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Essay on Gas Exchange And Cellular Respiration

All living organisms respire and they need energy to carry out their life processes in order for organisms to survive and produce. The gases involved in cellular respiration is oxygen and carbon dioxide. The process of cellular respiration is releasing energy from sugars using oxygen and the product is carbon dioxide and water and in the process, ATP is made that can then be used for cellular work. Oxygen is needed to be absorbed from the environment and into the organism’s blood so it can be transported to respiring cells. Carbon dioxide must be released into the environment from the organism’s blood.

The formula for cellular respiration is: The exchange of gases essentially occurs as a result of diffusion down a concentration gradient. Gas exchange is essentially the diffusion of oxygen and carbon dioxide into and out of cells, and this is vital for respiration to occur. Gas exchange is the getting oxygen from the lungs and to the bloodstream, and it is also removing carbon dioxide from the bloodstream to the lungs. Gas exchange happens between the alveoli and a network of tiny blood vessels which is called capillaries and it occurs in the lungs.

The capillaries are located in the walls of alveoli. Gas xchange occurs across cell membranes. Moving on to diffusion. Diffusion is the movement of particles from an area of high concentration to an area of low concentration until there is no longer a concentration gradient and the particles are all evenly distributed. For example- When there is a high concentration of oxygen in the air and a low concentration of oxygen in the blood, the high concentration of oxygen will move into the blood via diffusion until there is no longer a concentration gradient and the particles are all evenly distributed.

There is a high to low or low to high concentration because of the gas xchange at the gas exchange surface. The reason for the low concentration is because the cell is using the oxygen in the air through respiration. Oxygen is inhaled and carbon dioxide is exhaled. Diffusion is a passive process which means that no energy is used to make the molecules move as they have natural kinetic energy. Diffusion through a cell membrane in mammals are called alveoli, in fish is called gills and in insects, are called tracheales.

Ventilation is the most important factor in gas exchange as a ventilation system is needed to maintain the concentration gradients of gases in the alveoli. Ventilation is lso important as gas exchange is the ventilation of gases to and from the body cells of an animal so cellular respiration can take place. Without ventilation gas exchange will not occur. Also ventilation keeps one side of the concentration gradient higher.

The factors needed for diffusion and therefore gas exchange to occur quickly, there must be a large surface area so gas exchange can take place rapidly, and also needs to be a large surface area as it will provide more space. A moist gas exchange surface to protect and allow gases to dissolve and diffuse into and out of. We need a thin gas exchange surface so gases may iffuse rapidly, has less distance so less time and the rate is faster which means that a certain amount of gas gets through in a certain amount of time. A concentration gradient is also needed for gases to diffuse down. These conditions are called gas exchange surfaces.

The five system makes the gas exchange system work as diffusion is the movement of molecules from a high concentration area to a low concentration area. In diffusion, respiration keeps one of the gradient low and ventilation keeps one side of the gradient high. Surface area is also important as it allows gas exchange to take lace rapidly, and an increase in surface area provides more space and so more area. Moist gas exchange surface is good as you need a moist surface so gases may dissolve and diffuse into and out of cells. Also there is a constant supply of mucus that keeps the surface moist.

It is to protect and allow gas to dissolve. Thin gas exchange surface allows gases to diffuse rapidly. Also there is less distance to travel and less time so the rate is faster which means a certain amount of gas gets through in a certain amount of time. Ventilation also aids as in the bo there is a low oxygen level and a high carbon dioxide level and hen it comes out the carbon dioxide level is low and the oxygen level is high. Animals maximise gas exchange by having a large surface area so gas exchange can take place rapidly. They have a concentration gradient down which gases may diffuse.

They have a thin surface across which gases may diffuse rapidly. They also have a moist surface on which gases may dissolve and diffuse into and out of cells. If gas exchange surface was too thick it would be less efficient. Fish, insects and mammals are all living organisms that have different ways of carrying out gas exchange. They all need oxygen to survive and hey all carry out gas exchange. This report will analyse why they all need to have an efficient gas exchange system and how it’s environment aids in helping them achieve this, relating to its habitat in order to occupy a specific ecological niche.

Fish The fish we dissected was a snapper fish and its scientific name is Lutjanus campechanus. Fish live in the water where the water is very vicious and has a low concentration of oxygen. Having a low concentration of oxygen means that lots of water has to flow over the gas exchange surface for the fish to take in enough oxygen. Fish needs to use lots of energy for ventilation as water is also harder to ventilate than air as it is more viscous. Also the gas exchange surface is moist so there is no risk of the gas exchange surface drying out in the water.

