User talk:Claire Yvonne

Transport Systems

“Transport systems play an essential role in the survival of flowering plants and mammals”. In both plants and mammals the transport systems are used to transport essential nutrients to perform their normal processes. With out the transport systems in plants and animals many cells would die because their cells wouldn’t be getting enough nutrients to perform normal processes cells would undergo, such as cellular respiration. This is why ring barking kills a tree because it removes its phloem. In this essay the basic similarities of all three systems will be covered as well as what they transport, what common processes they undergo and how they get energy.

All the nutrients mentioned in the above Venn diagram in the plant circle are transported in two structures the Xylem and Phloem respectively. These to transport vessels are very different in their structure although they both form tubes for substances to pass along. The Xylem is made of many dead cells, which have no nucleus or cytoplasm. The cells in the Xylem have pores at the top and bottom effectively making a tube for nutrients to move up. These cells have an impermeable membrane, so no substances can come in or leave except at certain points this is because of their walls being made of lignin. The Phloem is made of living cells called “sieve” cells, and as the name suggests they have pores on the side to allow substances to move, also in the phloem are companion cells, which are closely associated with the processes of the sieve cells. The xylem and phloem create a vascular bundle with the Xylem on the inside and Phloem on the out side. Two important processes involved with the transportation systems in flowering plants are Transpiration and Translocation. Transpiration is a process in which water is pulled up the xylem by water evaporating; this evaporation is caused by heat and only when stomata are open, wind. The loss of water in the leaves causes a huge amount of pressure that effectively sucks up the water from the roots to the highest leaves, to regulate water loss; this pressure is very strong because it works against gravity. Translocation is the movement of sugars in phloem sap from one part of the tree for example to another part of the tree. These process’s are performed in two different parts of the transport systems the xylem and phloem, but they both involve movement of the substance from one place to another. In the blood vascular system, the structures of the vessels like veins and arteries help to move to blood around in a similar way to transportation and translocation. Veins and arteries are made of many layers of cells all which help to move the blood around, the layers are an endothelial layer, elastic layer (to help with contraction, which helps move the blood), muscle layer(to help with the contractions, to move blood), and connective tissue, for protection. Veins also have one way valves like the lymphatic system. Unlike veins and arteries, capillaries have only one layer of endothelial tissue, so that nutrients can diffuse more freely. The lymphatic vessels and cardiovascular vessels have the same composition of tissues protecting them, but lymphatic vessels and the veins in the body all have valves to prevent back flow. This is unlike the xylem and phloem because they don’t branch and get progressively smaller and also they don’t often have valves. All these process’s that the transport systems under go require energy in some form. In plants the energy comes from the photosynthesis, which makes glucose which plant cells then use to do cellular respiration, to make energy. As was mentioned in one of the above paragraphs translocation is the movement of sugars like glucose, so that the glucose can be used for making energy (cellular respiration). In mammals they obtain the energy to pump the heart in a different way. Chemicals like glucose and fats are pump around the body, the nutrients that are pumped are often used to make energy, because of their large amount of chemical bonds. The blood is pumped to the heart; this is the heart gets its energy to perform its natural processes of pumping blood. The movement of nutrient is either passive in both cases otherwise it require active diffusion, the energy needed for this process is taken from the fluid that are transported around, e.g. The roots of a tree get energy from the glucose which is transported by translocation to the roots. The transport systems found in mammals and plants are vastly different but they do share some similarities. Their differences include, the structure of the Xylem and Phloem, it differs vastly from that of the blood and lymphatic vessels which are made up of many different cell types, none of which are meant impermeable or as strong as the vessels found in plants. Also they differ in what substances they transport for example in animals hormones and white blood cells/anti-bodies are transported and are not in plants because they have no need of them. Two similarities already mentioned in this essay are that they all the transport systems use osmosis and active transport as well as diffusion to move substances around. These systems are also similar because they are both essential in the survival of plants and mammals.

By Claire Yvonne