Aim
I aim to examine gill filament under a microscope by dissecting a fish head to help me understand more about the gas exchange system of fish. Equipment
Oxygen is absorbed by a fish in a system known as countercurrent. This means that even as the blood reaches the end of the filament and is 80% or so saturated with oxygen, it is flowing past water which is at the beginning of the filament and is 90 or 100% saturated. So, even when the blood is highly saturated, having flowed past most of the length of the filament, there is still a concentration gradient and it can continue to absorb oxygen from the water.
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AimThe aim of this investigation is to see how the surface area to volume ratio affects the rate of diffusion of agar in HCL solution. Equipment
SafetyHydrocholric acid is an irritant so eye protection has to be worn. Importance must also be taken when using the sharp blade. Method
ResultThe y axis is time The x axis is the SA:Vol ratio AnalysisWe can see from the graph that as the difference in the surface area:volume ratio increased the time taken for the hydrochloric acid to diffuse through the cube also increased showing a positive correlation. As we can see from the graph when the surface area is greater than the volume e.g. in the 3:1 cube, it only took 30 seconds. This is compared to the 3:5 cube which has a larger volume than surface area causing it to take 7 minutes 20 seconds for the HCL to diffuse. This is because although there is a greater distance to the centre of the cube for the HCl to travel, and less points of contact for the molecules to collide, creating the diffusion.Therefore the higher the SA : Vol Ratio the quicker the diffusion throughout the cube. Factors That Must Remain ConstantTemperature
Shape of block Size of block Immersion method Volume of acid used Concentration of acid Type of agar Carnitine is an amino acid and nutrient which metabolise lipids by transporting them to mitochondria. This exists naturally in red meat and unnaturally in energy drinks. By studying how carnitine affects our body we can begin to explain why eating lots of meat increases the risk of heart disease.
Stanley Hazen at the Cleveland Clinic Lerner Research Institute in Ohio and colleagues gave large doses of carnitine to mice. The team found that this increased the incidence of atherosclerosis. Bacteria in the intestine use carnitine as an energy source, breaking it down and producing a waste product called trimethylamine (TMA). The liver converts this into another substance, trimethylamine-N-oxide (TMAO), which is excreted in urine. TMAO increases the uptake of “bad” cholesterol and prevents its destruction by macrophages white blood cells in artery walls. This causes a build-up of plaque that can lead to atherosclerosis. References: http://www.lerner.ccf.org/cmm/hazen/ https://www.newscientist.com/article/dn23352-red-meat-boosts-gut-bugs-that-raise-heart-disease-risk/ Atherosclerosis is a disease where arteries become narrowed by fat, cholesterol and calcium. Together this substance is known as plaque which can restrict blood flow causing damage to organs. Stages of AtherosclerosisStage 1 Endothelium becomes damaged (e.g. due to risk factors such as high blood pressure, or cigarette smoke) Stage 2 This damage causes inflammatory response so white blood cells move into the artery wall, and cholesterol from the blood begins to accumulate. The built up deposit is called an atheroma. Stage 3 Calcium salts and fibrous tissue build up at site and form a hard swelling known as plaque, making the artery lose some of its elasticity causing it to narrow. Stage 4 Plaque makes it difficult for the heart to pump blood around the body and results in high blood pressure. This in turn makes it more likely that plaque will form as there is now an even greater blood pressure. Symptoms
There are also symptoms of heart attacks and strokes which can occur when the plaque ruptures sending a blood clot into the coronary arteries which provide blood to the heart and carotid arteries which supply blood to the brain. The symptoms of a heart attack are:
Risk Factors
Equipment
Although my blood sample was a bit too thick, by friend Toby was kind enough to share his blood. We can clearly see the large cluster of red blood cells with the darker purple dots which indicate white blood cells.
References: http://tbrann.weebly.com |