Therefore, it is close to the surface of the fish’s body rather than deep inside. The diet of fishes varies as it depends what is available in their habitat. For example, the fish we dissected was a snapper. They are mostly carnivores. Their primary diet consists of crustaceans, mollusks and smaller fishes. They also feed on smaller animals, such as worms and plankton. They generally ive in areas with reefs or in other types of protected places. They can be found in shallow waters, especially young snapper. Larger predatory fish like sharks and barracuda prey on the relatively smaller snapper.

The snappers’ larvae and young are also targets of smaller predatory fish until they become large predators themselves. Also us, humans also consume large amounts of snappers throughout the world. Fish in general eat shrimp, krill, and crabs. Some also eat algae, detritus and plankton. Animals that eat fishes are sharks, pikes, walleye, barracudas, mackerel, tuna, etc. Mammals that eat fish are olphins, killer whales, seals and sea lions, etc. Birds also eat fishes and various snakes. There are many ways fish reproduce, one example is egg laying.

Egg laying fishes lay eggs instead of giving birth. Egg laying fishes have many methods of laying eggs and one example is that they lay eggs in areas such as plants, rocks, wood where these areas are protected. Fishes have a different method of carrying out gas exchange efficiently in a different way to mammals. Fish’s gas exchange system are the gills. The buoyancy of the water opens up the gills which results in exposing more surface to water. The fish’s gills have many fold providing a large surface area. A larger surface area means gas exchange can take place rapidly.

The gills collect dissolved oxygen from the water and release carbon dioxide. A fish lets the water in by opening it mouth to breath and then closes it mouth forcing the water to go through the gills and out through the operculum. The water flows through the gills in one direction which allows for a more efficient gas exchange than if the water had to go in and out the same way. The low concentration of oxygen in the water is why this is an important adaptation for fish. The water enters the gas exchange surface the same way as food enters the fish’s body, there might be unwanted food particles in the water.

There are gill rakers in fish which are bony and these filter out the food particles before water passes through the gills so to keep the gills clean. Within the gills, there are four gill arches and each is lined with thin gill filaments extending from them to increase the surface area. On the surface of the filaments, they are lined with rows of lamellae and gas exchange takes place as water flows through them. Lamellae have a large surface area but a short distance which is deal for effective diffusion. The lamellae also contain blood vessels.

Also the filaments and lamellae help give the gills a larger surface area which therefore increases the efficiency of diffusion of gases between the water and the blood by allowing more particles to diffuse at any one time. Blood is used to transport respiratory gases (oxygen / carbon dioxide) between the gills and respiring cells around the body. In the lamellae, blood moves though tiny capillaries in the opposite direction to the flow of water through the lamellae. This is called the counter-current exchange pathway which means that the blood lows in the opposite direction of water movement against the gills.

This movement maximise the amount of oxygen diffused into the body to maintain the concentration gradient right along the body. For example, if the blood and water flow in the same direction and when the blood reaches the same oxygen concentration in the water, the diffusion of oxygen in the blood will stop resulting in less oxygen being absorbed into the body. So to maximise gas exchange, the blood will always be next a different bit of water and so the blood is always passing water that is still oxygenated.

This allows the fish to be able to extract far more oxygen from the water by doing this process. This is very important as there is 25% less oxygen in water than in air, and fish need to absorb enough oxygen to survive. Also fishes maximise gas exchange as they can extract as much as 80% of available oxygen passing through its gills due to the large surface area for gaseous exchange, a short diffusion distance across the gaseous exchange system and a high concentration gradient between the blood in the gills and the water passing over them.

Fish need to exchange gas with the environment to carry out respiration. Fish have gills to extract oxygen from water and they have filaments which are thread like protein structure which comb through the water. There are lamellas on the filaments and lamellas are often one amongst many lamellae and they contain huge amount of capillaries and are used to increase the amount of oxygen intake of the blood. Also as blood travels across and through the capillaries, by diffusion it takes in oxygen. And then oxygenated blood flows through the body of the fish.

Fishes also carry out cellular respiration which means that ATP is produced to give the fish energy for its life processes and the energy release process is carried out in the mitochondria of all living cells to carry out respiration. Overall fish have several adaptations for them to be able to carry out and maximise gas exchange and to survive. Their structures and features have enable them to successfully exchange gas and to gain the maximum amount of oxygen needed from the vicious water they live in.

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