Flowering Plants
In flowering plants, the transport system is made of the xylem and phloem vessels, arranged in vascular bundles as so:
Xylem vessels are made of dead cells, with the cell walls at either end broken down. Their walls are thick and function secondarily as support. Primarily, though, they transport water and mineral ions throughout the plant.
Phloem vessels are made of living cells, but their top and bottom cell walls contain holes, and are called sieve plates. These vessels carry glucose and amino acids around the plant for use by cells. The process is know as translocation.
These nutrients are only able to get to the plant via absorption, which the root hair cells do via osmosis and diffusion. Their long, hair like structure increases the rate of diffusion and makes it ideal for absorbing water and nutrients.
Inside the plant, water is transported up the stem by the transpiration stream. Water molecules are cohesive (they stick together), so when water is evaporated from the leaves it causes the root hair cells to take in more in. The water is removed from the leaves via evapotranspiration, where the water first evaporates, then the vapour diffuses into the environment. This creates a sort of tension pull in the xylem, causing more molecules to take the place of the evaporated ones. This makes a larger water potential gradient about the roots, and causes more water to be sucked in.
The rate of transpiration is affected by the following factors:
These variables can be investigated using a potometer.
All of the variables should cause it to change proportionally.
- Set up apparatus so it is watertight, allowing a bubble to form in the capillary tube. The shoot should be cut diagonally to maximise surface area. Take note of where the bubble starts.
- Start a stopwatch and record the distance moved by the bubble per unit of time (e.g. cm/h)
- Record on a graph, and see how it changes with different variables.
All of the variables should cause it to change proportionally.
Humans
Transport in humans happens through the circulatory system.
Transport in humans happens through the circulatory system.
It is a double circulation system, involving the pulmonary system and the larger circulation system.
Zooming in, the circulatory system is made of the blood vessels, the heart and the blood.
Blood:
55% Plasma, 45% Red blood cells, and a very tiny amount phagocytes, lymphocytes and platelets. The blood carries nutrients and fights off infection.
The white blood cells are responsible for the immune response.
Phagocytes engulf foreign cells, while lymphocytes detect antigens on pathogens and produce antibodies that mark them for destruction by other white blood cells. The lymphocytes keep a memory of how to make certain antibodies, so upon second infection many antibodies are produced quickly.
Vaccinations play this to our advantage; by injecting inactive or dead pathogens, the lymphocytes are able to detect the antigens and produce antibodies and 'remember' how to for the next infection.
Red blood cells are biconcave to maximise surface area, and have no nucleus. They contain haemoglobin which allows them to carry oxygen around the body.
Platelets are small cell fragments that bond together in fibrin to form clots and scabs. This prevents blood loss and infection.
Plasma carries digested nutrients (sugar, amino acids, etc.), carbon dioxide, urea, hormones and heat energy to where it needs to be in the body.
Blood vessels:
There are three kinds of blood vessels: arteries, veins, and capillaries.
Arteries have small lumen, thick walls, and high pressure. They carry blood away from the heart, and are far under the skin. The largest is the aorta.
Veins have large lumens, thin walls and low pressure. The contain valves to control the direction of flow. Some are quite close to the surface, so these are favourable for injections. (also their thin walls are easier to penetrate and their large lumen allow more space more error)
Capillaries are very tiny. They have very thing walls (one cell thick) for easy diffusion. They carry nutrients to all of the cells and their lumen are tiny.
Heart:
The heart is made up of muscle and fat. The left side is more muscular than the right, because the left must pump blood around the entire body and the right only to the lungs (which must be low pressure as it has to squeeze through tiny capillaries). It is made up of four chambers, the left and right atriums and ventricles.
The atriums receive blood and the ventricles pump it out. In diagrams, the left side of the heart is usually on the right, because of how it lays in the body, it's as if you're facing the person and using their left and right. The right side of the heart deals with deoxygenated blood, and the left with oxygenated blood.
The right atrium is connected to the vena cava. It takes in deoxygenated blood from the body and passes it through the tricuspid valve to the right ventricle.
