by the difference in concentrations on the two sides of a membrane (Rbowen, L.). It occurs in both animals and plants cells. In human bodies, the process of osmosis is primarily found in the kidneys, in the glomerulus. In plants, osmosis is carried out everywhere within the cells of the plant (World Book, 1997). This can be shown by an experiment with potato and glucose/salt solution. The experiment requires putting a piece (or more) of potatoes into glucose or salt solution to see the result of osmosis (a hypertonic type of solution is mostly used as it would give the most prominent visual prove of

Water flows in and out of cells in an attempt to attain a state of equilibrium. The concentration of solutes to solvent in the cells environment is the cause of the water flow. Plant and animal cells can be negatively affected or positively affected due to the concentration balance in their environment. Potato cells were used to see the affects of sucrose in different concentrations. In some concentrations a weight change was seen in the potato.

The process by which water moves through membranes by a special kind of diffusion is called osmosis. Like solutes, water moves down its concentration gradient. Water moves from areas of high potential to low potential. The high potential contains low solute concentrations, while the low potential contains high solute concentrations. In surrounded cells, osmosis is affected not only by the solute concentration, but also by the defiance to water flow by the cell wall, known as turgor pressure.

This means that in the potato cells, water molecules will move in or out of the cell depending on the concentration of the sucrose solution and the water potential that the cell has. The process of water molecules moving out a cell is called exosmosis and the process of water moving into a cell is called endosmosis. Endosmosis occurs when the water potential