The right ventricle pumps deoxygenated blood at a low pressure to the lungs (through the semi-lunar valve to the pulmonary artery). This must be low pressure to fit through the tiny capillaries in the lungs without bursting them.
The left atrium receives oxygenated blood from the pulmonary vein, after it has passed through the lungs. The blood is then passed through the biscuspid valve into the left ventricle.
The left ventricle has a thick muscular wall that allows blood to be pumped around the body at high pressure. It squeezes strongly so the oxygenated blood passes through the semi lunar valve into the aorta.
Circulation is affected by adrenaline and exercise:
More exercise means more respiration, meaning there is more carbon dioxide being released into the bloodstream, and a higher demand for oxygen. This causes the heart to pump faster so more oxygen can reach the muscles.
Adrenal glands are hormonal glands that release a chemical called adrenaline. This is released when the organism is threatened. It sends a signal to the brain to make the heart pump faster in order to get more oxygen to the bodily tissues for action (fight or flight)
Blood:
55% Plasma, 45% Red blood cells, and a very tiny amount phagocytes, lymphocytes and platelets. The blood carries nutrients and fights off infection.
The white blood cells are responsible for the immune response.
Phagocytes engulf foreign cells, while lymphocytes detect antigens on pathogens and produce antibodies that mark them for destruction by other white blood cells. The lymphocytes keep a memory of how to make certain antibodies, so upon second infection many antibodies are produced quickly.
Vaccinations play this to our advantage; by injecting inactive or dead pathogens, the lymphocytes are able to detect the antigens and produce antibodies and 'remember' how to for the next infection.
Red blood cells are biconcave to maximise surface area, and have no nucleus. They contain haemoglobin which allows them to carry oxygen around the body.
Platelets are small cell fragments that bond together in fibrin to form clots and scabs. This prevents blood loss and infection.
Plasma carries digested nutrients (sugar, amino acids, etc.), carbon dioxide, urea, hormones and heat energy to where it needs to be in the body.
Blood vessels:
There are three kinds of blood vessels: arteries, veins, and capillaries.
Arteries have small lumen, thick walls, and high pressure. They carry blood away from the heart, and are far under the skin. The largest is the aorta.
Veins have large lumens, thin walls and low pressure. The contain valves to control the direction of flow. Some are quite close to the surface, so these are favourable for injections. (also their thin walls are easier to penetrate and their large lumen allow more space more error)
Capillaries are very tiny. They have very thing walls (one cell thick) for easy diffusion. They carry nutrients to all of the cells and their lumen are tiny.
Heart:
The heart is made up of muscle and fat. The left side is more muscular than the right, because the left must pump blood around the entire body and the right only to the lungs (which must be low pressure as it has to squeeze through tiny capillaries). It is made up of four chambers, the left and right atriums and ventricles.
The atriums receive blood and the ventricles pump it out. In diagrams, the left side of the heart is usually on the right, because of how it lays in the body, it's as if you're facing the person and using their left and right. The right side of the heart deals with deoxygenated blood, and the left with oxygenated blood.
The right atrium is connected to the vena cava. It takes in deoxygenated blood from the body and passes it through the tricuspid valve to the right ventricle.
The right ventricle pumps deoxygenated blood at a low pressure to the lungs (through the semi-lunar valve to the pulmonary artery). This must be low pressure to fit through the tiny capillaries in the lungs without bursting them.
The left atrium receives oxygenated blood from the pulmonary vein, after it has passed through the lungs. The blood is then passed through the biscuspid valve into the left ventricle.
The left ventricle has a thick muscular wall that allows blood to be pumped around the body at high pressure. It squeezes strongly so the oxygenated blood passes through the semi lunar valve into the aorta.
Circulation is affected by adrenaline and exercise:
More exercise means more respiration, meaning there is more carbon dioxide being released into the bloodstream, and a higher demand for oxygen. This causes the heart to pump faster so more oxygen can reach the muscles.
Adrenal glands are hormonal glands that release a chemical called adrenaline. This is released when the organism is threatened. It sends a signal to the brain to make the heart pump faster in order to get more oxygen to the bodily tissues for action (fight or flight)
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